The unprecedented episode was made at least 150 times as likely by rising temperatures, according to a rapid analysis
By Matthew Cappucci Washinton Post
By all estimates, last week’s heatwave in the Pacific Northwest and British Columbia was essentially unprecedented. Seattle hit 108 degrees, Portland spiked to 116 and Canada broke its national temperature record three days in a row, hitting 121 degrees on June 29.
Hundreds of excess deaths were blamed on the brutal heat, which established records by margins of 10 degrees or more in spots. This was not “just another heatwave,” Christopher Burt, an expert on world weather extremes, wrote in a Facebook message, but rather “the most anomalous extreme heat event ever observed on Earth since records began two centuries ago.”
An analysis conducted by the World Weather Attribution group, which specializes in using computer modeling to examine the links between ongoing weather events and climate change, finds that the extreme heatwave would have been “virtually impossible” without human influence.
“I want the public to know that climate change has already affected extreme weather in a big way, especially heat waves,” Michael Wehner, a senior scientist at the Lawrence Berkeley National Laboratory and a contributor to the analysis, wrote in an email. “Global warming is not our grandchildren’s problem; it is ours, here and now.”
Another intense heatwave to roast Western U.S., southwest Canada
The analysis concluded that a robust relationship exists between top-tier heat extremes and human-caused climate change, stating that greenhouse gas emissions made the heatwave at least 150 times more likely to occur.
Twenty-seven scientists from more than half a dozen countries, including Canada, the United States, Germany, the Netherlands, Switzerland, France, and the United Kingdom, worked on the attribution study.
The sobering findings reveal the real-time toll that human-caused climate change is having by making extreme weather more dangerous. The stakes will become even greater as the magnitude, duration, and frequency of heat events increase.
“Every heat wave occurring today is made more likely and more intense by climate change,” read the analysis, noting that the planet has warmed about 2.2 degrees since the late 1800s. It also made clear that the outbreak of extreme heat in the Pacific Northwest and Canada was so far outside the realm of anything observed previously that it was “difficult to quantify exactly how rare the event is in the current climate.”
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