Climate change: monsoon season likely to be delayed by 2-3 weeks annually: expert

Rapid climate change is likely to delay monsoon season for 2-3 weeks annually across the globe, Dr Moetasim Ashfaq, Computational Climate Scientist, Oak Ridge National Laboratory, USA said here on Monday. He was delivering a special lecture on "South Asian Summer Monsoon in 21st Century" organised by Sustainable Development Policy Institute (SDPI).
He said that high resolution climate models used at Oak Ridge National Laboratory, USA have predicted weakening of summer monsoon precipitation over South Asia towards the end of 21st century. Dr Qamar uz Zaman Chaudhry, Advisor Climate Affairs, was also present on the occasion.
Monsoon is traditionally defined as a seasonal reversing of the wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. The vagaries of South Asian summer monsoon rainfall on short and long time scales impact the lives of more than one billion people while due to the rapid climate change, the glaciers in Pakistan are receding at a rate of almost 40-60 meters per decade posing threat to the region.
In his lecture, Dr Moetasim, discussed simulation and projection of South Asian summer monsoon. He also showed reservations on projections of Intergovernmental Panel on Climate Change (IPCC) and said, there is a large uncertainty in projections of IPCC report based on multi Global Climate Models (GCM). Global models featured in IPCC report can resolve large-scale interactions, but have limitations while capturing atmospheric processes at regional level, he added. He also informed that simulations run in their model show an eastward shift in monsoon circulation, which would mean more rainfall over the eastern parts of South Asia.
Dr Moetasim while deliberating on the importance of monsoon projections said that variability of onset and duration of the summer monsoon exerts a strong control on water resources, agriculture, economics, ecosystems, and human mortality throughout South Asia.
Dr Qamar uz Zaman Chaudhry said that South Asian monsoon is the most complex weather system, which is very difficult to simulate and predict. He called for advance research on monsoon, which he said, is the life line of South Asian economies. "Around 75 percent of total annual rainfall in major parts of South Asia is contributed by summer monsoon and a slight change in the pattern can have disastrous impact on agriculture, economy and livelihood of millions of South Asians," he added.