From Hawaii’s flurry of hurricanes, to record high sea ice in Antarctica, and a heat wave that cooked the Australian Open like shrimp on a barbie, 2014 saw some wild weather. How much of that was tied to climate change is what scientists around the world tried to answer in the Bulletin of the American Meteorological Society’s annual attribution report, which was published Thursday.
What they discovered was that the clearest impacts of warming could be found in heat-related events, from heat waves on land to unusually hot ocean waters. Other events, like droughts in East Africa and the Middle East, California’s intense wildfires, and winter storms that continually swept across the eastern U.S., were harder to pinpoint. In part this is because such events are inherently complex, with a multitude of factors influencing them.
For example, while the East African drought was found to be both more likely and more intense because of warming, the situation in the Middle East was less clear, with no discernable climate change connection to the various factors that influenced it. Likewise, no direct push from climate change could be found in California’s wildfire activity, though it is clear that it is increasing the overall wildfire risk there.
And while some events, like the U.S. winter storms and the record high Antarctic sea ice extent, could be pinned to a particular cause, that cause could not be linked to climate change. For other events, like the drought in Brazil and flooding in the Canadian prairies, humans influenced the likelihood in other ways besides the greenhouse gases that continue to be emitted into the atmosphere.
What was clear, though, is that the fast-growing field of what is called extreme event attribution is gaining momentum. Researchers are casting a wider net for extreme events to examine and continually refining their methods. Attribution work has traveled a considerable distance since its inception just over a decade ago.
“Extreme event attribution” is a new topic for me. Very cool science right thar.