Earth System interactions: enhancing capabilities for the prediction of global, regional and local climate change - a. Nordic window of opportunity. A white paper ...
Earth System interactions: enhancing capabilities for the prediction of global, regional and local climate change - a Nordic window of opportunity A white paper on a proposed Nordic network in Climate and Earth System Modelling Co-ordinating authors Jens Hesselbjerg Christensen1, Trond Iversen2,8, Colin Jones3, Heikki Järvinen4 and Markku Rummukainen3,23 Contributing authors Andreas Ahlstrøm5, Bjørn Ådlandsvik6, Lars Bärring3,23, Claus Beier7, Terje Berntsen8, Halldór Björnsson9, Jørgen Brandt10, Deliang Chen11, Helge Drange12,17, Karin Edelvang13, Eirik Førland2, Hans-Christen Hansson14, Christoph Heinze15, Kim Holmén16, Øystein Hov2, Eystein Jansen17, Tómas Jóhanneson9, Eigil Kaas18, Erland Källén19, Leif Klemedtsson11, Jon Egill Kristjansson8, Nils Gunnar Kvamstø15, William Lahoz20, Ari Laaksonen4, Joakim Langner3, Gerrit de Leeuw4,21, Kari Lehtinen4,22, Anders Lindroth23, Jørgen E. Olesen24, Haraldur Olafsson9, Anders Omstedt11, Jens Christian Refsgaard5, Anna Rutgersson25, Ben Smith23, Árni Snorrason26, Anders Stigebrandt11, Johan.Strömqvist3, Andreas Stohl20, Frode Stordal8, Gunilla Svensson19, Michael Tjernström19, Peter Tunved14 1
Danish Climate Centre, Danish Meteorological Institute Norwegian Meteorological Institute 3 Swedish Meteorological and Hydrological Institute 4 Finnish Meteorological Institute 5 Geological Survey of Denmark and Greenland 6 Institute for Marine Research, Norway 7 RISØ, Technical University of Denmark 8 Department of Geosciences, University of Oslo, Norway 9 Icelandic Meteorological Office 10 National Environmental Research Institute, University of Aarhus, Denmark 11 Tellus, University of Gothenburg, Sweden 12 Nansen Environmental and Remote Sensing Centre, Norway 13 DHI, Denmark 14 Department of Applied Environmental Science, Stockholm University, Sweden 15 Department of Geophysics, University of Bergen, Norway 16 Norwegian Polar Research Institute 17 Bjerknes Centre for Climate Research, Norway 18 Niels Bohr Institute, University of Copenhagen, Denmark 19 Department of Meteorology, Stockholm University, Sweden 20 Norwegian Institute for Air Research 21 Department of Physics, University of Helsinki 22 Department of Physics, University of Kuopio 23 Department of Physical Geography and Ecosystems Analysis, University of Lund, Sweden 24 Faculty of Agricultural Sciences, University of Aarhus, Denmark 25 Department of Meteorology, University of Uppsala 26 National Energy Authority, Iceland 2
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Vision Collectively, Nordic research is in a position to extend the frontiers of climate research, towards a new generation of models that will allow climate prediction with unprecedented spatial detail and process accuracy. This will enable both policy-makers and stakeholders to better use emerging scientific findings for mitigation and adaptation strategies, to tackle environmental risks likely to dominate the political agenda in the 21st Century and beyond.
Primary research goals To achieve a balanced mitigation and adaptation to climate change, there remains an urgent need to narrow down uncertainties that are central to assessing future impacts of climate and environmental change. In particular, it is presently not possible to set an accurate upper bound on the climate response to increasing greenhouse gas emissions1. This uncertainty arises from a poor understanding of and ability to model key cloud feedback processes and aerosol-cloud interactions, as well as deep ocean water formation and its role in the global ocean thermohaline circulation. Earth System feedbacks that are presently represented only in a rudimentary manner in climate models, may also add significantly to this uncertainty. We are ready to attack such key research challenges, for which the collective Nordic research community holds world class excellence. In particular our efforts will be targeted at: • • •
an advanced modelling platform emphasizing major Earth System components for assessing multi-decadal and century-long climate change and associated risks; projections of regional to local climate with unprecedented spatial detail. enabling systematic research on the impacts and implied consequences for infrastructure and physical planning of future changes to: the hydrological cycle, the cryosphere, a range of biogeochemical cycles, sea level and extreme weather events.
