Keys to Economics of Global Warming: A Critique of the Dismal Theorem

In a recent paper on climate change, M. Weitzman argues that the traditional cost-benefit analysis cannot be used as a reference tool for designing a climate change policy due to a large uncertainty that cannot be reduced by further analyses. The findings of the ‘Dismal Theorem' are, however, based on two critical assumptions: a single geographical unit and two distinct points in time. It assumes a single geographical unit, disallowing the possibility of reallocating resources across different geographical regions under climate change. It also assumes only two time periods, the present and the year 2100, which rules out a dynamic dimension of climate policy such as burden sharing across generations and learning over time. On the empirical side, the author's apprehension of catastrophe is blown out of context since he assumes that all climate scenarios are equally likely to occur and that there would be no policy intervention to control greenhouse gases over time. Finally, impact studies do not support catastrophic results from climate change within this century.Climate Catastrophe, Dismal Theorem, Global Public Goods, Cost-Benefit Analysis.

A structural ricardian analysis of climate change impacts and adaptations in African agriculture

This paper develops a Structural Ricardian model to measure climate change impacts that explicitly models the choice of farm type in African agriculture. This two stage model first estimates the type of farm chosen and then the conditional incomes of each farm type after removing selection biases. The results indicate that increases in temperature encourage farmers to adopt mixed farming and avoid specialized farms such as crop-only or livestock-only farms. Increases in precipitation encourage farmers to shift from irrigated to rainfed crops. As temperatures increase, farm incomes from crop-only farms or livestock-only farms fall whereas incomes from mixed farms increase. With precipitation increases, farm incomes from irrigated farms fall whereas incomes from rainfed farms increase. Naturally, the Structural Ricardian model predicts much smaller impacts than a model that holds farm type fixed. With a hot dry climate scenario, the Structural Ricardian model predicts that farm income will fall 50 percent but the fixed farm type model predicts farm incomes will fall 75 percent.Crops&Crop Management Systems,Agriculture&Farming Systems,Livestock&Animal Husbandry,Climate Change,Rural Development Knowledge&Information Systems

Climate change impacts on Latin American farmland values: the role of farm type

This paper examines climate change impacts on South American agriculture using a set of Ricardian regressions estimated across different samples of farms in South America. Regressions are run for the whole sample and for subsamples of crop-only, mixed, and livestock-only farms. The results indicate that climate sensitivity varies a great deal across each type of farm. The analysis also reveals that the impacts will vary substantially across South America. The hot and wet Amazon and Equatorial regions are likely to lose the most from warming scenarios whereas the more temperate high elevation and southern regions of South America will likely gain.Climate change, Agriculture, South America, Environmental Economics and Policy,

Differential adaptation strategies by agro-ecological zones in African livestock management

This paper examines how farmers have adapted their livestock operation to the current climate in each agro-ecological zone in Africa. The authors examine how climate has affected the farmer's choice to raise livestock or not and the choice of animal species. To measure adaptation, the analysis regresses the farmer's choice on climate, soil, water flow, and socio-economic variables. The findings show that climate does in fact affect the farmer's decision about whether to raise livestock and the species. The paper also simulates how future climates may alter these decisions using forecasts from climate models and the estimated model. With a hot dry scenario, livestock ownership will increase slightly across all of Africa, but especially in West Africa and high elevation agro-ecological zones. Dairy cattle will decrease in semi-arid regions, sheep will increase in the lowlands, and chickens will increase at high elevations. With a mild and wet scenario, however, livestock adoption will fall dramatically in lowland and high latitude moist agro-ecological zones. Beef cattle will increase and sheep will fall in dry zones, dairy cattle will fall precipitously and goats will rise in moist zones, and chickens will increase at high elevations but fall at mid elevations. Livestock adaptations depend on the climate scenario and will vary across the landscape. Agro-ecological zones are a useful way to capture how these changes differ from place to place.Livestock&Animal Husbandry,Wildlife Resources,Peri-Urban Communities,Rural Urban Linkages,Dairies&Dairying

A ricardian analysis of the distribution of climate change impacts on agriculture across agro-ecological zones in Africa

