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.     

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.     

Climate change and mid-latitudes agriculture: Perspectives on consequences and policy responses

Because of population growth, economic development, and technological change, world and mid-latitudes agriculture will look very different than they do today by the time 2 × CO₂ climate change begins to have major impact. It does not appear that that impact would seriously restrain the growth of world agricultural capacity. However, significant shifts in regional comparative advantage in agriculture would be likely. Because the consequences of 2 × CO₂ climate change for agriculture would vary among countries - some suffering losses, others seeing themselves as potential winners - these consequences could impede international agreements to control climate change. However, even countries gaining agricultural advantage from climate change will need changes in policy to capture the gains. And policies to lessen the costs to the losers will be essential. If global warming continues beyond that associated with 2 × CO₂, all countries in time would be losers.     

Future cereal production in China: The interaction of climate change,water availability and socio-economic scenarios

Food production in China is a fundamental component of the national economy and driver of agricultural policy. Sustaining and increasing output to meet growing demand faces significant challenges including climate change, increasing population, agricultural land loss and competing demands for water. Recent warming in China is projected to accelerate by climate models with associated changes in precipitation and frequency of extreme events. How changes in cereal production and water availability due to climate change will interact with other socio-economic pressures is poorly understood. By linking crop and water simulation models and two scenarios of climate (derived from the Regional Climate Model PRECIS) and socio-economic change (downscaled from IPCC SRES A2 and B2) we demonstrate that by the 2040s the absolute effects of climate change are relatively modest. The interactive effects of other drivers are negative, leading to decreases in total production of ?18% (A2) and ?9% (B2). Outcomes are highly dependent on climate scenario, socio-economic development pathway and the effects of CO₂ fertilization on crop yields which may almost totally offset the decreases in production. We find that water availability plays a significant limiting role on future cereal production, due to the combined effects of higher crop water requirements (due to climate change) and increasing demand for non-agricultural use of water (due to socio-economic development). Without adaptation, per capita cereal production falls in all cases, by up to 40% of the current baseline.By simulating the effects of three adaptation scenarios we show that for these future scenarios China is able to maintain per capita cereal production, given reasonable assumptions about policies on land and water management and progress in agricultural technology. Our results are optimistic because PRECIS simulates much wetter conditions than a multi-model average, the CO₂ crop yield response function is highly uncertain and the effects of extreme events on crop growth and water availability are likely to be underestimated.     

Water resources for agriculture in a changing climate: international case studies

This integrated study examines the implications of changes in crop water demand and water availability for the reliability of irrigation, taking into account changes in competing municipal and industrial demands, and explores the effectiveness of adaptation options in maintaining reliability. It reports on methods of linking climate change scenarios with hydrologic, agricultural, and planning models to study water availability for agriculture under changing climate conditions, to estimate changes in ecosystem services, and to evaluate adaptation strategies for the water resources and agriculture sectors. The models are applied to major agricultural regions in Argentina, Brazil, China, Hungary, Romania, and the US, using projections of climate change, agricultural production, population, technology, and GDP growth.For most of the relatively water-rich areas studied, there appears to be sufficient water for agriculture given the climate change scenarios tested. Northeastern China suffers from the greatest lack of water availability for agriculture and ecosystem services both in the present and in the climate change projections. Projected runoff in the Danube Basin does not change substantially, although climate change causes shifts in environmental stresses within the region. Northern Argentina's occasional problems in water supply for agriculture under the current climate may be exacerbated and may require investments to relieve future tributary stress. In Southeastern Brazil, future water supply for agriculture appears to be plentiful. Water supply in most of the US Cornbelt is projected to increase in most climate change scenarios, but there is concern for tractability in the spring and water-logging in the summer.Adaptation tests imply that only the Brazil case study area can readily accommodate an expansion of irrigated land under climate change, while the other three areas would suffer decreases in system reliability if irrigation areas were to be expanded. Cultivars are available for agricultural adaptation to the projected changes, but their demand for water may be higher than currently adapted varieties. Thus, even in these relatively water-rich areas, changes in water demand due to climate change effects on agriculture and increased demand from urban growth will require timely improvements in crop cultivars, irrigation and drainage technology, and water management.     

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.     

