Climate change, water availability and future cereal production in China

Climate scenarios from a regional climate model are used to drive crop and water simulation models underpinned by the IPCC A2 and B2 socio-economic development pathways to explore water availability for agriculture in China in the 2020s and 2040s. Various measures of water availability are examined at river basin and provincial scale in relation to agricultural and non-agricultural water demand and current and planned expansions to the area under irrigation. The objectives are to understand the influences of different drivers on future water availability to support China's food production. Hydrological simulations produce moderate to large increases in total water availability in response to increases in future precipitation. Total water demand increases nationally and in most basins, but with a decreasing share for agriculture due primarily to competition from industrial, domestic and municipal sectors. Crop simulations exhibit moderate to large increases in irrigation water demand which is found to be highly sensitive to the characteristics of daily precipitation in the climate scenarios. The impacts of climate change on water availability for agriculture are small compared to the role of socio-economic development.The study identifies significant spatial differences in impacts at the river basin and provincial level. In broad terms water availability for agriculture declines in southern China and remains stable in northern China. The combined impacts of climate change and socio-economic development produce decreases in future irrigation areas, especially the area of irrigated paddy rice. Overall, the results suggest that there will be insufficient water for agriculture in China in the coming decades, due primarily to increases in water demand for non-agricultural uses, which will have significant implications for adaptation strategies and policies for agricultural production and water management.     

Effectiveness of the strategies to combat land degradation and drought

This paper focuses on the determination of the most effective set of mitigation and adaptation strategies applied to combat land degradation and drought in a latitudinal gradient. This study was carried out in Chile, in a latitude gradient between 17° 30′S and 36° 33′S. The northern regions are mostly formed by desert and dry land, which can be considered as marginal areas for agriculture. On the other hand, the area formed by the southern regions has an industrialized agriculture where an increased use of technology takes place and where the climate and water availability are optimal for the development of agriculture. The period considered in this study was between 2000 and 2007. We calculated an Investment Effectiveness Index. Afterwards, and in order to assess the effectiveness of the financial support, we performed multiple regressions (P?≤?0.05), where the Index was considered as the independent variable, and the annual difference of the area affected by a high risk of desertification was considered as the dependent variable. Our findings suggest that the effectiveness of the different set of the strategies applied to fight against desertification and drought varies in a latitudinal gradient. Thus, in arid and hyper arid areas the promotion of modern irrigation systems seems to be effective in combating desertification, while in Mediterranean climates the reforestation strategies seem to play an important role. Our results suggest that in areas heavily degraded by overgrazing, the most effective strategies are those oriented to obtain a permanent vegetation cover on degraded soils.     

Rural vulnerability to environmental change in the irrigated lowlands of Central Asia and options for policy-makers: A review

Climate change, land degradation and drought affect millions of people living in drylands worldwide. With its food security depending almost entirely on irrigated agriculture, Central Asia is one of the arid regions highly vulnerable to water scarcity. Previous research of land and water use in the region has focused on improving water-use efficiency, soil management and identifying technical, institutional and agricultural innovations. However, vulnerability to climate change has rarely been considered, in spite of the imminent risks due to a higher-than-average warming perspective and the predicted melting of glaciers, which will greatly affect the availability of irrigation water. Using the Khorezm region in the irrigated lowlands of northwest Uzbekistan as an example, we identify the local patterns of vulnerability to climate variability and extremes. We look at on-going environmental degradation, water-use inefficiency, and barriers to climate change adaptation and mitigation, and based on an extensive review of research evidence from the region, we present concrete examples of initiatives for building resilience and improving climate risk management. These include improving water use efficiency and changing the cropping patterns that have a high potential to decrease the exposure and sensitivity of rural communities to climate risks. In addition, changes in land use such as the afforestation of degraded croplands, and introducing resource-smart cultivation practices such as conservation agriculture, may strengthen the capacity of farmers and institutions to respond to climate challenges. As these can be out-scaled to similar environments, i.e. the irrigated cotton and wheat growing lowland regions in Central Asia and the Caucasus, these findings may be relevant for regions beyond the immediate geographic area from which it draws its examples.     

