The poverty implications of climate-induced crop yield changes by 2030

Accumulating evidence suggests that agricultural production could be greatly affected by climate change, but there remains little quantitative understanding of how these agricultural impacts would affect economic livelihoods in poor countries. Here we consider three scenarios of agricultural impacts of climate change by 2030 (impacts resulting in low, medium, or high productivity) and evaluate the resulting changes in global commodity prices, national economic welfare, and the incidence of poverty in a set of 15 developing countries. Although the small price changes under the medium scenario are consistent with previous findings, we find the potential for much larger food price changes than reported in recent studies which have largely focused on the most likely outcomes. In our low-productivity scenario, prices for major staples rise 10–60% by 2030. The poverty impacts of these price changes depend as much on where impoverished households earn their income as on the agricultural impacts themselves, with poverty rates in some non-agricultural household groups rising by 20–50% in parts of Africa and Asia under these price changes, and falling by significant amounts for agriculture-specialized households elsewhere in Asia and Latin America. The potential for such large distributional effects within and across countries emphasizes the importance of looking beyond central case climate shocks and beyond a simple focus on yields – or highly aggregated poverty impacts.     

Climate Change, Agriculture, and Water Quality in the Chesapeake Bay Region

Research on climate change and agriculture has largely focused on production, food prices, and producer incomes. However, societal interest in agriculture is much broader than these issues. The objective of this paper is to analyze the potential impacts of climate change on an important negative externality from agriculture, water quality. We construct a simulation model of maize production in twelve watersheds within the U.S. Chesapeake Bay Region that has economic and watershed components linking climate to productivity, production decisions by maize farmers, and nitrogen loadings delivered to the Chesapeake Bay. Maize is an important crop to study because of its importance to the region's agriculture and because it is a major source of nutrient pollution. The model is run under alternative scenarios regarding the future climate, future baseline (without any climate change), whether farmers respond to climate change, whether there are carbon dioxide (CO₂) enrichment effects on maize production, and whether agricultural prices facing the region change due to climate change impacts on global agricultural commodity markets. The simulation results differ from one scenario to another on the magnitude and direction of change in nitrogen deliveries to the Chesapeake Bay. The results are highly sensitive to the choice of future baseline scenario and to whether there are CO₂ enrichment effects. The results are also highly sensitive to assumptions about the impact of climate change on commodity prices facing farmers in the Chesapeake Bay region. The results indicate that economic responses by farmers to climate change definitely matter. Assuming that farmers do not respond to changes in temperature, precipitation, and atmosphericCO₂ levels could lead to mistaken conclusions about the magnitude and direction of environmental impacts.     

Impacts of a nuclear war in South Asia on rice production in Mainland China

A regional nuclear war between India and Pakistan with a 5 Tg black carbon injection into the upper troposphere would produce significant climate changes for a decade, including cooling, reduction of solar radiation, and reduction of precipitation, which are all important factors controlling agricultural productivity. We used the Decision Support System for Agrotechnology Transfer agricultural simulation model to simulate regional nuclear war impacts on rice yield in 24 provinces in China. We first evaluated the model by forcing it with daily weather data and management practices for the period 1980–2008 for 24 provinces in China, and compared the results to observations of rice yields in China. Then we perturbed observed weather data using climate anomalies for a 10-year period from a nuclear war simulation. We perturbed each year of the 30-year climate record with anomalies from each year of the 10-year nuclear war simulations for different regions in China. We found that rice production would decline by an average of 21 % for the first 4 years after soot injection, and would slowly recover in the following years. For the next 6 years, the reduction in rice production was about 10 %. Different regions responded differently to climate changes from nuclear war. Rice production in northern China was damaged severely, while regions along the south and east coasts showed a positive response to regional nuclear war. Although we might try to adapt to a perturbed climate by enhancing rice planting activity in southern and eastern China or increasing fertilizer usage, both methods have severe limitations. The best solution to avoid nuclear war impacts on agriculture is to avoid nuclear war, and this can only be guaranteed with a nuclear-weapon-free world.     