Strategic mission A broad and committed large-scale collaboration will enable Nordic researchers to both develop and utilize a shared set of world-leading climate modelling tools, for use in policyrelevant climate prediction and impact assessment. It will further support training of the next generation of Nordic interdisciplinary environmental scientists. Our mission is thus to: • • • • •
accelerate and expand Nordic research efforts in climate change, along with strong linkages to climate change impact assessments and strategies for adaptation; organize an interdisciplinary Nordic science network, dealing in particular, with specific Arctic and Nordic climate research issues while also making a major contribution to international research; couple the Nordic research communities (climate modelling, climate observations, climate impacts, and adaptation) with planners and local managers at international, Nordic, national and municipality levels; provide relevant guidance for managers and policy makers dealing with adaptation (regional and local climate change) and with mitigation (global long-term change); drive advanced education and training on Earth System Science and Global Change, leading to a new generation of interdisciplinary Nordic Earth System Scientists.
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For example, the IPCC AR4 report states that it is very unlikely (67% chance) that it is smaller than 4.5oC. There is a considerable risk (>10% chance) that the value is above 6oC. The value of the climate sensitivity has direct consequences for mitigation efforts and urgency. To limit global warming in some given way, such as the 2°C limit adopted by the European Union, a larger climate sensitivity will imply smaller allowable accumulated emissions.
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Summary This document motivates a strengthened Nordic collaboration, that can develop the next generation of Earth System Models (ESM) for climate prediction that: (i) are reliable; (ii) encompass the key climate processes pertaining to the Nordic and Arctic regions; (iii) include an improved description of processes that are presently considered to be highly uncertain; (iv) are computationally efficient; (v) possess advanced diagnostic tools for a detailed evaluation of model components; and (vi) provide better regional and local information to impact assessments, policy-makers and society at large. Global Earth System Modelling is highly complex and computationally intensive, requiring a broad multidisciplinary approach. Presently, modelling groups in the Nordic countries are integrally involved in a number of international consortia developing Global ESMs, and are thus at the forefront of this field. Through collaboration in these large consortia the enormous resources of the international community are made available for the benefit of predicting climate change over the Nordic region. To best utilize these efforts requires closer collaboration between the relevant Nordic groups, with improved exchange of knowledge, models and simulation results. Why and how this can be done is the essence of this document. In the Nordic and Arctic regions there are numerous specific processes that are likely to provide strong feedbacks to external climate forcing, both local to the region but also remotely, with clear consequences for future climate evolution. Some of these processes are among the most poorly described components of present-day climate models. To better understand, model and evaluate such processes, requires a means of bringing the complexity of Global ESM approach down to the Nordic-Arctic regional scale. Integration of a broader range of natural processes into a unified Earth System Model will enable quantitative assessments of a wider range of environmental impacts of climate change. Representing processes with higher resolution will also reduce important uncertainties in climate change projections. To achieve this necessary progress on both complexity and resolution, we propose a strengthened collaboration between Nordic groups that already possess a high level of expertise in understanding the relevant processes, assessing observations, and modelling the climate from global to local scales. The Nordic community has a very high standing in the international Regional Climate Modelling community, having some of the most advanced Regional Climate Models (RCMs) in the world. Global ESMs need to be complemented by regional and local climate prediction techniques, in order to support localized assessment of the impacts of climate change. We thus plan to bring together the entire Nordic community engaged in Earth System Modelling, as well as data and impact studies, to develop a joint Nordic-Arctic Regional System Model, applicable at high resolution (1-5km) with specific emphasis on key Nordic-Arctic processes. To significantly expand the frontiers of Nordic Earth System Modelling, along with impact and adaptation research, is an ambitious effort. The key to a successful collaboration is resources, both in terms of highly-qualified personnel and computational facilities. This effort must encompass all the intellectual capacity in the Nordic countries. Furthermore, such an effort will require increased computational capacity, advanced model development, training of new scientists, as well as outreach and policy contacts. To achieve a major advance in each of these areas requires a significant and long-term investment, in parity with recent Nordic Centres of Excellence; i.e. ~300-400 MDKK over a 5-year period, with a similar level of funding for a subsequent 5-year period, once significant progress has been demonstrated. The time is right for such an initiative, which will enable us to attack some of the major challenges of climate change with an adequate research effort, to support the development of mitigation and adaptation strategies with suitable efficiency and urgency. 3(14)
