Bitter cold has struck its icy fingers across the United States, bringing a frosty start to the new year. dubbed winter storm blair, A Tempest Winter Weather Warning has been issued More than 60 million people A swath from Illinois to New Jersey this week.
The ongoing storm has already happened Up to a foot of snow fell In some cities and At least six people were killed. From Monday morning, About 300,000 utility customers Power was lost across states including Virginia, Kentucky and Illinois. It’s storming More snow is forecast through Tuesday And the frosty weather next week is good. Freezing temperatures can reach as far south Texas And Florida and can provide First snow at Disney World in nearly 50 years.
Winter Storm Blair comes as a bookend to the warmest year on record, and while it’s freezing North America, its origins are actually in the Arctic.
There is evidence that — due to climate change — cold Arctic air may be more likely to break control at the northernmost tip of the planet and move south, bringing cooler temperatures to low latitudes like the continental United States.
It may seem counterintuitive, but the fact that global average temperatures are rising is not stopping cold trends, and for some Arctic-driven storms it may exacerbate them. Scientists are examining the mechanisms linking fossil fuels, the Far North and humanity’s insatiable appetite for storms like Blair. They reveal a complex picture showing that the most profound consequences of climate change occur in the coldest parts of the planet and at the coldest times of the year.
As average temperatures rise rapidly, their effects are manifesting in surprising ways, but with more monitoring and better forecasting tools, storms like Blair need not be so severe and destructive.
How warming at the North Pole can bring a winter storm to your commute
There are a few key mechanisms behind cold snaps like Winter Storm Blair. is a polar vortexA swirling band of strong, cold air that is usually confined 10 to 30 miles above the North Pole. The polar vortex tends to pick up strength in winter and stay circular, but because waves in the atmosphereIt can sometimes split into multiple eddies or deform into an oblong shape that reaches beyond the Arctic.
Another factor is a jet stream known as The polar jet. It is a band of winds blowing from west to east at a speed of 275 miles per hour at an altitude of 4 to 8 miles above the earth’s surface.
When the polar jet is strong, it forms a precise ring around the Arctic and holds the icy air in place. When it weakens, it wobbles and takes on the shape of a flower or clover when viewed directly from the North Pole. Within this lobe, cold arctic air spreads over land such as Asia and North America.
Blockages in the polar vortex can combine with polar jet divergence, causing more cold air to reach further south.
Such Arctic spillovers, however, have occurred naturally in the past. How does global warming play out? Jennifer FrancisA senior scientist at the Woodwell Climate Research Center, co-author a Review article Looking at a body of research published last month is trying to answer that question.
The bottom line is that while the Earth is warming on average, even the Arctic is warming Four times faster rather than the planet as a whole, a phenomenon called arctic amplification. That has important knock-on effects.
One is that a warm Arctic means there is a weak temperature gradient between the Arctic and its surrounding regions. Francis explained that the steep difference between Arctic and sub-Arctic temperatures is what powers the polar jet in the first place, so when the north starts to feel like the rest of the planet, the jet weakens, making its frigid air more likely. moving across the Northern Hemisphere – and creating more extreme winter storms like Blair.
At the same time, the planet’s oceans have warmed to extraordinary levels in recent years, and some of the planet’s water remains, such as the North Pacific Ocean. unusually smooth. This is pushing the tropical air further north, bending the jet stream northward over the Pacific Ocean and southward over North America.
D Loss of sea ice in the Arctic region Warming has the potential to reshape the polar vortex in a way that leads to cooler air reaching further south.
Francis and his co-authors acknowledge that there is much uncertainty in determining exactly how much human-caused warming is influencing the cold snap. It’s also unclear exactly how the planet will fare as it warms.
The effects of warming do not scale linearly, especially in the Arctic, and there are many complex feedback mechanisms that researchers are still trying to map. Melting of reflective sea ice, for example, yields a dark, heat-absorbing ocean that can melt more ice.
There are also researchers who aren’t sure whether climate change has a clear role in recent cold snaps, or whether they will become more common as global average temperatures rise. A study published last year Using climate models and historical records, the human impact we see on sudden periods of extreme cold is that they are not as cold as they used to be. The paper found that cold extreme temperatures are warming faster than average winter temperatures in North America.
Scientists generally agree that winters are getting warmer on average Warming up faster than summer. Nevertheless, dangerous winter weather will, at times, spread from the Arctic. “Although the Arctic is warming, it will remain cold for a very long time in the winter because it has no sun for 6 months,” Francis said in an email. “When the jet stream takes a big dip southward there will be plenty of cold air to feed the cold spell.”
The researchers also highlighted that the dangers of extreme cold flows come not only from the temperature but also from how prepared people are to deal with them. Winter Storm Uri of 2021 could be deadly if it grips an area that rarely experiences freezing temperatures like Texas. Killed 246 people. Threats escalate with little advance warning.
On this front, there is some warm comfort in this icy weather. Forecasters are getting a better handle on the warning signs of a cold spell. Scientists have identified The polar vortex gathered energy last monthand was a meteorologist Warning from last week That severe cold and snow cover much of the United States. With further advances in data collection and new AI forecasting tools, we will likely be able to see the bitter cold more intensely in the future and further away.
