WASHINGTON--The suffocating heat wave that killed hundreds of people across the Pacific Northwest last week would have been "virtually impossible" without climate change, a study has found.
Reporting the first research attributing the event to climate change on Wednesday, scientists said climate change had made such a heat wave in the region 150 times more likely. The scientists estimated the extraordinary temperatures were a one-in-a-thousand-year event, though noted this was difficult to quantify given the unprecedented heat in early summer.
But if current greenhouse gas emissions continue, an event so extreme could start occurring every five to 10 years by the 2040s, they warned. "People need to realize that heat waves are killers, and they are by far the deadliest extreme event," said co-author Friederike Otto, a climate scientist at the University of Oxford and co-leader of the World Weather Attribution, an international scientific collective that published the study.
The research by 27 scientists is still awaiting peer review but uses peer-reviewed rapid attribution methods to produce findings quickly after extreme events. "Heat waves are really changing so much more and so much faster than all other extreme events," Otto said. "Heat preparation and preventing death during heat waves need to be a No. 1 priority for every city authority."
The heat wave gripped parts of the United States and Canada for days at the end of June, smashing records in dozens of cities. Power lines melted in the heat. Roads buckled. Canada thrice broke its national temperature record, peaking on June 29 at 121 Fahrenheit (49.6 Celsius) - a full 8 degrees Fahrenheit (4.6 degrees Celsius) higher than the previous record set in 1937.
Another heat wave is expected to strike parts of Canada and the United States later this week.
The death toll in Oregon alone has topped 100, while British Columbia saw hundreds more deaths than usual. It will take months to calculate a full death toll, but scientists say these numbers will rise. Hospitals also saw jumps in the number of heat-related visits and emergency service calls.
The new research attributing the heat wave to climate change is not entirely surprising. Worldwide, climate change has made heat waves more common, more severe and longer lasting. The June heat wave, however, was far beyond the norm for the Pacific Northwest. For that, the authors suggested two possible explanations: Either many factors came together to produce a very rare event that was worsened by climate change, or climate change has altered the atmospheric conditions so that this type of heat wave is now more common than previously understood. Either way, industry-driven climate change played a key, and considerable, role, according to the study.
