Results from the United Kingdom Meteorological Office (UKMO) coupled climate model have been analysed over the Indian subcontinent in order to validate the model's performance and to assess the changes in climate and its variability in a simulation with a 1 per cent increase per year in CO2 (compound). The model produces a reasonable simulation of present-day climate over the Indian subcontinent. At the time of CO2 doubling, the model simulates temperature increases of the order of 1 K to 4 K over the Indian subcontinent during winter and monsoon seasons. The model-simulated monsoon circulation shifts by 10 degrees latitude towards the north and intensifies by approximately 10 per cent in the warmer atmosphere. The interannual variability of monsoon onset dates and intraseasonal variability of monsoon rainfall are not significantly different when the CO2 concentration doubles. However, the model simulates increased interannual variability of the monsoon rainfall and a greater number of heavy rainfall days during the monsoon.
