According to experts, the scorching heatwave that ravaged the Pacific Northwest last month would have been “nearly impossible” without the effect of climate change. Even with it, it was virtually impossible.
According to a recent study by World Weather Attribution, a climate research project that looks at the impact of climate change on specific weather occurrences, this is the case.
In a briefing yesterday, Geert Jan van Oldenborgh, a climate scientist at the Royal Netherlands Meteorological Institute and co-leader at World Weather Attribution, said, “As far as I can recall, we’ve never seen a spike in record temperature like the one in this hot wave.”
In the closing days of June, a heatwave raced across Oregon, Washington, and western Canada, sending temperatures soaring across the Pacific Northwest (Climatewire, June 28).
The temperature in Seattle reached an all-time high of 108 degrees. At 116 degrees, Portland also set a new record. And the small hamlet of Lytton, British Columbia, grabbed international news when temperatures reached a scorching 121 degrees. A catastrophic wildfire engulfed the hamlet only a few days later.
Hundreds of people have died as a result of the heat in the Pacific Northwest. Many more deaths, according to experts, are expected to be recorded.
The new research, which took only ten days to complete, aimed to quantify precisely how extraordinary the incident was. It finds that in a world without climate change, the heatwave would have been at least 150 times less likely—and may be considerably more unusual. Because this occurrence was so far beyond the normal range, it was impossible to estimate the exact quantity with models.
“This event would not have happened if it hadn’t been for climate change,” said Friederike Otto, associate director of the University of Oxford’s Environmental Change Institute and a co-leader at World Weather Attribution.
Even in today’s warming environment, the incident appeared improbable.
There are statistical upper limits to the types of temperatures that scientists may predict during heat waves. These boundaries are determined by the local climate, historical warming rates, and previous degrees of severe heat.
When the study team used a conventional statistical model to analyze the Pacific Northwest heatwave—which utilizes prior data as a type of baseline for what should be possible—the model concluded that it should not have happened at all.
Van Oldenborgh stated, “The temperatures broke well above this top bound.” “We couldn’t use our normal assessment procedures since they didn’t work.”
The researchers had to make changes to their model, pushing it to integrate current severe temperatures in its historical record. After then, the model predicted that the heatwave was at least a once-in-a-1,000-year occurrence.
Van Oldenborgh emphasized that the figure is very speculative and that it might be significantly lower. The primary conclusion is that the heatwave was unlike anything the Pacific Northwest — or, for that matter, most of the world — has ever seen.
Although additional study is needed to tell for sure, the team has many hypotheses regarding how this event became so severe.
Drought may have made things worse than they would have been otherwise. Alternatively, changes in the jet stream’s movement, potentially affected by climate change, might have had a role. It’s possible that the ideal storm of climate variables just aligned, allowing for an extremely rare event to occur.
It’s also likely that the region has now “passed a threshold” where such catastrophes are not only feasible but also considerably more often, according to van Oldenborgh. Climate change does not necessarily happen in a straight line. Once you exceed a particular level, the system might suffer “‘jumps’ that make this sort of heat more likely,” he added.
If that’s the case, ultra-extreme heat waves may occur more frequently than climate models presently indicate, and they may begin to appear in unexpected areas throughout the world.
For the time being, it’s uncertain what to expect. In the following months, the team intends to look more into the reasons for the incident.
“Everyone is quite concerned about the consequences of these events,” said van Oldenborgh. “No one saw this coming, and no one believed it was conceivable. We have the impression that we do not comprehend heat waves as well as we thought we did.”
‘HOW CLIMATE CHANGE KILLS the US’
A greater grasp of the future, as well as more accurate projections of future heatwaves, can save lives. Many communities across the country and around the world may currently be unprepared for what is ahead.
Households in the Pacific Northwest, for example, have less access to air conditioning than those in warmer climates. As a result, when high heat waves strike, they become much more hazardous.
At yesterday’s briefing, Kristie Ebi, global warming and public health specialist at the University of Washington, stated, “The most significant aspect from a public health standpoint is virtually all of the deaths are avoidable.” “People do not need to die in heat waves.” Climate models almost uniformly predict that as the globe warms, heat waves will grow more frequent and powerful, even though scientists are still working out the boundaries of such extremes. That means communities must establish emergency plans for high heat events and raise public awareness about the risks, according to Ebi.
Heat kills more people in the United States than any other meteorological event, with hundreds of people dying each year.
Furthermore, attribution studies show that heatwaves are becoming more severe as a result of climate change than hurricanes, droughts, or any other weather phenomenon. Its impact on severe temperatures is “orders of magnitude” greater, according to Otto.
“Today, heat waves are how climate change kills us,” she explained. “I believe this is the most visible manifestation of climate change.”