William Rees in the early 1990's (Wackernagel and Rees, 1996; Rees, 1992; Kitzes et al., 2009). Ecological. Footprint methods were designed to represent ...
Instituto Superior Técnico Environmental Engineering Doctoral Program Environmental Engineering Seminar Tatiana Valada
Ecological Footprint: An indicator of environmental (un)sustainability? A review and further analysis
November 2010
2
Table of Contents Executive summary ................................................................................................................................. 7 1 Introduction ..................................................................................................................................... 9 1.1
Goal .......................................................................................................................................... 9
1.2
Motivation ................................................................................................................................ 9
1.2.1
Global overview ................................................................................................................ 9
1.2.2
Inventory of applications ................................................................................................ 10
2 Description of the Ecological Footprint and Biocapacity ............................................................... 17 2.1
Overview ................................................................................................................................ 17
2.2
Concept .................................................................................................................................. 17
2.3
Methodology presented by the Global Footprint Network ................................................... 17
2.3.1
Introduction ................................................................................................................... 17
2.3.2
Land use types ................................................................................................................ 18
2.3.3
Yield and equivalence factors ......................................................................................... 20
2.3.4
Calculation formulas ....................................................................................................... 23
2.3.5
Results ............................................................................................................................ 24
3 Critical review of the Ecological Footprint and Biocapacity ........................................................... 31 3.1
Overview ................................................................................................................................ 31
3.2
Conceptual issues ................................................................................................................... 31
3.3
Methodological issues ............................................................................................................ 33
3.3.1
Space & time .................................................................................................................. 33
3.3.2
Technology ..................................................................................................................... 34
3.3.3
Data selection ................................................................................................................. 34
3.3.4
Land use types ................................................................................................................ 35
3.3.5
Use of land ..................................................................................................................... 37
3.3.6
Yield factors, equivalence factors and global hectares .................................................. 38 3
4 Further analysis of the methodology ............................................................................................. 41 4.1
Overview ................................................................................................................................ 41
4.2
Details of the methodology presented by the Global Footprint Network ............................. 41
4.2.1
Biocapacity and equivalence factors .............................................................................. 42
4.2.2
Carbon footprint ............................................................................................................. 44
4.3
Review of improvements proposed in the literature ............................................................. 46
4.3.1
Biocapacity and equivalence factors .............................................................................. 46
4.3.2
Carbon footprint and other wastes ................................................................................ 49
4.4
Methodological changes and results ...................................................................................... 49
4.4.1
Biocapacity and equivalence factors .............................................................................. 49
4.4.2
Carbon footprint ............................................................................................................. 52
5 Discussion, conclusions and future work ....................................................................................... 55 References ............................................................................................................................................ 59 Appendix A – Temporal evolution of the Ecological Footprint ............................................................. 64 Appendix B – Brief description of the Emergy and NPP methods ........................................................ 65 Emergy .......................................................................................................................................... 65 Net Primary Production (NPP) ...................................................................................................... 65
4
List of Tables Table 1 – Applications reported by the Global Footprint Network ....................................................... 11 Table 2 –Applications reported in the international scientific community. ......................................... 13 Table 3 – Sample yield factors for selected countries, 2006. ................................................................ 21 Table 4 – Equivalence factors, 2006. ..................................................................................................... 22 Table 5 – Biocapacity values presented by the Global Footprint Network, for 2006. .......................... 42 Table 6 – Data sources available to achieve the area, in ha, used in the Biocapacity calculation. ....... 43 Table 7 – Data sources used in the Biocapacity calculation. ................................................................. 43 Table 8 – Carbon footprint as calculated by Global Footprint Network. .............................................. 44 Table 9 – Land areas that support the calculation of Biocapacity and equivalence factors. ................ 50 Table 10 – Original and recalculated equivalence factors. ................................................................... 51 Table 11 – Original and recalculated equivalence factors. ................................................................... 52 Table 12 – Probabilities of exceeding 2°C in global temperature. ........................................................ 53 Table 13 – Ecological Footprint and Biocapacity time series. ............................................................... 64
List of Figures Figure 1 – Relative area of land use types worldwide in hectares and global hectares, 2006. ............ 25 Figure 2 – Ecological Footprint versus Biocapacity, 1961 – 2006. ........................................................ 26 Figure 3 – Ecological Footprint versus Biocapacity for the year of 2006. ............................................. 28 Figure 4 – Ecological Footprint versus Biocapacity for North America, 2006. ...................................... 28 Figure 5 – Ecological Footprint versus Biocapacity for Europe, 2006. .................................................. 29 Figure 6 – Ecological Footprint versus Biocapacity for Asia, 2006. ....................................................... 29 Figure 7 –Temporal evolution of Ecological Footprint and GDP (1961-‐2006). ..................................... 32 Figure 8 –Ecological Footprint and Gross Domestic Product, for a sample of countries (2006). .......... 33 Figure 9 Representation of the Ecological Footprint, as presented by the Global Footprint Network. 55 Figure 10 –Representation of the Biocapacity, as presented by the Global Footprint Network. ......... 55
5
List of Abbreviations CEC
Commission of the European Communities
EEF
Emergetic Ecological Footprint
EF
Ecological Footprint
EIONET
European Environment Information and Observation Network
ENPP
Emergy Net Primary Production
EQF
Equivalence factor
FAO
Food and Agriculture Organisation
FAOSTAT
Food and Agriculture Organisation Corporate Statistical Database
GAEZ
Global Agro Ecological Zones
GDP
Gross Domestic Product
GED
Global Empower Density
gha
Global hectares
GWP
Global Warming Potential
IEA
International Energy Agency
IPCC
Intergovernmental Panel on Climate Change
NPP
Net Primary Production
NRF
Net Radiative Forcing
OECD
Organisation for Economic Cooperation and Development
SERI
Sustainable Europe Research Institute
UK
United Kingdom
USA
United States of America
WBCSD
World Business Council for Sustainable Development
WRI
World Research Institute
WWF
World Wildlife Fund
YF
Yield factor
6
Executive summary This report contains 5 chapters: Introduction; Description of the Ecological Footprint and Biocapacity; Critical review of the Ecological Footprint and Biocapacity; Further analysis of the methodology and Discussion, conclusions and further work. In Chapter 1 we present the goals of this report, as well as the motivation. The overall goal of this report is to understand the utility and applicability of the concepts and application, done by the Global Footprint Network, of the Ecological Footprint and Biocapacity, in the context of environmental sustainability. As a motivation to this work, two major factors must be addressed: (1) The fact that, over the past 50 years, humans have changed the ecosystems more rapidly and extensively than in any comparable period of time in human history makes it crucial the use of metrics that allow us to document resource levels, set goals, identify options for action, and track progress towards desired outcomes; (2) The Ecological Footprint versus Biocapacity, as done by the Global Footprint Network, has been presented as a metric that can assess sustainability and has actually been used as such a metric by governments, enterprises and among the scientific community. Chapter 2 presents the concept, methodology and results of the Ecological Footprint. The Ecological Footprint measures human appropriation of ecosystem products and services in terms of the amount of bioproductive land and sea area needed to supply these services. The area of land or sea available to serve a particular use is called Biocapacity, and represents the biosphere’s ability to meet human demand for material consumption and waste disposal. The most used methodology for footprint accounts is the one presented by the Global Footprint Network. According to this methodological approach, the Ecological Footprint and Biocapacity accounts cover six land use types, namely cropland, grazing land, forest land, fishing ground, built-‐up land and carbon uptake land. The final results are expressed in global hectares, hectares normalized to have world-‐average biological productivity in a given year. The global results indicate that, in 2006, humanity used the equivalent of 1.4 Earths to support its consumption. Half of the global footprint was attributable, in 2006, to just 10 countries, with the United States of America and China alone each using 23 and 21 percent, respectively, of the Earth’s Biocapacity. Brazil has the most Biocapacity of any country. Chapter 3 performs a review of the critics done to the Ecological Footprint. Some important points to remark are the following: (3) When the Ecological Footprint is smaller than the Biocapacity we do not know if the harvest of the natural resources is being done in a sustainable or unsustainable way. Therefore, nothing can be concluded. The comparison between the Ecological Footprint and Biocapacity 7
can only be useful when the results show overshoot, as indicating environmental unsustainability; (4) The boundaries used does not always make environmental sense, and the time scale mostly considered, the year, is a snapshot, which does not allow to capture dynamic phenomena. (5) Regarding the land use types considered, only fishing grounds and carbon footprint can reveal overshoot, since with the other types, the Biocapacity and Ecological Footprint are measuring exactly the same amount; (6) As currently done there is not an analysis of the role of technological change, which may bias the Ecological Footprint interpretation; (7) There are also some questions about the data used, and the weighting and normalization. These items don’t always reflect the reality and allows trade-‐offs that do not make environmental sense. In Chapter 4 we perform a further analysis of the Biocapacity, equivalence factors and carbon footprint; analysis of the changes/improvements done in the literature and application of some methodological changes to the global results for 2006. The major changes done in Biocapacity are the use of emergy analysis; consideration of the total world area and the set aside area to provide for biodiversity. The major change done in the calculation of the equivalence factors is the use of Net Primary Production. Regarding the carbon footprint there is an attempt to include other wastes by their conversion in carbon dioxide equivalents. The proposed changes to the global data for 2006 is the consideration of all the world area and set aside area for biodiversity (14%). The new results indicate an increase of 15% in total Biocapacity but still a situation of overshoot. The changes done in the carbon footprint consider the possibility of a 2˚C increase in temperature. This represents a decrease in the Ecological Footprint of about 0.4 planets. In Chapter 5 we presented some discussion, conclusions and future work. The conclusion to be drawn from the exposed is that, as it is currently being done by the Global Footprint Network, the comparison between the Ecological Footprint and Biocapacity of a given population is not assessing environmental sustainability/unsustainability, regarding the use of resources and deposition of wastes. Despite the above, we understand the utility of such an analysis and plan to use the concepts of Ecological Footprint and Biocapacity as the basis to develop an absolute indicator of environmental unsustainability of resource use. In order to do that, we focus our attention on the resource instead of the population. The Biocapacity of the resource should correspond to the amount of material and services that can be used without damaging it. The Ecological Footprint of the resource should correspond to the materials/services actually harvested. We will also continue to study the global assessment, as it is presently done by the Global Footprint Network, with special attention to the Biocapacity, carbon footprint and other wastes. 8
1 Introduction 1.1 Goal The overall goal of this report is to understand the utility and applicability of the concepts and application, done by the Global Footprint Network, of the Ecological Footprint and Biocapacity, in the context of environmental sustainability. In order to lead the analysis to the overall goal, the following steps are considered: (1) Understand the need to analyse the Ecological Footprint and Biocapacity; (2) Describe the concept, methodology and results of the Ecological Footprint and Biocapacity; (3) Make a critical analysis of the Ecological Footprint and Biocapacity; (4) Analyse with special attention the Biocapacity, equivalence factors and carbon footprint. 1.2 Motivation 1.2.1
Global overview
Humanity depends completely on Earth’s ecosystems and the services they provide, such as food, water, climate regulation, and aesthetic enjoyment (Millennium Ecosystem Assessment, 2005). This dependence implies an impact on ecosystems that, depending on its characteristics, may result in degradation. In fact, over the past 50 years, humans have changed the ecosystems more rapidly and extensively than in any comparable period of time in human history, largely to meet rapidly growing demands for food, fresh water, timber, fibber, and fuel. This transformation of the planet has contributed to net gains in human well-‐being and economic development (Millennium Ecosystem Assessment, 2005). Regarding the human pressure, it must be noticed that, between 1960 and 2000, the demand for ecosystem services grew significantly, as the world population doubled to 6 billion people and the global economy increased more than sixfold. To meet this demand (Millennium Ecosystem Assessment, 2005): (1) Food production increased by roughly two-‐and-‐a-‐half times; (2) Water use doubled; (3) Wood harvests for pulp and paper production tripled; (4) Installed hydropower capacity doubled; (5) Timber production increased by more than half. As a result of the human pressure, and according to the analysis done during the Millennium Ecosystem Assessment, approximately 60% of the 24 ecosystem services examined are being degraded or used unsustainably, including fresh water, capture fisheries, and the regulation of regional and local climate. The full costs of the loss and degradation of these ecosystem services are difficult to measure, 9
but the available evidence demonstrates that they are substantial and growing (Millennium Ecosystem Assessment, 2005). Given their complexity, there is no simple fix to these problems. Nevertheless, there is a tremendous scope for action to reduce them in the coming decades (Millennium Ecosystem Assessment, 2005). An effective set of responses to ensure the sustainable management of ecosystems requires substantial changes in institutions and governance, economic policies and incentives, social and behaviour factors, technology, and knowledge (Millennium Ecosystem Assessment, 2005). In this context, just as it is in our self-‐interest to track our financial assets carefully, it is equally important to track our ecological assets (Wackernagel, 2009). Quantitative indicators may help us to manage those ecological assets. Such metrics can be designed to allow us to document resource levels, set goals, identify options for action, and track progress towards desired outcomes. Therefore, a metric tracking human demand on, and the availability of, regenerative and waste absorptive capacity within the biosphere could be useful to governments, businesses and all organizations planning for their mid-‐ to long-‐term success (Wackernagel, 2009). According to Ewing et al. (2008), providing such a metric is the goal of Ecological Footprint. As a matter of fact, the Ecological Footprint concept and indicator seems to be accepted by many scientists and policy makers. According to the CEC1 (2009), the Ecological Footprint has been formally recognised as a target for environmental progress by several nongovernmental organizations and public authorities, and the Commission continue to support the improvement of this indicator (CEC, 2009). The Report to the European Commission done by Best et al. (2008) states that the Ecological Footprint (National Footprint Accounts only) is a useful indicator for assessing progress on the EU’s resource policies. The rapid increase of its popularity and influence provides motivation for a further analysis (van den Bergh and Verbruggen, 1999). As an evidence of its influence, multiple applications have been reported, some of them described in the section below. 1.2.2
Inventory of applications
Much has been said about the Ecological Footprint (and its comparison with the Biocapacity), also, much has been written and there are already several applications of the concept and methodology. In this section we perform an inventory of the major applications. Two main sources are considered: (1) The applications reported by the Global Footprint Network2; (2) The applications done in the international scientific community. 1
Commission of the European Communities.
