A study has found that extreme cold weather is probably caused by the stretching of the polar vortex in the stratosphere, which results from global warming. Scientists have discovered that recent cold weather extremes may be linked to global warming, a study published in Science said on Thursday. Human-caused global warming was expected to lead to more heatwaves and heavy precipitation events, but the increase in cold air outbreaks and heavy snowfalls, most recently in January and February of 2021 in Asia, Europe and the United States, surprised the scientists, leading them to research the connection between extreme cold weather and global warming. One of the key manifestations of global warming is Arctic warming, otherwise known as Arctic amplification (AA) which causes sea ice to decrease. Because the decline in sea ice increases moisture in the air, AA ultimately leads to heavy snowfall in the Arctic.