Re-thinking water policy priorities in the Mediterranean region in view of climate change

Water is scarce in Mediterranean countries: cities are crowded with increasing demand; food is produced with large amounts of water; ecosystems demand more water that is often available; drought affects all. As climate change impacts become more noticeable and costlier, some current water management strategies will not be useful. According to the findings of CIRCE, the areas with limited water resources will increase in the coming decades with major consequences for the way we produce food and we protect ecosystems. Based on these projections this paper discusses water policy priorities for climate change adaptation in the Mediterranean. We first summarise the main challenges to water resources in Mediterranean countries and outline the risks and opportunities for water under climate change based on previous studies. Recognising the difficulty to go from precipitation to water policy, we then present a framework to evaluate water availability in response to natural and management conditions, with an example of application in the Ebro basin that exemplifies other Mediterranean areas. Then we evaluate adaptive capacity to understand the ability of Mediterranean countries to face, respond and recover from climate change impacts on water resources. Social and economic factors are key drivers of inequality in the adaptive capacity across the region. Based on the assessment of impacts and adaptive capacity we suggest thresholds for water policy to respond to climate change and link water scarcity indicators to relevant potential adaptation strategies. Our results suggest the need to further prioritise socially and economically sensitive policies.     

Economic impacts of climatic variability and subsidies on European agriculture and observed adaptation strategies

In order to assess agricultural adaptation to climate impacts, new methodologies are needed. The translog distance function allows assessing interactions between different factors, and hence the influence of management on climate impacts. The Farm Accountancy Data Network provides extensive data on farm characteristics of farms throughout the EU15 (i.e. the 15 member states of the European Union before the extension in 2004). These data on farm inputs and outputs from 1990−2003 are coupled with climate data. As climate change is not the only change affecting European agriculture, we also include effects of subsidies and other changes on inputs and outputs of farms throughout Europe. We distinguish several regions and empirically assess (1) climate impacts on farm inputs and outputs in different regions and (2) interactions between inputs and other factors that contribute to the adaptation to these impacts. Changes in production can partly be related to climatic variability and change, but also subsidies and other developments (e.g. technology, markets) are important. Results show that impacts differ per region, and that ‘actual impacts’ cannot be explicitly separated into ‘potential impacts’ and ‘adaptive capacity’ as often proposed for vulnerability assessment. Farmers adapt their practices to prevailing conditions and continuously adapt to changing conditions. Therefore, ‘potential impacts’ will not be observed in practice, leaving it as a mainly theoretical concept. Factors that contribute to the adaptation also differ per region. In some regions more fertilizers or more irrigation can mitigate impacts, while in other regions this amplifies impacts. To project impacts of future climate change on agriculture, current farm management strategies and their influence on current production should be considered. This clearly asks for improved integration of biophysical and economic models.     

Artificial lakes as a climate change adaptation strategy in drylands: evaluating the trade-off on non-target ecosystem services

Drylands are very susceptible to the effects of climate change due to water stress. One possible climate change adaptation measure is the construction of lakes to increase water availability for drinking and irrigation (food production) and decrease fire risk. These lakes can also increase local biodiversity and human well-being. However, other non-target services such as carbon (C) storage, water purification, and sediment retention might also change. Our main aim was to evaluate the trade-offs on non-targeted ecosystem services due to lakes construction in drylands. This was done using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling tools, comparing a Mediterranean area located in southwest (SW) Europe, with and without artificial lakes. Results showed that the construction of artificial lakes caused an increase of 9.4% in C storage. However, the consequent increase in agricultural area decreased water purification and sediment retention services. This could diminish the life span of the lakes changing the initial beneficial cost-benefit analysis on lakes as adaptation measures to climate change. As a global measure for mitigation and adaptation to climate change strategy, we consider lake construction in drylands to be positive since it can store C in sediments and reduces the vulnerability to water scarcity. However, as a general recommendation and when built to support or increase agriculture in semi-arid landscapes, we consider that lakes should be complemented with additional measures to reduce soil erosion and nutrient leaching such as (i) locate agricultural areas outside the lakes water basin, (ii) afforestation surrounding the lakes, and (iii) adopt the best local agriculture practices to prevent and control soil erosion and nutrient leaching.     