2
There are other methodologies used to calculate the Ecological Footprint, but the accounts done by the Global Footprint
Network are the most widely applied.
10
It must be noticed that, in this section, the description of the applications follows the information released by the involved entities and not a critical review of what has been said. The critical review of the concept and methodology is done in Chapter 3. 1.2.2.1 Applications reported by the Global Footprint Network The applications reported by the Global Footprint Network are done both at a local and regional scales, regarding private and public entities. To simplify, the country is used as the unit of analysis. The gathered applications are reported in Table 1. Table 1 – Applications reported by the Global Footprint Network (source: www.footprintnetwork.org, visited in July 2010) Country
Application The Environmental Protection Authority in the State of Vitoria, Australia, uses the Ecological Footprint as an engagement and resource accounting tool.
Australia
Canada
3
The GPT Group used the Ecological Footprint information to develop a standardized method of measuring the environmental impact of its properties to meet operational sustainability targets of impact reduction. In 2005, the government of the city of Calgary in the Province of Alberta, Canada, found that its footprint exceeded the Canadian average by over 30%. With the city´s EcoFootprint Program, Calgary plans to reduce its footprint to the national average by 2036. In the Province of Ontario, Canada, the Ontario Biodiversity Council, in conjunction with the Ontario Ministry of Natural Resources, released its “State of Ontario’s Biodiversity 2010” report, comprised of 29 indicators. One of these indicators is the Ecological Footprint.
Ecuador
Ecuador has established on its National Plan that, by 2013, the country´s footprint should be lower than its Biocapacity and that it will remain so going forward.
England
The footprint analysis have been used by local governments and business for policy planning, namely to understand how public and private sector might work together to reduce the Ecological Footprint. 4
France
SITA uses a footprint calculator to analyse its operation systems and determine how to lower the footprint and increase their operations efficiency.
Observations (scale and documentation) Local, regional and municipal application (http://www.epa.vic.gov.au/ecologicalfootprint /casestudies/)
Business application (http://www.footprintnetwork.org/newsletters/ footprint_network_enews_1-‐8-‐1.html)
Local, regional and municipal application (http://www.footprintnetwork.org/images/uplo ads/Calgary_ecological_footprint_Report.pdf)
Local, regional and municipal application (http://www.ontariobiodiversitycouncil.ca/files/ 1_MNR_OBC_Report_2010_v9.pdf)
National government application (http://www.footprintnetwork.org/en/index.ph p/newsletter/det/ecuador_sets_goal_to_reduc e_its_footprint)
Local, regional and municipal applications (http://www.citylimitslondon.com)
Business application (http://www.empreinte.sita.fr/)
3
It is a multinational commercial real estate development company that owns and manages retail shopping malls in
Australia (www.footprintnetwork.org, visited in July 2010). 4
Part of the SUEZ Group, is a waste management company (www.footprintnetwork.org, visited in July 2010).
11
Country
Application
Observations (scale and documentation) Local, regional and municipal applications
5
(http://www.provincia.milano.it/export/sites/d efault/pianificazione_territoriale/agenda_21_O FFLINE/progetti_iniziative/impronta_ecologica/ abstractEN.pdf)
Italia
Ambienteitalia calculated the Ecological Footprint of the Province of Milan.
Japan
After some reviews, the Ecological Footprint is now part of Japan’s Basic Environmental Plan.
Luxembourg
The government has completed a report of the footprint methodology as a basis for regular reporting on the country’s Ecological Footprint.
National government applications
In 2009, Agenda Cascais 21 and the Center for Sustainability Studies and Strategies completed a study of the Cascais’s city Ecological Footprint.
National government applications
Portugal
The government has done a scientific review of its National Accounts and the Ecological Footprint data is being incorporated into the nation´s Sustainability Development Plan. 6
Switzerland
The WBCSD has launched Vision 2050 to identify the pathways toward a one-‐planet economy in the next four decades. Global Footprint Network has participated in the process.
National government application
(http://www.myfootprint.lu/)
(http://www.cascaisnatura.org/Pesquisa.aspx?I D=79&M=News&PID=0&NewsID=1086)
National government applications Business applications (http://www.wbcsd.org/templates/TemplateW BCSD5/layout.asp?type=p&MenuId=MTYxNg&d oOpen=1&ClickMenu=LeftMenu)
7
Picket Asset Management has developed a new type of country bond fund: one which rates countries based on their ability to provide a high quality of life at a minimal ecological cost. In order to do this it uses the ratio between the Ecological Footprint and the Human Development Index. United Arab Emirates
In 2007, in response to its top-‐ranking, the government launched the “Al Basma Al Beeiya (Ecological Footprint) Initiative” to understand and reduce the country’s Ecological Footprint. In the State of California, the Marin County Community Development Agency used the Ecological Footprint to choose focus areas and set targets for reducing the county’s footprint by 15 percent.
United States of America
In the State of California, Sustainable Sonoma County, a local non-‐governmental organization, used the Ecological Footprint as the foundation of a 2002 campaign, “Time to Lighten Up”, which inspired every city in the county to sign up a commitment to reduce their CO2 output by 20 percent. In the State of Utah, the Utah Population and Environment Coalition prepared a footprint study as part of their Utah Vital Signs project on sustainability indicators.
Business applications (http://www.footprintnetwork.org/en/index.ph p/newsletter/det/rating_bonds_based_on_ecol ogical_return_on_investment)
National government applications (http://www.agedi.ae/English/national/Ecologic alFootprint/Pages/default.aspx)
Local, regional and municipal applications (http://www.co.marin.ca.us/depts/CD/main/pd f/BEST_pdf/eco_footprint_final2007-‐01-‐24.pdf)
Local, regional and municipal applications (http://www.sustainablesonoma.org/projects/s cefootprint.html)
Local, regional and municipal applications (http://www.utahpop.org/vitalsigns/UVS_ Report_v20b.pdf)
5
Research and consulting institute working in environmental and territorial planning (http://www.ambienteitalia.it/, visited
in September of 2010). 6
World Business Council for Sustainable Development, an organization that represents corporations.
7
Swiss investment firm.
12
Country
Application
Observations (scale and documentation)
The report “One Planet Wales: Transforming Wales for a prosperous future within our fair share of the Earth´s resources” highlights how Wales can transform its economy to reduce its Ecological Footprint. Wales
Resulting from the partnership between the Cardiff Council, the BRASS Research Centre at Cardiff University and Stockholm Environment Institute, in 2005, the city of Cardiff completed a footprint analysis and has since been using the Ecological Footprint in public sustainability outreach.
National government applications (http://assets.panda.org/downloads/25700_ww f_report_e.pdf)
Local, regional and municipal applications (http://www.cardiff.gov.uk/content.asp?Parent _Directory_id=2865&nav=2870,3148,4119)
Also worth of mention is that the European Union has undertaken a program called One Planet Economy Network, aimed at building an economy that works within nature’s means. The core of the project is the creation of a footprint tool that enables European decision-‐makers to explore future scenarios and create evidence-‐based policy that respects ecological limits. A tool, called EUREAPA, is being created through a collaborative effort by Global Footprint Network, Stockholm Environmental Institute, World Wildlife Fund (WWF) – United Kingdom, Twente University, Sustainable Europe Research Institute (SERI) and Ecologic. EUREAPA will provide data for a “footprint family of indicators” including carbon footprint, water footprint and Ecological Footprint in a way that allows them to be integrated and compared (www.footprintnetwork.org, visited in July 2010). 1.2.2.2 Applications done in the international scientific community The performance of a literature review revealed a large amount of papers discussing some aspect of the Ecological Footprint. Some of them focus on the theoretical concept or methodology and some make applications using real data. In Table 2 some of these applications are presented. Table 2 –Applications reported in the international scientific community. Title Importing terrestrial Biocapacity: The U.S. case and global implications
Author(s) Meidad Kissinger, William Rees
Year
Journal
2010
Land Use Policy
Twelve metropolitan carbon footprints: A preliminary comparative global assessment
Benjamin Sovacool, Mary Brown
2010
Energy Policy
Incorporating methane into Ecological Footprint analysis: a case study of Ireland
Conor Walsh, Bernadette O’Regan, Richard Moles
2009
Ecological Economics
The carbon footprint of UK households 1990 – 2004: A socio-‐ economically disaggregated, quasi-‐multi-‐regional input-‐output model
Angela Druckman, Tim Jackson
2009
Ecological Economics
Adaptative environmental management of tourism in the Province of Siena, Italy using the Ecological Footprint
Trista Patterson, Valentina Niccolucci, Nadia
2008
Journal of Environmental Management
13
Title
Author(s)
Year
Journal
Marchettini
Long-‐term dynamics of terrestrial carbon stocks in Austria: a comprehensive assessment of the time period from 1830 to 2000
Simone Gingrich, Karl-‐Heinz Erb, Fridolin Krausmann, Veronika Gaube, Helmut Haberl
2007
Regional Environmental Change
The Ecological Footprint as a key indicator of sustainable tourism
Colin Hunter, Jon Shaw
2007
Tourism Management
Beyond “more is better”: Ecological Footprint accounting for tourism and consumption in Val di Merse, Italy
Trista Patterson, Valentina Niccolucci, Simone Bastianoni
2007
Ecological Economics
Present and future Ecological Footprint of Slovenia – The influence of energy demand scenarios
Sašo Medved
2006
Ecological Modelling
Reducing the Ecological Footprint of inbound tourism and transport to Amsterdam
F. Schouten, P. Peeters
2006
Journal of Sustainable Tourism
The Ecological Footprints of fuels
Erling Holden, Karl Høyer
2005
Transportation Research
Ethanol as Fuel: Energy, Carbon Dioxide Balances, and Ecological Footprint
Marcelo Oliveira, Burton Vaughan, Edward Rykiel Jr.
2005
BioScience
Ecological Footprints and interdependencies of New Zealand regions
Garry McDonald, Murray Patterson
2004
Ecological Economics
Actual land demand of Austria 1926-‐2000: a variation on Ecological Footprint assessments
Karl-‐Heinz Erb
2004
Land Use Policy
Land-‐use related changes in aboveground carbon stocks of Austria´s terrestrial ecosystems
Karl-‐Heinz Erb
2004
Ecosystems
Assessing the Ecological Footoprint of a Large Metropolitan Water Supplier: Lesssons for Water Management and Planning towards Sustainability
Manfred Lenzen, Sven Lundie, Grant Bransgrove, Lisa Charet, Fabian Sack
2003
Ecological Footprint analysis as a tool to assess tourism sustainability
Stefan Gössling, Carina Hansson, Oliver Hörstmeier, Stefan Saggel
2002
Ecological Economics
Sustainable tourism and the touristic Ecological Footprint
Colin Hunter
2002
Environment, Development and Sustainability
A modified Ecological Footprint method and its application to Australia
Manfred Lenzen, Shauna Murray
2001
Ecological Economics
Ecological Footprints of Benin, Bhutan, Costa Rica and Netherlands
D. P. van Vuuren, E. M. W. Smeets
2000
Ecological Economics
The Ecological Footprint of New Zealand as a step towards sustainability
Alan Fricker
1998
Futures
Journal of Environmental Plannig and Management
14
Title
Author(s)
New methodology for the Ecological Footprint with an application to the New Zealand economy
Kathryb Bicknell, Richard Ball, Ross Cullen, Hugh Bigsby
Year
1998
Journal
Ecological Economics
15
16
2 Description of the Ecological Footprint and Biocapacity 2.1
Overview In order to make a correct use of a given tool is essential to understand the assumptions behind it as
well as its construction. In this chapter we present a description of the concept and methodology of the Ecological Footprint and Biocapacity, as presented by the Global Footprint Network. 2.2
Concept Ever since the publication of An Essay on the Principle of Population, by Thomas Malthus in 1798,
there have been some concerns that the human population is in danger of growing beyond the carrying capacity of the Earth (Raport, 2000). The carrying capacity of human activities consists of the maximum rate of resource consumption and waste discharge that can be sustained indefinitely, without progressively impairing the functional integrity and productivity of ecosystems (Deutsch et al., 2000). In this context, the Ecological Footprint concept was formally introduced by Mathis Wackernagel and William Rees in the early 1990’s (Wackernagel and Rees, 1996; Rees, 1992; Kitzes et al., 2009). Ecological Footprint methods were designed to represent actual human consumption of biological renewable resources and generation of wastes, in terms of appropriated ecosystem area. The Ecological Footprint can be compared to the biosphere’s productive capacity in a given area, which is called Biocapacity. The comparison between the Ecological Footprint and Biocapacity is here referred as Ecological Footprint analysis. 2.3
Methodology presented by the Global Footprint Network 2.3.1
Introduction
Nowadays, the methodology presented by the Global Footprint Network is the most known one. This methodology is developed and maintained by the Global Footprint Network and its more than 75 partner organizations. These accounts cover more than 150 nations and extend from 1961 (Kitzes et al., 2009)8. Although the accounts are refered as national, the methodology is also applied to the world. As currently done, the Ecological Footprint and Biocapacity methodology covers six land9 use types (Kitzes et al., 2008; Global Footprint Network, 2009a; Ewing et al., 2008; Ewing et al., 2009): (1) Cropland; 8
Official site of the Global Footprint Network: www.footprintnetwork.org.
