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.

Such attribution studies take some time to complete, so it is too soon for scientists to say how much of a role climate change is playing in the current heatwave stretching from the center of the US through to the northeast and into Canada.

In their new report, the scientists said such a heatwave was now four times more likely than it was in the year 2000, driven by planet-warming emissions.

Many extreme weather events including heatwaves are becoming more frequent and intense as a result of climate change, experts say.

“The results of our study should be taken as another warning that our climate is heating to dangerous levels," said Izidine Pinto, Researcher at the Royal Netherlands Meteorological Institute.