The effect of global climate change, population distribution, and climate mitigation on building energy use in the U.S. and China

Climate change will affect the energy system in a number of ways, one of which is through changes in demands for heating and cooling in buildings. Understanding the potential effect of climate change on heating and cooling demands requires taking into account not only the manner in which the building sector might evolve over time, but also important uncertainty about the nature of climate change itself. In this study, we explore the uncertainty in climate change impacts on heating and cooling requirement by constructing estimates of heating and cooling degree days (HDD/CDDs) for both reference (no-policy) and 550 ppmv CO₂ concentration pathways built from three different Global Climate Models (GCMs) output and three scenarios of gridded population distribution. The implications that changing climate and population distribution might have for building energy consumption in the U.S. and China are then explored by using the results of HDD/CDDs as inputs to a detailed, building energy model, nested in the long-term global integrated assessment framework, Global Change Assessment Model (GCAM). The results across the modeled changes in climate and population distributions indicate that unabated climate change would cause building sector’s final energy consumption to decrease modestly (6 % decrease or less depending on climate models) in both the U.S. and China by the end of the century as decreased heating consumption more than offsets increased cooling using primarily electricity. However, global climate change virtually has negligible effect on total CO₂ emissions in the buildings sector in both countries. The results also indicate more substantial implications for the fuel mix with increases in electricity and decreases in other fuels, which may be consistent with climate mitigation goals. The variation in results across all scenarios due to variation of population distribution is smaller than variation due to the use of different climate models.     

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.     

An Investigation of the Relationship between Pesticide Usage and Climate Change

One concern of agriculturalists when regarding climate change involves the effects on pest populations. Climate change may allow pest migration or population expansions which may adversely affect agricultural productivity, profitability and possibly even viability. We examine the effect of current climate variations on the average and variability of U.S. per acre pesticide costs across the U.S. as a proxy for investigating the consequence for pest populations. Empirically, we find that increases in rainfall increases average per acre pesticide usage costs for corn, cotton, potatoes, soybeans, and wheat while hotter weather increases pesticide costs for corn, cotton, potatoes, and soybeans but decreases the cost for wheat. We also investigated the influence of climate on the variability of pesticide costs. There we find that hotter temperatures increase pesticide cost variance for corn, potatoes, and wheat while decreasing it for soybeans. Rainfall increases cause an increase in cost variability for cotton while decreasing it for corn, potatoes, soybeans, and wheat.     

Assessing the Consequences of Climate Change for Food and forest Resources: A View from the IPCC

Important findings on the consequences of climate change for agriculture and forestry from the recently completed Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) are reviewed, with emphasis on new knowledge that emerged since the Second Assessment Report (SAR). The State-Pressure-Response-Adaptation model is used to organize the review. The major findings are:

