Searing heat waves could hit world every year by 2075

New York: A new study warns that if greenhouse gas emissions from human activities continue at the present rate, sweltering heat waves that typically strike once every 20 years could become yearly events across 60 percent of Earth's land surface by 2075.

But, if emissions are aggressively cut, the extreme heat events could be significantly reduced significantly, although 18% of the Earth would still face dangerous heat waves.

Resarchers put up in this way - for example, in 2075, almost a quarter, instead of more than a half, of land areas could experience 20-year heat waves that are at least five degrees Celsius hotter than today's.

"But even with such dramatic reductions in carbon dioxide emissions, future heat waves will be far more dangerous than they are now," said one of the researchers Michael Wehner from Lawrence Berkeley National Laboratory in the US.

The researchers used data generated by the NCAR-based Community Earth System Model to study 20-year extreme heat events -- those intense enough to have just a one-in-20 chance of occurring in any given year.

The researchers looked at two things: how frequently today's typical 20-year heat wave may occur in the future, as well as how much more intense future 20-year heat waves will be.

"The study shows that aggressive cuts in greenhouse gas emissions will translate into sizable benefits, starting in the middle of the century, for both the number and intensity of extreme heat events," said Claudia Tebaldi from the US National Center for Atmospheric Research (NCAR) in Colorado.

Tebaldi noted that even though heat waves are on the rise, humans still have time to avoid a large portion of the impacts.

Besides finding that today's 20-year heat waves could become annual occurrences across more than half of the world's land areas by 2075, the study also concluded that heat waves with a one-in-20 chance of occurring during a future year will be much more extreme than heat waves with the same probability of occurring today.

For example, if emissions remain unabated, such a heat wave in 2050 would be at least three degrees Celsius hotter for 60 percent of the world's land areas. For 10 percent of land areas, a 20-year heat wave in 2050 would be at least five degrees Celsius, the study projected.

The study, published in the journal Climatic Change, quantified the benefits society would reap, in terms of avoiding extreme heat events, if action is taken now to mitigate climate change.

(With IANS inputs)