The way forward The challenges and opportunities to radically advance Nordic climate research efforts touch particularly upon Earth System modelling and high-resolution climate prediction, with strong links to impact assessment, outreach and policy support. Advances in Earth System Science will lead to improved support for Nordic efforts on the development of suitable adaptation and mitigation strategies, as well as on climate politics and international collaboration. Compared to physical climate models, Earth System Models (ESMs) include explicit descriptions of a far greater number of natural processes, supporting a much wider range of impact assessment studies than traditional climate models. Significantly increased model resolution, both globally and regionally over the Nordic-Arctic region, will also contribute greatly to an improved ability to simulate key physical climate processes, as well as extreme weather events. To make significant progress in Earth System Modelling that will lead to tangible improvements in the reliability of climate projections over the Nordic-Arctic region, requires a revolution in the Nordic Earth System Sciences. The complexity of ESMs urgently calls for increased collaboration with a multi-disciplinary approach, bringing together the climate modelling community, observationalists and process modellers. It is critical that a continuous level of interaction and intellectual exchange occurs between physical climate modellers, terrestrial and ocean ecosystem modellers and computer scientists, as well as experts in the fields of biogeochemistry, hydrology, glaciology, sea-ice and permafrost. At the Nordic level, most of these individual elements already exist, but without an overly strong representation in any single country and little organized collaboration. With respect to developing a high-resolution, Nordic-Arctic Regional System Model, the Nordic science community must organize itself to address this challenge, both as a contribution to international efforts to address global change, but also to provide reliable estimates of future climate over the Nordic-Arctic region. Such a task can only be addressed by the Nordic Earth Sciences community, who possess the local process and modelling knowledge along with the observation base necessary to make progress in this endeavour. To achieve such a revolution requires a significant increase in, and coordination of funding. A Nordic programme must be ambitious enough to bring together a critical mass of intellectual diversity to collectively advance Nordic Earth System Science and training, while retaining the necessary public and policy relevance. The way forward that we would like to explore, is to initiate discussions over the coming months, with Nordic and national research councils, government authorities and universities, regarding the need for an organized and coordinated effort in Earth System Modelling involving all relevant scientists and stakeholders across the Nordic region. We wish to emphasize that the Nordic climate research community is keen to develop a joint effort to provide a significant climate science contribution both for the Nordic and Arctic regions. Furthermore, we emphasize that the Nordic Earth System Modelling and Global Change community, through such a proposed consortium, will be better placed to provide reliable and policy-relevant information on future climate and environmental change, at unprecedented spatial scales from local to global arenas. This will increase our ability to interact with and support Nordic and international efforts in climate impact assessment, adaptation and mitigation. The remainder of this paper motivates in more detail the need for a new Nordic Network in Earth System Modelling. It further describes the science foci for such a network, the likely partners and an initial estimate of the personnel and infrastructure costs of such a network. 4(14)
Introduction Climate change is the environmental and socio-economic grand challenge of our and future generations. The results of climate models make a large impact on society, as witnessed by the power of the latest IPCC Assessment on the public and political agenda. Despite recent advances there is a growing recognition that much research and development is still required. This has multiple dimensions. One is that important aspects of the climate system are missing or represented only in a rudimentary manner in contemporary models. This fundamentally limits our ability to narrow down uncertainties related to anthropogenic climate change, particularly with respect to setting a reliable upper limit to the sensitivity of the climate system to increased greenhouse gas forcing. Another dimension is the gap between demand and provision of relevant information on regional and local climate for use in developing sustainable adaptation strategies. Climate modelling is the backbone of climate prediction efforts. Climate models to date describe the physical and dynamical components of the coupled climate system, with detailed descriptions of the atmosphere, ocean, snow/sea-ice and land surface. Over the past two decades climate models have improved enormously, both in their ability to represent climate processes and in computational efficiency. Nevertheless, there are still many approximations in the representation of key processes in these models. Many of these approximations are associated with the cycling of water in the climate system, in particular (1) cloud feedbacks; (2) aerosol-cloud interactions; (3) feedbacks related to ice and snow. The water cycle is also central to a wide range of anticipated impacts of climate change. In addition, there are a range of important biogeochemical processes, which are presently represented only in a rudimentary manner. It is now recognized that a more complete description of the cycling of key gases and nutrients in the Earth System, along with a better treatment of the complete water cycle, is required to improve our ability to simulate future climate and environmental conditions. As an example, inclusion of a fully interactive carbon cycle, including sources, sinks and exchange processes between the oceans, terrestrial biosphere and atmosphere is required to achieve a reliable estimate of future concentrations of atmospheric carbon dioxide. Similar requirements hold for other radiatively active gases such as methane, ozone and nitrous oxide. To achieve an accurate representation of such biogeochemical cycles requires both an improvement in the accuracy of the simulated physical climate in models, along with inclusion of key biogeochemical processes. This leads to the development of Global Earth System Models (ESMs) from