A study based on 40 years of atmospheric observations suggests that the recent trends of unusually chilly winters in the United States and the Northern Hemisphere might be due to the climate warming in the Arctic. However, there is still not enough evidence to clearly say if this trend will continue in the future.
The study was first published in the journal Science and has claimed that the polar vortex has been stretched by warmer weather, causing the cold air normally trapped in the Arctic to move towards other parts of the world.
“We use observational analysis to show that a lesser-known stratospheric polar vortex (SPV) disruption that involves wave reflection and stretching of the SPV is linked with extreme cold across parts of Asia and North America, including the recent February 2021 Texas cold wave, and has been increasing over the satellite era,” as per the study.
The rate of warming in the Arctic is twice as much as the Earth as a whole and scientists have suggested for a long time that this could cause trouble in the winds around the North Pole with impact in a very larger area covering thousands of kilometres in the South as well, wrote Quirin Schiermeier in the journal Nature.
Judah Cohen, a climate scientist at the Massachusetts Institute of Technology in Cambridge, and the lead author of the study said, “Conventional wisdom is that while global warming means more heatwaves, it will definitely lead to less cold spells and snowfall. But that’s not quite true. There are mechanisms by which climate change can contribute to more severe winter weather too.”
The freezing weather in Texas in February went so high that the state of Texas was not able to handle the extreme weather and lost 170 lives and damage of billions of dollars, reported The Hill.
“It is counterintuitive that a rapidly warming Arctic can lead to an increase in extreme cold in a place as far south as Texas, but the lesson from our analysis is to expect the unexpected with climate change,” Cohen added.
The researchers used both the tactics of observational and modelling data to trace a physical link between anthropogenic climate change and stratospheric polar vortex (SPV) disruption.
This atmospheric feature is defined by the strong westerly winds that encircle the Arctic and – under normal conditions – keep its cold air contained, wrote Chrissy Sexton in Earth.com.
The researchers observed that episodes of polar-vortex stretching have increased substantially in the past few decades and that their models have produced similar behaviour when they included the effects of Arctic warming, reported Schiermeier.
Dim Coumou, a climate scientist at the Free University Amsterdam in the Netherlands, who was not involved in the study said, “This is an insightful new analysis.
Its strength is that they have very carefully looked at a specific pattern of the polar vortex that is important for cold spells in particular places, and backed up their observational analyses with climate-modelling experiments.”