CC 2.0: Andrew Bowden
Climate change is raising the odds of summer
heatwaves in Europe by a factor of 10, according to new research
from the Met Office. Over the past 10 to 15 years, the likelihood
of a 'very hot' summer has risen - from once every 50 years to once
every five years.
As the frequency of heatwaves increases, so do
risks to human health. Improving resilience to high temperatures is
critical to avoiding deaths caused by extended periods of hot
weather, the authors say.
A record heatwave
The summer of 2003 was
the hottest ever recorded for central and
western Europe, with average temperatures in many countries as much
as five degrees higher than usual.
at least 70,000 people died as a result of
the extreme high temperatures. In August alone, France recorded
over 15,000 more deaths than expected for that time of year, a 37
per cent rise in the death rate. The same month also saw almost
2,000 extra deaths across England and Wales.
To see how climate change is affecting the
likelihood of heatwaves and other extreme events, researchers carry
attribution studies. These
fingerprints of human influence on observed
changes in temperature, rainfall, and other climate
The heatwave was the first extreme weather event to be
attributed to the human influence on the climate, with research
suggesting it was made
more than twice as likely because of climate change.
Now a new study, published in Nature Climate
Change, finds that recent warming means a similar heatwave is
even more likely. The increasing impact of humans on the climate
means the risk of 'extremely hot' summers is now ten times greater
than when the 2003 European heatwave struck.
Very hot summers every five years
In the new study, Met Office researchers ran their climate
models twice: first with both natural climate fluctuations and
manmade warming included, and secondly with only natural influences
on the climate. They compared the results to see how rising
temperatures have altered the odds of heatwaves in Europe.
You can see in the left-hand chart below how
close the model simulations that include manmade warming (black
line) are to actual recorded summer temperatures (red line). By
contrast, modelled summer temperatures from a world where there's
no human influence on the climate don't match up well with what
scientists are seeing.
This shows summer temperatures can't be
explained by natural variability alone, and climate change is
playing a role, the paper explains.