what were formerly (physical) Global Climate Models (GCMs). This effort has begun within a number of large international consortia, to which Nordic countries actively contribute. It is, however, necessary to consider a trade-off between the need for extended process complexity with respect to biogeochemical processes in ESMs and the need for better spatial resolution in the description of key climate processes. Not least clouds and cloud dynamics, as well as mixing processes in the oceans, all of which are heavily parameterized due to the small spatial scales involved. As a consequence, there are at least two categories of sustained global climate model simulation; high-resolution (10-100km) climate predictions with some basic ESM complexity, and lower-resolution (200-300km) Earth System simulations with increased complexity. On regional and local scales, changes in the statistics of extreme weather events, associated risks, and their impact on society remain to be quantified. The present low level of understanding on regional and especially local scales, is in part due to lack of sufficient computational resources to support high-resolution modelling of sufficient complexity. Observational and theoretical process studies are also required to advance our understanding
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and thereby support advanced model development. To provide climate information of direct relevance to governments, society and business, global simulations or predictions need to be transposed to regional and local scales. The most comprehensive mechanism for this is by means of a Regional Climate Model (RCM) embedded within a Global Climate Model. Concurrent with the need to address the Earth System on the global scale, there also exists the need to develop the capability to perform high-resolution regional earth system modelling. This is also the case in the Nordic countries, with specific reference to key Nordic and Arctic processes. In summary, there is an urgent need to develop a Regional System Model, which combines both high-resolution (1-5km), with an advanced description of the key processes influencing the response of the Nordic-Arctic climate and environmental systems to global change. An important link between results from climate and Earth System models and the design and development of strategies for adaptation and mitigation, is impact assessment. Developing well targeted societal adaptation strategies requires knowledge of the nature of physical impacts and ecosystem responses, with higher spatial detail than present global climate models can provide. In order to motivate meeting the financial costs of mitigation, it is also necessary to emphasize the benefits of reducing the impacts of climate change. Climate research in the Nordic countries has been, and continues to be, heavily focused on providing input to impact and adaptation studies. Our proposal to develop and utilize the most advanced Global and Regional Earth System Models will greatly increase the quality, breadth and spatial detail of climate change information that will be available to the Nordic impact and adaptation community. Higher resolution models will bring the simulated information much closer to the spatial scales of concern to this community, while the increased breadth of Earth System processes included in future models will open a wider possibility to study the integrated impacts of climate change, across a range of coupled environmental sectors. The members of this proposed consortium, both on a personal and institutional level, already have a wide and established network of collaborations within the Nordic impact and adaptation community. We plan to increase this collaboration network substantially around the provision of high-resolution earth system information and look forward to an intense collaboration with parallel initiatives within the Nordic impacts research community.
Why Nordic Earth System modelling? The carbon cycle is a very important component of climate change. The changing buffering capacity of the ocean and the biosphere for CO2 in a warming world is an issue of fundamental importance with respect to the development of effective mitigation strategies. Release of methane in thawing permafrost is another such issue. Ocean acidification due to an increasing concentration of CO2 within the ocean, along with the response of the nitrogen cycle, both on land and in the oceans, are all factors that may have a large impact on the future evolution of the Earth System in relation to climate change. From a Nordic perspective, deep water formation in the North Atlantic and its role in oceanic carbon buffering, as well as the role of boreal forests in both the regional and global earth system are issues requiring increased attention. The role of land-based vegetation further links to nitrogen cycling and fertilization, the water cycle, as well as the carbon cycle. The nitrogen cycle also links to tropospheric ozone and thus the overall climate forcing. With increasing summer droughts, high levels of ozone may add nonlinearly to the negative effects of depleted soil water on vegetation. There are further links to aerosols and their duality with respect to climate and health/environment effects. Uncertainties with respect to the role of changing atmospheric aerosol loading, particularly its interaction with cloud microphysical processes are presently