Adaptations to climate change,drought and desertification: local insights to enhance policy in southern Africa

The impacts of climate change, drought and desertification are closely interlinked, and most acutely experienced by populations whose livelihoods depend principally on natural resources. Given the increases in extreme weather events projected to affect the Southern Africa region, it is essential to assess how household and community-level adaptations have been helped or hindered by institutional structures and national policy instruments. In particular, there is a need to reflect on efforts related to the United Nations’ environmental conventions to ensure that policies support the maintenance of local adaptations and help retain the resilience of socio-economic and environmental systems. This paper examines three interlinked drivers of adaptation: climate change, desertification and drought, assessing the extent to which international and national policy supports local adaptive strategies in three countries in southern Africa. We show that while common ground exists between desertification and climate change adaptations at the policy level, they are insufficiently mainstreamed within broader development approaches. Similarly, there are some overlaps between policy-driven and autonomous local adaptations, but the mutually supportive links between them are poorly developed. Further efforts to integrate local adaptation strategies within policy could increase local resilience to environmental change, while also contributing to wider development goals.     

Impact of climate change on regional irrigation water demand in Baojixia irrigation district of China

Water scarcity in China would possibly be aggravated by rapid increase in water demand for irrigation due to climate change. This paper focuses on the mechanism of climate change impact on regional irrigation water demand by considering the dynamic feedback relationships among climate change, irrigation water demand and adaptation measures. The model in implemented using system dynamics approach and employed in Baojixia irrigation district located in Shaanxi Province of China to analyses the changes in irrigation water demand under different climate change scenarios. Obtained results revealed that temperature will be the dominant factor to determine irrigation water demand in the area. An increase of temperature by 1 °C will result in net irrigation water demand to increase by about 12,050?×?10⁴ m³ and gross water demand by about 20,080?×?10⁴ m³ in the area. However, irrigation water demand will not increase at the same rate of temperature rise as the adaptation measures will eventually reduce the water demand increased by temperature rise. It is expected that the modeling approach presented in this study can be used in adopting policy responses to reduce climate change impacts on water resources.     

Adaptation to changing water resources in the Ganges basin, northern India

An ensemble of regional climate model (RCM) runs from the EU HighNoon project are used to project future air temperatures and precipitation on a 25 km grid for the Ganges basin in northern India, with a view to assessing impact of climate change on water resources and determining what multi-sector adaptation measures and policies might be adopted at different spatial scales.The RCM results suggest an increase in mean annual temperature, averaged over the Ganges basin, in the range 1–4 °C over the period from 2000 to 2050, using the SRES A1B forcing scenario. Projections of precipitation indicate that natural variability dominates the climate change signal and there is considerable uncertainty concerning change in regional annual mean precipitation by 2050. The RCMs do suggest an increase in annual mean precipitation in this region to 2050, but lack significant trend. Glaciers in headwater tributary basins of the Ganges appear to be continuing to decline but it is not clear whether meltwater runoff continues to increase. The predicted changes in precipitation and temperature will probably not lead to significant increase in water availability to 2050, but the timing of runoff from snowmelt will likely occur earlier in spring and summer. Water availability is subject to decadal variability, with much uncertainty in the contribution from climate change.Although global social-economic scenarios show trends to urbanization, locally these trends are less evident and in some districts rural population is increasing. Falling groundwater levels in the Ganges plain may prevent expansion of irrigated areas for food supply. Changes in socio-economic development in combination with projected changes in timing of runoff outside the monsoon period will make difficult choices for water managers.Because of the uncertainty in future water availability trends, decreasing vulnerability by augmenting resilience is the preferred way to adapt to climate change. Adaptive policies are required to increase society's capacity to adapt to both anticipated and unanticipated conditions. Integrated solutions are needed, consistent at various spatial scales, to assure robust and sustainable future use of resources. For water resources this is at the river basin scale. At present adaptation measures in India are planned at national and state level, not taking into account the physical boundaries of water systems. To increase resilience adaptation plans should be made locally specific. However, as it is expected that the partitioning of water over the different sectors and regions will be the biggest constraint, a consistent water use plan at catchment and river basin scale may be the best solution. A policy enabling such river basin planning is essential.     

