World trade as the adjustment mechanism of agriculture to climate change

This paper evaluates the role of trade as a mechanism of economic adjustment to the impacts of climate change on agriculture. The study uses a model of the world economy able to reflect changes in comparative advantage; the model is used to test the hypotheses that trade can assure that, first, satisfying global agricultural demand will not be jeopardized, and, second, general access to food will not decrease. The hypotheses are tested for three alternative scenarios of climate change; under each scenario, regions adjust to the climatic assumptions by changing the land areas devoted to agriculture and the mix of agricultural goods produced, two of the major mechanisms of agricultural adaptation. We find that trade makes it possible to satisfy the world demand for agricultural goods under the changed physical conditions. However, access to food decreases in some regions of the world. Other patterns also emerge that indicate areas of concern in relying on trade as a mechanism for the adjustment of agriculture to likely future changes in climate.     

A Ricardian analysis of the impact of climate change on agriculture in Germany

Based on a Ricardian analysis accounting for spatial autocorrelation and relying on recent climate change forecasts at a low spatial scale, this study assesses the impact of climate change on German agriculture. Given the limited availability of data (e.g., the unknown average soil quality at the district level), a spatial error model is used in order to obtain unbiased marginal effects. The Ricardian analysis is performed using data from the 1999 agricultural census along with data from the network of German weather observation stations. The cross-sectional analysis yields an increase of land rent along with both a rising mean temperature and a declining spring precipitation, except for in the Eastern part of the country. The subsequent simulation of local land rent changes under three different IPCC scenarios is done by entering into the estimated regression equations spatially processed data averages for the period between 2011 and 2040 from the regional climate model REMO. The resulting expected benefits arising from climate change are represented in maps containing the 439 German districts; the calculated overall rent increase corresponds to approximately 5–6% of net German agricultural income. However, in the long run, when temperature and precipitation changes will be more severe than those simulated for 2011–2040, income losses for German agriculture cannot be excluded.     

An Assessment of Integrated Climate Change Impacts on the Agricultural Economy of Egypt

This study used a quadratic programming sector model to assess the integrated impacts of climate change on the agricultural economy of Egypt. Results from a dynamic global food trade model were used to update the Egyptian sector model and included socio-economic trends and world market prices of agricultural goods. In addition, the impacts of climate change from three bio-physical sectors – water resources, crop yields, and land resources – were used as inputs to the economic model. The climate change scenarios generally had minor impacts on aggregated economic welfare (sum of Consumer and Producer Surplus or CPS), with the largest reduction of approximately 6 percent. In some climate change scenarios, CPS slightly improved or remained unchanged. These scenarios generally benefited consumers more than producers, as world market conditions reduced the revenue generating capacity of Egyptian agricultural exporters but decreased the costs of imports. Despite increased water availability and only moderate yield declines, several climate change scenarios showed producers being negatively affected by climate change. The analysis supported the hypothesis that smaller food importing countries are at a greater risk to climate change, and impacts could have as much to do with changes in world markets as with changes in local and regional biophysical systems and shifts in the national agricultural economy.     

A reassessment of the economic effects of global climate change on U.S. agriculture

This study uses recent GCM forecasts, improved plant science and water supply data and refined economic modeling capabilities to reassess the economic consequences of long-term climate change on U.S. agriculture. Changes in crop yields, crop water demand and irrigation water arising from climate change result in changes in economic welfare. Economic consequences of the three GCM scenarios are mixed; GISS and GFDL-QFlux result in aggregate economic gains, UKMO implies losses. As in previous studies, the yield enhancing effects of atmospheric CO₂ are an important determinant of potential economic consequences. Inclusion of changes in world food production and associated export changes generally have a positive affect on U.S. agriculture. As with previous studies, the magnitude of economic effects estimated here are a small percentage of U.S. agricultural value.     