• Constant or declining food prices are expected for at least the next 25 yr, although food security problems will persist in many developing countries as those countries deal with population increases, political crisis, poor resource endowments, and steady environmental degradation. Most economic model projections suggest that low relative food prices will extend beyond the next 25 yr, although our confidence in these projections erodes farther out into the 21st century.
• Although deforestation rates may have decreased since the early 1990s, degradation with a loss of forest productivity and biomass has occurred at large spatial scales as a result of fragmentation, non-sustainable practices and infrastructure development.
• According to United Nations estimates, approximately 23% of all forest and agricultural lands were classified as degraded over the period since World War II.
• At a worldwide scale, global change pressures (climate change, land-use practices and changes in atmospheric chemistry) are increasingly affecting the supply of goods and services from forests.
• The most realistic experiments to date – free air experiments in an irrigated environment – indicate that C₃ agricultural crops in particular respond favorably to gradually increasing atmospheric CO₂ concentrations (e.g., wheat yield increases by an average of 28%), although extrapolation of experimental results to real world production where several factors (e.g., nutrients, temperature, precipitation, and others) are likely to be limiting at one time or another remains problematic. Moreover, little is known of crop response to elevated CO₂ in the tropics, as most of the research has been conducted in the mid-latitudes.
• Research suggests that for some crops, for example rice, CO₂ benefits may decline quickly as temperatures warm beyond optimum photosynthetic levels. However, crop plant growth may benefit relatively more from CO₂ enrichment in drought conditions than in wet conditions.
• The unambiguous separation of the relative influences of elevated ambient CO₂ levels, climate change responses, and direct human influences (such as present and historical land-use change) on trees at the global and regional scales is still problematic. In some regions such as the temperate and boreal forests, climate change impacts, direct human interventions (including nitrogen-bearing pollution), and the legacy of past human activities (land-use change) appear to be more significant than CO₂ fertilization effects. This subject is, however an area of continuing scientific debate, although there does appear to be consensus that any CO₂ fertilization effect will saturate (disappear) in the coming century.
• Modeling studies suggest that any warming above current temperatures will diminish crop yields in the tropics while up to 2–3 ^°C of warming in the mid-latitudes may be tolerated by crops, especially if accompanied by increasing precipitation. The preponderance of developing countries lies in or near the tropics; this finding does not bode well for food production in those countries.
• Where direct human pressures do not mask them, there is increasing evidence of the impacts of climate change on forests associated with changes in natural disturbance regimes, growing season length, and local climatic extremes.
• Recent advances in modeling of vegetation response suggest that transient effects associated with dynamically responding ecosystems to climate change will increasingly dominate over the next century and that during these changes the global forest resource is likely to be adversely affected.
• The ability of livestock producers to adapt their herds to the physiological stress of climate change appears encouraging due to a variety of techniques for dealing with climate stress, but this issue is not well constrained, in part because of the general lack of experimentation and simulations of livestock adaptation to climate change.
• Crop and livestock farmers who have sufficient access to capital and technologies should be able to adapt their farming systems to climate change. Substantial changes in their mix of crops and livestock production may be necessary, however, as considerable costs could be involved in this process because investments in learning and gaining experience with different crops or irrigation.
• Impacts of climate change on agriculture after adaptation are estimated to result in small percentage changes in overall global income. Nations with large resource endowments (i.e., developed countries) will fare better in adapting to climate change than those with poor resource endowments (i.e., developing countries and countries in transition, especially in the tropics and subtropics) which will fare worse. This, in turn, could worsen income disparities between developed and developing countries.
• Although local forest ecosystems will be highly affected, with potentially significant local economic impacts, it is believed that, at regional and global scales, the global supply of timber and non-wood goods and services will adapt through changes in the global market place. However, there will be regional shifts in market share associated with changes in forest productivity with climate change: in contrast to the findings of the SAR, recent studies suggest that the changes will favor producers in developing countries, possibly at the expense of temperate and boreal suppliers.
• Global agricultural vulnerability is assessed by the anticipated effects of climate change on food prices. Based on the accumulated evidence of modeling studies, a global temperature rise of greater than 2.5 ^°C is likely to reverse the trend of falling real food prices. This would greatly stress food security in many developing countries.

     

Impacts of Climate Changes on Elk Population Dynamics in Rocky Mountain National Park, Colorado, U.S.A.

Changing climate may impact wildlife populations in national parks and conservation areas. We used logistic and non-linear matrix population models and 35 years of historic weather and population data to investigate the effects of climate on the population dynamics of elk in Rocky Mountain National Park (RMNP), Colorado, U.S.A. We then used climate scenarios derived from Hadley and Canadian Climate Center (CCC) global climate models to project the potential impact of future climate on the elk population. All models revealed density-dependent effects of population size on growth rates. The best approximating logistic population model suggested that high levels of summer precipitation accelerated elk population growth, but higher summer minimum temperatures slowed growth. The best approximating non-linear matrix model indicated that high mean winter minimum temperatures enhanced recruitment of juveniles, while high summer precipitation enhanced the survival of calves. Warmer winters and wetter summers predicted by the Hadley Model could increase the equilibrium population size of elk by about 100%. Warmer winters and drier summers predicted by the CCC Model couldraise the equilibrium population size of elk by about 50%. Managers of national parks have relied on effects of weather, particularly severe winters, to regulate populations of native ungulates and prevent harmful effects of overabundance. Our results suggest that these regulating effects of severe winter weather may weaken if climate changes occur as those that are widely predicted in most climate change scenarios.     

Adaptation of agriculture to warming in Northeast China

Northeast China comprises Heilongjiang, Jilin and Liaoning Provinces, with a total area of 790,000 km² and a population of about 107 million. Northeast China, located at relatively high latitudes, (from about 39 to 53°N), is one of the coolest regions in China with long and cold winters, a short growth season and frequent cold extreme events, which are adverse to agricultural production. However, since the 1980s, Northeast China has experienced significant warming with annual mean temperature rising by 1.0–2.5°C. The increase of accumulated temperature, the extension of the growth period and the recession of summer cool disasters all contributed to improved conditions for crop growth and led to a northward movement of the agricultural climate zone. In addition, the adaptation to warming including the adjustment of crop composition and structure as well as the adoption of advanced technologies greatly facilitated agricultural development. As a result, total grain production in the region increased rapidly. This paper describes in detail climate change, adaptation measures and final agricultural outcomes, alongside with economic and political factors and the role of different political actors in Northeast China.     

