Projected climate induced suitability changes in coffee prone areas of Uganda

Abstract

Knowledge about climate change over time provides a valuable insight into how the challenges posed by climate change and variability can be responded to. This study assessed the skill of various Global Climate Models (GCMs) and some highly skilful models were further used to project future rainfall and temperature over Uganda for the 2071-2100 period. The study further investigated the future effect of climate change on the suitability of coffee prone areas of Uganda based on the projected 2071-2100 climate. The latest IPCC models were evaluated using correlation, root mean square error and model bias techniques. The ensemble mean output of ECHAM4 and HadAM3P were downscaled using UK-Met Office version of Regional Climate Model (RCM) known as Providing REgional Climates for Impact Studies (PRECIS). Suitability change to coffee based on the projected climate was assessed using multi-criteria analysis in ILWIS version 3.3. Results showed that UKHADCM3, MPIECH-5, MRI-232A and ECHO---G were skillful over Uganda. However, ECHAM4 and HadAM3P versions were used for further analysis due to their availability. These models captured above average large scale flow signals influencing precipitation and temperature patterns over Uganda. The results further showed that precipitation and temperature patterns were better resolved by the RCMs than the GCMs. March to May (MAM) seasonal precipitation projections indicate likely increase while a decline in the other two seasons June to August (JJA) and September to November (SON) were observed. The model showed occurrence of intense precipitation in all seasons, especially along the boundaries of the country with wetter tendencies compared to the southern parts of the country particularly in areas which have been dry such as parts of the cattle corridor. Thus, areas which have been wet will be relatively dry. However, the current precipitation patterns are likely to remain the same and similar in seasonality. Temperatures are likely to increase during all seasons with increased concurrencies in the southern parts and a gradient temperature increase over the north-eastern and north-western parts of the country compared to the previously homogeneous patterns observed over the country. Thus, areas which have been cool are likely to be relatively warm hence the need for early adaptation. Future suitability coffee area based on the projected climate indicate that most of the coffee prone areas (84%) are likely to still be suitable for coffee growth. However, 14% of the area is likely to be marginally suitable and 2% will likely be unsuitable for coffee growth. The above prompts need for early Ex Ante Contingency planning.