Climate change impacts on global agriculture

Based on predicted changes in the magnitude and distribution of global precipitation, temperature and river flow under the IPCC SRES A1B and A2 scenarios, this study assesses the potential impacts of climate change and CO₂ fertilization on global agriculture. The analysis uses the new version of the GTAP-W model, which distinguishes between rainfed and irrigated agriculture and implements water as an explicit factor of production for irrigated agriculture. Future climate change is likely to modify regional water endowments and soil moisture. As a consequence, the distribution of harvested land will change, modifying production and international trade patterns. The results suggest that a partial analysis of the main factors through which climate change will affect agricultural productivity provide a false appreciation of the nature of changes likely to occur. Our results show that global food production, welfare and GDP fall in the two time periods and SRES scenarios. Higher food prices are expected. No matter which SRES scenario is preferred, we find that the expected losses in welfare are significant. These losses are slightly larger under the SRES A2 scenario for the 2020s and under the SRES A1B scenario for the 2050s. The results show that national welfare is influenced both by regional climate change and climate-induced changes in competitiveness.     

Climatic change impacts on the ecohydrology of Mediterranean watersheds

Impact of climate change on ecohydrologic processes of Mediterranean watersheds are significant and require quick action toward improving adaptation and management of fragile system. Increase in water shortages and land use can alter the water balance and ecological health of the watershed systems. Intensification of land use, increase in water abstraction, and decline in water quality can be enhanced by changes in temperature and precipitation regimes. Ecohydrologic changes from climatic impacts alter runoff, evapotranspiration, surface storage, and soil moisture that directly affect biota and habitat of the region. This paper reviews expected impacts of climatic change on the ecohydrology of watershed systems of the Mediterranean and identifies adaptation strategies to increase the resilience of the systems. A spatial assessment of changes in temperature and precipitation estimates from a multimodel ensemble is used to identify potential climatic impacts on watershed systems. This is augmented with literature on ecohydrologic impacts in watershed systems of the region. Hydrologic implications are discussed through the lens of geographic distribution and upstream-downstream dynamics in watershed systems. Specific implications of climatic change studied are on runoff, evapotranspiration, soil moisture, lake levels, water quality, habitat, species distribution, biodiversity, and economic status of countries. It is observed that climatic change can have significant impacts on the ecohydrologic processes in the Mediterranean watersheds. Vulnerability varied depending on the geography, landscape characteristics, and human activities in a watershed. Increasing the resilience of watershed systems can be an effective strategy to adapt to climatic impacts. Several strategies are identified that can increase the resilience of the watersheds to climatic and land use change stress. Understanding the ecohydrologic processes is vital to development of effective long-term strategies to improve the resilience of watersheds. There is need for further research into ecohydrologic dynamics at multiple scales, improved resolution of climatic predictions to local scales, and implications of disruptions on regional economies.     

An empirical study of the economic effects of climate change on world agriculture

The economic effects of a doubling of atmospheric carbon dioxide concentration on world agriculture under two alternative crop response scenarios are empirically estimated. These effects include both changes in the prices of agricultural commodities as a result of changes in domestic agricultural yields, and changes in economic welfare following altered world patterns of consumption and production of agricultural commodities. Under both scenarios, with a few exceptions, the effects on national economic welfare are found to be quite modest. However, prices of agricultural commodities are estimated to rise considerably under the more pessimistic scenario. Increased agricultural prices reduce consumer surplus and diminish the benefits from climate change that some countries with predicted positive yield effects would otherwise receive.Authorship is equally shared. Reilly and Tobey are with the Resources and Technology Division, Economic Research Service, United States Department of Agriculture. Kane is with the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. We are grateful for the research assistance of Rhonda Bucklin, and the thoughtful comments of three anonymous reviewers. The views expressed in this paper are the authors' own and do not necessarily represent the views of the U.S. Department of Agriculture or the U.S. Department of Commerce.     

