How the Indian summer monsoon rainfall (ISMR) would change in future is of broader scientific interest and critical for adaptation to climate change and sustainable development for the vulnerable population of the region. An Emergent Constraint (EC), to correct the projections of ISMR by the Coupled Model Inter-comparison Project-6 (CMIP6) models for systematic model biases is urgently needed but has been lacking. Founded on an observed association between the multi-decadal variability (MDV) of ISMR and North Atlantic (NA) sea surface temperature (SST), here we unravel a strong correlation between future changes in ISMR and biases in simulating the present-day ISMR MDV. The new emergent constraint renders a 32% reduction in the multi-model ensemble mean of projected ISMR increase, making the corrected future ISMR change (3.64 +/- 2.5) %/K. The estimate based on this EC is robust and more reliable than previous estimates for basing policy interventions toward adaptation and mitigation.
Rajesh, PV; Goswami, BN
A New Emergent Constraint Corrected Projections of Indian Summer Monsoon Rainfall
Geophysical Research Letters