The ice cold in the US could be the beginning - here's why

 

Jonathan Jeppsson  

The ice cold in the US may just be the beginning  

Published: Today 17.20  

Updated: Less than 2 hours ago  

This is a commenting text. Analysis and positions are the writer's.  

COLUMNISTS  

A crippling and deadly ice cold hits North America once again.  

The explanation may well be spelled the weakened jet stream.  

If warming continues, the jet stream could permanently change course in the coming decades – with enormous consequences as a result. 

"What has ... said about the ice cold in the USA?", wrote the moderate Member of Parliament Lars Beckman on Twitter before Christmas.  

It was a clever move – by leaving out who he really meant behind the dots, he could hint and insinuate with his back free. Anyone who based on Lars Beckman´s history as at climate ignorant - at worst climate denier - interpreted it as "Greta" hiding in the omitted word, could easily be dismissed in retrospect - he had never written that! So clever.  

Member of Parliament Lars Beckman (M). Photo: Henrik Montgomery/TT 

It wasn't the first time  

"Global warming" Beckman wrote in October 2019, in quotation marks along with a laughing emoji, when SMHI warned that cold polar air was moving down over Sweden unusually early in the year.  

Snow shoveling in Amherst N.Y, USA during Christmas Eve. Photo: Jeffrey T. Barnes/AP  

Yes, of course it can be hard to understand and easy to get carried away - how can it be so cold, record cold even, in so many places when we have severe global warming? Even Donald Trump had violent problems with that equation.  

In recent days, the USA has been hit by a so-called ”bombcyclone” - temperatures of minus 48 degrees have been measured, more than 20 people have died in weather-related traffic accidents and from the cold.  

Thousands of flights have been grounded. Two meters of snow has fallen since Thursday in Buffalo.  

Four people have died in Ohio after a 46-vehicle crash. Photo: Ohio State Highway Patrol  

Flow of air  

What is going on? Well, there are many indications that it is a weakened jet stream. If so, we face an unpleasant future if warming continues. 

The jet stream is like a river of air driven around at high altitude by the temperature difference between freezing air from the Arktis and warm air from the tropics. If you fly across the Atlantic and get the jet stream at your back, you know that the journey takes significantly less time.  

But the Arctic is warming four times faster than the average on the planet, which some scientists believe is why the jet stream is slowing. And just as a slower river meanders and forms bulges, so does a slower jet stream meander. 

 

Satellite images show how the giant storm is moving across the country with extreme cold and violent snowstorms.  According to the meteorologists, it is historically large - about 60% of the US population is affected. Photo: NOAA via AP/TT 

A weaker jet stream means that the weather patterns can become locked - as it was in the summer of 2018, when a high pressure parked itself over Scandinavia and refused to move. But it also means that it meanders so much that arctic air can push down over the continents (but also warmer air up towards the North Pole).  

Over the past 30 years, scientists have observed an intensification of the waves, that is, it winds more and more strongly, which coincides with increased global warming.  

What does that mean for the future?  

A research team believes that if the heating continues to be powerful, there is a risk that the jet stream will end up off course and move north.  

The researchers managed to map the position and intensity of the jet stream for the last 1250 years and were able to see clear – and terrifying – examples of what the consequences would be if this happens.  

In 1374, for example, the jet stream was unusually far north – when the Iberian Peninsula was hit by a drought that led to a widespread famine. 

Similarly, famines in the British Isles and Ireland in 1728 and 1740 coincided with years when winds blew at almost half their usual intensity, dramatically lowering temperatures and reducing rainfall.  

The latter of these events is believed to have cost the lives of half a million people.

Police Capt. Kevin Chabot carries away a woman stuck in her car in the violent flooding in Maine.Photo: Debra Cuddahy/AP/TT  

A jet stream that moves north would thus have far-reaching consequences. The researchers believe that a permanent shift in the path of the jet stream could occur as early as around 2060. 

These are things you should keep in mind when speaking out about global warming as an elected politician. It can be cold in different places on earth, without this meaning that warming has stopped. Snow removal in Des Moines, Iowa. Temperatures down to minus 40 degrees are now being warned in some places.

Snow removal in Des Moines, Iowa. Temperatures down to minus 40 degrees are now being warned in some places.  Photo: Charlie Neibergall / AP 

"Where's the heating?"  

Otherwise, you can easily sound like then-President Trump, visiting icy Chicago in 2019: 

“What the hell is going on with global warming? Come back soon, thanks, we need you!” he wrote on Twitter. 

In Sweden, Trump quickly gained a following. Not unexpectedly, a moderate Member of Parliament: "Where is the heating when you need it?" wrote Lars Beckman the following year.

Lars Beckman (M) Lars Beckman (M) Photo: MAGNUS WENNMAN  

The reassuring majority from the right and the left in Sweden's Riksdag today agree that climate change is ongoing and is a real threat - the major dividing lines lie in how the climate threat should be handled.  

It is always possible to base both arguments for and against climate change on individual weather events.  

But it is on the basis of the long trends and the scientific reports that one must build one's conclusions.  

At least if you want to be taken seriously.  

Facts 

What is a bomb cyclone?  

A bomb cyclone is a weather phenomenon where the pressure drops sharply over a 24-hour period. That the word bomb is used is due to the explosive effect that the storms have. 

The name was coined by the American meteorologists Fred Sanders and John Gyakum, but is based on work done by the Swedish researcher Tor Bergeron who was a professor at Uppsala University.  

For it to be a bomb cyclone, the rule of thumb is that the air pressure must drop by at least 24 millibars in 24 hours. Normal air pressure at sea level is approximately 1000 millibars and decreases by one millibar every eight meters of altitude.  

Formula for the weather geek  But the rule of thumb is not always correct.  

But to get it exact we need to get into trigonometry Take the sine of the latitude where the low pressure is located and divide it by the sine of 60 degrees.  

Then multiply the result by 24 and you get the number of millibars the pressure must drop during 24 hours for it to qualify as a bomb cyclone.  

Why exactly 60 degrees? That was the latitude Tor Bergeron was at when he described the phenomenon, i.e. Uppsala.  

(Sources: CNN, Smhi)