sheep and chickens, but not goats. This effect is most likely due to the change in landscape, associated with more precipitation, from savanna to forest. Combining all these changes, a 2.5 ° C warming results in a 32% loss in expected net income and a 5 ° C warming leads to a 70% loss in expected net income. Increasing precipitation by 15% results in a 1% loss in expected net income.

We also examine climate change impacts using the separate regressions for small and large livestock farms. With warming, small farms are expected to shift away from dairy cattle and chickens to goats and sheep. Net incomes will fall for all animals except for sheep. The number of animals will also fall. Expected income will fall by 13% with a warming of 2.5 ° C, but recover with more warming to current levels of income. A 15% decrease in precipitation is expected to increase small livestock farm incomes by 6%. For large farms, warming will cause a shift to dairy cattle and sheep and away from goats, chickens and especially beef cattle. The income per animal falls for all species as temperatures rise. With higher temperatures, large farms choose to have fewer beef, chickens and sheep and choose more goats and dairy cattle. Large farmers’ incomes are expected to fall by an average of 26% with a 2.5 _°_ C warming and by 67% with a 5 _°_ C warming, but a 15% decrease in precipitation is expected to increase these farmers’ incomes by 2%.

The study also examines the consequences of a range of climate predictions from three Atmospheric Oceanic General Circulation Models (AOGCMs). These models predict that climate change will cause beef cattle to decrease in Africa and sheep and goats to increase. In general, the climate models predict that the overall number of animals will fall although the number of goats may increase. They also predict that the net revenue per animal will fall. Combining all of these effects, the climate models predict average losses of 22% ($8 to $23 billion) in expected net income from livestock by 2020. These damages increase to 31% ($9 to $24 billion) by 2060, and to 54% ($25 to $40 billion) by 2100.

Examining the effect on small and large farms reveals that small farms will choose dairy cattle and sheep more often and goats and chickens less often as the primary animal. The income per animal will tend to fall over time except for sheep. The number of animals will tend to fall with warming with a few exceptions. The changes in the number of goats and sheep are relatively negligible. The expected income for small farms will tend to increase over time with the Canadian Climate Center (CCC) scenarios (34%), but fluctuate with the Parallel Climate Model (PCM) and Center for Climate System Research (CCSR) scenarios depending on precipitation. Large farmers, in contrast, will shift away from beef cattle and chickens in favor of dairy cattle, sheep and goats. Net revenues will fall across animals, but especially for beef cattle. The numbers of beef cattle and chickens will fall by large amounts, but the numbers of goats and sheep will increase depending upon the scenarios. Putting all these results together, CCC will lead to a $6000 reduction in expected net revenue per large farm (77%), CCSR to a $2,700 reduction (34%), and PCM to a $3,400 reduction (43%) by 2100.

The results indicate that warming will be harmful to commercial livestock owners, especially cattle owners. Owners of commercial livestock farms have few alternatives either in crops or other animal species. In contrast, small livestock farms are better able to adapt to warming or precipitation increases by switching to heat tolerant animals or crops. Livestock operations will be a safety valve for small farmers if warming or drought causes their crops to fail.

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