Could the extreme cold weather be tied to a warming climate?

Jan 7, 2014

The temperatures certainly are extreme. Last night, it was colder in Michigan than it was at the South Pole.

Parts of the state saw temperatures reach 16 below zero with wind chills exceeding 40 below zero.

The "polar vortex" has brought air to the Midwest that normally stays way up in the arctic.

Here's what that loop of cold air is expected to look like tonight at 7 p.m.:

Purple signifies the extreme cold in the U.S.
Purple signifies the extreme cold in the U.S.
Credit NWS

That's some cold weather.

But weather, of course, is not the same thing as climate.

Climate is all about long term average changes in the atmosphere. Weather events are short term snapshots of what we're experiencing now.

So how might this blast of cold air we're experiencing today relate to a warmer climate?

Jeff Masters, meteorologist and co-founder of the website Weather Underground, explains it this way:

In theory, the 1.5°F increase in global surface temperatures that Earth has experienced since 1880 due to global warming should reduce the frequency of 1-in-20 year extreme cold weather events like the current one. However, it is possible that climate change could alter jet stream circulation patterns in a way that could increase the incidence of unusual jet stream "kinks" that allow cold air to spill southwards over the Eastern U.S.

It has to do with how the jet stream is spinning around the polar region.

Most of the time, the jet stream keeps the extreme arctic air in the arctic regions of the northern hemisphere. But sometimes that air dips our way.

Like this:

An image showing how the jet stream develops a meander, bringing cold air south.
An image showing how the jet stream develops a meander, bringing cold air south.
Credit user Pflatau / Wikimedia Commons

The reverse could happen as well. We could experience extreme warm temperatures with a meandering jet stream like this. Think back to the extreme warm temperatures we saw in early 2012. (Michigan fruit farmers remember that one.)

Scientists suspect the warming in the Arctic could be affecting the strength of the jet stream.

Here's a video of Jennifer Francis from the Institute of Marine and Coastal Sciences at Rutgers University explaining this new research:

And here, Jennifer Francis and Jeff Masters explain this theory further.

The research is new, and as Jeff Masters points out, it still needs "several more years of data and additional research before we can be confident that this is occurring."

*This post has been updated.