Climate Cast: How our persistent winter may have climate change roots

Every Thursday MPR meteorologist Paul Huttner joins Kerri Miller on The Daily Circuit for "Climate Cast" on MPR News Stations to talk about the latest research on our changing climate and the consequences that we're seeing here in Minnesota and worldwide.

These days it seems like we are witnessing climate changes unfold right before our very eyes.

It's not our imagination.

The nature of our seasons is changing. Spring blooms come earlier. Summer is more humid with a documented increase in extreme localized flash flood events...and more frequent droughts. Fall lingers longer. Lakes freeze up later. Winters are trending shorter and noticeably, measurably milder. New plants are able to thrive in Minnesota's milder climate.

We're all living witnesses to rapid climate changes in our lifetime. This is no longer your grandparents "Minnesota."

In 2013 at MPR we're devoting more coverage to the science behind and the growing effects of our changing climate in Minnesota and around the globe.

An image of the Arctic sea ice on Sept. 16, 2012, the day that the National Snow and Ice Data Center identified to be the minimum reached in 2012. The yellow outline shows the average sea ice minimum from 1979 through 2010.

NASA image

You can hear me discuss the week's top climate stories in our new "Climate Cast" every Thursday morning at 9:50am with Kerri Miller on The Daily Circuit.

Climate Cast for March 28th, 2013

If it seems difficult to imagine how a warming climate can contribute to a cold, persistent winter like the one we've been experiencing, consider this: The rapid disappearance of sea ice and the overall warming of the Arctic tend to push the jet stream farther south. In turn, the jet stream tends to make weather patterns stay put.

Jennifer Francis, research professor with the Rutgers Institute of Coastal and Marine Science, is quoted in The Guardian as saying that the loss of Arctic ice "is affecting the jet stream and leading to the extreme weather we are seeing in mid-latitudes ... It allows the cold air from the Arctic to plunge much further south. The pattern can be slow to change because the [southern] wave of the jet stream is getting bigger. It's now at a near record position, so whatever weather you have now is going to stick around."

The melting ice not only results from the warming pattern but contributes to it, because the exposed ocean absorbs sunlight that ice would bounce back into space. Scientists say the annual accumulation of ice has now reached its maximum for the season and is beginning to recede. The maximum ice this season was the sixth-lowest accumulation on record.

Francis sat in for MPR News Chief Meteorologist Paul Huttner on Thursday's Climate Cast. Here's an edited transcript of the conversation:

Say What? Warmer Arctic means colder weather in USA?

It seems counterintuitive. How can a warmer Arctic drive colder air into the northern USA & Europe?

As high latitude temperature changes shift jet stream, unusual near record jet stream patterns may be playing a role in our everlasting winter in Minnesota.

John Vidal from The Guardian expands on research by Jennifer Francis.

"The sea ice is going rapidly. It's 80% less than it was just 30 years ago. There has been a dramatic loss. This is a symptom of global warming and it contributes to enhanced warming of the Arctic," said Jennifer Francis, research professor with the Rutgers Institute of Coastal and Marine Science.

According to Francis and a growing body of other researchers, the Arctic ice loss adds heat to the ocean and atmosphere which shifts the position of the jet stream - the high-altitude river of air that steers storm systems and governs most weather in northern hemisphere.

"This is what is affecting the jet stream and leading to the extreme weather we are seeing in mid-latitudes," she said. "It allows the cold air from the Arctic to plunge much further south. The pattern can be slow to change because the [southern] wave of the jet stream is getting bigger. It's now at a near record position, so whatever weather you have now is going to stick around," she said.

Arctic Ice Hits Annual Max and it's 6th Lowest on Record

Thinner "1st year ice" reformed in the Arctic this winter as expected. The annual ice maximum was reached Monday, and it's the 6th lowest on record.

Climate Central's Andrew Freedman and Michael D. Lemonick expand on the story, and how the thin ice is more prone to fracturing...and quicker melting this summer.

The skin of sea ice that covers the Arctic Ocean has reached its maximum extent for 2013, the National Snow and Ice Data Center announced Monday, and the annual melt season has begun. As of March 15, ice covered 5.84 million square miles of ocean, the sixth-lowest since satellite observations began in the 1970's, and 283,000 square miles lower than the 1979-2000 average. Reflecting the influence of global warming, the 10 lowest sea ice maximums have all occurred over the past 10 years

Last summer's ice minimum, moreover, was the lowest on record, with 2007 coming in a distant second. Taken together, it's one more sign that the planet is warming under the influence of heat-trapping greenhouse gases.

The Arctic is warming especially quickly, however, thanks to a sort of vicious cycle that operates between ice, ocean and sunlight. When the sea is covered with bright, reflective ice, incoming sunlight bounces back into space. When the darker water underneath is exposed, some of the Sun's energy is absorbed, heating the seawater. That warms the air in turn, increasing the melting and exposing even more dark seawater to the incoming sunlight, and so on.

[image]

Animation of the ice fracture using satellite AVHRR data.

Credit: Arctic Sea Ice blog via NSIDC.

Climate Cast resources:

Want to know more about climate change? Here are few quick links to credible climate change sources.

-Read the Minnesota Public Radio primer on Climate Change

-NOAA NCDC's "State of the Climate" report

-AMS Statement on Climate Change

-NASA key evidence of climate change

-Great summary of Modern Day Climate Change from SUNY-Suffolk

-Minnesota Climate Working Group climate change resources

-Mark Seeley's Weather Talk

-Common climate change myths

-Climate change in the news from Climate Central

-More coverage from The Yale Forum on Climate Change and Media

Paul Huttner