Soaring temperatures and severe heat waves will increase in the next few decades, regardless of efforts to cut emissions in the next few decades, researchers have warned.
The last decade has seen an exceptional number of extreme heatwaves around the world, hitting the US in 2012, Russia in 2010, Australia in 2009, and Europe in 2003 – having a devastating impact on health, the economy, agriculture and wildlife.
Monthly and seasonal temperatures associated with heat waves can now largely be attributed to global warming of around 0.5C over the past 50 years, a new study has shown.
Worryingly, by 2040 there will be a "several-fold" increase in heatwaves regardless of how much carbon dioxide goes into the atmosphere, according to the study, published in the Institute of Physics' journal Environmental Letters.
Although only 5% of the world's land – mostly in the Tropics but also over parts of Europe – currently suffers extreme summer heatwaves, researchers have warned the extent of the crisis will soon dramatically widen.
The study's lead author Dim Coumou, from the Potsdam Institute for Climate Impact Research in Germany, said that up until 2040, the frequency of monthly heat extremes will increase "several fold, independent of the emissions scenario we choose to take."
The percentage of land experiencing summer months of extreme heat is set to double by 2020, and quadruple by 2040 to cover a fifth of the global land surface, the projections using computer climate models found.
Even more severe summer heatwaves will increase from being virtually non-existent today to covering around 3% of the world's land.
However, future efforts to slash pollution could stem the rise in extreme heat events later on in the century, the research revealed.
"Mitigation can, however, strongly reduce the number of extremes in the second half of the 21st century," Coumou added.
After 2040, the frequency of extreme heat events will be affected by whether or not the world takes action to slash greenhouse gases, the researchers claimed.
If there are only low emissions, the frequency of periods of extremely hot weather will remain constant after 2040, the study suggested.
But, the research warned, with high emissions of carbon dioxide going into the atmosphere, heatwaves will continue to increase, and by 2100 monthly heat extremes will cover around 85% of the world's land area and very severe heat events will occur over 60% of the land.