Climate Change and Its Impact on Food and Nutrition ...

Part III Simopoulos AP (ed): Healthy Agriculture, Healthy Nutrition, Healthy People. World Rev Nutr Diet. Basel, Karger, 2011, vol 102, pp 175–182

Climate Change and Its Impact on Food and Nutrition Security and Food Safety in China Duo Lia,b ⭈ Kok-Seong Yapa,b of Food Science and Nutritionand bIAES, Zhejiang University, Hangzhou, China

In order to build a more comfortable and better life, humankind has and will continue to damage the environment to an almost irreversible state. Pollution, excessive resource consumption and deliberate environmental damage are just a few of the means by which the human race are upsetting the environmental state and influencing the climate system. Earth is approaching the critical point, causing the global environment to reach a dangerous situation which we have never seen before [1]. The ecosystem is a basic fundamental for human life and society sustainable development. Food, environment and human health is tightly connected as a micro-ecosystem, which are mutually dependent and influential, and can be vulnerable, ineffective and degraded. The ecosystem should be automatically adapted and self-aligning if it was interfered with within the threshold value. Unfortunately, anthropogenic interference to obtain what they need leads to a bad ecosystem state, which could be irreversible if transgressed, leading to a state less conducive to human development. Industrialization, deforestation and excessive population have caused a big change in global climate. The three main hypotheses of climate

change include global warming, global cooling and climatic periodicity. However, global warming has been recognized as the climate change factor most influenced by human activity. CO2 concentration enrichment caused by anthropogenic activities is the main contributor of climate change, and brings a range of phenomena such as elevated temperature, change in the distribution and regime of precipitation, sea acidification and so forth. It does not only influence live stock and aquaculture, but also agriculture which is most sensitive to the changes in natural conditions. Finally, the system that we rely on is complex as it is influenced by feedback, indirect effects and nonlinear factors [2]. More in-depth investigations are needed to comprehensively analyze these challenges we face as we step into an unpredictable future.

Climate Change in China

The scientific research data show that the global average atmospheric temperature increased by 0.74°C over the past century, it is expected that this will continue to rise by 1.1–6.4°C in the 21st century [3, 4]. Scientists have been conscious of

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the sea level may continue to rise. Therefore, special attention should be paid to climate change causing challenges in food supply in China.

Effect of Climate Change on Food and Nutrition Security and Food Safety

After development of industrialization, global warming has become an ongoing and increasingly important issue for China and the rest of the world. Data from the World Data Center for Greenhouse Gases (WDCGG) showed that the highest concentration of CO2 measured was 390 ppm during 1994–2008 in China [11]. CO2 enrichment has caused a range of adverse effects, such as increased temperature, precipitation regimes anomalies, ocean acidification and so forth [11], which has negatively influenced food supply in China. Unfortunately, there is no data available on the effect of climate changes on nutritional composition of foods in China. Agriculture China is the largest agricultural country and crops are the staple food consumed by the Chinese people. Although harvesting crops could increase through favorable infrastructure and reasonable governance, climate change will negatively impact on crops productivity directly and this is difficult to account. The agricultural sector is very sensitive to changes in the natural conditions, principally atmospheric evaporation, water scarcity, solar radiation, CO2 level, ambient temperature and inorganic nutrients [12]. Temperature elevation accelerates the rate of crops growth, but crop yielding will decline, because even though it initially promotes crop growth, the benefit is temporary in China. Rice is the most vulnerable to climate warming, the temperature rise will make rice spikelet infertility, and rice production will decline. Heilongjiang province is having the greatest benefit from climate warming on crop yield [13]. Climate warming

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climate change since the mid-20th century, mainly caused by fossil fuel combustion and land-use change, greenhouse gas emissions from human activities which mainly consist of carbon dioxide, methane and nitrous oxide, which leads to increased atmospheric concentrations of greenhouse gases [4]. China’s climate has significantly changed in recent years, especially the last 50 years, which is consistent with the world climatic warming change. According to the China Meteorological Administration, the latest observations have shown in the last hundred years, mean surface temperature increased by 1.1°C in China, slightly higher than the global average temperature over the same period [4]. In terms of geographical distribution, regions of northwest, north and northeast China are significantly warmer in terms of mean annual temperature, while Southwest China is cooler, and summer mean temperature in middle and lower part of Yangtze River is decreased [3]. Furthermore, average annual precipitation trend is not significant, but distribution of precipitation has undergone significant changes by the past 50 years in China [5, 6]. Frequency of precipitation in Western China and Southern China is increasing, while rainfall is reducing in most parts of North China and Northeastern China. Therefore, extreme weather events have increased in frequency and intensity due to climate warming in China. As droughts became more serious in North China and Northeast China, the Yangtze River region and Southeast region have experienced severe flooding. In the past 30 years, Chinese coastal sea surface temperature has increased by 0.9°C, and sea level rose by 90 mm [7–9]. According to scientific research, the future of further climate warming in China will continue to have negative effect on the country, and the frequency of extreme weather events may increase. Furthermore, uneven distribution of precipitation is more significant, and there will be increased frequency of heavy precipitation events [10]. Moreover, arid zones may be expanded and