Estimating economic effects of changes in climate and water availability

Social, economic, and environmental systems can be vulnerable to disruptions in water supplies that are likely to accompany future climate changes. Coupled with the challenges of tightening environmental regulations, population growth, economic development and fiscal constraints water supply systems are being pushed beyond the limits of their design and capacity for maintenance. In this paper we briefly review key economic concepts, various economic measures and metrics, and methods to estimate the economic effects on water resources from water supply changes that could accompany climate change. We survey some of the recent empirical literature that focuses on estimates developed for U.S. watersheds at both national and regional scales. Reported estimates of potential damage and loss associated with climate and water supply changes that we observe are significant, though often the metrics vary and make valid and consistent direct cross-comparisons difficult. Whether in terms of changes in GDP or in terms of estimated changes in economic welfare based on associated changes in economic costs and benefits, both national and regional estimates suggest that governments and organizations incorporate prudent steps to assess vulnerabilities to plausible future water supply and demand scenarios and develop responsive adaptation strategies.     

Effects of Greenhouse Gas Emissions on World Agriculture, Food Consumption, and Economic Welfare

Because of many uncertainties, quantitative estimates of agriculturally related economic impacts of greenhouse gas emissions are often given low confidence. A major source of uncertainty is our inability to accurately project future changes in economic activity, emissions, and climate. This paper focuses on two issues. First, to what extent do variable projections of climate generate uncertainty in agriculturally related economic impacts? Second, to what extent do agriculturally related economic impacts of greenhouse gas emissions depend on economic conditions at the time of impacts? Results indicate that uncertainty due to variable projections of climate is fairly large for most of the economic effects evaluated in this analysis. Results also indicate that economic conditions at the time of impact influence the direction and size of as well as the confidence in the economic effects of identical projections of greenhouse gas impacts. The economic variable that behaves most consistently in this analysis is world crop production. Increases in mean global temperature, for example, cause world crop production to decrease on average under both 1990 and improved economic conditions and in both instances the confidence with respect to variable projections of climate is medium (e.g.,67%) or greater. In addition and as expected, CO₂ fertilization causesworld crop production to increase on average under 1990 and improved economic conditions. These results suggest that crop production may be a fairly robust indicator of the potential impacts of greenhouse gas emissions.A somewhat unexpected finding is that improved economic conditions are not necessarily a panacea to potential greenhouse-gas-induced damages, particularly at the region level. In fact, in some regions, impacts of climate change or CO₂ fertilization that are beneficial undercurrent economic conditions may be detrimental under improved economic conditions (relative to the new economic base). Australia plus New Zealand suffer from this effect in this analysis because under improved economic conditions they are assumed to obtain a relatively large share of income from agricultural exports. When the climate-change and CO₂-fertilization scenariosin this analysis are also included, agricultural exports from Australia plus New Zealand decline on average. The resultant declines in agricultural income in Australia plus New Zealand are too large to be completely offset by rising incomes in other sectors. This indicates that regions that rely on agricultural exports for relatively large shares of their income may be vulnerable not only to direct climate-induced agricultural damages, but also to positive impacts induced by greenhouse gas emissions elsewhere.     

Effects of Climatic Change on a Water Dependent Regional Economy: A Study of the Texas Edwards Aquifer

Global climate change portends shifts in water demand and availability which may damage or cause intersectoral water reallocation in water short regions. This study investigates effects of climatic change on regional water demand and supply as well as the economy in the San Antonio Texas Edwards Aquifer region. This is done using a regional model which portrays both hydrological and economic activities. The overall results indicate that changes in climatic conditions reduce water resource availability and increase water demand. Specifically, a regional welfare loss of $2.2–$6.8million per year may occur as a result of climatic change. Additionally, if springflows are to be maintained at the currently desired level to protect endangered species, pumping must be reduced by 9–20% at an additional costof $0.5 to $2 million per year.     

