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The scorching heat of the Pacific Northwest is unprecedented, but the reason is quite simple. In summer, the air above the land or ocean heats up and rises into the atmosphere. A peculiar air dome is formed, which prevents other air masses from penetrating. That is why the new term “heat dome” has become part of the dictionary of Canadian and American climatologists.
According to Carlo Schreck, a researcher at the University of North Carolina, the high pressure inherent in a heat dome can shift the flow of the atmosphere north, in this case north of Canada, and slow it down. Over time, the formation will simply become “too massive and dissipate,” and the airflow will begin to move south, he explained.
Until that happens, the heat will remain trapped in one place and the people under the heat dome will have to endure it.
US President Joe Biden has linked extreme heat in the northwestern country to rising greenhouse gas emissions. “Faced with increasing weather conditions due to climate change, we need to invest in building a more resilient energy system,” he said Tuesday in La Crosse, Wisconsin, calling for approval of the infrastructure agreement reached with a group of senators from both countries. parties.
So far, no heat dome has created Phoenix-like weather conditions in Phoenix, which is mostly mild. Last Sunday, the city’s heat record was 41.6 ° C, last recorded in 1981. The highest temperatures were unlikely, let alone the highest five degrees, but that’s exactly what happened. on Sunday. When it seemed simply impossible to improve on the new record, the thermometer bars rose to 46.7 ° C on Monday.
“Typically, in such cases, meteorologists have to rely on their intuition to say ‘something is wrong’ or that ‘an error has occurred,'” said Daniel Swain, a climate scientist at the University of California who studies how it changes. extreme weather. on a warming Earth. Still, this time there was no mistake. When the air temperature in Portland reached 46.7 ° C on Monday, the developers of the weather forecasts were happy.
Heat domes form naturally and are not necessarily related to climate change, except for the fact that warmer climates around the world increase average and extreme temperatures. Today, scientists are no longer investigating the possibility that climate change has affected the intensity of the heat wave; explore the scope of influence.
In fact, climate change regularly exacerbates many extreme weather events, so scientists can now assess its impact in near real time. Participants in the World Weather Attribution research project to analyze the weather during or immediately after the onset of weather events are currently investigating the ongoing heat wave in the Pacific Northwest. In recent years, scientists have done so many heat wave analyzes that they can tell what kind of weather phenomenon is relatively new.
Swain, who graduated from meteorology and climate science, calls the Pacific Northwest heat dome “impressive.”
Usually the warmer weather is released because any indicator increases: the highest temperature recorded during the day, the duration of the period of warmer weather, the highest temperature recorded at night. The heat wave that hit the western United States is different.
“In this case, all these indicators are exceeded,” he said. “There is no record that this heat wave would not have improved.”
Climate change may also have contributed to the prolonged heat. 2018 In a scientific journal, a team of American and European researchers hypothesized that a rigid and undulating area of atmospheric circulation could form in the Northern Hemisphere, as if imprisoning extreme weather in one place.
Such an area has been observed for the past few weeks. As global temperatures rise in this age, the frequency of their formation can increase by 50 percent.
Despite these characteristics of the atmospheric circulation, meteorologists do not see the full extent of the effects of climate change.
“As a result, the impact of climate change on climate change in phenomena like the current unprecedented heat wave in the west of the country is even underestimated,” said Michael Mann, professor of atmospheric sciences at the University of Pennsylvania, who was the lead author of the 2018 article.
Unfortunately, the inconvenience will not end even if the heat dome dissipates.
Extreme heat in the Pacific Northwest will exacerbate the effects of the drought, warned Erica Fleishman, director of the Oregon Climate Change Research Program. The heat wave will also increase the risk of large fires as the plants dry out and the wind strengthens.
Last year, devastating fires in Oregon burned 1.2 million people. acres and destroyed more than 5,000. home even without record heat. According to a report released by the state in January, the remediation work cost about $ 622 million. AMERICAN DOLLAR.
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