Climate Change and Food Security in China

generally increases, the scope of diseases and pests are expanding, which show from low altitude to higher altitude, extending trend from the equator to the poles. In other words, in the past the low temperature limited the pests which increased in high altitude and poles. As temperatures rise, the prevalence of pests and diseases are increasing, and this has caused serious endangerment to crops. Water availability is crucial for agriculture production. However, due to increases in demand in other sectors, water availability for agriculture is decreasing. Therefore, irrigated agriculture is necessary and most of the grain production in China is from irrigated land [17]. The North China Plain is one of the most important regions for food production in China, with its agricultural system being significantly affected by the ongoing climate change and vulnerability with water stress [17]. Simulation results show that maize is more efficient to agricultural management than wheat, in that wheat relies more on irrigation than maize does. The yield level of maize is higher than that of wheat, the water consumption of maize is lower, and the response of maize yield to agricultural management is larger than that of wheat yield [18]. In addition, precipitation is a key factor affecting food production. South-east of Northeastern China, Northern China and east of Northwestern China has shown a significant decrease in precipitation, whereas middle and lower regions of the Yangtze River and west of Northwestern China have shown an increase. Therefore, global warming has influenced the snow and rainfall patterns because atmospheric temperature, sea surface temperature and sea level pressure has changed. Even without CO2 fertilization effects, water would be a significant limitation to crop production [19]. Extreme events such as drought, severe precipitation and excessive human activities have caused environmental degradation and desertification. Desertification is one of the most serious

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causes the crop planting boundaries northing such as maize, rice and soybeans, where it was not suitable for growing crops in the past. Guo et al. [14] through the CERES model predicted that CO2 fertilization on crops growth has a positive effect on irrigation in North China Plain. It has been predicted that total crop production will change with the spatial patterns by the 2040s, causing a general increase in the northeast and north and decrease in the central, eastern and southern provinces with the effect of CO2 fertilization. Crops are dependent on the relationship between CO2 enrichment and atmospheric temperature, but its sensitivity responses to the other climate parameters need further investigations [14]. The influence of temperature on crops yielding can be divided into three parts: First, climate warming causes significantly increased crop yielding. Second, while climate warming has not significantly influenced the northern, northwestern and southwestern region of China, temperature elevation has accelerated crops growth and maturity, and caused reduction of crops quality; however, water shortages in Northern China has intensively limited crops growth. Thirdly, productivity of crops of Eastern and Central Southern region is not sensitive to the climate warming, but the yield has decreased slowly, possibly because the regions are the most economically developed region, and the arable land is reduced due to land expansion for urbanization. The negative effect of temperature rise on crop yield is partially mitigated by fertilization. The response of a C3 crop to the temperature rise is significantly more sensitive to CO2 fertilization and less negative than the response of C4, implying a challenge to the present double wheat-maize systems in the Huang-HuaiHai Plain of China. Warmer atmosphere would cause a change in food quality, CO2 enrichment is to be expected, and there would be decreased protein and nutrient concentrations, as well as altered lipid composition [15]. Insect pests can be geographically distributed by climate warming [16]. As the temperature