An assessment of the potential impact of climate change on rice farmers and markets in Bangladesh

Bangladesh, the sixth largest rice producer in the world, has been identified as high risk from the effects of climate change. Many of the adverse impacts of climate change such as land inundation and changes in weather patterns and CO₂ levels will impact the agricultural sector. This study develops a partial-equilibrium multi-regional farm household model of Bangladesh rice and non-rice agricultural markets to quantify the impacts of climate change on consumption, production, prices, and farmers’ welfare. The model is calibrated to the Bangladesh rice market using Household Income and Expenditure Survey data. The model is simulated to analyze the impact of land reduction and productivity decline resulting from climate change. The results show that the decline in production in the coastal and northern regions offsets the production increase in the central and eastern regions, and the simulation predicts that total rice production for Bangladesh falls by about 2%. As total rice consumption falls and imports rise, the net effect leads to a rise in the rice price by 5.71% and a decline in farmers’ welfare. Sensitivity analysis shows that more- (less-) effective abatement technology could play a key role in mitigating (exacerbating) the price and welfare effects. The model predicts that many farmers in regions directly impacted by climate change could leave farming in search of off-farm work. Thus, the government can ease this transition by promoting urban development to provide more job options and technical training for farmers.     

Study on the Impacts of Climate Change on China's Agriculture

This paper measures the economic impacts of climate change on China's agriculture based on the Ricardian model. By using county-level cross-sectional data on agricultural net revenue, climate, and other economic and geographical data for 1275 agriculture dominated counties, we find that under most climate change scenarios both higher temperature and more precipitation would have an overall positive impact on China's agriculture. However, the impacts vary seasonally and regionally. Autumn effect is the most positive, but spring effect is the most negative. Applying the model to five climate scenarios in the year 2050 shows that the East, the Central part, the South, the northern part of the Northeast, and the Plateau would benefit from climate change, but the Southwest, the Northwest and the southern part of the Northeast may be negatively affected. In the North, most scenarios show that they may benefit from climate change. In summary, all of China would benefit from climate change in most scenarios.     

Exploring the effects of drastic institutional and socio-economic changes on land system dynamics in Germany between 1883 and 2007

Long-term studies of land system change can help providing insights into the relative importance of underlying drivers of change. Here, we analyze land system change in Germany for the period 1883–2007 to trace the effect of drastic socio-economic and institutional changes on land system dynamics. Germany is an especially interesting case study due to fundamentally changing economic and institutional conditions: the two World Wars, the separation into East and West Germany, the accession to the European Union, and Germany's reunification. We employed the Human Appropriation of Net Primary Production (HANPP) framework to comprehensively study long-term land system dynamics in the context of these events. HANPP quantifies biomass harvests and land-use-related changes in ecosystem productivity. By comparing these flows to the potential productivity of ecosystems, HANPP allows to consistently assess land cover changes as well as changes in land use intensity. Our results show that biomass harvest steadily increased while productivity losses declined from 1883 to 2007, leading to a decline in HANPP from around 75%–65% of the potential productivity. At the same time, decreasing agricultural areas allowed for forest regrowth. Overall, land system change in Germany was surprisingly gradual, indicating high resilience to the drastic socio-economic and institutional shifts that occurred during the last 125 years. We found strikingly similar land system trajectories in East and West Germany during the time of separation (1945–1989), despite the contrasting institutional settings and economic paradigms. Conversely, the German reunification sparked a fundamental and rapid shift in former East Germany's land system, leading to altered levels of production, land use intensity and land use efficiency. Gradual and continuous land use intensification, a result of industrialization and economic optimization of land use, was the dominant trend throughout the observed period, apparently overruling socio-economic framework conditions and land use policies.     

The contribution of future agricultural trends in the US Midwest to global climate change mitigation

Land use change is a complex response to changing environmental and socioeconomic systems. Historical drivers of land use change include changes in the natural resource availability of a region, changes in economic conditions for production of certain products and changing policies. Most recently, introduction of policy incentives for biofuel production have influenced land use change in the US Midwest, leading to concerns that bioenergy production systems may compete with food production and land conservation. Here we explore how land use may be impacted by future climate mitigation measures by nesting a high resolution agricultural model (EPIC – Environmental Policy Indicator Climate) for the US Midwest within a global integrated assessment model (GCAM – Global Change Assessment Model). This approach is designed to provide greater spatial resolution and detailed agricultural practice information by focusing on the climate mitigation potential of agriculture and land use in a specific region, while retaining the global economic context necessary to understand the far ranging effects of climate mitigation targets. We find that until the simulated carbon prices are very high, the US Midwest has a comparative advantage in producing traditional food and feed crops over bioenergy crops. Overall, the model responds to multiple pressures by adopting a mix of future responses. We also find that the GCAM model is capable of simulations at multiple spatial scales and agricultural technology resolution, which provides the capability to examine regional response to global policy and economic conditions in the context of climate mitigation.     