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the largest single source of uncertainty in global warming projections for the 21st Century. Furthermore, the reduction of global aerosol loading over the past 20 years is recognized to have the potential to speed up the global warming trend associated with increasing CO2 concentrations. Of special interest for the Arctic is that, so-called short-lived pollutants (mainly black carbon and ozone) and methane, through various feedback mechanisms may influence the Arctic climate proportionally more than was originally envisaged. This has resulted in policy discussions to curb the emissions of key species in northern regions. The present level of understanding of the relevant Arctic-specific processes is, however, insufficient for a reliable quantification of the benefits of emission reductions Up to now, many of these aspects of the Earth System have been studied in isolation. This has suppressed the ability to understand potential links and feedbacks across all components of the full Earth System and a reduced ability to fully sample all potential feedbacks in the system. An increased Earth System Modelling capability is absolutely necessary to proceed beyond this rudimentary state of knowledge, thereby increasing the reliability of future climate simulations. The extreme complexity of Earth System Models needed to address this range of issues, requires a well organized Nordic collaboration, particularly to develop a Regional Nordic-Arctic System Model, but also to make a strong contribution to larger international efforts. State-of-the-art: Nordic regional climate models Past Nordic climate modelling research has had a strong focus on regionalization of global climate change projections. The aim has been to support studies on impacts of climate change and, increasingly, on adaptation. These activities started out at the Danish Meteorological Institute around 1995, in the SWECLIM programme in Sweden (presently at the Rossby Centre, SMHI) and in the RegClim programme in Norway (presently NorClim), around 199798. Activities in Finland and Iceland are also well established, and focus on various impacts and key climate processes. Throughout these activities, there has been extensive international collaboration. Initially Nordic RCMs were predominantly atmospheric models coupled to land surface models with rudimentary vegetation. The Danish activities at DMI have been based on the HIRHAM RCM, in co-operation with the Max-Planck-Institute in Germany. At met.no, the same model was set up for Norway and coupled to a regional ocean model. The Rossby Centre model RCA at SMHI has been developed from the operational HIRLAM weather prediction model. The RCA is today extended with an interactive module for the Baltic Sea and being complemented with interactive vegetation. The Nordic RCMs are also being applied over a number of other regions of the world, such as the Arctic, where fully coupled Arctic Regional climate scenarios are now being produced. The Nordic RCMs are, in terms of quality and complexity, among the very best in the world. State-of-the-art: Nordic global modelling activities A sub-Arctic position, with the North Atlantic Ocean to the west and the Arctic Ocean to the north, has always been important for framing Nordic climate modelling activities and warranted the development of global modelling capabilities. Initially, DMI co-operated with and used the ECHAM models developed at the Max-Planck-Institute for Meteorology. In Norway there was a strong focus on issues with potentially strong relevance to the region, such as the Atlantic Ocean meridional overturning circulation (AMOC) and aerosol-cloud interactions. At the Bjerknes Centre for Climate Research, the Bergen Climate Model (BCM)
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delivered a full contribution to the IPCC AR4. In parallel, aerosols and clouds were included in a dedicated version of the NCAR climate model (CAM-Oslo), a version of which (CCSM3) is also used at the Rossby Centre of the SMHI, at MISU, the University of Stockholm and at Tellus, University of Gothenburg. At present, Nordic groups contribute to three major international ESM consortia; A common Norwegian global climate model/ESM is under development at the national level in the NorClim project, with strong links to the development of the CCSM model at NCAR in the United States. Sweden and Denmark are partners within the EC-Earth project, a multinational European initiative to develop a coupled prediction system from the ECMWF forecast model, spanning weather prediction to centennial climate timescales. In Finland, activities are linked to the COSMOS ESM activity, coordinated by the MPI for Meteorology in Germany. Why a common Nordic ESM activity? The main reason for proposing a common Nordic ESM activity is the existence of a large, but distributed pool of high-level competence within a range of ESM fields. Nordic countries are integrally involved in three major international consortia developing Global Earth System Models. This facilitates Nordic access to a pool of international expertise at the forefront of efforts to develop Earth System Models. However, only the forging of a much closer interaction between the involved Nordic groups can fully bring the resources available in these consortia to the concentrated benefit of climate prediction for the Nordic and Arctic region. Furthermore, the development of a high-resolution, Nordic-Arctic Regional System Model will only be addressed by the Nordic science community. This effort requires a large degree of coordination across all the potentially contributing institutes. Present activities in the Nordic countries will be considerably strengthened by better sharing and coordination of knowledge, models and simulation results. This will lead to a critical mass being achieved in several of the major scientific and technical areas at the forefront of Earth System science and applications. It will further benefit Nordic research if there is a shared computational infrastructure, software and computer expertise, data management facilities as well as outreach and training activities. A number of these Nordic partners have been, and are, involved in past and present European efforts to homogenize and better organize climate modelling activities across Europe (e.g. the ENES and PRISM initiatives being 2 examples). Developing a closer collaboration between all Nordic ESM groups will lead to a stronger and more coordinated Nordic contribution to European and international efforts aimed at improving our ability to model the Earth System and its response to greenhouse gas emissions and land-use change.
The main elements of the common Nordic activity Four elements are necessary for a sustained Nordic Earth System Science initiative: first, a computational platform with sufficient capacity to support the most advanced Earth System Models in the world; second, a strong network among all Nordic Earth System scientists; third, a strong university involvement to train the next generation of Earth System Scientists and, fourth, an outreach and information activity to support knowledge transfer and decision making in the Nordic countries.
