Climate model predictions for Honduras, with emphasis on water availability

Abstract

We use two climate models selected for their skill at predicting Honduran precipitation and temperature to estimate year 2100 climate. We selected greenhouse gas emission scenarios that are consistent with observed trends (RCP8.5 and SSP585). Climate model CESM1 CAM5 predicts that year 2100 rainfall in Honduras will decrease by 20% from today, and water availability (the rainfall that makes it into rivers, lakes and aquifers) by 41%. The reduced water availability by itself is not considered large enough to cause water stress in Honduras, as availability will still surpass generally accepted levels indicating water stress.  However, given recent water shortages in Tegucigalpa and other cities, Honduras will be strongly challenged in supplying sufficient water for its people. Future year-to-year variability in rainfall may involve periods of time one year or longer without sufficient rainfall, despite the long-term rainfall average being adequate. Using output from climate model CESM2, temperatures across Honduras are predicted to increase by an average of 5.3 ˚C in year 2100. CESM2 predicts an increase in year 2100 wind speeds by 10% over today. These increases would theoretically cause an increase of 30% in wind energy power output. CESM2 also predicts cloud cover will decrease by 5%, relative humidity by 9% and specific humidity will increase by 22%. The increase in atmospheric moisture is likely to exacerbate the severe storm floods to which Honduras is frequently subject