Agricultural risk management policies under climate uncertainty

Climate change is forecasted to increase the variability of weather conditions and the frequency of extreme events. Due to potential adverse impacts on crop yields it will have implications for demand of agricultural risk management instruments and farmers’ adaptation strategies. Evidence on climate change impacts on crop yield variability and estimates of production risk from farm surveys in Australia, Canada and Spain, are used to analyse the policy choice between three different types of insurance (individual, area-yield and weather index) and ex post payments. The results are found to be subject to strong uncertainties and depend on the risk profile of different farmers and locations; the paper provides several insights on how to analyse these complexities. In general, area yield performs best more often across our countries and scenarios, in particular for the baseline and marginal climate change (without increases in extreme events). However, area yield can be very expensive if farmers have limited information on how climate change affects yields (misalignment in expectations), and particularly so under extreme climate change scenarios. In these more challenging cases, ex post payments perform well to increase low incomes when the risk is systemic like in Australia; Weather index performs well to reduce the welfare costs of risks when the correlation between yields and index is increased by the extreme events. The paper also analyses the robustness of different instruments in the face of limited knowledge of the probabilities of different climate change scenarios; highlighting that this added layer of uncertainty could be overcome to provide sound policy advice under uncertainties introduced by climate change. The role of providing information to farmers on impacts of climate change emerges as a crucial result of this paper as indicated by the significantly higher budgetary expenditures occurring across all instruments when farmers’ expectations are misaligned relative to actual impacts of climate change.     

Adapting dryland agriculture to climate change: Farming implications and research and development needs in Western Australia

The Western Australian wheat-belt has experienced more rainfall decline than any other wheat-cropping region in Australia. Future climate change scenarios suggest that the Western Australian wheat-belt is likely to see greater future reductions in rainfall than other regions, together with a further increase in temperatures. While these changes appear adverse for water-limited rain-fed agriculture, a close analysis of the changes and their impacts reveals a more complex story. Twentieth century changes in rainfall, temperature and atmospheric CO₂ concentration have had little or no overall impact on wheat yields. Changes in agricultural technology and farming systems have had much larger impacts. Contrary to some claims, there is no scientific or economic justification for any immediate actions by farmers to adapt to long-term climate change in the Western Australian wheat-belt, beyond normal responses to short-term variations in weather. Rather than promoting current change, the most important policy response is research and development to enable farmers to facilitate future adaptation to climate change. Research priorities are proposed.     

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.     

Impact of climate change on irrigation water demand of dry season Boro rice in northwest Bangladesh

Climate change will affect irrigation water demand of rice via changes in rice physiology and phenology, soil water balances, evapotranspiration and effective precipitation. As agriculture is the main sector of water use in Bangladesh, estimation of the agricultural water demand in the changing environment is essential for long-term water resources development and planning. In the present paper, a study has been carried out to estimate the change of irrigation water demand in dry-season Boro rice field in northwest Bangladesh in the context of global climate change. The study shows that there will be no appreciable changes in total irrigation water requirement due to climate change. However, there will be an increase in daily use of water for irrigation. As groundwater is the main source of irrigation in northwest Bangladesh, higher daily pumping rate in dry season may aggravate the situation of groundwater scarcity in the region.     

