Potential impacts of climate change on grazingland forage production and runoff in Kenya. Angerer, Jay ^*,1, Dyke, Paul², Stuth, Jerry¹, Butt, Tanveer³, ¹ Department of Rangeland Ecology and Management, College Station, TX, USA² Blackland Research and Extension Center, Temple, TX, USA³ Department of Agricultural Economics, College Station, TX, USA

ABSTRACT- As part of a broader study on environmental and economic impacts of projected climate change on agriculture in Kenya, impacts of climate change on Kenya grazinglands were examined. The objectives were to simulate changes in livestock forage production and rangeland runoff that could occur given the projected changes in climate. To effectively examine these changes, spatially-explicit climate data was needed that incorporated projected climatic changes across the diverse agro-ecological zones of Kenya. We used splined surfaces of monthly weather generator (WXGEN) coefficients that were adjusted for climate change (Canadian Global Coupled Model) to generate 50 years of climate data for use in the PHYGROW simulation model. Major forages and rangeland plant communities for 460 distinct agro-ecological zones were simulated for both a baseline (present day) and a climate change (Year 2030) scenario. Results of the analysis indicated that under climate change, areas that are predominantly rangelands would have an average decrease in cattle forage yields of 14% countrywide, with some regions decreasing 25%. These effects were mainly the result of the projected increases in temperatures and reduced rainfall under climate change in many areas of Kenya, especially in the northern regions. Under climate change, runoff response was quite variable spatially and was related to the changes in rainfall and the status of the grazingland vegetation. In areas where rangelands were degraded, runoff increased in areas where rainfall increased. However, in areas where pasturelands predominated, increased rainfall led to increased plant cover and decreased runoff.

KEY WORDS: splining, climate change, weather generator, Kenya