Assessment of temperature and rainfall changes in the Karoun River basin

An increase in greenhouse effect leads to climate change, a rise in sea levels, higher heat waves, an increase in extreme climatic frequency, an increase in wildfire risks, and other consequences pregnant with several different natural hazards. In Karoun River basin, SW Iran, climate change is likely to affect nearly every aspect of surface and underground water. The outputs from representative concentration pathways (RCPs) are applied in simulating the maximum and minimum temperature and rainfall changes in this basin. The assessments are tested based on the ability of models in reproducing the regional climatological trends. The best goodness of fit among RCP scenarios is involved through RCP 4.5. The simulated results of each scenario indicate a significant increase above 1 °C in the minimum temperature during warm months over most areas of the basin. The change in maximum temperature at most stations is linked to seasonal cold to warm transition months of the year. A reduction in autumn and winter rainfall and an increase in spring rainfall are expected for the coming three decades. The changes in rainfall pattern lead to a higher 24-h maximum precipitation which increases flooding probability especially at discharges greater than 2000 m3/s.