The Pacific Northwest Heat Wave Is Now a ‘Mass Casualty Event’

The Pacific Northwest Heat Wave Is Now a ‘Mass Casualty Event’
Photo: Nathan Howard, AP

The Pacific Northwest is still reeling from the mind boggling heat wave that gripped it late last month. The past two days have made it clear that hundreds died in the region, and that the climate crisis played a role in driving the extreme heat. It underscores the reality that climate change’s deadly impacts aren’t waiting in some imagined future, they’re here now.

Temperatures in the Pacific Northwest rose to unheard of levels last week, with triple-digit heat baking the region from Oregon to British Columbia. Coroners on both sides of the border observed a major uptick in deaths, and the exact causes and role heat played are becoming clearer. In Oregon, the scorching temperatures killed at least 107 people. Medical officials in Multnomah County, which includes Portland and parts of the surrounding metro area, suspect that at least 67 of those deaths were from heat-related illnesses (40 of those cases have been confirmed). On Wednesday, they declared the heat wave a “mass casualty event,” a label usually applied to other horrors like a mass shooting.

“The sheer volume of work requires weeks of staff time to properly complete their forensic investigations that will inform future planning,” officials wrote. “The picture of what occurred is expected to come into focus as details from each death come together for analysis. That information will form the basis for change to the County’s heat response and is hoped to ultimately save lives in future events.”

At this point, scientists are operating under the assumption every heat wave is being influenced by climate change, whether by increasing the odds or increasing how hot it gets. Or, in the Northwest’s case, both. In a separate analysis published on Wednesday, researchers quantified the exact role of the climate crisis in the Northwest’s brutal heat.

The study, conducted by international scientists with the World Weather Attribution group, found that the climate crisis was responsible for boosting peak temperatures by 2 degrees Celsius. It also made the extreme temperatures at least 150 times more likely to occur. The research also shows that the heat wave was a 1-in-1,000-year event in our current climate, which means it’s still a rarity. But consider that it would’ve been a 1-in-150,000-year event in the pre-industrial era.

If the world heats up by another 0.8 degrees Celsius, breaching the Paris Agreement’s goal of limiting warming to 2 degrees Celsius above pre-industrial temperatures, events like this will become almost commonplace, occurring every five to 10 years.

The report itself isn’t peer-reviewed yet, but it relies on peer-reviewed techniques that have been repeatedly used for snap analyses, including recent heat waves in Siberia and Australia, and later peer-reviewed. That gives scientists confidence in the disturbing results.

Though it was clearly more likely to happen due to the climate crisis, the extreme heat event proved difficult for the scientists to analyse. Temperatures rose so much that the heat wave challenged the very assumptions about how the climate works and the impact carbon pollution is having on it.

“Everyone is just worried about the implications of this event,” Geert Jan van Oldenborgh, a scientist at the Royal Netherlands Meteorological Institute and co-author of the report, told BuzzFeed News. “This is something that nobody saw coming, that nobody thought possible. And we feel we do not understand heat waves as well as we thought we did.”

The authors stress that the time to curb emissions to avoid even more hellish heat is now, but also that at this point, some amount of it is inevitable and we must be ready.

“Adaptation and mitigation are urgently needed to prepare societies for a very different future,” the authors write.

As Pacific Northwest officials gather more information about the death toll, including who died and why, it will be vital to figure out how to use that data to ensure a heat-related mass casualty event doesn’t happen again. Among potential solutions are high tech ones like climate-friendly air conditioning and improving the electrical grid as well as low tech ones like planting trees to mitigate the heat island effect and programs to check on the elderly, alone, and unhoused.