Yield Variability as Influenced by Climate: A Statistical Investigation

One of the issues with respect to climate change involves its influence on the distribution of future crop yields. Many studies have been done regarding the effect on the mean of such distributions but few have addressed the effect on variance. Furthermore, those that have been done generally report the variance from crop simulators, not from observations. This paper examines the potential effects of climate change on crop yield variance in the context of current observed yields and then extrapolates to the effects under projected climate change. In particular, maximum likelihood panel data estimates of the impacts of climate on year-to-year yield variability are constructed for the major U.S. agricultural crops. The panel data technique used embodies a variance estimate developed along the lines of the stochastic production function approach suggested by Just and Pope. The estimation results indicate that changes in climate modify crop yield levels and variances in a crop-specific fashion. For sorghum, rainfall and temperature increases are found to increase yield level and variability. On the other hand, precipitation and temperature are individually found to have opposite effects on corn yield levels and variability.     

美国退出《巴黎协定》的原因、影响及中国的对策

综合应用定性与定量分析方法,分析美国宣布退出《巴黎协定》的原因,评估美国退出《巴黎协定》对《巴黎协定》履约前景的影响并提出中国的应对策略。美国宣布退出《巴黎协定》是全球气候治理的重大事件,将对《巴黎协定》的履约产生多重影响,包括将对《巴黎协定》的普遍性构成严重伤害,动摇以《巴黎协定》为核心的国际气候治理体制的基础;将导致《巴黎协定》履约中的领导力赤字问题显著恶化;可能引发不良示范效应,降低国际气候合作信心;将会对其他地区碳排放空间形成不可忽视的挤压,进而推高其他地区碳减排成本;美国大幅削减国际气候援助资金将削弱发展中国家减缓和适应气候变化的能力;美国延迟采取气候行动可能导致全球减排错失最佳时间窗口;美国大幅削减气候变化基础研究经费将对未来全球气候科学研究产生不利影响,进而影响《巴黎协定》履约谈判的权威性等,最后显著加大实现温控目标的难度,甚至导致目标无法实现。就全球气候治理的全局而言,全球气候治理的框架不会坍塌,但确实会受到动摇;全球气候治理的进程不会逆转,但确实会迟滞。美国宣布退出《巴黎协定》使中国面临多重挑战,其中之一是中国面临急剧上升的期望中国承担全球气候治理领导的国际压力。为此,中国对内应实现国家自主贡献的上限目标,对外应积极重建全球气候治理集体领导体制,即用C5取代G2,同时继续努力改变美国对气候变化的消极立场。     

The impact of climate change on continuous corn production in the Southern U.S.A.

The Goddard Institute for Space Studies (GISS) General Circulation Model (GCM) has been used in conjunction with a field level plant process model (CERES-Maize) and a field level pesticide transport model (PRZM) to study the impacts of doubled levels of atmospheric CO₂ on various aspects of corn production in the Southern U.S.A. Grid-box scale GCM output has been applied to a 38-year time series of historical weather data at 28 different locations for several typical soil profiles throughout the South. Limitations on the use of the climate scenario in conjunction with the process models are discussed. Major shortcomings include: 1) no direct impacts of atmospheric CO₂ on plant growth and development in the plant process model; 2) neither macro-pore solute transport nor chemical decay rate response to temperature are included in the pesticide transport model; and 3) the climate change scenario output does not provide information concerning changes in temperature extremes and variability or precipitation frequency, intensity or duration. The latter are particularly critical parameters for the detailed simulation of hydrological processes. In spite of these omissions, the combination of the three models facilitates the study of the impacts of GCM modeled climate change on several inter-related agro-climatic issues of interest to agricultural policy makers. These issues include: changes in dryland and irrigated corn yields; changes in sowing and harvest dates; modification of crop water demand; and estimates of effects on pesticide losses from the soil surface and through leaching from the bottom of the active corn root zone. Model generated results which address these issues are presented but must be used with caution in light of the GCM and process model limitations. The results of this study suggest that substantial changes in agricultural production and management practices may be needed to respond to the climate changes expected to take place throughout the Southern U.S.A.     