Baseline scenarios of global environmental change

This paper presents three baseline scenarios of no policy action computed by the IMAGE 2 model. These scenarios cover a wide range of coupled global change Indicators, including: energy demand and consumption; food demand, consumption, and production; changes in land cover including changes in extent of agricultural land and forest; emissions of greenhouse gases and ozone precursors; and climate change and its impacts on sea level rise, crop productivity and natural vegetation. Scenario information is available for the entire world with regional and grid scale detail, and covers from 1970 to 2100. The scenarios indicate that the coming decades could be a period of relatively rapid global environmental change as compared to the period before and after. The natural vegetation in industrialized regions could be threatened by climate change, but abandonment of agricultural lands could also make new lands available for reforestation and revegetation. The opposite is true for most of Asia and Africa. Here the impacts of climate change on vegetation may not be as significant as in temperate climates, but the demand for food will lead to a significant expansion of agricultural lands at the expense of remaining forests and other natural areas.     

基于信息扩散方法的中国西北地区春季沙尘暴灾害风险分析

通过收集大量沙尘暴灾情资料,整理出我国西北地区春季沙尘暴造成的经济损失及农业损失数据,采用基于信息扩散理论的风险评估方法对因灾造成的经济和农业损失风险分别进行了分析.结果表明:①在春季沙尘暴发生日数总体减少的气候背景下,沙尘暴造成的经济和农业损失均呈现出上升的趋势.②经济损失风险高值区主要分布在阿拉善、锡林郭勒、塔里木、阿勒泰、塔城及吐鲁番地区.农业损失风险高值区主要分布在吐鲁番、阿克苏、和田、瓜州、阿拉善地区.     

The Vulnerability of the Australian Beef Industry to Impacts of the Cattle Tick (Boophilus microplus) under Climate Change

An integrated assessment is presented of the potential impacts of the cattle tick (Boophilus microplus Canestrini) on the Australian beefindustry under climate change. The project was carried out as a case study to test an impact assessment approach that was designed to integrate biological, production and socio-economic impacts on managed and natural systems. A climate-driven, tick population model was run for European, zebu and crossbred cattle breeds having different levels of resistance to cattle ticks. A geographical information system (GIS) was used to organise spatial data on climate scenarios and industry statistics and to undertake regional analyses.A comparison was made of the two available approaches to conducting impact assessments, namely a bottom-up approach using sensitivity analysis and a top-down approach using climate change scenarios from a global circulation model (GCM) (CSIRO, 1996). The output, in terms of the abundance of tick populations and reductions in cattle productivity for each breed showed significant expansions in potential geographical impacts. In the absence of any adaptation measures, the results indicated changes in the losses in live weight gain of cattle tick ranging from 7780 tonnes per year by 2030 to 21637 tonnes per year by 2100, in comparison with estimates for current losses of 6594 tonnes per year.The principal adaptation options available to the beef industry are to switch to breeds that are more resistant to cattle ticks, or to increase the frequency of treatments with various tick control products. In this paper we focus on switching breeds as an adaptive measure when appropriate damage thresholds are triggered under the climate change scenarios. When adaptation measures were put in place, the losses ranged from 4962 tonnes in 2030 to 5619 tonnes in 2100 compared with 2636 tonnes at present if all producers adopted the optimal breed structure. Optimal breed structure was defined as one that would prevent tick numbers per animal exceeding 100 ticks per animal for European and 700 ticks per animal for crossbred breeds of cattle in any week of the year under a tick control strategy that was suitable for present climatic conditions. The lower threshold for European breeds reflects their vulnerability to explosive increases in numbers because of their low resistance to ticks. The results of the analyses using the GCM scenarios were used in an economic model to calculate costs of lost live-weight gain for 2030, 2070 and 2100. The greatest increases in costs were incurred in the southern parts of the current distribution in Queensland and potentially in northern New South Wales if the present quarantine barrier failed.Given the great uncertainty of the nature of possible regional changes in climate, analyses of the sensitivity of losses in live weight gain to changes in climatic variables were also undertaken. The analyses included a measure of likely impacts of cattle tick on the beef cattle industry, in the absence of adaptation measures, as a baseline measure of sensitivity. The likely impacts on crossbred cattle were insensitive to the climatic variables.When adaptive breed changes were allowed, the economic impacts on the industry were insensitive to the GCM scenarios. This suggests that, at least in this instance, reducing the uncertainties in climate change scenarios is not a priority if the adaptation strategies can be implemented in a cost-effective manner. Finally we made a qualitative assessment of the sustainability and robustness of alternative approaches to adaptation and assessed regional vulnerability to cattle tick under climate change. The conclusions were so strongly dependent on assumptions about the future of other global changes, in particular the ability to maintain quarantine barriers and to retain effective acaricides at comparable costs to the present, that we strongly recommend that risk assessments of climate change extend to all relevant variables in involved in global change where possible.     

