Human-induced climate change made recent extreme heat in the US southwest, Mexico and Central America around 35 times more likely, scientists say.

The World Weather Attribution (WWA) group studied excess heat between May and early June, when the US heatwave was concentrated in southwest states including California, Nevada and Arizona.

Extreme temperatures in Mexico also claimed lives during the period.

The scientists said that such a heatwave was now four times more likely than it was in 2000, driven by planet-warming emissions.