A former chief economist at the World Bank has warned South Asian countries that even a moderate rise in temperatures could cause serious changes in environment.
These nations thus must prepare for the effects of global warming, even as they work to combat the human causes of climate change, said Sir Nicholas Stern, who led the eponymous Stern Review, which last year examined the economic impact of climate change.
In Washington for a two-day legislators' conference on climate change, Stern who also served as senior vice-president of the World Bank said, "In India and China, I think people understand the rising water stress, and how vulnerable they are to melting glaciers and snows from the Himalayas."
"You have to give examples from around the world for people to really understand what's going on," he said using the analogy of the Himalayas as a sponge, moderating the impact of precipitation as seasons change.
"Precipitation comes, and it's held there. That's how you get water in the rivers. That effect will not be there if the glaciers and snow are not there. Which means you'll get torrents during the wet season and dry rivers in the dry season. So you'll get a combination of flood and drought," Stern said.
"We also don't know what effect that will have on the monsoon, and it could have quite a strong effect. That kind of thing is being studied now," he added.
The Indian Institute of Tropical Meteorology supplies climate change data to SAARC nations, and is engaged in its largest recruitment drive in a decade.
Agriculture represents a fourth of India's national income, and that sector could be seriously disrupted by changes to the monsoon. Mitigation strategies are needed to deal with the risks.
"We have to adapt how we handle water extraction, and irrigation. Water management is involved in all of this. Work has to be done on what crops would be resilient," Stern said.
Urban areas throughout the region are also at risk, as water supplies could be disrupted over time. Infrastructure must be upgraded for sanitation and drinking water, as well as for adequate storm drainage in areas prone to flooding, he said.