Why some of the planet’s coldest areas are experiencing heatwaves

Why some of the planet’s coldest areas are experiencing heatwaves
Western Canada and Siberia are currently enduring worrying record-breaking temperature highs being caused by a ‘heat dome’

Why are we asking this now?

Parts of 加拿大, the US Pacific NorthwestArctic Circle are currently suffering sweltering unseasonal heatwaves that have already caused dozens of sudden deaths.

The baking conditions in regions better known for their hard winters are breaking local temperature records and making everyday life “intolerable” and rendering it “almost impossible” to venture outside away from air conditioning, one British Columbia resident 告诉 The Globe and Mail.

The phenomenon is being attributed by meteorologists to a “heat dome” lingering over the northern hemisphere and trapping concentrations of hot air in place but many suspect this is the latest evidence of the worsening climate crisis at work.

Where is this happening?

In Canada, 这 worst affected areas are the western provinces of British Columbia and Alberta, as well as parts of Saskatchewan, the Northwest Territories and the Yukon, for all of which Environment Canada has issued heat warnings.

The country recorded its all-time highest temperature for the third day in a row on Tuesday when the mercury hit a staggering 49.5C in Lytton, British Columbia.

Temperatures in the Vancouver area reached just under 32C on Monday with the humidity making it feel closer to 40C in areas that are not near water, according to Environment Canada.

The city’s police force meanwhile says it has responded to 130 sudden deaths since Friday, with elderly people or those with underlying health conditions accounting for the majority of lives lost.

Over the border in the US, Seattle, 华盛顿, and Portland, Oregon, are currently sweltering in the heatrecording temperatures well above 37.8C on Monday – 照原样 Siberia in northern Russia.

Land temperature in the Arctic Circle region has peaked at 48C in recent days in what has been described as a “persistent heatwave” in a region increasingly hit by wildfires and above-average temperatures.

The European Union’s Copernicus Atmosphere Monitoring Service said land surface temperature across Siberia had “widely exceeded” 35C on the first day of summer on 20 六月. Saskylakh, an Arctic town, recorded 31.9C on that date, according to the Copernicus programme, who said it was the small community’s hottest temperature before the summer solstice since 1936. The EU programme’s satellites also found land surface temperatures peaking at 48C near the town of Verkhojansk, 43C in Govorovo and 37C in Saskylah on 20 六月.

That follows a temperature rise above 30C in areas of the Arctic in May, which is much higher than average for the time of year and was described as “mind boggling” by climate scientists.

They warn that the climbing temperatures are causing the ice and permafrost to melt, which in turn causes previously trapped methane to be released into the atmosphere and contributes to global warming, worrying developments following on from the record-breaking delay in the freezing of Arctic sea ice in late 2020.

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What is the definition of a heatwave?

The UK’s Met Office defines a heatwave simply as “an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity”.

It goes on to explain that heatwaves are most common during the summer months when high pressure is most likely to build up. Such systems are slow moving and can linger for a prolonged period of time, typically lasting for days but sometimes for weeks

Explaining the “heat dome” ratcheting up the temperature in North America, Environment Canada’s David Phillips told broadcaster CBC on Wednesday morning: “This dome stretches half way up to the atmosphere and it is a cap, a lid, putting a lid on top of boiling water, and inside that lid there’s no, no weather comes in, it’s just progressively warmer, and because it’s high pressure… that air squeezes each other and little air molecules jingle and jangle and create heat and it doesn’t escapethat heat stays within that kind of dome.”

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What are the experts saying?

The world’s most prominent climate activist Greta Thunberg has been sounding the alarm about the heatwaves, tweeting on Tuesday: “Heat records are usually broken by decimals, like a tenth of a degree. And not in JuneThis heat-wave is just getting started.”

Zeke Hausfather, a California-based scientist at the climate data NGO Berkeley Earth, said that the US Pacific Northwest has warmed by about 1.7C in the last half-century and commented: “In a world without climate change, this still would have been a really extreme heatwave. This is worse than the same event would have been 50 几年前, and notably so.”

Also explicit in connecting the phenomenon with the climate crisis was Washington State governor Jay Inslee, a former Democratic presidential candidate who ran on a green platform, WHO told MSNBC: “This is the beginning of a permanent emergency. We have to tackle the source of this problem, which is climate change.”

His counterpart in British Columbia, John Horgan, said the hottest week the province had ever experienced had led to “disastrous consequences for families and for communities”.

Are the heatwaves a one-off, will they become more frequent and might they happen elsewhere?

Climate scientists say global warming has increased the frequency and intensity of extreme weather events like these heatwaves but usually stress that it is difficult to link any one event to the earth’s increasing temperature, which is on course to rise by 3C by 2100 without global action to prevent it.

But Governor Inslee’s “permanent emergency” warning is likely to ring true for many, with few seriously doubting the likelihood of global warming having played a role in cultivating or exacerbating the current alarming conditions, which would suggest these are very unlikely to prove a one-off event.

Another person in little doubt about the impact of climate change on the current crisis is meteorologist and author Eric Holthaus, who notes its adverse effects on North America’s Pacific mountains as a contributing factor to the present phenomenon.

Writing in 守护者, Mr Holthaus says: “Climate change is not just warming the surface of the planet, it’s warming earth’s entire troposphere – the lowest layer of the atmosphere where all our weather occurs. That’s particularly true in mountainous areas, where temperatures are rising even faster than elsewhere. When snow and ice recedes or even disappears from mountains, the bare soil beneath can warm unimpeded.”

He says that this effect, coupled with the extreme drought in the western and southern US states of Oregon, Nevada, 犹他州, 亚利桑那, 加利福尼亚州, New Mexico, Texas and Colorado, is enabling the heat dome.

“Dry, descending air rushing down the mountain slopes offshore towards the ocean created a literal pressure cooker, sending temperatures soaring to never-before-seen values,” Mr Holthaus writes.

Without urgent intervention to relieve the pressure on the natural world and avert episodes like this, it certainly seems likely that further heatwaves and other extreme weather events will become more prevalent across the world with the passing of time.

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