Prioritising resilience policies to reduce welfare losses from natural disasters: A case study for coastal Bangladesh

Quantified flood risk assessments focus on asset losses, neglecting longer-term impacts to household welfare via income and consumption losses. The extent of welfare losses depends upon resilience – the ability to anticipate, resist, cope, recover and learn from a shock. Here, we use a novel welfare loss modelling framework and perform a high-resolution spatial analysis in coastal Bangladesh to quantify welfare losses from a tropical cyclone under present and future climatic and socio-economic conditions. We further test various adaptation options that are intended to enhance resilience. Results show that poor households experience, on average, 7% of the asset losses, but 42% of the welfare losses. Combining dike heightening, post-disaster support and stronger housing can reduce welfare losses by up to 70%, and foster sustainable development by benefitting the poor, increasing resilience and demonstrating robustness under socio-economic and climatic uncertainties. Thus, a welfare-orientated perspective helps to identify adaptation options that enhance resilience and leave no-one behind.     

South African crop farming and climate change: An economic assessment of impacts

This paper assesses the economic impact of the expected adverse changes in the climate on crop farming in South Africa using a revised Ricardian model and data from farm household surveys, long-term climate data, major soils and runoffs. Mean annual estimates indicate that a 1% increase in temperature will lead to about US$ 80.00 increase in net crop revenue while a 1 mm/month fall in precipitation leads to US$ 2.00 fall, but with significant seasonal differences in impacts. There are also significant spatial differences and across the different farming systems. Using selected climate scenarios, the study predicts that crop net revenues are expected to fall by as much as 90% by 2100 with small-scale farmers been most affected. Policies therefore need to be fine-tuned and more focused to take advantage of the relative benefits across seasons, farming systems and spatially, and by so doing climate change may be beneficial rather than harmful.     

Where are Germany’s gains from Kyoto? Estimating the effects of global warming on agriculture

Motivated by the high abatement costs of the Kyoto Protocol for Germany, this paper is estimating the economic impact of global warming on agriculture in that country. The hedonic approach is used as theoretical background. Stating that land prices are – among others – determined by climatic factors, this approach can consequently be used to value global warming. To avoid a priori restrictions stemming from functional forms, the land price function is modeled as quadratic Box–Cox function that nests a wide range of specifications. In a second step, the estimated results are used to forecast the impact of climate change. The results indicate that German farmers will be winners of climate change in the short run, with maximum gains occurring at a temperature increase of +0.6°C against current levels. In the long run, there may be losses from global warming. However, the net present value from climate change is under the most probable scenarios positive.