Thermal Climate Variations and Potential Modification of the Cropping Pattern in Bangladesh

Summary Changes in the thermal climate due to inter-annual climatic variability can potentially modify existing cropping pattern by forcing farmers to rearrange transplanting and harvesting dates. In the present study, a crop climate model, the YIELD, has been applied to 12 meteorological stations located in major rice growing regions in Bangladesh to estimate the effect of thermal climate variations on the transplanting and harvesting dates of boro rice and the resultant potential changes in cropping pattern and spatial shift. The abnormal thermal climate scenarios have been created by synthetically perturbing mean air temperatures (T_air) up to −5 °C to +5 °C with an interval of 1 °C for each of these stations. Historical meteorological records of air temperature in Bangladesh have been used to prepare these scenarios. The study finds that under abnormally cool conditions transplanting dates will be pushed well into February to avoid plant injury and harvesting dates will be moved into the monsoon. The growing seasons will be longer under cooler than normal thermal conditions. Under abnormally warm conditions harvesting dates will be established well into March and will cause reduction of yield due to a shorter growing season. These conditions will also cause spatial shift in crop potential and changes in the cropping pattern. Due to a longer boro rice growing season farmers will lose a significant amount of cropping land which is usually used for low and deep water rice cultivation. New crops will need to be introduced during the beginning of a year to overcome the loss of production under abnormally cool conditions. Wheat and potato can be good options for the farmers for such conditions. New aus rice variety needs to be introduced after the boro harvesting under warmer than the normal conditions to overcome the loss of yield due to a shorter growing season. Received September 16, 1996 Revised September 8, 1997     

Spatial modelling of rice yield losses in Tanzania due to bacterial leaf blight and leaf blast in a changing climate

Rice is the most rapidly growing staple food in Africa and although rice production is steadily increasing, the consumption is still out-pacing the production. In Tanzania, two important diseases in rice production are leaf blast caused by Magnaporthe oryzae and bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae. The objective of this study was to quantify rice yield losses due to these two important diseases under a changing climate. We found that bacterial leaf blight is predicted to increase causing greater losses than leaf blast in the future, with losses due to leaf blast declining. The results of this study indicate that the effects of climate change on plant disease can not only be expected to be uneven across diseases but also across geographies, as in some geographic areas losses increase but decrease in others for the same disease.     

气候变化对我国农作物种植结构的影响

气候变化引起水热条件的变化,从而影响到我国农业生产的方方面面,人们采取不同措施以适应气候变化带来的各种影响。为了清楚地认识气候变化对我国主要粮食作物生产的影响以及适应措施,利用《中国农业统计年鉴》1980-2007年资料和1961-2007年全国逐日平均温度观测数据及前人的研究成果,分析了气候变化对我国三大粮食作物布局和种植结构的影响。结果表明,由于气候变暖,粮食作物种植比例变化明显。小麦种植比例对气候变化最为敏感,波动大;水稻种植比例变化南北方反向,且变化幅度趋缓;玉米种植比例持续增加,增幅加大。三大粮食作物种植结构变化均以2000年为分界点,呈现不同增减趋势。而作物熟制、复种指数也发生明显变化,种植北界持续北推。黑龙江地区大面积扩种水稻,原来的玉米优势种植区为水稻所替代。     

Agricultural Impact Assessment, Vulnerability, and the Scope for Adaptation

Climate change assessments which have considered climate impacts of a 2xCO₂ climate, using models of the global agricultural system, have found small impacts on overall production, but larger regional changes. Production shifts among regions can be considered one mechanism for adaptation. Adaptation at the farm level, through changes in crops, cultivars, and production practices, is another adaptation mechanism. Existing studies differ in how important these mechanisms will be. Studies that have considered yield effects at specific sites have found very wide ranges of impacts. A useful way to evaluate the impacts of climate change, given the uncertainty about future impacts, is to consider vulnerability. Studies have defined vulnerability in terms of yield, farm profitability, regional economy, and hunger. Vulnerability and climate impacts, particularly in terms of higher order effects on profitability and sustainability, will depend on how society and the economy develop. Lower income populations and marginal agricultural regions, particularly arid or flood prone areas, are most vulnerable to climate change.     