9
This represents a language abuse, since the actual methodology also consider ocean areas. This abuse is done in order to
simplify the explanation.
17
(2) Grazing land; (3) Forest land; (4) Fishing ground; (5) Built-‐up land; (6) Carbon uptake land (to accommodate the carbon footprint). For all land use types there is a demand on the area (for human consumption and waste disposal), as well as a supply of such an area (Ewing et al., 2009). Before describing the land types and the calculation methodology, we present some fundamental assumptions taken (Ewing et al., 2008): (1) The majority of the resources that people consume and the wastes they generate can be tracked; (2) Most of these resource and waste flows can be measured in terms of the biologically productive area necessary to maintain flows. Resource and waste flows that cannot be measured are excluded from the assessment, leading to a systematic underestimate of humanity’s true Ecological Footprint; (3) Area demanded can exceed area supplied if demand on an ecosystem exceeds that ecosystems regenerative capacity (for example, humans can temporarily demand more Biocapacity from forests, or fisheries, than those ecosystems have available). This situation is known as overshoot. 2.3.2
Land use types
2.3.2.1 Cropland The Ecological Footprint of cropland consists of areas used to produce food and fibber for human consumption, feed for livestock, oil crops, and rubber. Agriculture typically uses the most suitable and productive land areas, unless they have been urbanized. Therefore, cropland is considered the most bioproductive of all the land uses types (Ewing et al., 2010; Ewing et al., 2009; Ewing et al., 2008). Cropland footprint calculations do not take into account the extent to which farming techniques or unsustainable agriculture practices cause long-‐term degradation of soil (Ewing et al., 2010; Ewing et al., 2009). The Biocapacity of cropland consists of the area currently categorized as used for cropland (within the borders of the system analysed). Locally, cropland can be in deficit when countries consume more crops or embodied cropland in livestock than they have the Biocapacity to produce themselves. However, on a global scale cropland Biocapacity represents the combined land area devoted to growing all crops, which the cropland footprint cannot exceed (Ewing et al., 2008). 18
2.3.2.2 Grazing land The Ecological Footprint of grazing land measures the area of grassland necessary, in addition to crop feeds, to support livestock (Ewing et al., 2008). It is comprised of grassland and sparsely wooded land and is used to raise livestock for meat, dairy, hide, and wool products (Ewing et al., 2008; Ewing et al., 2009). The Biocapacity of grazing land consists of the area currently categorized as used for grazing land (within the borders of the system analysed). Locally, grazing land can be in deficit when countries consume more embodied grazing land in livestock than they have the capacity to produce themselves. However, on a global scale, demand may not overshoot supply because grasses are annual plants and, thus, it is assumed that there are no stocks from the previous years to draw down (Ewing et al., 2008).The cropland and grazing land footprints are connected; an increase in crop feed may reduce demands on grazing capacity (Kitzes et al., 2008). 2.3.2.3 Forest land The Ecological Footprint of forest land assesses human demand for the regenerative capacity of the world’s forests. The forest land footprint is comprised of two broad types of primary products: wood for fuel, and timber used as a raw material to produce secondary timber products. As a summary, the forest land footprint represents the area of world average forest land needed to supply wood for construction, fuel and paper (Kitzes et al., 2008). The Biocapacity of forest land consists of the area currently categorized as used for forest land (within the borders of the system analysed). According to the definition presented, forest land footprint can be in overshoot locally but not globally. When overshoot occurs, forest stocks decrease over time (Ewing et al., 2008). 2.3.2.4 Fishing ground The Ecological Footprint of fishing grounds is calculated based on the estimate primary production required to support the fish caught. This primary production requirement is calculated from the average trophic level of the species in question. Fish that feed higher on the food chain require more primary production input and as such are associated with a higher Ecological Footprint (Ewing et al., 2008). The same calculation is currently used for marine and inland fish (Kitzes et al., 2008). The Biocapacity is calculated through the areas categorized as being used as fishing ground, namely the marine continental shelf and inland water.
19
Fishing grounds can enter overshoot if the area demanded for sustainable extraction of the fish exceeds actual area used as fishing grounds (Ewing et al., 2008)10. 2.3.2.5 Built-‐up land Both the Ecological Footprint and Biocapacity of built-‐up land represents bioproductive land which has been physically occupied by human activities (Kitzes et al., 2008), such as transportation, housing, industrial structures, and reservoirs for hydropower (Ewing et al., 2008; Ewing et al., 2009). Built-‐up land presumably occupies what would previously have been cropland. This assumption is based on the theory that human settlements are generally situated in highly fertile areas (Ewing et al., 2008). By definition, built-‐up land has a Biocapacity equal to its Ecological Footprint (Ewing et al., 2008). Therefore, there is no overshoot in this category. 2.3.2.6 Forest for carbon dioxide uptake Carbon uptake land is the only component of the Ecological Footprint dedicated to tracking a waste product: anthropogenic carbon dioxide. Most terrestrial carbon dioxide uptake in the biosphere occurs in forests. Taking this into account, carbon dioxide uptake land is assumed to be forest land (after discounting the ocean sequestration). The carbon footprint is, then, calculated as the amount of forest land required to absorb anthropogenic carbon dioxide emissions (Ewing et al., 2008). There is no correspondent Biocapacity area associated with this category since it “uses” the forest Biocapacity, also considered to fulfil the forest Ecological Footprint. This category can present overshoot, since it is possible to require more forest land to absorb the carbon dioxide than the existing forest land. 2.3.3
Yield and equivalence factors
Average bioproductivity differs between various land types, as well as between countries for any given use type. In order to permit comparisons across countries and land use types, Ecological Footprint and Biocapacity are expressed in units of world-‐average bioproductivity area – global hectares (Ewing et al., 2008; Ewing et al., 2009). In order to achieve this unit, two factors are used: (1) Yield factor (YF); (2) Equivalence factor (EQF).
10
In spite of wide acknowledgment of global overfishing, the current data set methods in the National Footprints Accounts
do not show that demand exceeds supply in this component. Therefore, and according to the Global Footprint Network, further research in this area is needed to clarify the way fish demand is being accounted for.
20
2.3.3.1 Yield factor This factor accounts for differences in productivity of a given land use type between a country and the global average in this area type. These differences are driven by natural factors, such as precipitation or soil quality, as well as by management practices (Ewing et al., 2008; Ewing et al., 2009). To account for these differences, the yield factor compares the production of a specific land use type in a country to a world average hectare of the same land use type. The yield factor for built-‐up land is assumed to be equal that for cropland since urban areas are typically built on or near the most productive cropland areas (Ewing et al., 2008). Yield factors weight land areas according to their relative productivities (see Table 3). For example, the average hectare of pasture in New Zealand produces more grass than a world average hectare of pasture land. Thus, in terms of productivity, one hectare of grassland in New Zealand is equivalent to more than one world average grazing land hectare; it is potentially capable of supporting more meat production (Ewing et al., 2009). Table 3 – Sample yield factors for selected countries, 2006. (source: Ewing et al., 2009)
Cropland Forest
Grazing Land Fishing Ground
World average yield
1.0
1.0
1.0
1.0
Algeria
0.6
0.4
0.7
0.9
Germany
2.1
4.1
2.2
3.0
Hungary
1.4
2.6
1.9
0.0
Japan
1.5
1.4
2.2
0.8
Jordan
1.0
1.5
0.4
0.7
New Zealand
1.9
2.0
2.5
1.0
Zambia
0.5
0.2
1.5
0.0
2.3.3.2 Equivalence factor The equivalence factor translates a specific land use type into a universal unit of biologically productive area, a global hectare. Equivalence factors are calculated for each year, and are identical for every country in a given year. The equivalence factor for built-‐up land is set equal to that for cropland and carbon uptake land is set equal to that for forest land. This reflects the assumptions that infrastructures tends to be on or near productive agricultural land, and that carbon uptake occurs on forest land. The equivalence factor for hydro area is set equal to one, which assumes that hydroelectric reservoirs flood world average land. The equivalence factor for marine area is calculated such that a single global hectare of pasture will produce an amount of calories of beef equal to the amount of
21
calories of salmon that can be produced by a single global hectare of marine area. The equivalence factor for inland water is set equal to the equivalence factor for marine area (Ewing et al., 2009). Equivalence factors are calculated using suitability indexes from the Global Agro Ecological Zones (GAEZ) model combined with data on the actual areas of cropland, forest land, and grazing land area from the Food and Agriculture Organisation Corporate Statistical Database (FAOSTAT). The GAEZ model divides all land globally into five categories, based on calculated potential productivity. All land is assigned a quantitative suitability index from among the following (Kitzes et al., 2008; Ewing et al., 2008): (1) Very suitable – 0.9 (2) Suitable – 0.7 (3) Moderately suitable – 0.5 (4) Marginally suitable – 0.3 (5) Not suitable – 0.1 The calculation of the equivalence factors assumes that the most productive land is put to its most productive use: the most suitable land available will be planted to cropland, the next most suitable land will be under forest land, and the least suitable land will be grazing land. The equivalence factors are calculated as the ratio of the average suitability index for a given land use type divided by the average suitability index for all land use type (Kitzes et al., 2008; Ewing et al., 2008). Table 4 presents the equivalence factors used in the 2006 calculations (Ewing et al., 2009). Table 4 – Equivalence factors, 2006. (source: Ewing et al., 2009) Area Type
Equivalence factor -‐1
[gha ha ]
Primary cropland
2.39
Forest
1.24
Grazing land
0.51
Marine
0.41
Inland water
0.41
Built-‐up land
2.39
22
2.3.4
Calculation formulas
For any land use type, the Ecological Footprint (EF) and the Biocapacity (BC) of a given population are calculated according to Equation 1 and Equation 2. EF [gha] =
P [t] ⋅ YF [−] ⋅ EQF [gha ⋅ ha−1 ] YN [t ⋅ ha−1 ]
Equation 1 – Ecological Footprint general equation. (sources: Ewing et al., 2009; Ewing et al., 2008; Kitzes et al., 2008)
BC [gha] = A [ha] ⋅ YF [−] ⋅ EQF [gha ha −1 ] Equation 2 – Biocapacity general equation. (sources: Ewing et al., 2009; Ewing et al., 2008; Kitzes et al., 2008)
P:
amount of a product harvested or waste emitted.
YN:
national average yield for P.
A:
area available for a given land use type.
YF:
ratio of national to world average yields. It is calculated as the annual availability of
usable products and varies by country and year. EQF:
translate the area supplied or demanded of a specific land use type into units of world
average biologically productive area (global hectares) and varies by land use type and year. 2.3.4.1 Ecological Footprint When we are dealing with primary products, the calculation of their Ecological Footprint is very intuitive (e.g. area of cropland necessary to produce maize). However, in some cases, it is necessary to know the Ecological Footprint of products derived from the primary flows of ecosystem goods (Ewing et al., 2008). In this case, the demand for manufactured or derivative products (e.g. flour or wood pulp), is converted into primary product equivalents (e.g. wheat or roundwood) through the use of extraction rates. These quantities of primary product equivalents are then translated into an Ecological Footprint. The Ecological Footprint also embodies the energy required for the manufacturing process (Ewing et al., 2009). Typically, the Ecological Footprint of a given population refers to the consumption of that population (Ewing et al., 2009). This measures the Biocapacity demanded by the final consumption of all members of the population, including their household consumption as well as their collective consumption, such as schools, roads, fire brigades, among others, which serve the household, but may not be directly paid for by the households (Ewing et al., 2009). In contrast, the Ecological Footprint of production is the sum of the footprints for all resources harvested and all wastes generated within the population’s geographical borders. This includes all the area within the borders necessary for supporting the actual 23
harvest of primary products (cropland, grazing land, forest land, and fishing grounds), the population’s infrastructure and hydropower (built-‐up land), and the area needed to absorb fossil fuel carbon dioxide emissions generated within the borders (carbon footprint) (Ewing et al., 2009). The difference between the production and consumption footprint is trade (see Equation 3) (Ewing et al., 2008; Ewing, et al., 2009):
EFC [gha] = EFP [gha] + EFI [gha] − EFE [gha] Equation 3 – Components of the Ecological Footprint of consumption. (sources: Ewing et al., 2009; Ewing et al., 2008; Kitzes et al., 2008)
EFC:
Ecological Footprint of consumption.
EFP:
Ecological Footprint of production.
EFI:
Ecological Footprint of importation.
EFE:
Ecological Footprint of exportation.
