Climate Change CAN Worsen Winter Storms. But It's Complicated

Upper level forecast shows how cold weather
in eastern U.S will last into early Februarty.
Green lines depict the jet stream. Note how
wavy it is and how it heads southeastward
into the United States. Those red dotted
areas indicate areas of high pressure and warm
air for the region. That so much of the red
dots mean there's an Arctic amplification,
which means cold air is being squashed 
southward toward us. Scientists are 
studying whether climate change is making
weather patterns like this more likely. 

I suppose I can't blame President Trump for wondering where global warming went. 

There's massive amounts of ice and snow from New Mexico to southeast Canada. The South is locked in ice after a bunch of freezing rain. People are shivering in their homes without electricity. 

Dozens of daily record low high temperatures and record low overnight temperatures have already been set this weekend, mostly in Kansas, Oklahoma and Texas.  More records will fall in the next few days, mostly across the South and southeastern parts of the U.S.  

Whether this storm, or any other extreme winter event in recent years can be tied to climate change is iffy. But there are some picky scientific details that suggest the warming world can paradoxically helping create these epic winter storms and cold snaps. 

As Meteorologist Jeff Berardelli explains, climate change can during relatively brief periods enhance the cold in places like the United States.

Sometimes - and this is occurring now - blocking high pressure settles over the Arctic, especially near or over Greenland - making them warm. At least warm compared to the insane cold you should expect up there. 

This setup shoves the cold air down into places like the United States and western Europe. 

Meanwhile, the Arctic overall is warming at a pace up to four times greater than most of the rest of the world.  That's called Arctic amplification. In fact, right now it's super warm for the season in parts of Greenland. In Nuuk, on the relatively mild southwest coast of Greenland, normal highs this time of year are around 20 degrees with a low of about 12.

The Weather Channel says Nuuk will have a high temperature of 42 degrees today, and it probably won't go below freezing tonight. 

Berardelli notes that the extra warming from climate change amplifies the blocking high pressure over the Arctic or Greenland.  That, in turn even more firmly pushes the cold air toward the United States and other mid-latitude places .

The air coming down from the Arctic because of this pattern isn't any colder than it used to be. In fact it's somewhat warmer. Punches of frigid air that have always blasted into the Upper Midwest are generally a bit milder than the were a generation or two ago. 

For instance, one study by Climate Central noted that the lowest temperature of the year has increased by 12 degrees since 1970. 

But when these Arctic air masses get pulled all the way down into the southern half of the United States, big trouble ensues. Like the winter storm we're having this weekend. 

There's at least circumstantial evidence that a wavier jet stream has started to occasionally send at times unprecedented blasts of Arctic air far south, all the way to the Gulf of Mexico.

We had the big Texas freeze and utility collapse in 2021, the one that killed nearly 250 people. Last January, an unprecedented snowstorm swept the Gulf Coast, burying places from New Orleans to Pensacola, Florida in more than six inches of snow. New Orleans was actually under a blizzard warning in that event. 

Just last week, it snowed again in northwest Florida. Now this storm. 

The Arctic and Greenland blocking helps make the jet stream wavier, which helps explain why there's such a harsh cold spell going on now.  When jet stream plunges south from northern Canada, it's going to be horribly, miserable cold.

There's still a lot of debate in the scientific community on whether climate change itself is making the jet stream much wavier, especially in the winter. 

When that happens, we could see bigger southward dips in the jet stream, like we're seeing now. 

There's at least circumstantial evidence that a wavier jet stream occasional has started  sending at times unprecedented blasts of Arctic air far south, all the way to the Gulf of Mexico.

Per Grist:

"'The problem is that it's really hard to show whether or not that's happening,' said Jacob Chalif, who studies the phenomenon at Dartmouth College. 'Arctic amplification started really kicking off in the '90s, and we only have really solid record of the jet stream going back to 1979.'"

That leaves about a decade of records to help determine whether what's going on now is something new. 

Dartmouth researchers are now using machine learning to get a picture of jet stream patterns during the  the entire 20th century. There's evidence there were even wilder swings in the jet stream between 1900 and 1979. 

So, the jury is still out as to whether a warmer Arctic is increasing the chances that the U.S. will have terrible winter storms due to whacked-out jet streams. 

Another factor is the polar vortex. It's that big whirl of absolutely ridiculous frigid air that roams the high latitudes. When it's in Canada, closer to the United States, chances are at least part of the nation will be on the cold side.

Sometimes, the polar vortex stretches, and becomes more oblong. if it stretches toward the U.S., we get frigid and fast.

Some science suggests that the polar vortex is stretching more frequently than it used to

Per CNN

"Judah Cohen, a research scientist at MIT, said the stretching of the vortex is tied in part to sea ice loss in parts of the Arctic from human-caused climate change. He also said above average snowfall in parts of Siberia raises the likelihood of such stretching events, and this too is influenced by a paucity of sea ice in the Barents and Kara Seas in the Atlantic Ocean."

'"On the southern flanks of the polar vortex, over the U.S. and Asia, an under that where that stretching is happening, there's been an increase in severe winter weather,' Cohen said. 'I'm not saying any one weather event is attributed to climate change,' he said. 'But I do think it loaded the dice here.'"

Even if you ignore the polar vortex and the Greenland Block and the wonky jet stream, the fact of the matter is it's winter. Sure, the climate is warmer, hut that doesn't mean winter is canceled. It can still get brutal out there.

We're living that out right now.