India, May 9 -- It isn't just getting hotter. The nature of the heat we face, on our warming planet, is changing.

Have you stepped out of a cooled car recently and felt like your clothes were on fire? This is the result of what meteorologists call "oppressive" heat: high temperatures paired with high humidity.

An oppressive heatwave is a step up, in intensity, from an extreme heatwave, says Subhankar Karmakar, a professor withthe Environmental Science and Engineering Department and the Centre for Climate Studies at the Indian Institute of Technology-Bombay (IIT-B).

As we know by now, when humidity rises, it makes it harder for the human body to cool - because sweat cannot evaporate as easily.

"Extreme heatwave conditions are uncomfort...