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A common Nordic Computational Infrastructure To advance Nordic competence in Earth System Science requires a computational platform with world-class capacity and capability. A common resource will promote networking and coordinated production of climate projections for both national and Nordic-Arctic needs. Technical arguments support a joint climate computing platform: to avoid inadequate and costly data transfer links, to facilitate code sharing and to provide efficiency at a reduced cost. A common infrastructure also enables support and incorporation of a wide range of Nordic university groups, allowing students to receive training on the most advanced modelling systems. The new capacity should be sufficient for an advancement of computational climate modelling in areas such as; increased resolution, new ESM components, increased simulation length, and ensemble simulations. This calls for a computational resource of the order of several 100 teraflops of sustained computing power and a data storage capacity in the petabyte range2. The Human network (A Nordic Earth System Science community) It is necessary to establish a true Nordic Earth System Science community. Currently, some Nordic collaboration exists, but it is almost in parity with the very small common resources available. Our common culture, established mobility of scientists within the region and networks funded by the Nordic Council of Ministers do add activity beyond the level of core national funding. Nevertheless, far more extensive contacts and networks exist today within the European and US communities than within the Nordic countries. A regional network of Earth System Modelling efforts would, in particular, support a wide variety of Nordic and Arctic specific impact and adaptation research in related disciplines, including social, economic and political sciences. Outreach and training Basic and applied research efforts are the foundation for decision-making and planning for climate change. However, the science has to get across to the users, and the user needs to research, only then will research efforts directly benefit society and relevance to users and stakeholders be truly ensured. Building on existing expertise within the Nordic countries in communicating climate change results to the public, government and a range of stakeholders, we envisage a major outreach component on dissemination and communication. Training is an integral part of our envisioned collaboration. The Nordic community must raise the next generation of researchers, capable of addressing future challenges in Earth System Science. This requires a strong university involvement, along with a willingness of the main government agencies to be involved in training students in the use and development of advanced Earth System Models. Training also needs to involve users and stakeholders so as to inform them of both the benefits and limitations of Earth System Models within their own fields of concern.
2
Teraflops = one trillion or 1×1012 FLoating point Operations Per Second, which is a measure of a computer’s performance. Petabyte= one quadrillion or 1×1015 bytes, a unit of data such as stored in a climate model simulation. Both of these measures are an order of magnitude or more beyond present Nordic climate modelling facilities,
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A joint Earth System Modelling strategy Global Modelling Strategy We propose that Nordic efforts in Global Earth System Modelling, that benefit from and contribute to wider international collaborations, are collected around a coordinated common agenda. This will facilitate better use of key expertise and an increased focus on questions pertinent to the Nordic-Arctic region. Earth System Models are highly complex and involve interacting processes that are still only on the edge of being fully understood. More than ever, it is imperative for the scientific community to join forces to make progress in this challenging arena. This involves the need to have a variety of global modelling systems, as there is no single best way of representing the inherently non-linear and complex global climate system in a single approach. Using a variety of high-quality global models will provide an estimate of the uncertainty range inherent in predicting future climate, facilitating a probabilistic approach to the question of future risks. A coordinated Nordic ESM network will allow easy exchange amongst partners of climate change simulations from 3 of the world’s leading global ESMs. Furthermore, in a less complex setting, the same models can be set up with significantly higher resolution emphasizing physical climate system processes. In particular, a range of phenomena related to the water cycle (aerosol-cloud interactions, cloud feedbacks, ice and snow feedbacks, and freshwater forcing of the global thermohaline ocean circulation), all of which impact on climate predictability on decadal and longer timescales, will benefit from such an approach. Processes in the middle atmosphere, such as climate impacts of ozone recovery and increased stratospheric water vapour, are also important in this connection. This approach is needed along with that of the complex ESM in order to reduce the considerable uncertainties in estimating climate sensitivities, both on decadal and longer timescales. Regional and Local Modelling Strategy We propose that the entire Nordic community engaged in Earth System Modelling, process understanding and evaluation, jointly develops a common Nordic Regional System Model. This model will build on the considerable expertise already available in the Nordic countries and will be specifically developed for application at very high-resolution (1-5 km spatial resolution), emphasising the key processes in the Nordic-Arctic region. Combined with the spectrum of Global ESMs which the Nordic community is actively engaged in, a highresolution Nordic-Arctic Regional System Model will offer an unprecedented level of detailed, high-resolution estimates of future climate and environmental conditions over the Nordic-Arctic region. Such a Regional System Model will fully engage the wide spectrum of government and university researchers engaged in modelling, observational and theoretical studies related to Earth System Science around a single common platform, putting the Nordic countries at the forefront of Earth System Science. Furthermore, such a modelling system will attract highly-qualified scientists from other countries to the Nordic region to work on Earth System Modelling and will constitute a community modelling system, through which the next generation of Earth System scientists can be trained. Science foci Some of the open questions with respect to understanding the future evolution of the climate system are simply not possible to answer with present day capabilities. To accelerate progress requires a major leap in research efforts. We identify the following focus areas for Nordic
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ESM research and development, chosen so that they are of particular importance to the Nordic and Arctic regions, as well as being highly policy relevant: •
Aerosols and their interaction with radiation and the freshwater cycle, with a particular emphasis on aerosol-cloud-radiation interactions;
•
Processes in the ocean bodies surrounding the Nordic region. In particular, the North Atlantic and Arctic Ocean, Norwegian and Greenland Seas, the Barents Sea and the Baltic Sea, including sea-ice, terrestrial freshwater inputs and biogeochemical/water quality issues;
•
Land-use and land-use change with emphasis on the Baltic Sea region, Arctic and subArctic including snow, permafrost, wetlands and boreal forests;
•
The carbon cycle with interactive vegetation and ocean biogeochemistry, along with associated biogeochemical cycles that strongly interact with, and influence, the carbon cycle;
•
High-impact weather events, particularly those related to strong wind and intense precipitation;
•
Boundary layer processes, including interactions with boundary layer clouds, large scale dynamics and surface exchange processes, with a particular emphasis on stably stratified conditions.
