Analysis of the changes in historical and future extreme precipitation under climate change in Adama city, Ethiopia

Under the conditions of climate change, extreme events occur more frequently with higher energy for devastation. Planning for effective management of climate-related risks demands clear information at the local scale. This study aims to characterize the extreme events in the daily precipitation records and to assess the changes under future climate conditions in flood vulnerable city of Adama. For this, the extreme rainfall events during 1965 and 2016 were analyzed on the basis of 10 selected extreme precipitation indices. Using a statistical downscaling model (SDSM), future daily precipitation in the city for the period 2021-2080 was downscaled from the outputs of two Global Circulation Models (CanESM2 and HadCM3) under five climate change scenarios. Taking the climate conditions during 1971 and 2000 as a base, changes in precipitation extreme events in future periods (2021-2050 and 2051-2080) were investigated using the delta approach. The study reveals that the extreme precipitation events in Adama city were increasing over the period of 1965-2016. The results also indicate a successful application of the SDSM for downscaling local-scale future daily precipitation from the outputs of large-scale atmospheric information for the study area. Moreover, under future climate change scenarios, the extreme precipitation would increase up to 2080, despite the changes will be highest during 2050 and 2080, indicates the study area could experience frequent and more severe floods during the coming 60 years due to the changes in global climate. This study would support planning for effective management of flood risks due to the impacts of climate change on extreme precipitation in Adama city.