Global warming

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'Indian summers may last 8 months by 2070'

Prolonged heat-wave conditions–in other words, a summer lasting up to eight months–could be the new norm by the 2070s for the Gangetic plains, if greenhouse-gas emissions are not cut to limit the global temperature increase to 2°C, according to a new study in the journalEnvironmental Research Letters.

The world is getting not only hotter but also more humid. The combined scientific measure of heat and humidity is called “wet-bulb temperature”, which hardly ever crossed 32°C between 1985 and 2005. The nature of

such heat waves has since changed because of rapidly growing greenhouse gas emissions, exacerbating climate change. in the Gangetic plain, one of the world’s most climate sensitive regions, wet-bulb temperatures currently touch 31°C, on average, one day every year. By the 2070s, these heat waves may become 100 to 250 times more frequent, said the study.

Using a suite of 18 climate models, two emissions scenarios, and five population-growth scenarios, Ethan Coffel, 27, a final year doctoral student at Columbia University, and two other scientists, also estimated the possibility of the wet-bulb temperature approaching or exceeding 35°C, the theoretical human heat tolerance limit by then.

So, will wet-bulb temperatures rise enough to imperil human life?

“Our emissions trajectory is likely to determine whether such extreme heat occurs this century,” Coffel, the lead author of the study, told IndiaSpend.

“But if it does occur, it will likely be in India, the Middle East, the Amazon, and parts of eastern China.” This temperature rise, he said, is“one of the most serious threats to our society”.

The poor, those with outdoor jobs, cardiovascular and respiratory conditions are likely to be the most vulnerable. High temperatures could even give rise to new diseases–as already evident in part of South America–and threaten agriculture, which currently employs 228 million people or48.8% of India’s working population.

What could exacerbate the situation is the finding that in some of those areas, by then, the dry bulb temperature–a measure of air temperature alone–is expected to hit the average of the single hottest temperature each year between 1985 and 2005, anywhere between 50 and 125 times annually, as against once per year currently.

“Climate change is a problem that’s both scientifically interesting and societally urgent,” said Coffel. “What makes it more interesting for me is weather and physics, my favourite subjects, come together in climate science.”

Article source- BUSINESS STANDARD