An Assessment of the impact of climate change on crop suitability in Eastern Uganda.

Abstract

Climate change refers to any systematic change in the long-term statistics of climate sustained over several decades or longer. It is as a result of changes in rainfall and temperature. This study examined observed and projected patterns in the rainfall and temperature characteristics during the MAM and SON seasons over Eastern Uganda particularly in the three Agro ecological zones for the observed period (1981-2022) and projected period (2025-2060) using the climate data tool for analysis. Data sets used include CHIRPS rainfall estimates merged with MERRA2 observed temperatures as well as CORDEX for projected rainfall and temperature data under RCPs 4.5 and 8.5. The standard anomalised index was computed for both scenarios to determine decadal variations. The study also examined the suitability of some of the key crops grown in the region which are maize, sorghum and cassava basing on their minimum, optimal minimum, maximum, as well as optimal maximum rainfall and temperature required by each crop under RCPs 4.5 and 8.5 for years 2025-2035 and 2040-2050. Results indicate that rainfall both in the MAM and SON seasons have rains both above and below average for observed and projected years, however the SON seasons showed more enhanced rains as compared to the MAM season over the period 1981-2022. The trend of SON rains was a positive significant trend implying the rains were increasing and the increase is statistically recognized. Similarly, temperatures in the MAM and SON seasons are balancing between above and below average for both observed and projected years but show a positive significant trend. For the observed period, temperatures do not show significant changes however projected temperatures showed an increase in temperatures in the region especially from the 2050s. Results further show that each of the agro-ecological zones displays different rainfall and temperature characteristics from the entire region as a whole especially under the different RCPs. Crop suitability varies for the three crops with maize having the highest suitability in the region followed by sorghum and cassava having the least suitability for years 2025-2035 and 2040-2050 under RCPs 4.5 and 8.5 respectively. With changes in the rainfall and temperatures as projected by the RCPs, the suitability of these crops varies greatly within the seasons and the SON season poses greater potential for suitability of the crops. Understanding the rainfall and temperature patterns in relations to crops needs and determing crop suitability is crucial in preparation of short comings as well as future implications of climate variability and change on the agricultural sector which is the main sector of our country