Extreme weather events in our future climate

Temperatures will rise. Everything else gets complicated.

by John Timmer - Feb 28, 2015 1:00pm CST

• Share
• Tweet
• Google
• Reddit

125

NOAA

"When an extreme weather event happens, the public wants to know—is this climate change?" That statement by Lawrence Berkeley Lab's Michael Wehner provided a good background for the session on climate change and unusual weather events that happened at the meeting of the American Association for the Advancement of Science. The fact is, scientists aren't well equipped to answer that question—at least not in a way the public's likely to find satisfying.
Instead, Wehner said, science is on solid ground when it examines weather events in terms of probabilities: is the risk of a given event higher? Will the magnitude of a given type of event change?
Wehner went through some historic events and examined how climate change shifted these probabilities. For example, events similar to Europe's 2003 heat wave (which saw 70,000 deaths) are already twice as likely to occur given the amount we've warmed over pre-industrial conditions. If we allow the globe to warm by 2°C over preindustrial levels, that probability goes up to 154 times. "By the end of the century," Wehner said, "when we're likely to see 4°C warming, this event will likely seem cold."
Similar things were possible to say about the 2010 Russian heatwave (2-3 times more likely now, 5-8 times more likely at 2°C of warming) and the 2011 Texas drought (slightly elevated probability now, but up to 10 times more likely at 2°C). None of this is to say that climate change has caused any of these events; they occasionally appear in climate model runs without any added greenhouse gasses. It simply tilts the odds in their favor.https://www.blogger.com/blogger.g?blogID=6565483752503740244#editor/target=post;postID=1316121304915778836