Cold Spells in the United States are Normal and Not the Result of a Warming North Pole | NOW

Large parts of the United States are in the grip of a wave of very cold air coming from the North Pole. Some argue that there is no proof that global warming does not exist, while others link it to the melting arctic ice. This is how misunderstandings accumulate.

Cold air descended from Canada over the Midwestern United States, even reaching the Gulf of Mexico, where paralyzed sea turtles emerge from the water peach. The roads are hard to cross and millions of Texans have been without them for days sink. In many states, the immunization program is also performing poorly.

Is the cold exceptional? It depends on the condition you are looking at. Texas, in particular, experiences extreme weather conditions, with temperatures the state has not seen in thirty years. But in Florida, it’s hotter than normal right now, just like in eastern Canada.

The mountain range increases the temperature differences

The appearance of relatively large differences is not uncommon: North America has a more continental climate than what we have in Europe. Part of the reason is that the westerly winds that flow through the northern hemisphere are partially blocked by a large north-south mountain range, the Rockies. As a result, the air can alternately come from the north or the south. And if you compare Canada to Mexico, you can see that it makes a big difference.

But there is also a hypothesis (unproven explanation) that the risk of a cold north wind is favored by the warming of the Arctic, where the temperature rise is four times faster than the global average. This affects the jet stream, a strong westerly wind that circles the polar region at an altitude of 10 kilometers.

Simply put: the greater the temperature difference between the North Pole and areas further south, the stronger this westerly wind blows, and the less likely the cold polar air is to escape to populated areas. Due to the rapid warming of the polar region, the jet stream weakens and the polar air can walk more easily.

Difference between a tight jet stream and a sinuous jet, with a greater risk of cold waves. This image was tweeted by the UNFCCC, to which climatologist Tim Woollings responded.

It’s a nice hypothesis, but it doesn’t seem to explain what’s going on, jet stream researcher Tim Woollings of the University of Oxford tells NU.nl. It is true that the rapid warming of the North Pole is weakening the jet stream. But also over the subtropics, the warming goes very quickly and this makes the jet stream stronger. These two effects of climate change are mutually exclusive.

“If we compare the latest measurements with historical data, we don’t see that the jet stream would oscillate more strongly today than it was before,” Woollings says. It also shows a new to study in Nature Sure.

In Europe, there are indications that the jet stream becomes even stronger in winter, due to climate change. It has to do with it weaker of the warm Gulf Stream in the North Atlantic.

Winter cold is no proof against climate change

The alleged link to a warming North Pole isn’t the only climate misunderstanding circulating about the US cold snap. Others use frost as “proof” that the earth would not warm up. However, measurements show that the average temperature on Earth is rising everywhere, including the United States.

Fox News also claimed that the power outages in Texas are due to freezing wind turbines. In fact, most power outages have been caused by the failure of coal, gas and nuclear power plants.

Finally, what about the recent frost in the Netherlands? In January, we wrote this one on NU.nl. sudden warm-up over the North Pole would increase the risk of cold snaps in the following weeks. It was a warming at no less than 30 kilometers above sea level in the very thin stratosphere, a layer of air that can sometimes suddenly become several tens of degrees warmer.

This phenomenon can cause a temporary winding jet stream and therefore may be associated with both the freezing period we had last week and the current cold in the United States. But here too, there is no clear link with global warming.