Large areas of North America are facing freezing temperatures this week as cold Arctic air pushes south. Paradoxically, these cold spells may persist or even become more common as the planet warms, scientists say.
The polar jet stream, a narrow band of westerly winds circling the Arctic created where cold, northern air meets warmer air to the south. But the Arctic is almost certainly heating up four hours faster than the rest of the planet, narrowing this difference in temperature. The result, according to recently review of scientific research, is a weaker and meandering jet stream that allows frigid air to reach further south.
Even as the planet warms overall, “we still see extraordinary cold spells that sometimes last several days and attack areas that are not used to extreme cold,” coauthor said Jennifer Francis, of the Woodwell Climate Research Center.
She said, “It seems counterintuitive, but the Arctic winter will have plenty of ice, snow and cold air for decades to come, and cold can be sent south to populated areas with Arctic heat waves. “