In order to measure the footprint of imports and exports, we need to know both the amounts traded as well as the embodied resources (including carbon dioxide emissions) in all categories (Ewing et al., 2009). 2.3.4.2 Biocapacity Biocapacity refers to the amount of biologically productive land and water areas available within the borders of a given population (Kitzes et al., 2008). Biologically productive area refers to the land and water that supports significant photosynthetic activity and accumulation of biomass, ignoring unfruitful areas of low, dispersed productivity. Biocapacity is an aggregated measure of the amount of land available, weighted by the productivity of that land. It represents the ability of the biosphere to produce crops, livestock (pasture), timber products (forest), and fish, as well as to uptake carbon dioxide in forests. It also includes how much of this regenerative capacity is occupied by infrastructure (built-‐up land) (Ewing et al., 2009). 2.3.5
Results
2.3.5.1 Global analysis In 2006, the area of biologically productive land and water was nearly 11.9 billion hectares. World Biocapacity is also is also 11.9 billion global hectares, since the total number of average hectares equals the total number of global hectares (see Figure 1). But the relative area of each land type expressed in global hectares differs from the distribution in actual hectares. In 2006, the world had 3.7 billion global hectares of cropland Biocapacity, which corresponds to 1.6 billion hectares of real cropland area. This
24
difference is due to the relatively high productivity of cropland compared to other land use types (Ewing et al., 2009). 14
12 Hydro
Area (billions)
10
Infrastructure
8
Forest L and Inland W ater
6
Marine
4
Grazing L and
2
Cropland
0 Hectares
Global hectares
Figure 1 – Relative area of land use types worldwide in hectares and global hectares, 2006. (source: Ewing et al., 2009)
Natural resources and material consumption are not evenly distributed worldwide. Some countries and regions have a net demand on the planet greater than their respective Biocapacity, while others use less than their available capacity. Humanity as a whole, however, is not living within the means of the planet Earth. In 2006, humanity’s total Ecological Footprint worldwide was 17.1 billion global hectares, with world population at 6.6 billion people; the average person’s footprint was 2.6 global hectares. There were only 11.9 billion gha of Biocapacity available in that year, or 1.8 gha per person. This overshoot of approximately 40 percent means that, in 2006, humanity used the equivalent of 1.4 Earths to support its consumption (see Figure 2). It took the Earth nearly a year and four months to regenerate the resources used by humanity in that year (Ewing et al., 2009). In 1961, the first year for which National Footprint Accounts are available, humanity’s footprint was about half of what the Earth could supply. Human demand first exceeded the planet´s ability to meet this demand around 1980, and this state of overshoot has characterized every year since (see Figure 2) (Ewing et al., 2009).
25
1,6
1,4
1,2
Planets
1,0
Forest for carbon dioxide uptake Built-‐up land
0,8
Fishing ground Forest land
0,6
Grazing land Cropland
0,4
0,2
0,0 1961
1966
1971
1976
1981
1986
1991
1996
2001
2006
Year
Figure 2 – Ecological Footprint versus Biocapacity, 1961 – 2006. (source: Ewing et al., 2009)
2.3.5.2 Region and country’s analysis Regions and countries differ greatly in both their Ecological Footprint and Biocapacity. In a global view, half of the global Ecological Footprint was attributable, in 2006, to just 10 countries, with the United States of America and China alone each using 23 and 21 percent, respectively, of the Earth’s Biocapacity. In the top 10 of total available Biocapacity, Brazil has the most Biocapacity of any country, followed in decreasing order by United States of America, China, Russian Federation, Canada, India, Australia, Indonesia, Argentina, and Bolivia. Half the world’s Biocapacity is found within the borders of just eight countries (Ewing et al., 2009). Analysing the Ecological Footprint versus the Biocapacity for the world regions presented in Figure 3, North America has the higher deficit11 (3.05 gha per capita), followed by Europe (1.48 gha per capita) and Asia (0.79 gha per capita). The Oceania has the higher surplus12, 7.02 gha per capita. Within the North America, the United States of America (USA) is the responsible for the deficit. According to the 2006 national accounts, the USA has an Ecological Footprint of 9.02 gha per capita and a Biocapacity of 4.43 gha per capita (with a deficit of 4.59 gha per capita) (see Figure 4). The contribution of the carbon footprint to the overall Ecological Footprint of North America, 70 percent of the region’s footprint of consumption and 58 percent of its footprint of production, is higher than the world average. Home to 5 percent of the global population, North America accounts for 17 percent of the world’s total Ecological Footprint of consumption. Since 1961, North America’s total Ecological Footprint of consumption has grown by almost 1 800 million gha. The region’s total population 11
In this context, deficit measures the negative value resulting from Biocapacity minus Ecological Footprint.
12
Surplus measures the positive value resulting from Biocapacity minus Ecological Footprint.
26
increased by just 11 percent over that period, but the resource flows mobilized per person grew substantially. The 160 percent increase in North America’s total Ecological Footprint of consumption during that time is almost entirely attributable to growth in demand per person (Ewing et al., 2009). Within the Europe, the country with the higher deficit, 4.61 gha per capita, is Belgium (the country with the higher surplus, 7.48 gha per capita, is Finland); the country with the higher Ecological Footprint, 8.19 gha per capita, is Ireland (the country with the lowest Ecological Footprint, 1.75 gha per capita, is Moldova); the country with the higher Biocapacity, 12.99 gha per capita, is Finland (the country with the lowest Biocapacity, 1.02 gha per capita, is Albania) (see Figure 5). For this region, 54 percent of total Ecological Footprint of production, and 55 percent of its footprint of consumption, are attributable to carbon dioxide emissions. Europe’s total Ecological Footprint of consumption has increased by 1 070 million gha since 1961. This increase was driven primarily by growth in per capita resource flows, though population growth has also contributed: the Ecological Footprint of the average European resident grew by 33 percent between 1961 and 2006, while Europe’s total population increased by 12 percent. Within the Asia, the country with the higher deficit, 8.93 gha per capita, is the United Arab Emirates (the country with the higher surplus, 0.59 gha per capita, is the Myanmar); the country with the higher Ecological Footprint, 10.29 gha per capita, is the United Arab Emirates (the country with the lowest Ecological Footprint, 0.75 gha per capita, is the Pakistan); the country with the higher Biocapacity, 4.27 gha per capita, is the Kazakhstan (the country with the lowest Biocapacity, 0.04 gha per capita, is Singapore) (see Figure 6). Carbon dioxide emissions account for 56 percent of Asia’s total Ecological Footprint of production, and 53 percent of its footprint of consumption. However, Asia’s average Ecological Footprint per person is lower than the world average, so the per person carbon footprint is also less. Of the world’s regions, Asia has shown the greatest total growth in Ecological Footprint of consumption, increasing by 4 020 million gha since 1961. The Ecological Footprint of the average Asian resident increased by 46 percent between 1961 and 2006, while Asia’s total population grew by 185 percent. Thus, while population growth is a major factor in the increase in Asia’s total Ecological Footprint of consumption, growth in per capita footprint has also contributed substantially.
27
Figure 3 – Ecological Footprint versus Biocapacity for the year of 2006. (source: Ewing et al., 2009)
Figure 4 – Ecological Footprint versus Biocapacity for North America, 2006. (source: Ewing et al., 2009)
28
Figure 5 – Ecological Footprint versus Biocapacity for Europe, 2006. (source: Ewing et al., 2009)
Figure 6 – Ecological Footprint versus Biocapacity for Asia, 2006. (source: Ewing et al., 2009)
29
30
3 Critical review of the Ecological Footprint and Biocapacity 3.1
Overview Much has been said about the concepts of Ecological Footprint and Biocapacity, as well as their
application by the Global Footprint Network. The knowledge of the strengths and weaknesses of the Ecological Footprint and Biocapacity is particularly important since, as it was already discussed, the results released by the Global Footprint Network are used worldwide for many purposes, including policy making. It is necessary to understand the applicability of the concepts and results, what they actually mean, and the limitations of the numbers obtained. In the following sections a review of the main items discussed in the literature is presented. 3.2
Conceptual issues The Ecological Footprint (and its comparison with the available Biocapacity) has been pointed out as
“(…) an ideal tool for tracking progress, setting targets and driving policies for sustainability.” (Wackernagel, 2006). A general definition states that sustainability assessment is a tool that can help decision and policy-‐makers determining which actions should and shouldn’t be taken when the goal is to contribute to a sustainable development (Pope et al., 2004). In this context it must be noticed that, in addition to environmental needs and material needs that may be fulfilled through economic development, humans also need social development to improve social justice, equality, and security. Thus, sustainability has, at least, three overlapping dimensions: the simultaneous pursuit of economic prosperity, environmental quality, and social equity (Liu, 2009). The comparison between the Ecological Footprint and the available Biocapacity assesses, at most, one specific issue regarding the environmental dimension, and therefore cannot be used alone as an indicator of sustainability. Other important question that must be raised is if the Ecological Footprint (and its comparison with the available Biocapacity) says something about environmental sustainability. In fact, when the Ecological Footprint is smaller than the Biocapacity we do not know if the harvest of the natural resources is being done in a sustainable or unsustainable way. Therefore, regarding the environmental sustainability nothing can be concluded. This means that the comparison between the Ecological Footprint and Biocapacity can only be useful when the results show overshoot, as indicating environmental unsustainability. If correctly applied, this indicator gives an absolute measure of environmental unsustainability, which represents an advantage in this kind of analysis. In the context of this discussion, two additional items deserve special attention: (1) The interpretation of an overshoot situation; (2) The per capita and total analysis.
31
Considering the global application, the 2006 results indicate that it is necessary 1.4 planets to support human consumption of that year, but humanity still lives in one planet. This result seems to indicate that the comparison between the Ecological Footprint and Biocapacity gives a wrong result. But it is a fake question. Let’s not focus on the results presented by the Global Footprint Network, and analyse the concept. According to this one, it is possible to observe an overshoot situation and still live in one planet. In fact, the ecological limits can be exceeded for a period of time because nature reacts with inertia. More precisely, natural capital can be harvested faster than it regenerates, thereby depleting the capital stock (Wackernagel et al., 2000). Of course, this can only happen as long as the stock is non-‐zero. Regardless of the scale of application, the results can come is a total or per capita basis. According to van den Bergh and Verbruggen (1999), in a per capita basis, the comparison among regions or countries appears, in essence, to be a reflection of the distribution of wealth. In fact, an increase in the Ecological Footprint suggests an increase in the consumption. This last increase may take place due to an increase in wealth, which is translated into an increase in Gross Domestic Product (GDP). The analysis of Figure 7 suggests that, globally, the Ecological Footprint, as it is currently done by the Global Footprint Network, roughly follows the same path as the per capita GDP13. But, as presented in Figure 8, for similar levels of GDP it is possible to have different levels of consumption and corresponding Ecological Footprint. Therefore, the Ecological Footprint is not just a reflection of the distribution of wealth. 18,5
8000
16,5
7000
GDP
6000 t in r tp o o fl ac ig lo o cE
14,5
)a it p ac r 12,5 e p a h g( 10,5
5000 4000 3000 2000
8,5
GDP (current US$ per capita)
Ecological Footprint (gha per capita)
Ecological Footprint
a)t i p ac r e P p D $ G SU t n e rr u c(
1000
6,5
0
Year
Figure 7 –Temporal evolution of Ecological Footprint and GDP (1961-‐2006). (GDP source: http://www.worldbank.org/, visited in August 2010)
13
GDP is the sum of gross value added by all resident producers in the economy plus any product taxes and minus any
subsidies not included in the value of the products. It is calculated without making deductions for depreciation of fabricated assets or for depletion and degradation of natural resources (www.worldbank.org, visited in October of 2010).
