All the talk is of sea level rise. However the thing that is going to destroy habitat for human beings in fairly short order is extreme heat and climatic extremes.
Extreme Heat Is Defining Climate Change
5
November, 2015
The
lasting legacy of climate change will be heat. The land, the oceans,
all of it. It’s the tie that binds and while the global
average temperature is
the defining metric, the increasing incidence of heat waves and
longer lasting extreme heat is how the world will experience it.
Climate
change has helped shift the odds of extreme heat.
"Global
warming is the most obvious, well-documented effect of climate
change,” Stephanie
Herring,
a climate scientist at the National Oceanic and Atmospheric
Administration and organizer of this year’s attribution issue,
said. “As a result, the signal is very strong so we can more easily
detect it amongst noise of natural variability compared to other
types of extreme events."
In
the case of a strong signal, 2014 stands out as particularly notable.
It was the hottest
year on record,
though this year is on track to top last year’s record (and signs
are already pointing to 2016
continuing the record heat parade).
The
lift in background temperatures makes extreme heat more likely. “The
underlying processes that relate climate change to heat wave
intensity and frequency are fairly straightforward to understand: if
you increase the average temperature by even a modest amount, then it
turns out that you dramatically increase the area under the extreme
positive ‘tail’ of the distribution,” Michael
Mann,
a climate scientist at Penn State who wasn’t involved in any of the
new studies, said in an email.
Put
another way, it’s like
having Steph Curry on
your basketball team. He doesn’t always guarantee a win, but he
sure as heck increases the odds of a victory.
Unfortunately,
rising temperatures are not a game and can have dangerous
consequences. Heat at last
year’s Australian Open had
players hallucinating on the court and this year’s heat
wave in India killed
thousands.
Maximum
temperature anomalies for Australia's May 2014 heat wave.
Credit: Australia Bureau of Meteorology
Credit: Australia Bureau of Meteorology
The
May 2014 heat wave in Australia included some of the most dramatic
results, with climate change increasing the likelihood an
eye-popping, sweat-inducing 23 times.
For
that study, researchers zoomed down to the city-level in Adelaide and
Melbourne. Mitchell
Black,
the study’s lead author and Ph.D. student at the University of
Melbourne, said it is likely the first time such a localized analysis
has been done.
Climate
change is also making extreme heat even hotter. It’s
not just a game of odds when it comes to extreme heat, it’s also
one of intensity. An analysis of Europe’s incredibly warm year in
2014 shows that human greenhouse gas emissions are responsible for
roughly half of the extra warmth added to the system.
It’s
tougher to tease out these intensity connections, but in addition to
Europe’s hot year, the May 2014 Australian heat wave and a December
2013 Argentinian heat wave also got a boost in strength from global
warming.
The
findings could be moving from academia to the public discourse. The
new findings show that it isn’t a question of if climate change is
influencing extreme heat, it’s basically a question of how much of
an influence it has on a particular event.
“Heat
is the one event that is most ready for the science
community to have a discussion of whether or not every heat
attribution assessment necessarily needs to go through
the peer review process,” Herring said.
There
are already some efforts underway to do get these types of analyses
out to the public sooner rather than later, including World
Weather Attribution,
a project at Climate Central that involves the University of Oxford
Environmental Change Institute, the Royal Netherlands Meteorological
Institute, the University of Melbourne, and the Red Cross Red
Crescent Climate Centre. Herring also noted an effort by the U.K. Met
Office to do real time attribution of this summer’s heat wave in
Europe as an example of government agencies providing that
information directly.
One
of the challenges remaining for the science is reducing the range of
uncertainty around how much global warming is increasing the odds of
extreme heat and whether 1-in-1,000 year events will now be 1-in-100
year events or 1-in-5 year events.
Society
could benefit from improved climate change and heat predictions. With
heat waves likely tocontinue
increasing in
frequency and intensity, their impact on people around the world will
continue to row.
For
example, danger
days — when
the heat index tops 105°F — are becoming more common in the
U.S. and are set to rapidly increase in just 15 years.
Herring
believes that quantifying the extreme heat-climate change connection
could be a next step to making these types of analyses useful to
society.
“I
don't think there is a lot of value from the perspective of decision
makers to simply say climate changes impacted the risk of an extreme
event,” Herring said. “But there’s a real opportunity to be
able to deliver heat information in a more timely fashion.”
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