Hydroclimate risk to economic growth in sub-Saharan Africa

In order to plan strategies for adaptation to climate change, the current effects of climate on economic growth need to be understood. This study reviews evidence of climate effects on economic growth and presents original analysis of the effect in Sub-Saharan Africa (SSA). Case studies from the literature demonstrate that historically, climate has had significant and negative effects on household income, agricultural productivity and economic growth in SSA. This study focuses on the effects hydroclimatic variability on economic growth in the countries of SSA. We utilize a new national level precipitation statistic that incorporates spatial and temporal variability within each country. Country level economic growth statistics are analyzed in panel regressions. Persistent negative precipitation anomalies (drought) are found to be the most significant climate influence on GDP per capita growth. Temperature and precipitation variability show significant effects in some cases. Results imply the consideration of hydroclimatic risks, namely drought, may be the priority concern for adaptation to a changing climate for Sub-Saharan Africa. This conclusion is contrary to the premise of many climate change impact assessments that focus on temperature increases as the primary concern.     

美国退出《巴黎协定》对全球温室气体排放的影响

现有研究表明美国退出《巴黎协定》将会在2025年导致其国内排放增加约1.2 Gt CO₂-eq,然而美国退出《巴黎协定》对全球气候治理的影响不仅限于此,还包括资金效应、政治效应,以及惯性效应等对全球排放的间接和长期影响。本文通过构建体现不同效应的全球温室气体排放情景,分析了美国退出《巴黎协定》后对全球温室气体排放可能造成的不同影响。结果表明,美国退出《巴黎协定》的自身效应、资金效应、对伞形国家的政治效应和对发展中国家的政治效应,将分别导致全球2030年的年温室气体净排放量(扣除碳汇吸收量后的温室气体排放量)上升2.0、1.0、1.0和1.9 Gt CO₂-eq,并导致全球2015—2100年的累计排放量分别上升246.9、145.3、102.0和270.2 Gt CO₂-eq。为防止美国退出《巴黎协定》的不利影响进一步扩大,中国应积极引领全球气候治理制度的建设与发展,与各国紧密合作全面平衡地推进《巴黎协定》的落实和实施。     

Stockholm, Rio and beyond: Lessons from two decades of international environmental politics

Conclusion Studies that include moderate climate forecasts, farmer adaptation, carbon fertilization, and warm-loving crops tend to show that climate change will have only mild impacts on average global agricultural output and may even improve temperate agricultural production. On this point, recent studies yield strikingly consistent results. Of course, impact estimates still contain uncertainties. Key questions include how agriculture might change by 2060, how tropical and subtropical farming will be affected, and how effects will be distributed regionally. The most likely threat to agriculture from climate warming is regional damages in relatively poor areas that lack either the knowledge or the financial resources to adjust. Although it is not clear which regions will actually suffer, the ones that are most vulnerable lie predominantly in or near the tropics (IPCC, 1995). Nonetheless, on average, the factors discussed in this essay will help mitigate the impact of climate change on agriculture.The authors are grateful to the Electric Power Research Institute (EPRI) for financial support. We also wish to thank Richard Adams, Cynthia Rosenzweig, Kathleen Segerson, Joel Smith, Robert Unsworth and Thomas Wilson for their helpful comments. The authors alone are responsible for any remaining errors or omissions.     

The Impacts of Socioeconomic Development and Climate Change on Severe Weather Catastrophe Losses: Mid-Atlantic Region (MAR) and the U.S.

One strand of research relates the magnitude of severe weather disasters to climatic and human development factors; another highlights dramatic growth in catastrophe losses. However, there have been few attempts to put the two strands together. Here we use an explicit modeling framework to determine the contribution of climate variability relative to human factors in reported catastrophe losses. We then examine how future climate change can be expected to affect losses from natural disasters. Simultaneous regression models are constructed from three equations in which the dependent variables are U.S. flood loss, U.S. hurricane loss and U.S. catastrophe loss. Then two kinds of simulation under two climate change scenarios explore how climate change would affect losses. The climate change scenarios respectively project 13.5% and 21.5% increases in annual precipitation. The first simulation increases only the mean value of annual precipitation; the second simulation assumes that the mean and standard deviation of annual precipitation change in the same proportion. Results show that the growth in reported losses from weather-related natural disasters is due mainly to three socioeconomic factors: inflation, population growth and growth in per capita real wealth. However, weather variables such as precipitation and the number of hurricanes per period also clearly affect losses. The three stage least squares (3SLS) simultaneous equation model shows that a 1% increase in annual precipitation would enlarge catastrophe loss by as much as 2.8%. These findings are suggestive as planning signals to decision makers.     

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.