Climate change impacts on crop production in Busia and Homa Bay Counties, Kenya

Climate change is expected to impact crop production in the Lake Victoria Basin, yet little quantitative information is available on the extent and direction of these impacts. Without such quantitative information, however, developing appropriate adaptation strategies is difficult. While it may seem to make sense to promote measures that make fa rmers less vulnerable to climatic variability, such measures may not be economically recommendable. For example, putting in place irrigation infrastructure makes crops less vulnerable to water shortages, but this is only appropriate if there is a current o r future risk of drought. If there is no such risk, purchasing expensive irrigation equipment would be a bad investment for most farmers. It is therefore important to anticipate effects of future climate change as accurately as possible and identify those climatic factors that represent the greatest risk of compromising food security. Once these factors have been identified, appropriate and quantitatively informed adaptation strategies can be devised. This study attempts to accomplish this for two counties on the Kenyan shore of Lake Victoria, Busia and Homa Bay, as well as for surrounding areas. The current and future suitability of this region for major agricultural crop was evaluated using a range of methods. Doing such an analysis is impaired by a striki ng shortage of necessary input data. Except for isolated rainfall data, there are essentially no long - term weather records for either district. This means that even current climate cannot be reliably characterized, placing constraints on the accuracy, with which the future can be projected. Targeted climate change projections for the study region have also been scarce, for the same reasons. Observations of local weather are needed for calibrating climate models, and where no records are available, the accur acy of climate models is questionable. Similarly, soil information for the study region is scarce, yet soil data is an essential input into any crop model. Finally, information on what crop varieties farmers grow, how these respond to climate, and how exac tly they are managed, is unavailable. Some of this information could be obtained through detailed fieldwork, and recommendation will be made on how to go about improving the site - specific validity of modeling efforts. For the purposes of the current study, however, best - bet proxy datasets were used to arrive at the conclusions presented here. This study therefore provides a rough indication of the impacts of climate change on the production of major crops in the study region. It also presents an evaluation of which climatic factors are the most likely constraints for production of the various crops. Yet the results of this study should not be taken as completely accurate, because of the host of unknowns about essentially all important factors of climate, soi ls and cropping systems

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