32
45000
GDP
12,0
EF 40000 10,0
30000 )a ti p ac r e 25000 p $ S U t n re r 20000 cu ( P D G 15000
8,0
6,0
4,0
Ecological Footprint (gha per capita)
GDP (current US$ per capita)
35000
)a it ap cr e p a h g( F E
10000 2,0 5000
0
0,0 Italy
Singapore
Japan
Germany
France
Belgium
United A rab Emirates
Austria
Kuwait
Canada
Finland
Country
Figure 8 –Ecological Footprint and Gross Domestic Product, for a sample of countries (2006). (GDP source: http://www.worldbank.org/, visited in August 2010)
Likewise, the comparison of the total Ecological Footprint with the available productive land area per country or region presents important problems. This raises some question of fairness, to compare large – in terms of economic activity or land area – and small countries. And similarly, the comparison of sparsely populated, large countries, such as Australia, Canada and the USA, with densely populated, small countries in Europe, is a bit like comparing cities with continents. The latter category of countries necessarily shows a greater openness and trade dependency (van den Bergh and Verbruggen, 1999). 3.3
Methodological issues 3.3.1
Space & time
As proposed by Wackernagel and Rees and done by the Global Footprint Network, the Ecological Footprint and Biocapacity are calculated at global, regional, national and local (cities) scales, both on a total and on a per capita basis (van den Bergh and Verbruggen, 1999). However, from an environmental perspective, these boundaries are rather arbitrary (Fiala, 2008; van den Bergh and Verbruggen, 1999). While it may be very informative to understand what it takes to sustain a city, it should not come as a surprise that the Ecological Footprint of a city is significantly larger than the city boundaries (Fiala, 2008). National boundaries are of a geo-‐political and cultural nature and have no environmental 33
meaning (for example, country borders often cut right through natural areas or interconnected ecosystems). Taking this into account, it may make more sense to define the spatial scale from an environmental perspective, using environmental boundaries (hydrological, for example) (van den Bergh and Verbruggen, 1999). According to the concept developed by Wackernagel and Rees and the methodology used by the Global Footprint Network, both the Ecological Footprint and Biocapacity are accounted on a yearly basis. Since they are static measures, discounting is avoided. However, it is not possible to talk about soil erosion, carbon fluxes and ‘overshooting’ of ecological capacity, without taking into account dynamics, and this requires explicit or implicit assumptions about how one views (discounts) the future (van Kooten and Bulte, 2000). 3.3.2
Technology
In the calculation of the Ecological Footprint, the technology level that is assumed for producing a given product is a world average of technologies (considering data from the year under analysis) (Fiala, 2008). There is not an analysis of the role of technological change (Moffatt, 2000), which makes the Ecological Footprint not able to understand the effect of future growth in consumption (Fiala, 2008). As an example of what has been said, while individuals in the developing world are increasing their consumption very rapidly and could reach the consumption levels of the developed world, the Ecological Footprint cannot answer how this increasing consumption will look like. This issue is also reflected in statements such as that it would take 5 Earths to sustain consumption if everyone consumed like Americans. This reasoning assumes that the average consumption of an area extends to the entire world population, with all production at the current technology level. Before such a growth, much technological progress is expected to occur (Fiala, 2008). 3.3.3
Data selection
As it is done by the Global Footprint Network, the Ecological Footprint and Biocapacity calculations are based on a variety of international and national data sources, including databases from: (1) United Nations Food and Agriculture Organization; (2) United Nations Statistics Division; (3) International Energy Agency. The current methodology also uses published scientific papers, satellite land use surveys, and national and regional databases (Kitzes et al., 2009). A great amount of data is self-‐reported, and usually, although not always, publicly available (Kitzes et al., 2009). One identified problem in data is that the official statistics may not cover “off the books” transactions and may incompletely cover the household
34
extraction and consumption that does not enter into markets, such as subsistence farming (Kitzes et al., 2009). Even if the data were accurate, the fact that multiple data sources are used raises some issues, namely of consistency. To minimize this issue, researchers should exercise caution when comparing calculation results derived from different data sources, as different product lists and classification systems are likely to produce corresponding differences in Ecological Footprint and Biocapacity estimates (Kitzes et al., 2009). 3.3.4
Land use types
3.3.4.1 Cropland, Grazing land and Forest land In the cases where the trade is not considered (such as the global assessment), these categories cannot show overshoot, since, by definition, the yields of harvest are equal to the yields of growth. The lack of overshoot cannot be interpreted as environmental sustainability of these land types. The wrong interpretation of the results can be disastrous and encourage actions that drive us away from sustainable development. 3.3.4.2 Forest for carbon sequestration The carbon footprint estimates the forest land needed to assimilate all the CO2 anthropogenic emissions. The idea behind this is that, in order to achieve environmental sustainability, the carbon sink cannot be exceeded, thus focusing only on the emission and not on the resource scarcity (van den Bergh and Verbruggen, 1999). van den Bergh and Verbruggen (1999) point out several problems about this approach: (1) There may not be sufficient land available that is suitable for forests, which makes the assimilation scenario not even technically or environmentally feasible; (2) The solution would depend on the availability and cost of land as well as the productivity or reforestation, which are likely to differ between countries or regions; (3) The Ecological Footprint is not consistent with marginal cost thinking, and therefore unnecessarily unrealistic from an economic perspective. The most straightforward effect is that the more land will be (re)forested, the more expensive this option will become, due to increased scarcity of appropriate land. Other sustainable solutions, less land-‐intensive and thus less sensitive to increasing land prices, may become attractive then. In this context, Kitzes et al. (2009) suggests the inclusion of the amount of world-‐average bioproductive land of all types to sequester the anthropogenic carbon emissions. Fiala (2008) also points out that, while a major reduction in greenhouse gas production is needed, it is not at all clear, from an environmental point of view that all greenhouse gases mankind produces 35
need to be sequestered or eliminated. There is also the possibility of considering in the calculation ways of decreasing the carbon dioxide emissions, namely through the generation of useful electric energy with fewer emissions, ranging from to windmills to tides, water power and photovoltaic electricity or even photovoltaic hydrogen (by electrolysis of water) (Ayres, 2000). Kitzes et al. (2009) points out the possibility of measuring the carbon footprint as the number of global hectares that would be required to produce a quantity of biofuels equal in energy potential to the fossil fuels being combusted, consistent with a thermodynamic equivalency framework. As it was said, the carbon footprint only accounts for the anthropogenic carbon dioxide emissions. Globally, carbon dioxide emissions from land use change may be as large as 30% of carbon dioxide emissions from fossil fuel combustion (Kitzes et al., 2009). Although its potential impact, these emissions are not considered in the current accounts. Besides this, gases such as methane, nitrous oxide, fluorocarbons, and sulphur hexafluoride, are not calculated to have an additional footprint beyond the energy required for their creation (Kitzes et al., 2009; Ayres, 2000). The most common suggested method for including these gases in footprint accounts is through the use of global warming potentials14, which reflect the radiative forcing and atmospheric lifetime of each gas (Kitzes et al., 2009). Current emission levels of these other greenhouse gases have a warming potential equal to as much as 30% of present carbon dioxide emissions (Kitzes et al., 2009). A second method could involve calculations of the atmospheric lifetime and biospheric sequestration pathways for these other gases (Kitzes et al., 2009). 3.3.4.3 Fishing grounds The marine Ecological Footprint is calculated by dividing the amount of the primary production consumed by an aquatic species over its lifetime by an estimate of the harvestable primary production per hectare of marine area. This harvestable primary production estimate is based on a global estimate of sustainable aquatic species production, converted into primary production equivalents, and divided by the total available marine area (Kitzes et al., 2009). According to Pauly (1996), estimates of the sustainable aquatic harvested suffer from a number of data limitations and errors. Besides this, estimates of the actual landings in a given year may be subject to reporting bias (Kitzes et al., 2009). Methods for including bycatch are based on single year estimates rather than on time series observations. All of these issues weaken the calculations of the fisheries Ecological Footprint and Biocapacity under current accounting methods (Kitzes et al., 2009). Most significantly, calculations of the Ecological Footprint and Biocapacity for fisheries based only on primary production requirements and a single estimate of the sustainable yield ignore the importance of the availability and quality of 14
These potentials convert each gas into its carbon dioxide equivalent based on its ability to absorb and re-‐release radiation
in the atmosphere over its projected atmospheric lifetime (Kitzes et al., 2009).
36
fishing stocks in determining actual regenerative capacity in a given year (Kitzes et al., 2009). The current very small estimate of overshoot in global marine fisheries accounts may be due to exactly this problem, as the accounts are insensitive to any declining quality and yearly sustainable yield of fisheries over time (Kitzes et al., 2009). 3.3.4.4 Built-‐up land Built-‐up land, or land under human infrastructure, is calculated by assuming that built infrastructures occupies formerly productive cropland. This assumption was developed for use in temperate countries, where this calculation may hold reasonably true, but it is clearly violated elsewhere. In tropical countries, for example, infrastructures often occupy the previously forested areas, and in the Middle East and Central Asia, built infrastructure almost certainly occupies formerly arid non-‐productive land (Kitzes et al., 2009). Because cropland is the most productive of all land types, according to current methodology, the assumption that built space occupies cropland can create a counter-‐intuitive result when the infrastructure replaces other land types. In this instance, the estimated Biocapacity of the nation will actually increase, even though the land itself is degraded (Kitzes et al., 2009). 3.3.4.5 Other land types Since their beginning, the accounts have excluded several land types that supposedly do not provide significant amounts of concentrated resources for human extraction or waste absorption services, including tundra deserts, lagoons and other wetlands (Kitzes et al., 2009). As an example of the importance of these areas, let´s consider the case of lagoons. At a local level, a study by Tiezzi et al. (2004) focus the attention on calculating the Biocapacity of lagoons and other wetlands, finding that the Biocapacity of the lagoon under analysis may be higher on a per hectare basis than open sea. Although at a global level the additional ecosystems, such as wetlands, characterized by high productivity but low coverage, may not be significant, their contribution to Biocapacity may be important at national or sub-‐ national scales (Kitzes et al., 2009). 3.3.5
Use of land
In the Ecological Footprint accounts there isn’t a distinction between sustainable and unsustainable use of land. Such a distinction is of extreme importance to determine to what extent an activity or region is contributing to sustainable development (van den Bergh and Verbruggen, 1999). An implication of this is that the Ecological Footprint does not allow for a trade-‐off between environmental sustainability and intensive/extensive land use, notably in agriculture. Using this example, intensive land use, which has a small contribution to the Ecological Footprint of cropland (high productivities allows the use of small amounts of land), is usually associated with high environmental pressure due to the use 37
of pesticides and fertilizers, groundwater control and irrigation (van den Bergh and Verbruggen, 1999; Fiala, 2008; Herendeen, 2000). For a given year, the use of machinery and chemicals is evaluated in terms of carbon footprint, but not in terms of other important impacts such as land, water degradation and biodiversity. In fact, and in a more general way, the Ecological Footprint fails to capture land degradation (Fiala, 2008). Land that has been degraded can either no longer be used, or it is used at a decreased efficiency. If an area that was once producing for a given population becomes unusable, other land will need to be found to farm. Destroying land, and needing to move from one land area to another, clearly presents an important sustainability problem for a population. The only way the land degradation would possibly be captured is through the alterations in soil use reflected in the FAOSTAT. The problem with this dependence is that is very difficult, if not almost impossible, to understand the cause-‐effect relationships. Besides this, the time gap between each statistical update can compromise all the assessment. Also notice that, if a population is using land inefficiently, but is doing so without destroying the land, the system could be sustainable. A large land footprint then could be more sustainable than a small one, depending on how the land is used (Fiala, 2008). Besides that, and according to the methodology presented by the Global Footprint Network, land use is regarded to be associated with single functions only. However, in many cases, land use (and land cover) provides multiple services or functions, and land is subject to multiple use regimes. Neglecting multiple uses associated with land use will bias the Ecological Footprint upwards (van den Bergh and Verbruggen, 1999). 3.3.6
Yield factors, equivalence factors and global hectares
Yield factors accounts for differences in productivity of a given land use type between the system under analysis (most commonly a country) and the global average in this area type. Equivalence factors are used to convert world-‐average land of a specific type, such as cropland or forest, to global hectares. Global hectares are defined as hectares with world-‐average biological productivity, or ability to produce useful goods and services for humans (Kitzes et al., 2009). Some issues have been raised regarding these factors. First of all, when comparing different years, it must be taken into account that yield values change over time (a single hectare does not necessarily produce the same amount of goods or services each year). Therefore, time trends calculated using different yields each year reflect changes in both total consumption and in yield. These two factors can be difficult to distinguish under annual yield methods. At a global level, for example, both average material consumption and average yields have increased over the past forty years (Kitzes et al., 2009). Recent analyses suggest that a global hectare in 2003 yielded at least 15% more material than a global 38
hectare in 1961 (Kitzes et al., 2009). Kitzes et al. (2009) points out that an alternate method that could isolate changes in total consumption would be to calculate time series using yields for a single reference year. Under this method, time trends will reflect changes in absolute consumption and material extraction (Kitzes et al., 2009; Ferguson, 1999; Kitzes et al., 2008). The use of fixed equivalence factors allows a fixed rate of substitution between different categories of environmental pressure. Some categories receive identical weight, even if it is clear that their environmental impacts are very distinct. For instance, in the Ecological Footprint procedure, land used by infrastructure has the same weight as land use by agriculture, although designating land for road infrastructure clearly may be more environmentally destructive than designating it for crop production (van den Bergh and Verbruggen, 1999). According to these assumptions, the Ecological Footprint procedure may produce odd results that are unwanted from both an environmental and a socio-‐ economic point of view (van den Bergh and Verbruggen, 1999). Concerning the global hectares, this aggregation into a single number is related to the most important advantage pointed to the Ecological Footprint, its conceptual simplicity and intuitive appeal (Rees, 2000; Templet, 2000). Nevertheless, with the aggregation, one can easily be ignorant of where the numbers came from, how they are aggregated, the uncertainties, weights, and assumptions involved (Costanza, 2000). The information is not lost, usually it is possible to look at the details of how any aggregate indicator has been constructed (Costanza, 2000). Another question raised has to do with the duality between global hectares and local hectares15. While the global hectares approach assesses local demand (and supply) in the global context, and is thus particularly useful for comparisons across geographic regions, for some applications, such as projects focused on local resource management, the use of local yields, and local hectares, may be more appropriate (Kitzes et al., 2009). In this last situation, local hectares footprints can be determined either through (Kitzes et al., 2009): (1) Measured area approach, which draws area occupied estimates directly from land use and land cover surveys, and often combines these areas with disturbance weightings. In this method, footprints are generally measured in actual hectares; (2) Calculated area approach, in which product flows are simply divided by local yields, instead of global yields. Importantly, neither measured area nor calculated area methods provide specific information about the long term impacts of current practices, but only uncover whether current practices are within or exceed the capacity of the biosphere (Kitzes et al., 2009). 15
This discussion does not include the global scale.
