Modeling the Potential Impact of Climate Change on Cotton (Gossypium hirsutum) Production in Northeastern Semi-Arid Afar and Western Tigray Regions of Ethiopia

Abstract

Cotton (Gossypium hirsutum) is a globally important fiber plant. Impact of climate change and variability is already being felt in Ethiopia in the form of higher temperature, erratic nature of rains (spatially and temporally), floods and drought. The aim of this study was to characterize the climate of the study areas, analyze the impact of climate change on cotton production and to recommend suitable adaptation strategies for cotton production under changing climate at Amibara, Dansha and Kebabo areas of Ethiopia. Historical climate data during 1980-2010, were collected from National Meteorological Agency and National aeronautical space administration while soil and cotton experimental data of the study areas were collected from respective agricultural research center. DSSATV4.6 model was calibrated and evaluated to assess the possible impact of climate change on cotton yield under the baseline and future climate. Model performance was assessed statistically by using quantitative statistical indicators: coefficient of de-term ination (R2), root mean square error (RMSE) and index of agreement (IA). In order to estimate the level of climate change impact (rainfall and temperature) on cotton production for the study areas, two Representative path ways as a threetime segment: Near-term i.e., 2010-2039, Mid-term i.e., 2040-2069) and End-term i.e., 2070-2099 using the coupled atmosphere-ocean HadGEM2-ES GCMs model. Time series anomaly plots for temperature showed that the mean temperature over Amibara, Dansha and Kebabo has increased by about 0.5 to-2ºC, 0.5 to 1.65oC and 0.5 to 1.5oC and rainfall showed slight variability in start and end of season during the period of 1980-2010. The projected temperature and rainfall pattern shows that an overall increasing trend in annual temperature and significant variation of monthly and seasonal rainfall from the historical period of time. The rainfall varies between-1.6 to 3.3%,-0.7 to 3.8% and-0.8 to 3.3% at Amibara, Dansha and Kebabo respectively. Climate change analysis indicated a strong influence of temperature on cotton production in Amibara and Dansha sites and yield will be substantially decreased on average by 12% to 13% with projected increasing temperature and erratic nature of rainfall. Projected model simulations predict that climate change will shift planting dates towards late planting (May 15 and July 15) for the period of 2010-2099 at Amibara and Dansha while for Kebabo site early planting June 15 is preferable. In general cotton yield, will decrease but, late planting date and further research on different agronomic management practices will result in increased yield for Amibara and Dansha.