Monsoon Response in a Warming Planet


The seasonal mean rainfall associated with the Asian summer monsoon dictates agricultural output, water resources, and the livelihood of millions of people, thus, we need to know if monsoon precipitation will increase or decrease as climate changes.  A new DOE study examines the response of the mean monsoon precipitation in simulations with 1% per year CO2  increases from pre-industrial concentrations so-called quadrupled CO2 runs.  The model projects that in a warmer climate, the monsoon precipitation over peninsular parts of India increases by about 10-15%.  Analysis with a high spatial resolution regional model indicates that there will be an increase in the number of monsoon synoptic systems or storms that have wind speeds of 15-20 meters per second.  The model results presented, though plausible, need to be taken with caution since even in this best model, systematic errors still exist.


M. Stowasser, H. Annamalai, and J. Hafner, 2009: Response of the South Asian Summer Monsoon to Global Warming: Mean and Synoptic Systems. J. Climate, 22, 1014-1036.