39
40
4 Further analysis of the methodology 4.1 Overview Inspired by some of the critics done in the previous chapter, in this one we aim to further understand the current methodology, the improvements already done in the literature and apply some methodological changes. The items under analysis are the Biocapacity, equivalence factors and carbon footprint. According to the Global Footprint Network, our planet is in an overshoot situation, and it is necessary approximately one year and four months to regenerate the resources humanity consumed in the year of 2006. When the results are analysed, there are two main items that contribute to the overshoot, the Biocapacity and the carbon footprint. The Biocapacity is considered this way because it represents the physical limit of consumption, and the value against which the total Ecological Footprint is compared. In the carbon footprint accounts, by now, it is considered that the total carbon dioxide emitted must be sequestered in forest. According to the Global Footprint Network, in 2006, 33 876 Mt CO2 were emitted worldwide (see Table 8), which is equivalent to 9 063 591 443 global hectares, and represents 53% of total Ecological Footprint, 0.8 planets (Global Footprint Network, 2009b)16. The carbon footprint, by itself, is responsible for more than half of the total Ecological Footprint, and, therefore, should be carefully analysed. The calculation of the equivalence factors is attached with both the Biocapacity and carbon footprint. 4.2 Details of the methodology presented by the Global Footprint Network This section uses the data and results presented in two workbooks released by the Global Footprint Network: National Footprint Accounts, 2009 Edition and the equivalence factor calculation. The year considered is 2006, and for a global scale.
16
Global Footprint Network 2009. All rights reserved. These materials contain confidential information of Global Footprint
Network and may only be used for non-‐commercial academic research and study purposes and may not be further reproduced or disclosed. Commercial and free academic licenses may be received from the Global Footprint Network at www.footprintnetwork.org.
41
4.2.1
Biocapacity and equivalence factors
According to the methodology proposed by the Global Footprint Network, the Biocapacity accounts for: (1) Cropland area; (2) Grazing land; (3) Forest land; (4) Fishing grounds (marine and inland waters); (5) Built-‐up land (infrastructure and hydro). The sum of the Biocapacity of each land type gives the total Biocapacity (see Equation 2) For the year of 2006, the values are presented in Table 5. Built-‐up land is included here because, although it does not generate resources, buildings and infrastructure do occupy the Biocapacity of the land they cover. The carbon uptake land use is assumed not to have Biocapacity since it is based on the forest land and this way double counting is avoided (Kitzes et al., 2008). Table 5 – Biocapacity values presented by the Global Footprint Network, for 2006. 17
(source: Global Footprint Network, 2009b ) Land Cover
Area
YF
[ha]
[wha ha ]
-‐1
EQF
Biocapacity
[gha wha-‐1]
[gha]
Cropland
1 553 693 000
1.00
2.39
3 713 326 270
Grazing Land
3 384 091 000
1.00
0.51
1 725 886 410
Marine
2 423 046 900
1.00
0.41
993 449 229
432 797 000
1.00
0.41
177 446 770
3 944 643 000
1.00
1.24
4 891 357 320
167 368 480
1.00
2.39
400 010 667
40 013
1.00
1.00
40 013
11 905 679 393
11 901 516 679
Inland Water Forest Land Infrastructure Hydro Total
The sources typically used by the Global Footprint Network are presented in Table 6. In this case, the sources effectively considered in the 2006 accounts are the ones presented in Table 7. There is one exception, the hydro area. Since country specific areas inundated are not available, these areas are estimated based on an assumed average area inundated per MWh of generating capacity. The 17
Global Footprint Network 2009. All rights reserved. These materials contain confidential information of Global Footprint
Network and may only be used for non-‐commercial academic research and study purposes and may not be further reproduced or disclosed. Commercial and free academic licenses may be received from the Global Footprint Network at www.footprintnetwork.org.
42
Ecological Footprint of hydroelectric power generation is estimated based on the assumption that hydroelectric plants operate at 45% of their rated generating capacity (Kitzes et al., 2008). Since we are dealing with the world calculation, the yield factors assume the value 1. The equivalence factors are the ones already presented in Table 4. Table 6 – Data sources available to achieve the area, in ha, used in the Biocapacity calculation. (source: Kitzes et al., 2008) Data
Data Source
First source for land areas of cropland, grazing land, forest, other wooded land, inland waters, and built-‐up land. Limited to EU member countries.
Corine Land Cover 2000. European Topic Center on Land 18 Use and Spatial Information, 2000. Barcelona: EIONET .
Second source for data on cropland, grazing land, other wooded lands, inland waters
FAO ResourcesSTAT Statistical Database.
Second source for built-‐up land areas.
Global Agro-‐Ecological Zones (GAEZ). FAO and International Institute for Applied Systems Analysis 2000.
Third source for built-‐up land areas
Global Land Cover 2000. Institute for Environment and Sustainability, Joint Research Center and European Commission. Italy
Fourth source for built-‐up land areas
Global Land Use Database. Center for Sustainability and the Global Environment, University of Wisconsin-‐Madison. 1992.
Only source for area of marine continental shelf
WRI Global Land Cover Classification Database.
19
Table 7 – Data sources used in the Biocapacity calculation. (source: Kitzes et al., 2008) Source
Land Use Type
Description
Area [1 000 ha]
FAOSTAT
Cropland
Arable land and Permanent crops
1 553 693
FAOSTAT
Fishing grounds – inland
Inland water
FAOSTAT
Forest
Forest area
3 944 643
FAOSTAT
Grazing land
Permanent meadows and pastures
3 384 091
GAEZ
Infrastructure
Settlement and infrastructure
WRI
Fishing grounds -‐ marine shelf
Continental shelf area
432 797
167 368 2 423 047
The calculation of the equivalence factors, as done by the Global Footprint Network, is explained in the following numbered items:
18
European Environment Information and Observation Network.
19
World Resource Institute.
43
(1) For each country is considered the total available area within the classification of “very suitable”, “suitable”, “moderately suitable”, “marginally suitable” and “not suitable”, using data from the GAEZ model. This data does not include several countries, so, the sum of all areas cannot be considered as the “world”; (2) For each country is also gathered information about the areas occupied with cropland, built-‐ up land, forest land and grazing land; (3) For each country, the area of cropland and built-‐up land is allocated to the most suitable land. The forest land is allocated to the most productive remaining area and after, the same is done with the grazing land. In the end there is a final remaining land, which is not used to cropland & built-‐up land, forest or grazing land. This remaining land it mostly “not suitable”, but, nevertheless, has non-‐zero productivity; (4) For each land occupation, the equivalence factor is obtained as a weighted value of productivity. The final remaining area is not used neither to calculate the equivalence factor nor the Biocapacity, but since it has some productivity, it should be accounted for. 4.2.2
Carbon footprint
According to the Global Footprint Network, the calculation of the carbon footprint follows the reasoning presented in Table 8. Table 8 – Carbon footprint as calculated by Global Footprint Network. 20
(source: Global Footprint Network, 2009b )
Name
CO2 emissions -‐1
[Mt CO2 yr ]
Fossil fuel emissions Other sources Bunker fuel Total
CO2 emissions considering the ocean uptake fraction (22%)
Yield -‐1
EQF -‐1
[tCO2 ha yr ]
-‐1
[Mt CO2 yr ]
-‐1
[gha ha ]
Carbon footprint [gha]
28 003
21 706
3.59
1.24
7 492 079 745
4 894
3 794
3.59
1.24
1 309 408 203
980
759
3.59
1.24
262 103 495
33 876
26 260
3.59
1.24
9 063 591 443
The carbon footprint calculation follows the Equation 4:
20
Global Footprint Network 2009. All rights reserved. These materials contain confidential information of Global Footprint
Network and may only be used for non-‐commercial academic research and study purposes and may not be further reproduced or disclosed. Commercial and free academic licenses may be received from the Global Footprint Network at www.footprintnetwork.org.
44
Carbon footprint [gha] = CO2 emitted [tCO2 ⋅ yr −1 ] × (1 − ocean uptake fraction [-‐]) ×
EQF [gha ⋅ ha-‐1 ] Yield [tCO2 ⋅ ha-‐1 ⋅ yr -‐1 ]
Equation 4 – Calculation formula of the carbon footprint. (source: Kitzes et al., 2008)
As presented in Table 8, three “kinds” of carbon dioxide sources are considered: (1) Fossil fuel emissions. It accounts for all emission from fossil fuel combustion (Kitzes et al., 2008); (2) Other sources. This value is a combination of carbon dioxide emissions from industrial processes (mainly concrete manufacture), forest land clearing, flaring associated with oil and natural gas extraction, and 10% of biofuels emissions (assumed to be the fraction produced unsustainably, according to IPCC21 Sink/Source Category 5) (Kitzes et al., 2008); (3) Bunker fuel. This item assesses the footprint of the international travel and shipping (Kitzes et al., 2008). Worldwide airplane and ship bunker fuels are added as a ‘’tax’’ on all countries relative to their total fossil fuel combustion footprint. The bunker fuels ‘’tax’’ is calculated by multiplying the fossil fuel footprint by a value representing the percent of world fossil fuel emissions stemming from international transport. This percentage has historically been near 3-‐4 of total global carbon dioxide emissions. This is also the value used in the global accountings (Kitzes et al., 2008). There are two sources typically used in the emissions gathering (Kitzes et al., 2008): (1) IEA22 CO2 Emissions from Fuel Combustion Database. This is the preferential source data, and the one used in National Footprint Accounts, 2009 Edition23; (2) Marland, G., T.A. Boden, and R. J. Andres. 2007. Global, Regional, and National Fossil Fuel CO2 Emissions. In Trends: A Compendium of Data on Global Change. Oak Ridge, TN: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory and U.S. Department of Energy. The ocean sequestration percentage reflects the percentage of global fossil fuel carbon emissions that are sequestered by oceans. This percentage is calculated for each year as the ratio of the estimated annual oceanic carbon sink to total global emissions from fossil fuel combustion in that year (Kitzes et al., 2008). 21
Intergovernmental Panel on Climate Change
22
International Energy Agency.
23
Global Footprint Network 2009. All rights reserved. These materials contain confidential information of Global Footprint
Network and may only be used for non-‐commercial academic research and study purposes and may not be further reproduced or disclosed. Commercial and free academic licenses may be received from the Global Footprint Network at www.footprintnetwork.org.
45
The yield factor presented in Table 8 allows the conversion of CO2 emissions to forest area (see Equation 6). Yield [tCO2 ⋅ ha-‐1 ⋅ yr -‐1 ] =
Carbon sequestration factor [tC ⋅ ha-‐1 ⋅ yr -‐1 ] C to CO2 ratio [tC ⋅ (tCO 2 )−1 ]
Equation 5 – Calculation formula of the yield factor. (source: Kitzes et al., 2008)
In the National Footprint Accounts, 2009 Edition workbook, the total amount of carbon dioxide (after discounting the ocean sequestration) is converted into global hectares by using the net annual growth of forests as the yield for carbon uptake. The carbon uptake rate used to convert tones of carbon dioxide to global hectares is derived from data on the net annual growth of forests drawn from the IPCC (the carbon sequestration factor estimates the annual carbon uptake of a hectare of world average forest land; this factor is based on the average sequestration potential of world forest, and is calculated using IPCC data). The uptake rate is calculated assuming that carbon comprises half of that net increase in biomass. This ‘yield’ for carbon uptake, combined with the forest equivalence factor, converts tones of carbon dioxide into a footprint in global hectares (Kitzes et al., 2008). Summing up, it is possible to say that carbon footprint is the most important contributor to the total Ecological Footprint and, as it is done by the Global Footprint Network, after discounting the ocean sequestration, considers the sequestration of total carbon emissions by forest. Regarding the forest sequestration, this methodology is not to propose that forestry is the solution to climate change but rather demonstrates how much larger the world would have to be in order to negate the effects of carbon emissions (Walsh et al., 2009). Concerning the need of sequestration of the total CO2 emissions, according to Meinshausen et al. (2009) and Allen et al. (2009), a global warming limit of 2˚C or below (comparative to pre-‐industrial levels) can be permitted. This indicates that maybe there is no need to sequester all the CO2 emissions. Besides this, instead of looking of the area needed to sequester the emissions, it is also possible to analyse the possibility of reducing the carbon dioxide emissions. It should also be noticed that the carbon footprint is the only waste accounted, ignoring all the others. 4.3 Review of improvements proposed in the literature 4.3.1
Biocapacity and equivalence factors
Regarding the Biocapacity calculation, Zhao et al. (2005) was the first to propose a change of the methodology using the emergy analysis. In fact, Zhao et al. (2005) aims to show a modified form of Ecological Footprint calculation by combining emergy analysis with conventional Ecological Footprint form of calculation (see Appendix B to a brief description of emergy). The modified method starts from the energy flows of a system in calculating Ecological Footprint and carrying capacity. Through a study of the energy flows, and using the method of emergy analysis, the energy flows of a system are translated 46
into corresponding biological productive units (Zhao et al., 2005). Here, we focus on the calculation of the carrying capacity24. According to this author, the carrying capacity can be defined as the maximum (entropic) “load” that can safely be imposed on the environment by people. A better understanding of carrying capacity can be gained by separating the natural resources for society into renewable and non-‐ renewable components. The non-‐renewable resources are depleted because they are being used at a rate that exceeds their rate of replacement. Carrying capacity is not sustainable unless it is based on the use of resources in a renewable way. In this context, only the renewable resources are taken into account in this calculation of carrying capacity. The Equation 6 is used to calculate the carrying capacity (CC): CC[m2 ] =
e [sej ⋅ yr -‐1 ] p 1 [sej ⋅ yr -‐1⋅ m -‐2 ]
Equation 6 – Calculation of the carrying capacity using an emergy approach. (sources: Zhao et al., 2005)
e:
renewable resources of emergy amount per capita.
p1:
Earth emergy density.
p 1 [sej ⋅ yr -‐1⋅ m-‐2 ] =
total emergy of the earth [sej.yr -‐1 ] 1.583 × 10 25 sej.yr -‐1 = = 3.1 × 10 10 [sej ⋅ yr -‐1⋅ m-‐2 ] 2 14 2 areas of the earth [m ] 5.1 × 10 m
The total emergy amount of the Earth is the sum of the emergy of solar insolation, deep Earth heat and tidal energy (Zhao et al., 2005). In the calculation of the carrying capacity, first, the emergy amounts of available renewable resources are estimated. Here, five kinds of renewable resources emergy are considered: sun, wind, chemical energy in rain, geopotential energy in rain, and Earth cycle energy. In order to avoid duplicate calculation, the maximum item of emergy amount is regarded as the total available emergy. Thus, this amount is divided by the amount of population. The value e is gathered that way, the emergy supply of natural resources per capita. Then, the amount of e is divided by the emergy density p1. This method considers that 12% of total carrying capacity should be discounted to provide for biodiversity (Zhao et al., 2005). Chen and Chen (2006) uses a very similar method, compared to the one used by Zhao et al., 2005. In this case, as the emergy due to the Earth’s heat and the gravitational effect associated with the sun and the moon is negligible, the global emergy sustaining the Earth is approximately 9.44 x 1024 sej/yr. The total surface area of the Earth is 5.1 x 1014 m2. Therefore, the global empower density (GED) is the ratio of the annual global emergy consumption to the surface area of the Earth, 1.85 x 1010 sej/m2yr 24
Here, the carrying capacity is not exactly equivalent to the concept of Biocapacity, as presented by the Global Footprint
Network, but is also the value with which the Ecological Footprint is compared.
