2024-01-17 04:28:02
Much of the United States is shivering in brutal cold while much of the rest of the world is feeling unseasonably warm. As strange as it may seem, this contradiction fits perfectly into the explanations of what climate change is doing to Earth, according to scientists.
On a map of global temperatures over the past few days, large portions of the world — the Arctic, Asia, parts of Africa, the Middle East and South America — appear dark red, meaning regarding 7 degrees Celsius — or 12 degrees Fahrenheit. above the average of the end of the 20th century. But the United States stands out as a bluish-purple stain, only because it is cold.
The wind chill in some areas of North Dakota reached 56°C below zero (70°F below zero), while in Miami it was 33°C (92°F). The fourth coldest American football game in NFL history was played in Kansas City, while in the rest of the world the thermometer on Friday read no less than 33 ° C (92 ° F), which is 6.8 ° C (12°F) warmer than average during the Australian Open in Melbourne. During the night, records for warm temperatures were broken in Aruba, Curacao, some areas of Argentina, Oman and Iran.
Cases in which the weather was warmer than usual were recorded both in the southern hemisphere, where it is summer, and in the northern hemisphere, which is in winter. For example, Oman in the north had its warmest January night ever, at 26.4°C (79.5°F). Argentina, in the south, recorded the record for the warmest January night, at 27.3°C (81.1°F).
If it seems like the world has turned upside down, in a way it has. Because this is all due to what is happening in the Arctic, which used to warm twice as fast as the rest of the planet. Now, it is warming three to four times faster.
“When the Arctic warms more than necessary (like now), the intense cold is more likely to invade places like Texas, which are not prepared to deal with it,” explains Jennifer Francis, a climatologist at the Woodwell Research Center and a pioneer in the theory. of Arctic amplification, which links cold outbreaks to climate change. “Rapid warming of the Arctic is one of the clearest symptoms of human-caused climate change, making extreme winters more likely even as the planet warms overall.”
The way the cold is creeping up on us is through a weather phrase increasingly familiar to Americans: The polar vortex. It is a meteorological term that dates back to 1853, but has only been used frequently in the last decade.
This might be because cold snaps are occurring more frequently, according to winter weather expert Judah Cohen of Atmospheric Environmental Research, a commercial firm outside Boston.
According to Cohen, the polar vortex is a strong, icy weather phenomenon that typically lingers in the northernmost part of the planet, trapped by strong winds around it.
It’s like an ice skater spinning quickly with her arms raised. But when the polar vortex weakens, her arms begin to extend, the skater slips, and “all the cold air is released from the center of the polar vortex,” Cohen explained.
The current cold outbreak is consistent with the Arctic shift and the polar vortex, Cohen said. “What we have found is that when the polar vortex stretches like a rubber band, extreme winter weather is much more likely to occur in the United States. “That’s where it tends to concentrate and in January we have an extreme case of that stretching of the polar vortex.”
This one is stronger and can last longer than most, Cohen said.
Cohen and others have conducted studies showing that polar vortex events have become more frequent in recent decades.
The idea is that the jet stream — the upper air circulation that alters the climate — is more wavy with amplified global warming, said climatologist Steve Vavrus of the University of Wisconsin-Madison campus. And those wave changes in the upper air knock the polar vortex out of place and toward the United States, Cohen explained.
It is a theory that is still being debated by climatologists, but is increasingly accepted. Initially, Vavrus and Francis theorized that it was due to the melting of the Arctic sea, causing changes in barometic pressure. Now, several scientists say that it is more complicated, although it is still related to climate change and the overheating of the Arctic, which is also influenced by other factors such as the Siberian snow cover and other atmospheric waves.
“For me, the most important thing right now is that Arctic amplification is happening and has complex interactions within our climate system. “Winter will always bring us cold weather, but like the warm season it may be changing things we understand and things we are still learning regarding,” said meteorology professor Marshall Shepherd of the University of Georgia. “Unlike the Las Vegas slogan, what happens in the Arctic does not stay in the Arctic.”
Think of what’s happening as an orchestra making a symphony, and “what’s driving all those orchestral instruments is a warming planet,” said Northern Illinois University meteorology professor Victor Gensini.
Gensini and Cohen stated that this cold wave in the United States will fade in several days to be replaced by unusually warm weather, due to climate change. But another polar vortex seems to arrive at the end of the month, although not as strong as this one, they indicated.
Despite the American cold, Earth’s global average temperature continues to flirt with daily, weekly and monthly records, as it has for more than seven months. This is because the United States only represents 2% of the Earth’s surface, scientists explain.
“In places like Chicago, Denver, Lincoln, Omaha, Oklahoma City, Dallas or Houston, we’re all experiencing it,” said Gensini, who said the temperature outside his window on Tuesday was minus 6 degrees Fahrenheit. “If you look at it on a global scale, we are an isolated bubble.”
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Seth Borenstein is on X as: @borenbears
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