A Theoretical Foundation for Count Data Models

The paper develops a theoretical foundation for using count data models in travel cost analysis. Two micro models are developed: a restricted choice model and a repeated discrete choice model. We show that both models lead to identical welfare measures.

Crop selection : adapting to climage change in Africa

This paper examines whether the choice of crops is affected by climate in Africa. Using a multinomial logit model, the paper regresses crop choice on climate, soils, and other factors. The model is estimated using a sample of more than 7,000 farmers across 11 countries in Africa. The study finds that crop choice is very climate sensitive. For example, farmers select sorghum and maize-millet in the cooler regions of Africa; maize-beans, maize-groundnut, and maize in moderately warm regions'and cowpea, cowpea-sorghum, and millet-groundnut in hot regions. Further, farmers choose sorghum, and millet-groundnut when conditions are dry; cowpea, cowpea-sorghum, maize-millet, and maize when medium wet; and maize-beans and maize-groundnut when wet. As temperatures warm, farmers will shift toward more heat tolerant crops. Depending on whether precipitation increases or decreases, farmers will also shift toward drought tolerant or water loving crops, respectively. There are several policy relevant conclusions to draw from this study. First, farmers will adapt to climate change by switching crops. Second, global warming impact studies cannot assume crop choice is exogenous. Third, this study only examines choices across current crops. Future farmers may well have more choices. There is an important role for agronomic research in developing new varieties more suited for higher temperatures. Future farmers may have even better adaptation alternatives with an expanded set of crop choices specifically targeted at higher temperatures.Crops&Crop Management Systems,Climate Change,Agriculture&Farming Systems,Renewable Energy,Global Environment Facility

A ricardian analysis of the impact of climate change on African cropland

This study examines the impact of climate change on cropland in Africa. It is based on a survey of more than 9,000 farmers in 11 countries: Burkina Faso, Cameroon, Egypt, Ethiopia, Ghana, Kenya, Niger, Senegal, South Africa, Zambia, and Zimbabwe. The study uses a Ricardian cross-sectional approach in which net revenue is regressed on climate, water flow, soil, and economic variables. The results show that net revenues fall as precipitation falls or as temperatures warm across all the surveyed farms. In addition to examining all farms together, the study examined dryland and irrigated farms separately. Dryland farms areespecially climate sensitive. Irrigated farms have a positive immediate response to warming because they are located in relatively cool parts of Africa. The study also examined some simple climate scenarios to see how Africa would respond to climate change. These uniform scenarios assume that only one aspect of climate changes and the change is uniform across all of Africa. In addition, the study examined three climate change scenarios from Atmospheric Oceanic General Circulation Models. These scenarios predicted changes in climate in each country over time. Not all countries are equally vulnerable to climate change. First, the climate scenarios predict different temperature and precipitation changes in each country. Second, it is also important whether a country is already hot and dry. Third, the extent to which farms are irrigated is also important.Climate Change,Environmental Economics&Policies,Global Environment Facility,Common Property Resource Development,Crops&Crop Management Systems

A Ricardian analysis of the impact of climate change on Latin American farms

This study estimates the vulnerability of Latin American agriculture to climate change using a Ricardian analysis of both land values and net revenues. Examining a sample of over 2,500 farms in seven countries, the results indicate both land value and net revenue are sensitive to climate. Both small farms and large farms have a hill-shaped relationship with temperature. Estimating separate regressions for dryland and irrigated farms reveals that dryland farms are more sensitive to temperature but irrigated farms are more sensitive to precipitation. Examining the effects from future climate change scenarios reveals thatsevere scenarios could reduce farm earnings by as much as 62 percent by 2100, whereas more moderate scenarios could reduce earnings by about 15 percent. Small and large farms are equally sensitive to global warming. Land value and net revenue analyses produce quite similar results.Climate Change,Rural Development Knowledge&Information Systems,Agriculture&Farming Systems,Crops&Crop Management Systems,Common Property Resource Development

An analysis of livestock choice : adapting to climate change in Latin American farms

The authors explore how Latin American livestock farmers adapt to climate by switching species. They develop a multinomial choice model of farmer's choice of livestock species. Estimating the models across over 1,200 livestock farmers in seven countries, they find that both temperature and precipitation affect the species Latin American farmers choose. The authors then use this model to predict how future climate scenarios would affect species choice. Global warming will cause farmers to switch to beef cattle at the expense of dairy cattle.Livestock&Animal Husbandry,Climate Change,Wildlife Resources,Peri-Urban Communities,Rural Urban Linkages

An analysisof crop choice : adapting to climate change in Latin American farms

The authors explore how Latin American farmers adapt to climate by changing crops. They develop a multinomial choice model of farmer's choice of crops. Estimating the model across over 2,000 farmers in seven countries, they find that both temperature and precipitation affects the crops that Latin American farmers choose. Farmers choose fruits and vegetables in warmer locations and wheat and potatoes in cooler locations. Farms in wetter locations are more likely to grow rice, fruits, and squash, and in dryer locations maize and potatoes. Global warming will cause Latin American farmers to switch away from wheat and potatoes toward fruits and vegetables. Predictions of the impact of climate change must reflect not only changes in yields or net revenues per crop but also crop switching.Crops&Crop Management Systems,Climate Change,Rural Poverty Reduction,Agriculture&Farming Systems,Global Environment Facility