Coping with changing water resources: The case of the Syr Darya river basin in Central Asia

This paper discusses how climatic-hydrological and socio-political developments will affect water allocation in the Syr Darya river basin and which adaptation measures will be needed to cope with changing water resources. In view of the geo-political complexity, climate-driven changes in water availability are of particular importance in this region. Water shortages during summer will become more frequent as precipitation is expected to further decrease and glacial meltwater releases will decrease in the long-term due to reduced glacier volume. Being the main valve to the entire Syr Darya river system, the Toktogul reservoir in Kyrgyzstan could take over, at least partly, the role of glaciers as seasonal water redistributors, thus allowing the generation of energy in winter – benefiting upstream countries – and irrigation for large-scale agriculture in summer – benefiting downstream countries. To date, however, there is no regional consensus on a balanced reservoir management, which currently favours irrigation according to past Soviet priorities. Moreover, the perception of water as a ‘national concern’ in Central Asia discourages efforts towards cooperation between states at the regional level. So far, climate change adaptation has focused on technical rather than institutional solutions. We suggest that policy-relevant adaptation measures should include consistent data collection and dissemination, cross-sectoral collaboration, promotion of national responsibility and initiative, and agreeing on a regional strategy.     

Estimating the non-market benefits of climate change adaptation of river ecosystem services: A choice experiment application in the Aoos basin,Greece

Mountains are important global reservoirs of water resources. However they are highly vulnerable to climate change as limited alterations in temperature and precipitation may cause harmful effects to water systems. Southern Europe and especially Greece are expected to undergo a drought trend over the next decades, resulting in less recharge for the aquifers and water services reduction. Thus, climate change may distort both natural and socioeconomic characteristics of freshwater ecosystem services deteriorating the general social welfare related to them. This paper examines the economic impacts of climate change on river uses of the Aoos basin in Greece. In this regard, a choice experiment is conducted to estimate the value changes in different ecological and economic services in a mountain community. The econometric simulations using conditional logit, random parameters logit and latent class models reveal that despite existing preference heterogeneity, respondents on average derive positive and significant welfare effects from climate change adaptation measures. The findings of the survey may assist in adaptation planning for the Aoos River basin, with possible extensions to other river systems enduring similar climate change indications.     

巢湖流域水资源可持续性评价方法研究

水资源可持续性评价模型(WRSEM,Water Resource Sustainability Evaluation Model)能够定量地评价流域水资源的可持续性,是流域水资源管理的一个有效工具。本文为了科学地衡量巢湖流域水资源开发、利用和管理的可持续性,构建了巢湖流域水资源可持续性评价模型和评价指标体系。巢湖流域水资源可持续性评价指标体系由4个一级指标(经济效率、社会公平、环境保护和保障能力)和20个二级指标构成。最后根据相对权重综合计算得到流域水资源可持续性指数。评价结果表明了巢湖流域水资源可持续性的程度,同时研究结果为巢湖流域水资源管理及其相关政策制定提供了科学依据。     

