Climate Change Induced Variability in Forage Production in A Semi-Arid Ecosystem In North Eastern Uganda

Abstract

Climate change constitutes a major threat to semi-arid vegetation productivity. There are few studies that have simulated the effect of climate change on forage production in East Africa. This study projected change in climate and determined potential forage production under different time slices (2040-2069 and 2070-2099) and emission scenarios (RCP 4.5 and RCP 8.5). A delta method approach was utilised to project change in climate. Meanwhile, net primary production (NPP) was used as an indicator of forage production estimated using the Miami model. Results showed that there will be a non-significant increase in annual rainfall under all time-slices but multi-year deviation of rainfall below average will be expected in mid-century. Sub-regionally, rainfall onset and cessation will be expected to shift to the 16th and 63rd pentads respectively. A significant increase in minimum temperature from the baseline period (1980-2009) will be expected such that by mid-century (2040-2069) it will have increased by 1.8⁰C (RCP 4.5) and 2.1⁰C (RCP 8.5) and by 2.2⁰C (RCP 4.5) and 4.0⁰C (RCP8.5) during end-century. Further, merged data revealed that mean temperature under RCP 4.5 and maximum, minimum and mean temperature under RCP 8.5 will significantly increase. Forage production under rain controlled conditions will progressively increase but with a non-significant trend under RCP 4.5 and RCP 8.5. Results also showed that temperature induced forage production under RCP 4.5 will moderately increase however continued increase in temperature to RCP 8.5 level, forage production will be hindered taking a negative trend. Therefore, higher temperature will become limiting to forage production in the sub-region.