•
Advanced evaluation of model processes through data assimilation, regional water cycle budgets, lagrangian transport assessment, in situ and remote sensing data.
Data Accessibility An important aspect of a Nordic collaboration is more efficient access to both observational and modelling data. This bears on detection and attribution efforts, model evaluation and development, assessing uncertainties and transposing scientific results into relevant information for users. In order for this to become efficient, common data policies, data management and handling are crucial. One priority is to establish an inventory of available model and observational data, and ease access to these. Defining needs for additional data, and strategies to meeting these needs is an integral part of the proposed network. An open consortium Advantages of working together in an interdisciplinary environment can become undermined if too strong regulations are enforced on the consortium. Collaboration that builds on mutual reliance and confidence enables the participants to jointly profit from links with collaborators also outside the core Nordic effort. It is important to see this collaboration as an addition to a wider Nordic strategy in Earth System modelling, rather than an obstacle to present progress. We envisage that the network will consist of a number of core centres from each country, interacting closely around the development of a common set of modelling tools. On a national level, the core centres will collaborate with their respective networks of Earth System Science groups. Direct collaboration between Nordic expert groups in a given Earth System Science discipline will be strongly encouraged, although it will be important to ensure that results emanating from these multifarious links feed back into the common Nordic modelling system for the benefit of all participating groups.
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Foreseen resources Substantial new funding is envisaged for a Nordic-Arctic Climate Change and Earth System Modelling network. For the required computational capacity, outlined above, an investment of the order of 100120 MDKK is necessary. Furthermore, to maintain such a capacity at the forefront of international facilities requires an investment of similar magnitude roughly every 5 years. This level of investment will clearly be conditional upon a detailed international peer-review process. Such a facility also requires funds for general operations and maintenance, along with technical and application support. In order to establish a research community requires that all partners are truly engaged in establishing and maintaining such a network. In addition to a shared vision, this translates into dedicated resources, including qualified personnel. We envisage, as a minimum, support for 20-25 full-time postdoctoral or research scientist level positions, located at the main modelling centres. These scientists would each work on the dedicated common Nordic ESM agenda. An overall project leader will also require support from a full time project coordinator, to handle day-to-day management and coordination issues. Furthermore, a fulltime position managing network outreach and information dissemination is seen as crucial. Along with model development and application efforts, a parallel training track is needed. Full benefit from an interdisciplinary network will only be achieved once an educational programme is an integral part of the network. We envisage a PhD programme with around 3040 PhD projects, run by university partners, with tight links to the main modelling centres. In summary, the staff to be involved would be around 20-25 postdoctoral or research scientist level positions, 30-40 PhD students, 4-5 technical staff, one Project Manager and one Information Officer. This would be equivalent to approximately ~45 MDKK per year. Some of the partners’ senior staff commitments need also to be covered, although sizeable in kind contributions can be foreseen. Outreach activities will include regular stakeholder meetings to discuss results and research agendas; Policy briefings; Scientific meetings and workshops with public access; Maintaining a critical dialogue with media and experts; Development of TV documentaries as well as debates. Such outreach activities would require additional funding of ~2 MDKK per year. A suggested overall programme cost (in MDKK) for a five-year period. 2009
2010
2011
2012
2013
Total
Computing facility, incl electricity etc and technical staff
85
45
5
5
5
145
Senior staff (excl in kind contributions)
10
10
10
10
10
50
Postdocs/Research Scientists (science)
20
20
20
20
20
100
PhD students (training and science)
15
15
15
15
15
75
Programme administration and common activities
2
2
2
2
2
10
Outreach, including Information Officer
3
3
3
3
3
15
Total
135
95
55
55
55
395
In order to establish a common platform with a broad shared Nordic knowledge base, a minimal time frame for the project to be realised is 10 years: an initial 5 years with a further 5 years based on a successful mid-term review of network activities. 12(14)
