As a result of climate change, much of the Indo-Gangetic plain and parts of northwest India could see increasing temperatures and worsening heat-waves from the middle to the end of this century, say researchers in the U.S.

A global warming of a few degrees may not be meaningful to people and policy-makers who are worried about local and regional-scale issues, observed Auroop Ganguly of the Oak Ridge National Laboratory. So he and his colleagues used a climate model to examine regional variations in the warming that could occur during this century. Their work was published recently in the journal Proceedings of the National Academy of Sciences.

“Global temperature trends are higher than what we previously thought,” remarked Dr. Ganguly in an email that explained their key findings. Such trends appeared more plausible given that the recent emissions have surpassed what used to be a considered a relatively high projection from the Intergovernmental Panel on Climate Change, he pointed out.

Their paper indicates that it is places in the higher latitudes in the northern hemisphere such as Russia and Canada that could see some of the sharpest rises in temperature during this century. This could also have implications for the melting of Arctic sea ice. Besides, the rise in temperatures could be very high in other regions like the western U.S., Spain, Portugal, north and south Africa, northern South America and parts of Australia, he added.

It is places in or near the tropics that are most likely to suffer from severe heat waves. Northern India, the U.S. midwest, parts of western Europe, north Africa, and eastern China could also see an increase in the average intensity of heat waves.

In India, the increase in regional temperatures as well as the worsening heat waves from the middle to the end of this century appeared to coincide with some of the most densely populated parts of the country as well as some of its most productive in terms of agriculture, he noted in his email.

The warming could also hasten the melting of Himalayan glaciers. Heating up of the Indian Ocean and other oceans could produce changes in monsoon rainfall patterns.

But Dr. Ganguly cautioned that their work showed that there was significant uncertainty associated with the projections. But this could also imply that “the worst-case possibility may be even worse than what we expect currently.” South Asia, with its large population and vulnerability to changing climate and extreme weather events, needed to be prepared for such contingencies.