Abstract
Attributes of climate change in Pakistan using high resolution outputs from a General Circulation Model (GCM) viz. GCM20 and from a Regional Climate Model (RCM) viz. RegCM4.3 are presented in this paper. Recently published reanalysis dataset AgMERRA is used as standard observation over the country. Scenarios induced (A1B under AR4 and RCP8.5 under AR5) spatial changes in 2008- 2025 and 2080-2098 projection periods as compared to 1980 1998 baseline period are presented. It is seen through the results that under A1B scenario GCM20 mean DJF temperature change in 2008–2025 projection period suggests an up to 5°C rise in the North–most region of the country. GCM20 JJAS precipitation rate of change under A1B scenario in the 2008–2025 projection period suggests a relative decrease of up to 20 mm/day over the central parts of the country. RegCM4.3 under RCP8.5 scenario suggests an up to 11°C rise in the mean temperature projection of 2008–2025 DJF season over the Northern region of the country. Moreover RegCM4.3 under RCP8.5 suggests a mean JJAS precipitation decrease of up to 0.5 mm/day in 2008–2025 projection over South–eastern region of the country. The regional forcing, internal dynamic of the models and high level of uncertainties in the observational–based climate dataset could undermine the confidence on the future projection as well as the mitigation and adaptation strategies under a changing climate.
Keyword(s)
Pakistan region, AgMERRA, GCM20, RegCM4.3, A1B; RCP8.5, Seasonal climate change