Heat waves from man-made climate change could quadruple in land area coverage by 2040 and double in less than a decade.
Heat extremes during the summer months are already present on about five percent of the planet, a Potsdam Institute for Climate Impact Research press release reported.
The researchers examined the combined results of "comprehensive set of state-of-the-art climate models" to reach their conclusion.
"We show that these simulations capture the observed rise in heat extremes over the past 50 years very well." Alexander Robinson of UCM said. "This makes us confident that they're able to robustly indicate what is to be expected in future."
"In many regions, the coldest summer months by the end of the century will be hotter than the hottest experienced today - that's what our calculations show for a scenario of unabated climate change," Dim Coumou of PIK, said. "We would enter a new climatic regime."
By 2100 heat waves could cover 80 percent of the planet if CO2 emissions don't drop in the very near future.
Even if CO2 emissions are greatly reduced, the rising temperatures projected for 2040 are most likely irreversible.
"There [is] already so much greenhouse-gases in the atmosphere today that the near-term increase of heat extremes seems to be almost inevitable," Coumou said.
The changes will vary throughout the globe. Russia's recent heat wave raised its average daily temperature by seven degrees Celsius; the variable would be smaller in tropical regions such as Brazil.
"In general, society and ecosystems have adapted to extremes experienced in the past and much less so to extremes outside the historic range," Robinson said. "So in the tropics, even relatively small changes can yield a big impact - and our data indicates that these changes, predicted by earlier research, in fact are already happening."
The team believes if greenhouse-gas emissions are greatly reduced, the rising temperatures could slow down at the end of the century.