Adaptation to climate change in Bangladesh

Climate change is expected to disproportionately affect agriculture in Bangladesh; however, there is limited information on smallholder farmers’ overall vulnerability and adaptation needs. This article estimates the impact of climatic shocks on the household agricultural income and, subsequently, on farmers’ adaptation strategies. Relying on data from a survey conducted in several communities in Bangladesh in 2011 and based on an IV probit approach, the results show that a 1 percentage point (pp) climate-induced decline in agricultural income pushes Bangladeshi households to adapt by almost 3 pp. Moreover, Bangladeshi farmers undertake a variety of adaptation options. However, several barriers to adaptation were identified, noticeably access to electricity and wealth. In this respect, policies can be implemented in order to assist the Bangladeshi farming community to adapt to climate change.

Policy relevance

This study contributes to the literature of adaptation to climate change by providing evidence of existing risk-coping strategies and by showing how a household’s ability to adapt to weather-related risk can be limited. This study helps to inform the design of policy in the context of increasing climatic stress on the smallholder farmers in Bangladesh.     

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.     

A FARMer's View of the Ricardian Approach to Measuring Agricultural Effects of Climatic Change

During the past few years two new methods, each based on the analogous region concept, have been developed to account for farmer adaptation in response to global climatic change. The first, called 'Ricardian' by Mendelsohn, Nordhaus, and Shaw (1994), econometrically estimates the impact of climatic and other variables on the value of farm real estate. Under some conditions, estimates of climate-induced changes in farm real estate capture first-round adaptations by farmers and represent the economic value of climatic change on agriculture. The second method, promulgated by Darwin et al. (1994) in the Future Agricultural Resources Model (FARM), uses a geographic information system to empirically link climatically derived land classes with other inputs and agricultural outputs in an economic model of the world. FARM provides estimates of economic impacts that fully account for all responses by economic agents under global climate change as well as estimates of Ricardian rents. The primary objective of this analysis is to evaluate how well changes in Ricardian rents measure agricultural or other effects of climatic change after all economic agents around the world have responded. Results indicate that changes in Ricardian rents on agricultural land are poor quantitative, but good qualitative, measures of how global climatic change is likely to affect the welfare of agricultural landowners, if one recognizes that increases in Ricardian rents actually indicate losses in landowner welfare and vice versa. Results also indicate that regional changes in Ricardian rents on all land are good qualitative measures of changes in regional welfare. They are poor quantitative welfare measures because they systematically overestimate both benefits and losses and are on average upwardly biased because inflated benefits are larger than exaggerated losses. Results also indicate that, when based on existing land-use patterns, changes in Ricardian rents on all the world's land are poor quantitative and qualitative measures of changes in world welfare. Despite these shortcomings, changes in Ricardian rents can provide useful information when other measures are not available. In this analysis, for example, estimated changes in Ricardian rents on all land indicate that climatic change would likely have detrimental effects in Latin America and Africa, beneficial effects in the former Soviet Union, and either detrimental or beneficial impacts in eastern and northern Europe and western and southern Asia. This is consistent with previous studies showing that climatic change would likely have detrimental, beneficial, and mixed effects on economic welfare in, respectively, equatorial, high latitude, and temperate areas. Estimated changes in Ricardian rents also indicate that aggregating Africa, Latin America, the former Soviet Union, eastern and northern Europe, and western and southern Asia into one region causes FARM's economic model to generate upwardly biased changes in world welfare. Modified results from scenarios with moderately flexible land-use change and which account for current land-use patterns indicate that world welfare may increase if the average surface land temperature does not increase by more than 1.0 or 2.0°C. If the average surface land temperature increases by 3.0°C or more, however, then world welfare may decline.     