Complementarity between mitigation and adaptation: the water sector

The water cycle, a fundamental component of climate, is likely to be altered in important ways by climate change. Climate change will most likely worsen the already existing water related problems. Then the question is how should policy makers respond to this dilemma. Climate change mitigation, through greenhouse gas (GHG) emissions reduction and sequestration is not a sufficient response. Adaptation will also need to feature as a response strategy. Mitigation and adaptation need to be viewed as complementary responses to climate change. Complementarity between adaptation and mitigation in the water sector will be addressed in this paper. The paper will also outline the main impacts of climate change on water resources and identify those areas that are most dependent and vulnerable to hydrological systems (e.g., hydroelectric systems, irrigation, agriculture) and any changes thereof resulting from climate change. It will aim to assess the impact of water demand and water use, with a view to identifying the main relationships between mitigation and adaptation in the water sector and the means through which individual mitigation and adaptation actions can potentially interact with each other for the benefit of the water sector as a whole. It will also explore the implications of climate change on the management of water resources. Adaptation and mitigation options would be considered in the context of their socio-economic and environmental impacts and their contribution to sustainable development. A brief evaluation of how this information can be directly used for planning purpose will also be presented.

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Adapting food systems of the Indo-Gangetic plains to global environmental change: key information needs to improve policy formulation

The Indo-Gangetic plain (IGP; including regions of Pakistan, India, Nepal, and Bangladesh) is generally characterised by fertile soils, favourable climate and an abundant supply of water. Nevertheless, the challenge of increasing food production in the IGP in line with demand grows ever greater; any perturbation in agriculture will considerably affect the food systems of the region and increase the vulnerability of the resource-poor population. Increasing regional production is already complicated by increasing competition for land resources by non-agricultural sectors and by the deterioration of agri-environments and water resources. Global environmental change (GEC), especially changes in climate mean values and variability, will further complicate the agricultural situation and will therefore, have serious implications for food systems of the region. Strategies to reduce the vulnerability of the region's food systems to GEC need to be based on a combination of technical and policy options, and developed in recognition of the concurrent changes in socioeconomic stresses. Adaptation options need to be assessed with regard to their socioeconomic and environmental efficacy, but a greater understanding of the interactions of food systems with GEC is needed to be able to do this with confidence. This paper discusses information needs relating to resource management and policy support to guide the development of research planning for increasing the robustness of IGP food systems to GEC. Further information is needed to develop a range of adaptation strategies including augmenting production and its sustainability, increasing income from agricultural enterprises, diversification from rice–wheat systems, improving land use and natural resource management, and instigating more flexible policies and institutions.     

Impacts of Global Climate Change on Mediterranean Agrigulture: Current Methodologies and Future Directions. An Introductory Essay

Current trends in Mediterranean agriculture reveal differences between the Northern and Southern Mediterranean countries as related to population growth, land and water use, and food supply and demand. The changes in temperature and precipitation predicted by general circulation models for the Mediterranean region will affect water availability and resource management, critically shaping the patterns of future crop production. Three companion papers analyze in detail future impacts of predicted climate change on wheat (Triticum aestivum L.) and maize (Zea mays L.) production in Spain, Greece, and Egypt, and test farm- level adaptation strategies such as early planting and cultivar change with the aid of dynamic crop models. Strategies to improve the assessment of the potential effects of future climate change on agricultural production are discussed.     

农田水利设施抗旱效果评估:基于全国7省(市)的实证研究

农田水利设施建设薄弱被认为是导致灾情日益严重的重要原因。研究目的是评估不同农田水利设施在粮食生产中的抗旱效果。基于全国7省(市)、 123村和1 162户农户的大规模实地调研数据,在描述性统计分析的基础上,通过计量经济学模型,定量分析了农田水利设施的抗旱效果。研究结果表明,最近5 a内,有1/3的农户受旱灾而减产,减产25%以上的农户占到22%;大中型水库、 水池和水泵的抗旱作用显著高于河流引水渠道,文章对研究结果的政策含义做了讨论。     

