An arctic cold wave hit the United States, with the perceived temperature in the American Midwest plummeting to -57 degrees Celsius. Due to climate change, the global temperature rose 1.48 degrees Celsius last year compared to pre-industrial standards. Why will winter cold become more severe even though global warming is occurring?
According to the U.S. CNN broadcast on the 15th (local time), some scientists explain that extreme cold may be occurring because the warming of the Arctic increases the possibility of extremely cold air being pushed south.
Earth’s weather is greatly influenced by the jet stream, a wave of air that moves quickly from left to right in the atmosphere. If the jet stream swings south, it can push cold Arctic air into North America, Europe, and Asia. As it retreats north, warm air is also pushed further north. As a result, a large high-pressure movement occurred in Europe last January, resulting in record-breaking warmth even though it was winter.
But there is another factor to consider. In other words, it is the polar vortex, a band of strong winds located extremely high in the stratosphere (higher than the jet stream height) around the North Pole.
The Arctic Vortex is like a spinning top. Under normal conditions, it rotates very quickly, trapping cold air in the Arctic region. But if they are disturbed, thrown off course, stretched or distorted, they can release trapped cold air and affect the path of the jet stream.
The Arctic vortex collapse is what brought extreme cold to Texas in 2021, killing nearly 250 people and leaving most of the state without power.
Some scientists believe that the Arctic vortex collapse and changes in the jet stream are caused by warming in the Arctic. The Arctic is heating about four times faster than the rest of the Earth.
The idea has been gaining attention since a 2012 paper by Jennifer Francis, a senior scientist at the Woodwell Center for Climate Research in Massachusetts. According to the paper, as the Arctic warms, the difference between cold temperatures in the north and warm temperatures in the south weakens the jet stream and increases the waves of the air current, pushing very cold air southward.
In 2021, MIT climatologist Judah Cohen published research showing that rapid heating in parts of the Arctic and high snowfall in Siberia have caused the polar vortex to veer off course and make jet stream waves stronger. “We’re not claiming that winters are getting colder overall,” Cohen added in an interview with CNN last year.
However, some scientists still believe that the connection between Arctic warming and extreme cold waves in the Northern Hemisphere is not clear. Regardless of whether Arctic warming was the cause or not, the conclusion of all scientists was unexpected: “Winters are getting warmer.” “The data shows that over the long term, global warming will lead to fewer days of extreme cold spells and cold spells becoming less severe,” said James Screen, a professor of climate science at the University of Exeter in the UK.
Source: Donga
Mark Jones is a world traveler and journalist for News Rebeat. With a curious mind and a love of adventure, Mark brings a unique perspective to the latest global events and provides in-depth and thought-provoking coverage of the world at large.