Global warming has been blamed for causing heatwaves and extreme temperatures, which is understandable since temperature records have shown that the earth has warmed more than one degree Celsius.
However, the same phenomenon is to blame for cold temperatures as well.
Advances in Atmospheric Sciences-a journal explains that extreme zero temperature events are caused by the collapse of the polar vortex- a huge ring of low-pressure, cold winds in Earth’s stratosphere above the North Pole.
“When the temperature abruptly increases due to global warming, the interaction between the polar vortex and jet stream (relatively narrow bands of strong wind in the upper levels of the atmosphere) can be dramatically altered. The resulting extreme weather due to the interplay can be further amplified by changes in Arctic Ocean sea ice.”
Led by Xiangdong Zhang, a professor of climate and atmospheric sciences at the University of Alaska Fairbanks, researchers sought to examine two cold air outbreaks that broke the record in China in Late December 2020 to mid-January 2021, when Beijing and Tianjin cities recorded temperatures at -19.7 degrees Celsius and -19.9 degrees Celsius, the lowest that had been recorded in 54 years.
The researchers also examined record breaking cold weather that was recorded in North America in February 2021, which saw the coldest temperatures in Texas and Austin, at -13.3 degrees Celsius and -8.3 degrees Celsius respectively.
Using observational data from the past 42 winters, they plugged temperature readings into climate models to simulate how sea and atmospheric events may impact extreme weather.
They found out that even though global warming and loss of Arctic Sea ice occurs annually, extreme weather events do not occur every year.
However, when it happens, it is as a result of a combination of new global warming and weakening of the jet stream that allows for cold air to penetrate farther than normal.
Environmental Defense Fund, one of the world’s leading environmental organisations explains that because of a rise in global temperature, the planet is evaporating more water into the atmosphere, with the added moisture leading to more precipitation in the form of heavy snowfall or downpours.
“During warmer months, this can cause record-breaking floods. But during the winter – when our part of the world is tipped away from the sun – temperatures drop, and instead of downpours we can get massive winter storms.”
This fact check was produced by Nation with support from Code for Africa's Pesa Check, International Fact Checking Network, and African Fact Checking Alliance Network.