Aquaculture China is one of the biggest fishery and aquaculture countries in the world, accounting for 70% of the world’s aquaculture production [21]. Major aquatic products of the southeast coastal aquaculture zone including Zhejiang, Fujian, Guangxi, Guangdong and Hainan province, include eel, shrimp, tilapia and large yellow croaker. The main layout of the Yellow Sea and Bohai culture zone are in Shangdong, Hebei and Liaoning province, where the focus is on shrimp and shellfish products. Middle-downstream of the Yangtze River culture area including Jiangsu, Anhui and Jiangxi province mainly focus on crab exports [22]. The impact of global warming will not only influence food production on terrestrial land, but also marine organisms. Climate change challenges the sea environment of marine organisms, including changes in sea-water temperature, sea acidification and so forth. Greenhouse gases are causing the world’s oceans to accumulate acid, which poses a serious threat to coral and other marine life. When too much CO2 is dissolved in the ocean, it causes ocean acidification, which would make calcification of coral and plankton skeleton difficult [23]. Lower pH makes extracting oxygen from sea water more difficult. This phenomenon will negatively affect the breeding and growth of squid which is a high oxygen consuming animal. As the pH decreases, the rate of soluble forms of toxic metals will increase [24, 25]. The calcium carbonate shell of marine life may be affected the most, from lobster and shrimp to other crustaceans, as well as certain types of plankton and corals. Corals are very sensitive to temperature changes. Coral reefs in the share of the total global ocean area may be small, but it is the most biologically diverse marine ecosystem and is the place where juvenile fish spend their time, and there is more than a quarter of marine fish reliant on

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this mutual interdependence [26, 27]. The importance of coral cannot be ignored, as its decline can cause serious consequences to the sustainability of marine life. Water in the carbonate ion saturation state means the calcium carbonate does not dissolve in water [28]. As water acidity levels rise, in which carbonate ion content decreases, the natural phenomenon of marine crustacean shell formation will become more difficult, and some ocean shell structures of these creatures may even start to dissolve [29]. Climate change may increase the proportion of males in some fish, thereby leading to changes in the sex ratio of fish. The sex of many fish and reptiles is determined by the temperature of the surrounding environment, rather than genetic information [30, 31]. Reduction in female fish will be a serious threat to the continuation of species. In order to avoid the impact of climate warming on the population, some fish will begin to migrate from the original living waters to the regions of lower temperature, so that they can thrive normally [32]. The anomaly of fish migration will have a devastating impact on marine ecology, as it will lead to desertification of the original place. Cold-water fish have slower metabolism, are generally larger in size and have a longer lifespan relative to the warm-water fish. Therefore high sea-water temperature could affect fish size, reproductive capacity, and undermine the marine food chain and ecosystem balance [33]. Global warming will cause sea water temperature increase, which would directly affect fish growth, spawning, migration, cause changes in fish population, and ultimately affect the quantity, quality and exploitation of fishery resources. Water temperature has the potential to narrow the distribution of cold-water fish, cause early age of sexual maturity, fecundity decreased ovulation and a reduced juvenile survival rate, which in turn leads to shorter adult fish age, weight loss and the emergence of ‘escape action’ [34]. Climate-induced environmental change may lead to changes in their habits, which can lead to

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environmental events concerning China, especially in arid, semi-arid and dry sub-humid areas in Northwest China and North China [20].

1,200

Wild

n-3 PUFA content (mg/100 g)

Cultured 1,000 800 600 400 200 0 Crucian carp

degradation of germplasm and increased investment costs [35]. Marine and aquaculture products, especially fish is high in n–3 polyunsaturated fatty acids (PUFA), protein, vitamin A, D, B6, B12, niacin and biotin, as well as minerals such as phosphorus, copper, magnesium, potassium, iron and iodine, etc. [36]. n–3 PUFA from marine and aquaculture products have multiple beneficial health effects such as decreased risk of stroke via antithrombotic and vasodilative effects, reducing serum triacylglycerol and blood pressure, increased heart rate variability, anti-inflammatory activities, improving visual function, improving attention-deficit conditions/hyperactivity disorder, schizophrenia and dementia, and may be effective in managing depression in adults. All these beneficial effects are thought to be mediated through altering cell membrane composition, fluidity, receptors and membrane-bound enzymes, gene expression and eicosanoid production [37]. However, natural marine and freshwater fish population is declining as a result of climate changes together with overfishing, etc. To reestablish and maintain the fish population for


Mandarin fish

Silver fish

Snake-headed fish

sustainability and affordability in China, fishing has been banned for 2–3 months during specified periods of the year, which differs depending on the area, since 1995. After the fishing moratorium had been implemented for 7 years from 1995 to 2001, the average yield of fishing rose by 2.71 million tons, of which hairtail, small yellow croaker and pomfret, the three main commercial fish, increased by 538 thousand tons annually [38]. A question rose here that what is the content of n–3 PUFA in aquaculture when compared with wild fishes? To clarify this issue, we have investigated the n–3 PUFA content in common commercial available four species natural (wild) and cultured freshwater fishes. Total and individual n–3 fatty acid contents in three of four species of fish, crucian carp, silver fish and snake-headed fish were higher in the cultured sample than in the wild (fig. 1). We concluded that there is big variation on n–3 PUFA content in different fish species; it is not necessarily that wild is more nutritious than cultured fish [39]. There has been increasing concern over safety, from contaminants in some fishes, especially cultured freshwater species. The public is facing bipartite conflicting reports on the benefits and risks

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Fig. 1. n–3 PUFA contents of four species of wild and cultured freshwater fish (mg/100 g).