This paper examines the distribution of climate change impacts across the 16 agro-ecological zones in Africa using data from the Food and Agriculture Organization combined with economic survey data from a Global Environment Facility/World Bank project. Net revenue per hectare of cropland is regressed on a set of climate, soil, and socio-economic variables using different econometric specifications"with"and"without"country fixed effects. Country fixed effects slightly reduce predicted future climate related damage to agriculture. With a mild climate scenario, African farmers gain income from climate change; with a more severe scenario, they lose income. Some locations are more affected than others. The analysis of agro-ecological zones implies that the effects of climate change will vary across Africa. For example, currently productive areas such as dry/moist savannah are more vulnerable to climate change while currently less productive agricultural zones such as humid forest or sub-humid zones become more productive in the future. The agro-ecological zone classification can help explain the variation of impacts across the landscape.Climate Change,Global Environment Facility,Common Property Resource Development,Rural Poverty Reduction,Transport and Environment

The impacts of climate change on Australia and New Zealand: a Gross Cell Product analysis by land cover

This paper examines the newly constructed geographically scaled economic output measure, Gross Cell Product (GCP), of Australia and New Zealand to quantify the impacts of climate change in the region. The paper discusses advantages of using the GCP instead of the Gross Domestic Product. The paper reveals that the GCP falls sharply as temperature increases in the region. A 1 degree Celsius increase in temperature would decrease the productivity with an elasticity of )2.4. A 1 per cent decrease in precipitation would decrease productivity with an elasticity of )2.3. However, forest vegetation on the coasts will benefit from initial warming. We find that the changes in climate means are potentially more harmful than changes in climate variability. In the long term, a 3.4 warming coupled with 6.6 mm decrease in rainfall would decrease the GCP by 34 per cent by 2060. The damage is largely accounted for by population effects. The paper confirms that Australia is highly constrained by climate and geographic factors

Managing forests, livestock, and crops under global warming: a micro-econometric analysis of land use changes in Africa

This paper examines potential land use changes in Africa under climate change by building an integrated model of crop management, animal husbandry, and forestry. Using micro-level decisions from around 9000 household surveys in 11 countries, we analyze the choice of land types across the landscape with a multinomial discrete choice model. The choices and future adaptation measures are analyzed as a mosaic based on the typology of Agro-Ecological Zones. The results indicate that if climate becomes hotter and drier, Africa will adapt by increasing a joint production of crops and animals, especially in the lowland savannahs. On the other hand, if climate becomes wetter, it will switch more to forests, either with crops or with both crops and livestock, especially in the mid and high elevation humid zones. Forestry will play a significant role in adaptation when a substantial increase in precipitation makes animal husbandry an unattractive alternative

An analysis of public adaptation to climate change using agricultural water schemes in South America

This paper provides an analysis of public adaptation to climate change using agricultural water schemes in South American farms. Unlike other studies of adaptation, this paper examines the differences between private irrigation and public irrigation schemes based on around 1400 farm surveys collected across seven countries in South America which recorded detailed water schemes. We analyze the choice of water schemes in the first stage and the land values for each scheme in the second stage. We find that public irrigations do not increase in response to a warmer climate, but private irrigations do. On the other hand, we find that public irrigation schemes are provided primarily as a response to water scarcity. Moreover, we find that private irrigations are taken gradually while public irrigations are provided as a lump sum, resulting in either too much or too little provision. Therefore, public adaptations to climate change will likely involve two inefficiencies. No provision of irrigation in a hotter climate may result from a lack of knowledge. Overprovision of irrigation in dry zones may result from a lump-sum provision of a public good.Climate change Public adaptation Irrigation South America

Is an integrated farm more resilient against climate change? A micro-econometric analysis of portfolio diversification in African agriculture: Reply

Climate change Adaptation Behavioural model Agricultural systems

Is an integrated farm more resilient against climate change? A micro-econometric analysis of portfolio diversification in African agriculture

This paper examines whether an integrated farm that owns both crops and livestock is more resilient under global warming than a specialized farm in crops. Using around 9000 farm surveys across Africa, we explore how farmers choose one of the farm types and how the net revenue of each type varies across the range of climate in Africa. The results indicate that an integrated farm increases in number while a specialized farm decreases across Africa under climate predictions for 2060. The relative profitability of each system against each other also changes. An integrated farm becomes relatively more profitable over specialized farms half a century from now. The impacts of climate change on integrated farms range from 9% loss to 27% gain depending on climate scenarios. Behavioral models can capture portfolio diversification benefits that agro-economic models cannot measure.Climate change Africa Integrated farm Livestock Adaptation Micro-econometrics