47
(comparable to 3.1x1010 sej/m2 yr). Renewable resources, including surface wind, physical energy of rain on land, chemical energy of rain on land, physical stream energy, waves absorbed on shores, Earth’s sedimentary cycle and chemical stream energy, are calculated as the ecological capacity. To avoid double accounting, only the largest renewable emergy flow is chosen to determine the carrying capacity. Siche et al. (2010b) uses as basis the study by Zhao et al. (2005) and aims to discuss some weak points found in Zhao’s approach, trying to overcome them through a new approach called Emergetic Ecological Footprint (EEF). The main difference between Zhao’s approach and EEF, regarding the carrying capacity calculation, is that EEF accounted for the internal storage of capital natural. Natural capital is an internal storage of a country that was filled up during several decades (or even centuries) by external natural energy flows. Nowadays, mainly the under development countries are dependant of that storage. For that reason, natural capital is considered as a supplier of renewable resources (Siche et al., 2010b). Besides this, the calculation is similar to the one presented in Zhao et al. (2005). All the flows in global hectares per capita are summed and 14.2% is subtracted, aiming at the preservation of other species (Siche et al., 2010b). Other studies, like Venetoulis and Talberth (2008) and Siche et al. (2010a), consider the ecosystems that are not considered by the Global Footprint Network since their productivity is low. Venetoulis and Talberth (2008), as well as Siche et al. (2010a), use a Net Primary Production (NPP) approach to calculate the equivalence factors (see Appendix B for a brief description of NPP). In the Venetoulis and Talberth (2008) study, the GAEZ suitability indices are replaced with NPP. Here, EQF’s are the ratio of each biome´s NPP per unit of area to the global average. NPP figures for each biome are based in Amthor (1998), which provides area, annual NPP, plant carbon content, and soil carbon content for 16 distinct biomes. To illustrate how EQF’s were derived, consider the 2.12 EQF for cropland and global NPP for cropland of 6.3 Pg Carbon over an area of 14.8x1012 m2 (0.43 Pg Carbon/m2). The crop land EQF of 2.12 is simply 0.43 Pg Carbon/m2 divided by the global average NPP (0.20 Pg Carbon/m2). Thus, EQF’s here calculated represent the ratio of productivity of one land type to the average, where productivity is measured in NPP (Venetoulis and Talberth, 2008). According to Siche et al. (2010a), the EQF for each category is calculated through the ratio between its Emergy Net Primary Production (ENPP) and the system total ENPP, both in sej m-‐2 year-‐1. To calculate the ENPP for each ecosystem is necessary to multiply its NPP value in energy units (NPPENERGY) by its respective Transformity. NPPENERGY is obtained through the multiplication of energy content in the dry biomass (J/gbiomass) by the NPP in mass units (NPPMASS).
48
4.3.2
Carbon footprint and other wastes
Lenzen and Murray (2001) consider emissions of CO2 and other greenhouse gases (CH4, N2O, CF4 and C2F6) that are not from energy use but from sources such as land clearing, enteric fermentation in livestock, industrial processes, waste, coal seams, venting and leakage of natural gas, among others. Non CO2 emissions are converted into units of carbon dioxide equivalent using Global Warming Potential (GWP). Walsh et al. (2009) analyses the incorporation of methane in the Ecological Footprint. According to these authors, perhaps the most obvious method for calculating a footprint of methane is to emulate standard CO2 footprinting. This requires methane to be translated into carbon equivalents (through GWP), which allows an estimation of the area of new forest growth required to sequester it and subsequently into a land area of global average bioproductivity. This study also considers the possibility of using the net radiative forcing25 (NRF), instead of the GWP. In terms of anthropogenic emissions, net radiative forcing is related to GWP and measures the increase in net energy gain due to emissions realised since pre-‐industrial times. This quantifies incoming radiance in W/m2 and a positive value indicates that human activity is contributing to a net increase in temperature. The main rationale for its application is that it quantifies the actual effects of climate change as opposed to expressing methane emissions in terms of a related variable. In order for radiative forcing to be incorporated into a national footprint account, annual methane consumption needs to be translated into a unit comparable with pre-‐industrial conditions, in this case concentration in parts per billion (Walsh et al., 2009). 4.4 Methodological changes and results 4.4.1
Biocapacity and equivalence factors
As a first iteration, we consider the total world area both in the calculation of the Biocapacity and equivalence factors, and a percentage of Biocapacity available to biodiversity. As seen in the previous section, other improvements have already been done in the literature. But we consider that, prior to their application more research has to be done to make sure that a real improvement is done. This is especially true to the emergy analysis, since it is blind to the current human need for resources. In order to consider the remaining area in the Biocapacity, it is necessary to re-‐calculate two items: (1) Areas, including the remaining area, in ha; (2) Equivalence factors. 25
NRF estimates the overall increase in irradiance reaching the tropopause due to the action of a climate change driver
such as GHG emissions or increased solar insolation (Walsh et al., 2009).
49
To recalculate the areas used, several issues must be addressed. First of all, it is necessary to combine data from the two workbooks (National Footprint Accounts, 2009 Edition and equivalence factor calculation), so, its compatibility must be assessed. The areas considered in the National Footprint Accounts, 2009 Edition workbook are world areas (from the sources already presented). The areas used to calculate the equivalence factors do not include the entire world and are the ones presented in Table 9. Table 9 – Land areas that support the calculation of Biocapacity and equivalence factors. 26
(source: Global Footprint Network, 2009b )
Land type
Areas considered in the equivalence factors workbook
Areas considered in the National Footprint Accounts workbook
[1 000 ha]
[1 000 ha]
Cropland & built-‐up land
1 715 174
1 721 101
Forest land
2 922 299
3 944 643
Grazing land
3 372 649
3 384 091
Remaining area
5 105 091
13 115 214
9 049 835
Total
It must be noticed that, in the “cropland & built-‐up land” category, according to the data of the National Footprint Accounts, 2009 Edition workbook, it is considered the “hydro” referred in Table 5. The main difference between the two sources of information is the forest land27, and, besides the hypothesis of an error, it must be due to the lack of some countries in the equivalence factors calculation. To include the remaining area in the calculation we considered that the upper bond of total land area is the one given by FAOSTAT, also for the year of 2006. According to FAOSTAT, land area is the total area of the world excluding area under inland water bodies (http://faostat.fao.org visited in May 2010) and assumes the value of 13 009 151 500 ha. The total area used in the calculation of the equivalence factors is higher than that value, even though not all countries of the world are considered. This difference can be, once again, explained by the difference of data sources. Although the land occupied by cropland, forest and grazing came from the FAOSTAT, the total areas and the built-‐up land came from
26
Global Footprint Network 2009. All rights reserved. These materials contain confidential information of Global Footprint
Network and may only be used for non-‐commercial academic research and study purposes and may not be further reproduced or disclosed. Commercial and free academic licenses may be received from the Global Footprint Network at www.footprintnetwork.org. 27
According to the Global Footprint Network the source data used is the same, FAOSTAT, and for the same year.
50
the GAEZ. In order to keep the upper bond from FAOSTAT, it is considered that the remaining area used in calculations assumes the value of 3 959 316 x 103 ha. To recalculate the equivalence factors it is only necessary to also consider the remaining area, and apply to it the exact same equations that are applied to the other areas. The results obtained are presented in Table 10. Table 10 – Original and recalculated equivalence factors. Land Cover
EQF
Recalculated EQF -‐1
-‐1
[gha wha ]
[gha wha ]
Cropland/Built-‐up land
2.39
2.76
Forest
1.24
1.43
Grassland/Other Wooded Land
0.51
0.60
0.41
0.48
-‐
0.53
28
Marine Remaining area
Considering these recalculated values of equivalence factors, as well as the remaining area, is now possible to recalculate the Biocapacity (see Table 11). The results indicate an increase of about 33% in the available Biocapacity. According to these accounts the total world area could be used to fulfil human needs, which is not an expected sustainable situation in terms of biodiversity conservation. Besides this, the exploration of all the world area certainly represents a challenge. We intent to further analysis these questions, but just to illustrate the biodiversity issue, we considered that 14% of the total Biocapacity is reserved to biodiversity. In this scenario, the increment in the Biocapacity (relative to the value released by the Global Footprint Network) is 15%. Nevertheless, the comparison of the Ecological Footprint and Biocapacity still indicates overshoot. This analysis does not pretend to make important improvements in the Biocapacity accounts, it is just a first iteration that wishes to understand the vulnerabilities of the calculation.
28
The values for the category “marine” are calculated based on a comparison of beef protein per hectare grassland and
salmon protein per hectare marine area.
51
Table 11 – Original and recalculated equivalence factors. Land Cover
Area
Original
YF EQF
[-‐]
-‐1
[ha]
Recalculated
Biocapacity -‐1
[wha ha ]
[gha wha ]
EQF
Biocapacity -‐1
[gha]
[gha wha ]
[gha]
Cropland
1 553 693 000
1
2.39
3 713 326 270
2.76
4 294 162 058
Grazing Land
3 384 091 000
1
0.51
1 725 886 410
0.60
2 016 254 415
Marine
2 423 046 900
1
0.41
993 449 229
0.48
1 154 928 520
432 797 000
1
0.41
177 446 770
0.48
206 289 692
3 944 643 000
1
1.24
4 891 357 320
1.43
5 643 751 866
167 368 480
1
2.39
400 010 667
2.76
462 580 044
40 013
1
1
40 013
1.00
40 013
3 959 316 007
1
0.53
2 086 988 844
15 864 995 400
-‐
-‐
11 901 516 679
-‐
15 864 995 452
-‐
-‐
-‐
-‐
-‐
13.643.896.089
Inland Water Forest Land Infrastructure Hydro Remaining land Total Total (-‐14% )
4.4.2
Carbon footprint
In order to start to understand the influence of the change on the assumptions taken by the Global Footprint Network regarding the calculation of the carbon footprint, we considered the possibility of not sequester the total carbon dioxide emissions. More than 100 countries have adopted a global warming limit of 2° C or below (relative to pre-‐ industrial levels as a guiding principle for mitigation efforts to reduce climate change risks, impacts and damages (Meinshausen et al., 2009; Allen et al., 2009). Limiting cumulative CO2 emissions over 2000-‐50 to 1000 Gt CO2 yields a 25% probability of warming exceeding 2˚C – and a limit of 1440 Gt CO2 yields a 50% probability – given a representative estimate of the distribution of climate system properties (Meinshausen et al., 2009). In Table 12 it is possible to find a relationship between the cumulative emissions of carbon dioxide and the corresponding probability of exceeding 2°C. According to Meinshausen et al. (2009), the focus on 2°C relative to pre-‐industrial levels, as such a warming limit has gained increasing prominence in science and policy circles as a goal to prevent dangerous climate change. The author also recognize that 2°C cannot be regarded as a ‘safe level’, and that, for example, small island states and least developed countries are calling for warming to be limited to 1.5°C (Meinshausen et al., 2009).
