Climate change: The North West heat wave is ‘unprecedented’. Here’s what pushes him into uncharted territory.


Growing up in Portland, Oregon, Oswill became more concerned with extreme weather changes, from wildfires to heat waves that she sees year after year.

The 44-year-old mother of two compares it to a pandemic, but never ending.

“It’s like a lockdown, but we’re not going to fix it by putting on a mask or getting vaccinated,” Oswill told CNN. “It’s just sort of perpetual. It’s scary.”

Portland has established a all time record temperature three days in a row, peaking at 116 degrees on Monday. Seattle hit 108 degrees, breaking the all-time record set a day earlier. Across the border, Lytton, B.C. recorded 117.5 degrees on Monday – the highest temperature on record in Canada and about 48 degrees above normal for this time of year .

Kristina Dahl, senior climatologist at the Union of Concerned Scientists, said the heat wave was “unprecedented”.

“We saw some heat records over the weekend only to be broken again the next day,” Dahl told CNN, “especially for a part of the country where this type of heat doesn’t happen very often”.
Extreme heat will be more common in the Pacific Northwest.  Experts say he's unprepared.
Michael E. Mann, climatologist at Pennsylvania State University, put it very simply: Climate change is making heat waves more frequent and intense. “You’re warming the planet, you’re going to see an increased incidence of extreme heat,” Mann told CNN.

Experts like Dahl and Mann say climate change is reshaping the planet’s weather patterns. As humans emit more greenhouse gases that heat the planet into the atmosphere, more energy is added to the climate system. The excess energy, according to Kristie Ebi, a climate and health researcher at the University of Washington, shows up in the form of extreme weather events.

“Heat waves have always happened and always will happen, but now we have a very different heat wave pattern than we did a few decades ago,” Ebi told CNN. “And it’s not just the intensity, it’s also the geographic extent.”

Across the country, more than 40 million people in the northeastern United States are also subject to a heat advisory, including in metropolitan areas of New York, Philadelphia and Boston. While the heat is not as hot as in Oregon and Washington, records for the date could be set in the northeast before temperatures cool down on Thursday.

Extreme heat is one of the deadliest consequences of climate change, killing more people than any other weather-related event.
Kate Weinberger, an environmental epidemiologist at the University of British Columbia, analyzed the number of extreme heat-related deaths in the United States each year. A 2020 study, of which Weinberger was the lead author, found an underestimated number of heat-related deaths in the country, as records typically only focus on medical terms such as heatstroke and carelessness. other potentially heat-related causes of death, such as the heart. attacks.
Portland and Seattle see record highs surpass 100 degrees as heat wave sweeps northwest

“The heat probably contributes to many more deaths from causes other than heat stroke, as the heat can exacerbate other chronic illnesses, such as heart and lung disease,” Weinberger told CNN. “Given the danger posed by the heat, events like the ongoing heat wave in the Pacific Northwest must be taken very seriously.”

Officials in Multnomah County, home to Portland, told CNN on Monday morning that there had been at least 43 visits to heat-related emergencies and emergency care clinics in the county on Friday, Saturday and Sunday. Sheriff’s office said monday that “ambulances are overloaded due to demand.”

“Normally, we would expect about 1 or 2 visits for heat illness over the same period,” Kate Yeiser, communications coordinator for Multnomah County, told CNN. “This weekend’s visits alone represent almost half of the heat visits we typically see over an entire summer.”

One appalling aspect of heat-related deaths in the United States is the number of premature deaths caused by heat exposure, especially among babies and children left unattended in cars.

A 2020 study published in the journal GeoHealth, co-authored by Ebi, found a sharp increase in the number of premature deaths in the United States each year due to exposure to heat as the planet warms.

“Many don’t understand how quickly cars heat up and how babies’ physiology cannot tolerate this,” Ebi said. “Making sure people really care about protecting babies and children during these heat waves is important. “

To understand how the climate crisis is changing the rules of the game, Mann suggests thinking about weather events on a bell curve. The highest point of the curve is where the most common weather conditions are and the tails are where the extreme events are. A warming planet shifts the bell curve to the right, pushing already extreme events into uncharted territory.

Mann says climate models, which predict general global conditions in the future, can capture change well and predict increases in extreme heat. But, he said, they don’t paint a full picture of the impacts of climate change during the summer.

“This is an area where current generation models don’t capture an actual climate connection,” said Mann, who was also the lead author of a study that shows climate change is driving the current. – summer jet – rapid air currents in the upper atmosphere that influence the weather day by day – behaving strangely.

“In that sense, climate models actually underestimate the impact of climate change on events such as the unprecedented heat wave we are currently witnessing in the West,” Mann added.

Climate change can cause the jet stream to jam in a static wave pattern during the summer. Daniel Swain, a climatology researcher at the University of California, Los Angeles, explains that this is best illustrated by spinning a skipping rope up and down until its waves seem to stop. Likewise, in the atmosphere, high and low pressure systems can jam, creating extreme weather events like intense heat, drought or forest fires.

People take refuge in a cooling center in Portland on Monday.

This is what happened in the Pacific Northwest this weekend, where a so-called thermal dome, a strong ridge of high pressure, acts as a cover over the atmosphere. The lid traps the hot air that tries to escape and heats it even more when it sinks.

“Even though the jet stream does what it did historically, with no specific contribution to climate change, climate change still dramatically increases the likelihood of these extreme heat events,” Swain told CNN. “If you warm the atmosphere, you would expect these heat waves to be hotter than they otherwise would have been.”

If the United States fails to reduce global warming emissions and improve climate adaptation systems, climate experts say people in the United States and around the world will suffer more severe impacts from climate change. extreme heat.

By the middle of this century – 2036 to 2065 – large swathes of the United States that do not typically experience extreme heat, such as the upper Midwest region and New England, are expected to experience severe heat on a regular basis, according to a study by the Union of Concerned Scientists of which Dahl is a co-author.

“When we look at where we are heading in the future, our analysis has shown that if we do not reduce our heat trapping emissions, we are poised to see a staggering expansion of dangerous heat across the States- United, ”Dahl told CNN.

But, she adds, if the United States aggressively cuts emissions and limits future global warming to 2 degrees Celsius, we can “save millions of people in the United States and many more around the world. relentless summer heat ”.

Camila Bernal contributed to this report from Portland. Taylor Ward and Monica Garrett of CNN Weather contributed from Atlanta.

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