A summer that really scared scientists.
|
|
Illustration by Nicholas Konrad / The New Yorker
|
|
Author
Bill McKibben
is a founder of the grassroots climate campaign 350.org and a
contributing writer to The New Yorker.He writes The Climate Crisis, The New Yorker’s newsletter on the environment. |
Raging wildfires produced plumes of smoke that spread around the world; President Joe Biden tried to free up a lot of money for climate work and, so far, Senator Joe Manchin has prevented him from doing so.
But some unexpected things happened, too—such as December tornadoes and windstorms, which have devastated parts of the country, and which are increasingly linked to warming.
The most unexpected event by far, though—the thing that was truly off the charts—came in June. Toward the end of the month, torrential rains across China created a lot of atmospheric moisture, which the jet stream sucked out over the Pacific.
Meanwhile, the remnants of a heat wave in the American Southwest moved north. The two weather events met over the Pacific Northwest and western Canada, forming a giant dome of high pressure that diverted moisture to both the north and the south. Gradually, over a period of several days, the core of the high-pressure area freed itself of clouds, allowing the sun’s rays to blast down during the days immediately after the solstice.
The result was the most remarkable heat wave in recorded history. On Sunday, June 27th, Canada broke its all-time heat record, of a hundred and thirteen degrees Fahrenheit, when the temperature reached nearly a hundred and sixteen degrees in Lytton, a community of around two hundred and fifty residents on the Fraser River, in southern British Columbia.
The next day, that record was broken, again in Lytton, when the temperature hit a hundred and eighteen degrees. On Tuesday, it was smashed again, when the temperature in the town soared to a hundred and twenty-one degrees. On Wednesday, Lytton, now parched dry, burned to the ground in a wildfire; only a few buildings were left standing.
Breaking a long-standing record is hard (Canada’s old high-temperature record dated to 1937); surpassing it by eight degrees is, in theory, statistically impossible. It was hotter in Canada that day than on any day ever recorded in Florida, or in Europe, or in South America.
“There has never been a national heat record in a country with an extensive period of record and a multitude of observation sites that was beaten by 7°F to 8°F,” the weather historian Christopher C. Burt said.
Records of almost equally incredible magnitude came in from across the region. Quillayute, Washington, broke its all-time temperature high by eleven degrees, at a hundred and ten degrees Fahrenheit, even though the town is just three miles from the Pacific. It was over a hundred and three at Fort Smith, in the Northwest Territories, beating an eighty-year-old record.
According to Maximiliano Herrera, a weather historian who maintains a Web site devoted to unprecedented temperatures, “the number of all times records beaten by more than 5C in this heat wave is greater than all cases worldwide together” in the past eighty-five years.
Jeff Masters and Bob Henson, meteorologists who blog for a Yale climate Web site, wrote, “Never in the century-plus history of world weather observation have so many all-time heat records fallen by such a large margin.”
The reason, of course, is the climate crisis: within days, researchers had demonstrated—with the modelling techniques of the new attribution science—that global warming had made such a heat wave a hundred and fifty times more likely.
Essentially, this couldn’t have happened on the Earth we used to know. James Hansen, the planet’s most important climatologist, put it this way when I talked to him last month: “We’ve been expecting extreme events. But what happened in Canada was unusually extreme.”
The reason all this is so frightening is that it suggests fundamental parts of the way that the planet works have begun to shift, allowing for physical phenomena we’ve never seen before. It suggests, that is, that the predictions provided by global-climate models—which are frightening enough—may be too optimistic.
The impossible heat in that week seems to be connected with the increasingly unstable operation of the jet stream, which in turn seems to be connected with the rapid melt of the Arctic Ocean—as the temperature difference between the equator and the pole lessens, the jet stream seems to get stuck in odd positions.
Meanwhile, a flood of freshwater from that same melting Arctic seems also to be disrupting the Gulf Stream.
A new study, which was conducted by European scientists and released a few months before the heat dome appeared, strengthened the theory that the immense ocean current—which is a hundred times the flow of the Amazon, and which, like the jet stream, distributes heat poleward—had slowed by roughly fifteen per cent since 1950. We’re breaking really big things.
Scientists have done a good job of calculating how much the world will warm as we increase the amounts of carbon dioxide and methane in the atmosphere. They’re pretty confident that, having raised the temperature more than a degree Celsius already, we’re on our way to a planet that will be, on average, three degrees warmer.
That’s if we keep on our current track; the scientists are hopeful that, if we take actions more dramatic than those promised at Glasgow, we might hold that average increase below two degrees.
But researchers are not as confident—especially since the June heat wave—that we really understand how much damage those global averages represent. Scientists are inherently conservative in their predictions.
The world is clearly more fragile than the models have led us to believe. And that’s what was terrifying about 2021.
Links
- (USA National Geographic) Year In Review: 2021's Weather Disasters Brought Home The Reality Of Climate Change
- The Year in Climate | The New Yorker
- Climate change in review: 2021 - YouTube
- 2021 was a remarkable year for Earth's climate
- 2021 in Review: Our Reports on Climate Change
- Articles in 2021 | Nature Climate Change
No comments :
Post a Comment