52
Table 12 – Probabilities of exceeding 2°C in global temperature. (source: Meinshausen et al., 2009) Cumulative emissions over 2000-‐2050 Probability of exceeding 2° C [Gt CO2]
[%] 886
8 – 37
1000
10 – 42
1158
16 – 51
1437
29 -‐ 70
In order to re-‐calculate the carbon footprint, the value of 886 Gt CO2 of cumulative emissions over 2000 – 2050 is used (a conservative scenario). Since 2000 – 2006 emissions were about 234 Gt CO2 (Meinshausen et al., 2009), there are about 652 Gt CO2 of cumulative emission over 2006 – 2050. Assuming that the cumulative emission over 2000 – 2050 will be fulfilled, several scenarios can be considered in the calculation of the emissions that are allowed to emit in the 2006 year (considering a uniform distribution): (1) The value can be an average emission considering the 2000 – 2050 cumulative emissions (886 Gt CO2), which implies an emission of 18 Gt CO2 yr-‐1; (2) The value can be an average of the emissions that took place between 2000 and 2006 (234 Gt CO2), which represents a permitted emission of 39 Gt CO2 yr-‐1 ; (3) The value can be an average of the remaining emissions allowed between 2006 – 2050 (652 Gt CO2), which represents 15 Gt CO2 yr-‐1. Once again, since we already have information about the 2000 – 2006 cumulative emissions, we will use the most conservative value, 15 Gt CO2 yr-‐1 and apply it as the permitted emissions for 2006. Comparing the values from Table 8 with the ones from Table 13, considering the possibility of a 2°C increase, there is a decrease of 5 233 507 552 gha, which represents about 0.4 planets. Considering the possibility of the CO2 emission permit, and applying the same methodology as the one used by the Global Footprint Network, there is not a situation of overshoot. Although it is obvious that is not possible to sequester all the carbon dioxide emissions, a 2°C increase may have serious negative effects. It might be necessary to review the viability of such an increase. Despite all the reservations regarding the 2˚C assumption, this calculation serves to show the vulnerability of the Ecological Footprint analysis to changes in the carbon footprint. This vulnerability reveals that the values released for the Ecological Footprint analysis must be carefully interpreted. Another issue to discuss is the reduction of carbon dioxide emissions, instead of discussing the ways of sequestering it.
53
54
5 Discussion, conclusions and future work In order to lead the discussion to the conclusions, we start with the analysis of the schematic representations of the Ecological Footprint and Biocapacity, as they are presently considered by the Global Footprint Network (see Figure 9 and Figure 10). As presented in Figure 9, the Global Footprint Network focuses the concept and calculation of the Ecological Footprint in the consumption (and generation of wastes) of a given population that lives within the borders of a given region. In this context, the Ecological Footprint considers the resources that are harvested within the borders, minus the resources that are exported, and plus the resources that are imported. In the Biocapacity (see Figure 10), the Global Footprint Network considers and calculates the resources that are available for human consumption and are produced inside the borders of the region under analysis (also the ability to absorb the residues). Resource 1
Resource 2
Resource…
used
Resources
used
Resources
Population released
Waste1
released
Waste 2
Waste…
Figure 9 Representation of the Ecological Footprint, as presented by the Global Footprint Network.
Resource 1
Resource 2 available
Resource… available
Population can be absorbed
Waste1
can be absorbed
Waste 2
Waste…
Figure 10 –Representation of the Biocapacity, as presented by the Global Footprint Network.
This approach has, at least, three important problems. The first problem is related with the trade considered in the Ecological Footprint, and consequent comparability with the available Biocapacity. The second problem is related with the methodology followed in the calculation of the Biocapacity. The third problem concerns the inclusion of wastes in the analysis. In order to explore the question of trade, let´s consider a given region with a known level of resource exploitation. As said in Chapter 3, the comparison between Ecological Footprint and Biocapacity is only interesting when it shows overshoot. In this case, we expected the result to reflect a situation of over-‐
55
exploitation of the resources that are within the borders of the region. There are two items positively contributing to the Ecological Footprint of consumption (see Equation 3), the Ecological Footprint of production29 and the Ecological Footprint of the imported goods. The Ecological Footprint of production represents the consumption of the resources available within the borders of the region (and generation of wastes). Instead, in the case of the Ecological Footprint of importation, the resources where harvested elsewhere with an effect on the resources of the region of origin. This effect happens in the region of origin but it is accounted in the region of consumption. In our opinion, this approach does not allow a correct comparison between the Ecological Footprint of consumption of a given population in a given region and the Biocapacity available within the border of the region. This approach assigns a confuse connotation to trade. In fact, the region under analysis may have a poor Biocapacity, and therefore, may be highly dependent on importations. In this case, the region shows overshoot, but the imported goods can be harvested in a sustainable way in their region of origin, which is not reflected on the results. Neither is reflected the economic and social advantages of such trade. This question is not a problem at a global scale, where the trade is zero. Regarding the Biocapacity, it must be noticed that, according to the methodology presented by the Global Footprint Network, it measures the areas that are indeed used as cropland, grazing land, forest land and built-‐up land. Therefore, at a global scale, by definition, these categories cannot show overshoot. The only items that can show overshoot are the fishing grounds and the carbon footprint. These assumptions reflect the fact that, in this calculation, the Biocapacity is not assessing the areas that would be sustainably available to fulfil the human needs, but the areas that are indeed used. In this case, the resource soil, which supports the cropland, grazing land, forest land and built-‐up area, and that we know it is, in many cases, subject to unsustainable harvesting, by definition, can only be in overshoot through trade, which does not reflect the bad practices. Besides that, as was seen in chapter 4, it does not consider neither the total area that could be harvested, nor the area necessary to sustain biodiversity. As demonstrated, the inclusion of these areas affects the final results. Concerning the wastes, only the carbon dioxide is assessed, which by itself does not reflect the current situation in terms of the residues production. Besides this, the carbon footprint, alone, is responsible, for the year of 2006, for the appropriation of 0.8 planets. Therefore, it is the category that most contributes to the overshoot reported, 1.4 planets. Given the importance of this category, the 29
A country’s Ecological Footprint of production is the sum of the footprints for all resources harvested and all wastes
generated within the population’s geographical borders. This includes all the area within the borders necessary for supporting the actual harvest of primary products (cropland, grazing land, forest land, and fishing grounds), the population’s infrastructure and hydropower (built-‐up land), and the area needed to absorb fossil fuel carbon dioxide emissions generated within the borders (carbon footprint).
56
corresponding calculation should be robust and reflect a plausible situation. The assumptions taken in the calculation of the carbon footprint do not reflect a plausible scenario, namely because: (1) It assumes the need for sequestration of all the anthropogenic CO2 emissions. Although it is not clear the cause-‐effect relationships related with the increase of the concentration of CO2 in the atmosphere, the sequestration of all the emissions nowadays does seem like a possible situation; (2) It is considered that the ocean is responsible for the sequestration of about 20% of the emissions and the remaining percentage should be sequestered by the forest. Although forest is actually very efficient in carbon sequestration, this assumption does not reflect a real situation. Besides this, and according to this assumption, it is not considered the implementation of methods of emissions reduction. In chapter 4 it was assumed the possibility of allowing an increase in the concentration of the CO2, and, as expected, the final results are highly affected. Given the importance of the category, a more robust calculation is expected. The conclusion to be drawn from the exposed is that, as it is currently being done by the Global Footprint Network, the comparison between the Ecological Footprint and Biocapacity of a given population is not assessing environmental sustainability/unsustainability, regarding the use of resources and deposition of wastes. Despite the above, we understand the utility of such concepts. In one hand it is of extreme importance to capture the unsustainable use of renewable resources. And that is exactly what we plan to do. We plan to use the concepts of Ecological Footprint and Biocapacity as the basis to develop an absolute indicator of environmental unsustainability of resource use. In order to do that, we focus our attention on the resource instead of the population. Our work will start at a regional scale, in the continental territory of Portugal, and for the resource soil. The borders of analysis correspond to the borders of the resource. The Biocapacity of the resource corresponds to the amount of material and services that can be used without damaging it. The Ecological Footprint of the resource should correspond to the materials/services actually harvested. This approach presents several advantages (comparative to the methodology presented by the Global Footprint Network): (1) Since it focus on the resource instead of the population, the problems related with trade are not an issue; (2) The Biocapacity measures the amount of materials/services that can be used without damaging the resource, instead of the use of the resource; (3) Since it is expected to be a less aggregated indicator, less factors of normalization and aggregation are needed, and therefore less relationships of possible trade-‐offs are expected;
57
(4) It should allow a better understanding of what is happening wrong, and therefore lead the analysis to the set of actions needed to decrease the damage; This approach also shows some weaknesses, such as: (1) The difficulty of defining the amounts of resource that can be used without damage, in the calculation of the Biocapacity. Here, some very important assumption will be taken. These assumptions are expected to be subjective and have an associated error; (2) It still has the issue of the technology described in the chapter 3; (3) This method only assesses renewable resources. The non-‐renewable resources analysis is of extreme importance in the context of environmental sustainability and therefore, a further analysis should be done to incorporate them. Besides the challenge that exists when the resource under analysis exchanges flows and damages with other resources, the quantitative and qualitative analysis of the damages done to the studied resource represents a huge challenge. Those are not static phenomena and their incorporation in the analysis will require a carefully analysis of the available tools. One possibility that has been identified, but not studied yet, is the consideration of shadow projects. In this context, and according to Edward-‐ Jones et al. (2000), a shadow project is a project that provides an equal, alternate environmental good or service elsewhere in the area that suffers an environmental loss. The proposed alternatives, by definition, will have differing qualities to the original site. It may therefore be problematic to determine how successfully any shadow scheme can provide the benefits of the original. Rather than focusing on directly equivalent sites, planners may prefer to consider instead planning gains, where developers guarantee protection of other non-‐related environmental sites to compensate for damaging the site under development. We intend to further analyse this question and include it in our assessment. On the other hand it is also useful to work with the global assessment, as presently done by the Global Footprint Network, in the sense that it gives a glimpse of the “big picture”. Here, we will mainly work on the Biocapacity calculation in two main essential issues: (1) If we can measure a Biocapacity that both reflect the human needs and the ability of the ecosystems to fulfil them (instead of simply reflecting the current use). In order to do this, we will start by analysing the Human Appropriation of Net Primary Production tool and find out if it is useful in this context; (2) After this, we will study how to distribute the Biocapacity in a fair way by all nations. We will also continue our work with the carbon dioxide and other wastes, taking into account the critics and improvements already done in this report.
58
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Appendix A – Temporal evolution of the Ecological Footprint Table 13 – Ecological Footprint and Biocapacity time series. (source: Global Footprint Network, http://www.footprintnetwork.org/, visited in May 2010) 1961
1965
1970
1975
1980
1985
1990
1995
2000
2005
2006
Global Population (billion)
3.1
3.3
3.7
4.1
4.4
4.8
5.3
5.7
6.1
6.5
6.6
Total Ecological Footprint
7.1
8.1
9.6
10.6
11.7
11.9
13.3
13.8
15.1
16.8
17.1
Cropland footprint
3.3
3.4
3.5
3.5
3.6
3.6
3.7
3.7
3.7
3.7
3.7
Grazing land footprint
1.3
1.3
1.4
1.4
1.4
1.1
1.3
1.4
1.4
1.5
1.4
Forest footprint
1.1
1.2
1.2
1.2
1.3
1.4
1.5
1.4
1.8
1.9
1.8
Fishing ground footprint
0.3
0.3
0.4
0.4
0.4
0.4
0.5
0.6
0.6
0.6
0.6
Carbon footprint
0.9
1.7
2.9
3.8
4.7
4.9
5.9
6.4
7.3
8.7
9.1
Built-up land
0.2
0.2
0.2
0.3
0.3
0.3
0.3
0.3
0.4
0.4
0.4
Total Biocapacity
11.4
11.5
11.6
11.6
11.7
11.7
11.9
12.0
12.0
11.9
11.9
Ecological Footprint to Biocapacity ratio
0.62
0.70
0.83
0.92
1.00
1.01
1.12
1.15
1.27
1.41
1.44
64
Appendix B – Brief description of the Emergy and NPP methods Emergy Emergy analysis has been developed by Odum (Zhao et al., 2005) as a tool for environmental policy and to evaluate quality of resources in the dynamics of complex systems (Brown and Ulgiati, 1997). It measures both the work of nature and that of humans in generating products and services, as a science-‐ based evaluation system that represents both natural values and economic values with a simple, universal unit (Zhao et al., 2005). Emergy is defined as the energy of one type required in transformations to generate a flow and storage (Zhao et al., 2005). In other words, and according to Odum (2002): “(...) the emergy of anything is the available energy of one kind previously used up to make it.” For example, the solar energy previously required is called the solar emergy (Odum, 2002). To keep from confusing energy that is in a product with that which has been used up to make it, emergy units are called emcalories (or emjoules). The emergy of one kind, required to be transformed to make one unit of energy of another kind, is called transformity (Odum, 2002). Using the example, the units of transformity are solar emjoules/Joule, abbreviated sej/J or solar emjoules/g (sej/g). The higher the transformity, the higher that item is located in the energy hierarchy chain. This is based on the assumption implicit in the maximum power principle that the more energy required to make a product or service, the higher its emergy value (Zhao et al., 2005). The transformity can be used to transform a given energy into emergy, by multiplying the energy by its transformity. Once transformities are known for a class of item, the total energy on an item can be expressed according to Equation 7 (Zhao et al., 2005).
emergy [sej] = available energy of item [J or g] × transformity [sej/J or sej/g] Equation 7 – Calculation of the emergy. (sources: Zhao et al., 2005)
Net Primary Production (NPP) NPP quantifies the conversion of atmospheric CO2 into plant biomass. Thus, NPP is a rate process that tracks the net flux of carbon from the atmosphere into green plants per day, week, or year. It is highly variable year to year and seasonally. For some seasons and biomes NPP may be negative, indicating that plant respiration is greater than the uptake of carbon by plants, as during months when vegetation is stressed by drought conditions or low temperatures. In addition, succession can influence NPP though allocation of fixed carbon to maintenance rather than growth. Net primary productivity provides the basis for maintenance, growth, and reproduction of all consumers and decomposes (Venetoulis and Talberth, 2008). Because of this, NPP is also referred to as a measure of the ‘‘total food resource’’ available on the planet 65
