Projections of future climate are made using dynamically or statistically downscaled General Circulation Models and Regional Climate Models. The current state of knowledge indicates that climate warming is likely to continue during the 21st century. The projections of precipitation change are uncertain as the climate models project a wide range of possible futures, including strong precipitation increases and precipitation decreases. An increase in precipitation is most likely for the upstream Ganges and Brahmaputra, but the magnitude is highly uncertain. Precipitation projections for the upstream Indus show increases as well as decreases with large uncertainties related to the projections. Extreme precipitation events are likely to be more severe and occur with higher frequency. For the Indian summer monsoon precipitation totals, precipitation intensity, inter-annual variability in monsoon strength, and inter-daily variability are likely to increase. It is important to note that the current state-of-the-art climate models have significant difficulties in simulating the complex climate in the HKH region. Only a limited number of models can satisfactory simulate the monsoon dynamics and no single model is able to simulate all important features in the HKH precipitation regimes.
