Deadly continental-type heatwaves will be the norm by the 2040s, Met Office forecasters are predicting.
Based on climate projections, the weather will become intolerable as the amount of carbon dioxide entering the atmosphere fails to drop.
According to the latest statistics from the US Energy Information Administration, worldwide carbon dioxide emissions are expected to increase from 31 billion metric tonnes in 2010 to 45 billion metric tonnes in 2040 - a 46% increase.
The knock-on effect could mean us experiencing intense heat of up to 40C or more during summers - similar to the sweltering conditions in Europe in 2003 which claimed the lives of 70,000 people.
That heatwave was the hottest summer on record in Europe since 1540. Scientists concluded that it was likely to have been exacerbated by manmade global warming.
Met Office scientists said that 2003 and subsequent summers represent a warming trend across Europe and that more than half the summers in southern Europe will be warmer by the 2040s.
Prof Stephen Belcher, head of the Met Office's Hadley Centre, said: "Summer 2003 certainly had an influence in the UK. We're able to say that by the 2040s we can expect events like 2003 to be normal."
Warmer summer temperatures will also be accompanied by heavier rain as warmer air can hold more moisture, Belcher said.
"Heavy rain is becoming heavier and that's consistent with our picture of a warming world and warming atmosphere. There is evidence that in the UK we are seeing more heavy rainfall."