Effects of climate change and agronomic practice on changes in wheat phenology

Phenological changes in crops affect efficient agricultural production and can be used as important biological indicators of local and regional climate change. Although crop phenological changes and their responses to climate change, especially temperature, have been investigated, the impact of agronomic practice such as cultivar shifts and planted date changes on crop phenology remains unclear. Here, we used a long-term dataset (1981–2010) of wheat phenology and associated local weather data from 48 agro-meteorological stations in four temperature zones in China to analyze phenological changes of spring and winter wheat. Trend analysis method was used to estimate changes in the date of growth stages and the duration of growth phases, while sensitivity analysis method was used to qualify the response of growth phase duration to mean temperature (T_mean), total precipitation (PRE), and total sunshine duration (SSD). Using the Crop Environment Resource Synthesis-wheat model, we isolated the impacts of climate change, cultivar selection, and sowing date on phenological change of wheat. Results show that phenological changes were greatest in the warm-temperate zone. Sensitivity analysis indicates that growth phase duration was generally negatively related to T_mean and positively related to PRE and SSD. The positive sensitivity response to T_mean occurred in the tillering to jointing and sowing to maturity growth periods in the warmer temperature zones, suggesting that warmer temperatures during the overwintering period hampered effective vernalization in winter wheat. Modeling results further indicate that reductions in wheat growth duration caused by climate change could be offset by the introduction of new cultivars with high thermal requirements and accelerated with delayed sowing date.     

Paper 6. consequences of climate change for the mink economy: impacts and responses

The impacts of climate change on the agricultural, energy, forestry, and water sectors of MINK would reverberate negatively throughout the regional economy. Allowing for sectoral adjustments to the new climate, however, the decline in regional income and production would not likely exceed 1–2%. The largest economy-wide impacts would be by way of the agricultural and water sectors. The impacts by way of forestry and energy would be negligible, unless the nation adopts a program of massive reforestation to capture CO₂, which would positively affect the regional economy.     

气候变化对中国农业生产影响研究展望

综述了气候变化背景下中国农业气候资源、农业气象灾害(干旱、洪涝、高温热浪、低温灾害)和农业病虫害的变化趋势与规律,从农业生产潜力变化、作物种植制度变化和作物品质变化等方面阐明了气候变化对中国农业生产的影响事实,分析了气候变化对中国农业生产的可能影响和中国农业生产适应气候变化的对策措施。在此基础上,针对气候变化背景下中国气候资源的时空分布特点及农业生产出现的新情况、新问题,指出了当前中国关于气候变化对农业影响研究存在的不足,提出了未来气候变化对中国农业生产影响研究需要重视的方面,为确保气候变化背景下中国的农业生产安全及粮食安全提供决策支持。     

Social risk perceptions of climate change: A case study of farmers and agricultural advisors in northern California

Crop and livestock farmers must respond to climate change, including a range of physical and cultural impacts and risks. In rural northern California, farmers face extreme drought and catastrophic wildfires with increasing frequency. I draw on an extended case study of farmers and agricultural advisors in Siskiyou County to understand how rural agriculturalists perceive risks when navigating climate change discourses. While farmers are changing their management practices in response to the physical effects of climate change, many perceive substantial social risks within their communities if they align themselves publicly with climate change beliefs or actions. Perceived social consequences included loss of access to the benefits of membership in formal and informal farming groups. Efforts focused on educating or convincing farmers of climate science may, in some contexts, increase rather than decrease the perceived social risks of climate action. The framing of climate policies, programs, and practices – especially by public agricultural advisors like Cooperative Extension Advisors and local USDA staff (e.g., Farm Service Agency) – is important not only for increasing farmer participation, but also for reducing perceived social risks associated with climate change. Interventions that focus on livelihood impacts and validate existing land stewardship-oriented values have more potential to increase the pace and scale of climate change mitigation and adaptation in agriculture.     

Farm programs and climate change

The view that the agricultural sector could largely offset any negative impacts of climate change by altering production practices assumes the government will not create disincentives for farmers to adapt. U.S. farm programs, however, often discourage such obvious adaptations as switching crops, investing in water conserving technologies, and entry or exit. We outline a simple portfolio model describing producer decision making: we then use this framework to assess how specific U.S. farm programs might affect adaption to climate change. Three future climate scenarios are considered and in each the present structure of U.S. farm programs discourages adaptation.     

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.