Livestock Pastoral livestock is mainly distributed in the 5 provinces: Inner Mongolia, Xinjiang, Qinghai, Tibet and Sichuan. Over 75% natural grassland of mainland China is found there, and the main livestock includes sheep, cattle, horses and camels [40]. Animal husbandry of China refers to pastoral and semipastoral areas that are surrounded by crop cultivation, livestock products are pigs, cattle, sheep and various poultry, to provide their products to city consumers. Despite livestock being homoeothermic animals, they are still undoubtedly affected by climate change indirectly. If the rainfall is relatively stable and CO2 elevated, there is increased grass in pastures for herbivore breeding. Livestock is affected by changes in ambient temperature, humidity and other climatic factors, and this can even influence their survival [41, 42]. The variability and adaptability of micro-organisms to environmental change is better than in mammals, and this would lead to damage to livestock immunity and disease resistance. Meanwhile, climate change may lead to increased frequency and intensity of heat waves, and this may lead to death and illnesses of livestock. The emission of greenhouse gases from livestock represents a significant impact on climate warming [43, 44]. Thus, efficient and intensive livestock farming should be a boost to reduce the emission of greenhouse gasses.

Challenges of Climate Changes for Sustainable Development in China

In light of the current global climate changes which are challenging the world, China is determined to continue to develop and thrive. Therefore, in the process of climate change for sustainable

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development, there are efforts to achieve a ‘winwin’ situation of economic development and climate change. Both mitigation and adaptation are integral components for sustainable development in the light of climate change. Mitigation is a relatively long-term and difficult task; adaptation is more realistic and urgent in China [45, 46]. In dealing with solutions to sustainable development, we must have a clear understanding of the challenges we face. First of all, China’s climate conditions are complex and with a vulnerable ecological environment adaptation will be difficult. China is part of a continental monsoon climate, characterized by hot summers and cold winters in most regions [47, 48]. Uneven spatial and temporal distribution of precipitation in China mostly occurs during the flood season, with disproportion, annual rainfall descending from the southeast coast to the northwest inland area [49, 50]. In addition, China’s ecological environment is vulnerable, as it is experiencing a serious state of soil erosion and desertification [51]. China has a relatively small area of natural wetlands compared with alpine steppe and desert steppe, and even northern temperate grassland is affected by drought, environmental degradation and other effects, and is facing a degradation and desertification crisis [52, 53]. Apart from mainland degradation, China is also vulnerable to the adverse effects of a rising sea level along its long coastline [54]. China is a developing country which requires further development in the areas of industrialization and urbanization. Therefore, future energy demand will continue to increase. Meanwhile, the coal-dominated energy structure in China will not be phased out in the foreseeable future, and therefore greenhouse gas emissions will be difficult to control in the meantime [55, 56]. In order to achieve sustainable development in the light of climate change, the government has adapted different measures such as control of greenhouse gas emissions, increased scientific research and technological development,

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of fish intake, resulting in confusion over the role of fish consumption in a healthy diet. However, there are no data to show that certain clinical condition is caused by the fish consumption.

strengthened public awareness and government management for tackling immediate climaterelated problems in China [57]. In conclusion, it is clear that regional environment, food and human health are closely related as a micro-ecosystem, mutually dependent and influential; however, climate change can significantly render this system vulnerable, ineffective and degraded. The climate in China, as with other nations, has changed significantly during the past 50 years. It affects national food and

nutrition security and food safety, and also threatens the sustainability of the nation’s development. China has successfully solved the hunger issue of 1.4 billion people through science and technology to improve the yield of agriculture, aquaculture and livestock. China’s success has contributed greatly to food and health security and will serve as a good model for other developing countries. However, a bigger challenge for China is how to maintain sustainable development whilst maintaining low carbon emissions.

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