UK heatwave made 30 times more likely by global warming

UK heatwave 2018

From Carbon Brief.

This year’s summer heatwave, which saw temperature records broken across the UK, was made up to 30 times more likely by climate change, a new assessment says.

A preliminary study by scientists at the Met Office Hadley Centre finds that the extreme heat experienced by the UK this year had around a 12% chance of occuring. In a world without climate change, it would have had a 0.5% chance, according to the results*.  [I.e., once every 8 years vs once every 200 years]

The influence of climate change on the odds of the 2018 summer heatwave is the highest recorded for a study of this kind looking at extreme events in the UK, the study scientist tells Carbon Brief at the UN’s 24th Conference of the Parties (COP24) in Katowice, Poland.

And, by 2050, the chances of such a heatwave occuring could reach 50%, the scientist adds. “With continued emissions, we’ll eventually make it impossible to adapt.”

This year’s summer heatwave dominated front pages in the UK – with all-time temperature records broken in, among other places, Belfast (29.5C), Glasgow (31.9C) and Porthmadog, Wales (33C).

The new analysis suggests that such extreme heat was made around 30 times more likely by human-caused climate change.

The results are “surprising”, says study author Prof Peter Stott, who leads on climate monitoring and attribution at the Met Office Hadley Centre: 

“This is a piece of scientific evidence showing that this is not just chance; we’re not just unlucky. We’re reaping the results of our emissions.

“If you look right back at global temperatures, it’s effectively impossible to have the temperatures that we’re having now without human-induced climate change. Zooming in to a region like the UK, this is probably the highest I’ve seen in that context.”

[Read more here]

To cut greenhouse gas emissions by 80% by 2050, we need to reduce them by 5% per year.  Even a 4% per annum decline would still cut emissions by 72%, which would be a pretty good result.  This year, however, it looks as if emissions rose by 2.7%.  I despair, sometimes.


* I think '0.5%' is a typo and it should read '0.4%', which is once every 250 years.  Below the section I quoted, the text says once every 245 years, so that makes more sense.  A rounding error?  Anyway, somewhere between 25 and 30 times as likely.