The cost of mitigation strategies for agricultural adaptation to global change

Land recovery and the improvement of lands affected by desertification for agricultural use, is achieved when a sustained recovery of agricultural productivity over time is obtained. In the areas affected by desertification and drought, it is common that the ecosystems do not have enough funding for water management and irrigation. This situation leads to an inadequate assessment of the environmental goods and services in arid zones. As a result we have a misuse of these dry lands. Many countries are implementing policies and making investments and efforts to mitigate arid land degradation and desertification through the National Action Programs (NAP). However, for the long term planning of mitigation and adaptation strategies, it is necessary to know the cost of recovery and land improvement in certain areas in order to forecast the budgets. This is the main objective of this paper in order to combat desertification and drought in central northern Chile. We have calculated a recovery cost per hectare by region and for each of the agriculture, livestock and forestry (ALF) promotion agencies. The results indicate that the cost of land reclamation in the northern regions is much higher than in the southern regions of this studied area. The cost is especially high for Region II, where investment per hectare is almost to 3000 US$ per hectare. At the other extreme is the Region VII, in the south of the studied area where the investment required per hectare barely reaches 500 US$. The contribution of the promotion agencies to the total cost also varied among regions and agencies. We discuss the results within a context of recovery cost per hectare depending on the different environmental characteristics and agricultural development of each of the studied regions.     

水资源短缺对北京农业的不利影响分析与对策

北京市农业水资源短缺状况十分严峻。针对水资源短缺对北京农业经济、农村生态环境和社会稳定产生的影响,进行了全面、深入的分析,认为北京市目前的用水政策会进一步加剧农业用水的紧张趋势。进而提出了诸如发展利用和推广节水农业技术、大力建设节水灌溉工程设施、调整种植结构、发展特色农业、适度发展污水灌溉、建设地下水应急备用水源、加速推广雨洪利用技术、实施人工增雨工程、加强农村水资源的宏观和微观管理等相应的对策和建议。     

黄河流域干旱状况变化的气候与植被特征分析

应用干旱的气候分析方法和遥感监测方法,分别利用1982～1998年(1999年)降水和气温气象数据,以及AVHRR的NDVI遥感数据计算了黄河流域气候干旱指数和距平NDVI。以像元为单位,应用线性回归斜率和相关系数分析了流域内干旱状况的气候特征和植被特征的变化状况,并进行了流域干旱状况类型的区域划分,从气候和植被特征方面分析了黄河流域近18年来干旱变化状况。通过研究得出以下结论:黄河流域在1982～1999年间干旱的气候特征比较突出,在101°20'E以东地区受干旱威胁,共占黄河流域面积的71%;黄河流域在101°20'E以西的源头地区,干旱的气候特征和植被特征目前都处在相对减弱的趋势中,干旱没有进一步严重恶化的迹象;黄河流域灌溉农业地区植被基本不受气候干旱的影响。     

Water resource management and climate change adaptation: a holistic and multiple criteria perspective

Anthropogenic climate change is likely to significantly increase human exposure to droughts and floods. It will also alter seasonal patterns of water availability and affect water quality and the health of aquatic ecosystems with various implications for social and economic wellbeing. Policy development for water resource adaptation needs to allow for a holistic and transparent analysis of the probable consequences of policy options for the wide variety of water uses and users, and the existing ecosystem services associated with any stream basin. This paper puts forward an innovative methodological framework for planning development-compatible climate policies drawing on multi-criteria decision analysis and an implicit risk-management approach to the economics of climate change. Its objectives are to describe how the generic methodology could be tailored for analysis of long-range water planning and policy options in developing countries, and to describe the place of climate change considerations in water governance and planning processes. An experimental thought-exercise applying the methodology to water policy development in Yemen provides further insights on the complexity of water adaptation planning. It also highlights the value of conducting sensitivity analysis to explore the implications of multiple climate scenarios, and the importance of accounting for policy portfolios rather than individual policy options. Rather than constituting a tool that can generate clear measures of optimal solutions in the context of adaptation to uncertain climate futures, we find that this approach is best suited to supporting comprehensive and inclusive planning processes, where the focus is on finding socially acceptable paths forward.