The partners in Earth System Science Denmark In Denmark climate and Earth System modelling using comprehensive computationally demanding models, is mainly taking place at the Danish Climate Centre at DMI. Here developing, maintaining and utilising global and regional models have been central for more than a decade. The centre now contributes to global ESM efforts through the EC-Earth consortium (e.g. technical development, coupling, atmosphere, stratosphere, ocean, and terrestrial cryospheric modelling development). University partners with Earth System modelling activities include different institutes at the Copenhagen University (global modelling, hydrology, ice sheets, terrestrial cryosphere), the National Environmental Research Institute (NERI) at Aarhus University (ocean and atmospheric modelling, soot and other aerosols, Arctic boundary layers and chemistry), DHI (urban water resources, hydrology, lakes, streams and estuaries plus shallow waters around Denmark). Faculty of Agricultural Sciences at the University of Aarhus also has relevant activities on agricultural system modelling. The Geological Survey of Denmark and Greenland (GEUS) is a formal partner with DMI on aspects of climate research on the development of the Greenland Ice Sheet, but strong collaboration on linkages between climate and hydrological modelling and climate impact assessments on water resources are also evident. Activities towards a better understanding of the terrestrial carbon cycle and climate feedbacks are strongholds at RISØ/Technical University of Denmark and represent a collaborative link with DMI. Finland Earth system modelling activities are coordinated by the Finnish Meteorological Institute (FMI) as a major contribution to the COSMOS ESM network, led by the Max Planck Institute for Meteorology, Germany. In Finland, Earth system modelling builds on dedicated in-situ observations of key climate variables and expertise on related climate processes. Observational stations, such as Pallas-Sodankylä and Hyytiälä, are operated by Universities of Helsinki and Kuopio, FMI and Finnish Environmental Institute. Scientists from these institutes form a collaborating core group for Finnish Earth system modelling. In Finland, there is special expertise on atmospheric aerosols, clouds and radiative transfer, terrestrial biosphere and soil processes, and on computational aspects of coupled systems (especially at the Centre for Scientific Computing). Iceland In Iceland, Earth System Modelling and research is mainly carried out in close collaboration between the University of Iceland, the Icelandic Meteorological Office and the Institute for Meteorological Research. There is an ongoing collaboration on hydrological and glaciological aspects with the Hydrological Service and on agriculture with the Agricultural University and the National Forest Service. Ocean research is hosted at the Marine Research Institute and to some extent also at the Icelandic Meteorological Office and the University of Iceland. The Iceland group has concentrated on processes on regional to local scale, including dynamic downscaling and modelling at high resolutions. In Iceland, there is special expertise on processes related to mountains, including high-resolution temporal and spatial variability in weather and climate, glaciers and hydrological processes. There is also ongoing research in atmosphere-ocean interactions and their impact for the climate and the ocean at regional scales.
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Norway Climate modelling in Norway is mainly organized in a virtual centre: The Norwegian Climate Centre, which involves The Bjerknes Centre for Climate Research, Norwegian Meteorological Institute, Institute for Marine Research, Norwegian Polar Institute, Dep. of Geosciences at University of Oslo, Cicero – Centre for Climate Research, the Nansen Environmental and Remote Sensing Centre and the Geophysics Institute at the University of Bergen. In this virtual centre a global climate model / ESM is presently being developed. Activities at Norwegian Institute for Air Research (NILU) are relevant, as well as international co-operation (e.g. National Center for Atmospheric Research in USA). Foci are on the fresh water cycle, aerosols and clouds, atmospheric chemistry, sea-ice, snow and cryospheric processes, deep ocean circulation and carbon cycling, land-surface modelling and biogeochemistry. Middle and upper atmospheric processes are studied off-line. Regional climate modelling involves global time-slices, regional dynamical downscaling, empirical downscaling, and statistical adjustments to local features. Model diagnostics include land data assimilation for evaluating land surface parameters, use of water tracers in regional climate models, Lagrangian modelling, and remote sensing and in-situ observation of meteorological variables, cloud characteristics, aerosols, and atmospheric trace gases. Sweden The central Swedish climate modelling partner is the Rossby Centre at SMHI, excelling in coupled regional climate modelling (e.g. coupling strategies, high resolution modelling, land surface and terrestrial biosphere processes, sea ice, ocean biogeochemistry, clouds/radiation) and also contributing to global ESM efforts through the EC-Earth consortium (e.g. technical development, modular coupling, sea ice modelling, cloud/radiation parameterization and decadal predictability studies). University partners with Earth System modelling activities include Lund University (ecosystems, vegetation, land-use change, biogenic aerosols), Stockholm University (ocean modelling, sulphate, soot and aerosol modelling and observations, atmospheric boundary layer modelling and observations and atmospheric chemistry), the University of Gothenburg (terrestrial biospheric process modelling and observations, ocean modelling, process evaluation of biogeochemical cycling and statistical downscaling) and Uppsala University (waves and marine boundary layer, high resolution modelling). The Swedish Agricultural University also has relevant activities on soil, carbon and forest system modelling.
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