Statistical downscaling for projections of future temperature and rainfall over the Lower Chenab Canal command area, Pakistan based on SDSM–CanESM2

Abstract

Climate change and global warming are major events in the twenty-first century. Lower Chenab Canal (LCC) command area has been reflected as a hot spot, for impact of climate change on agriculture and water availability. The study aimed to project future changes in temperatures and rainfall in 2020s, 2050s and 2080s. Data outputs of CanESM2 GCM under RCPs scenarios RCP4.5 and RCP8.5 were used. Three weather stations data (1976−2005) was used as Statistical Downscaling Model (SDSM) inputs. The results projected an increase in mean annual Tmin and Tmax from 2020 to 2080s under both scenarios but a more distinct change by 0.59 °C in Tmax and 1.06 °C Tmin was projected in 2080s under RCP8.5. In winter and spring Tmax will increase under both scenarios in all future time series with maximum increase of 3.30 °C under RCP4.5 and 3.33 °C under RCP8.5 in spring (2080s). In summer 2080s Tmax will decrease under RCP 4.5 (− 0.88 °C) and RCP8.5 (− 1.14 °C). Spring will remain distinctive in increasing Tmin as compared to other seasons with maximum increase in 2080s by 2.48 °C (RCP4.5) and 3.00 °C RCP8.5). In autumn Tmin will decrease under both scenarios with maximum decrease by − 1.63 °C (RCP4.5) and − 0.68 °C (RCP8.5) in 2080s). Mean annual rainfall projected an increase in all future time series with a maximum increase of 52.62% under RCP4.5 and 65.13% under RCP8.5 in 2080s. An increase in rainfall was also projected in autumn, winter and summer with a major increase of 107.84% under RCP4.5 and 106.1% under RCP8.5 in winter 2020s, respectively. The autumn, winter and summer would be wetter than before and these future climate changes might have a negative effect on agriculture and water resources in LCC command area, temporally and spatially. Projected increase in climate will affect cropping season, crop growth and crop evapotranspiration in areas projecting higher temperature and vice versa. Effective adaptation measures should be applied to mitigate the effects of climate change on water resources. The study findings will help water managers and representatives in creating a background for sustainable and adaptive water management in the face of climate change.