Climate News - March 2021

Climate Change Linked to Current Cold Spell in the U.S.

Caroly Shumway, Ph.D.

 

Throughout a wide swath of the United States in February, people suffered from extreme cold: frozen pipes, no heat for days, and water unsafe to drink. The situation caused some to falsely  claim that the cold shows that climate change does not exist. 

What is the connection to climate change?

People often confuse climate and weather. Atmospheric scientist Dr. James Marshall Shepherd  on a recent NPR episode had a good analogy: "Weather is your mood; climate is your personality."

Generally, the day-to-day temperatures and precipitation that we experience are weather-related and not climate. Climate describes the averaged weather conditions of a region. But weather extremes can be linked to climate change. Some have quirkily termed that global "weirding." Observational scientific evidence from 1988 to today points to Arctic warming being linked to more extreme cold weather here and in Europe, like the extreme cold spell that much of the U.S. experienced in February. 

 How does Arctic warming affect us? It's a bit complicated; you need to understand some key terms. Light surfaces (like snow) reflect more sunlight than dark surfaces. That's called the Albedo effect. Normally, the Arctic is covered with white snow and ice. As such, the Arctic acts as a thermal regulator for the planet, helping to maintain an atmospheric thermal gradient across latitudes, and minimizing extreme weather events. 

When the Arctic warms due to climate change, however, less white sea ice or white snow is available to reflect the sun's rays, and the surrounding ocean absorbs the rays, causing more warming, just as black pavement gets hot in the summer. Positive feedback loops in the Arctic cause additional warming, a process called Arctic amplification which leads to temperature and variability trends being 2-3 times larger in this region than elsewhere in the world. 

When the polar vortex (an area of low pressure and cold air) at the North Pole is weakened, it expands, sending cold Arctic air southward. This causes extreme cold temperatures in the mid-latitudes in the United States and Europe. While the southward movement of cold Arctic air can happen naturally, observational studies show that when the Arctic is warmer, we are significantly more likely to have colder temperatures in the mid-latitudes in the winter.The increasingly warming Arctic (due to the Arctic amplification) also weakens the Jet Stream, making it more unstable, wobblier, and wavier. In February, the wavier Jet Stream pulled the cold polar air down to large swaths of the lower 48 states.  

So climate change means that we are more likely to experience such severe weather events more frequently. That said, the extreme cold we experienced in February is a singular weather event. One can't identify with certainty that any particular weather event is linked to climate change. A good primer for this complicated topic is the recent article written by Dr. Marshall here 

Do you want to know more about this and other climate change topics; to be conversant about climate change with family or friends? The YouTube channel Just Have a Think has just the solution for you! Dave Borlace has created 140 short and entertaining videos about all topics related to climate change: the latest gee-whiz technologies as well as ancient wisdom that could help us solve the climate crisis: climate change impacts in the Arctic, climate change and the oceans, and climate change impacts on our land, food, and water. Dave provides a wealth of information in a self-deprecating, funny, and visually arresting manner. He's also just created a Just Have a Think app that provides access to the videos as well as curated news and information to keep you informed.  

If you want to retain the information or delve deeper into certain subjects, you can check out our free DiveDeeper courses that supplement what Dave teaches in the videos. Our courses are designed for individual learners and high school students. We are proud to announce that we've just completed a course on Arctic Disintegration, covering the topics discussed here! 

P.S. We are seeking CBC volunteers to help us research and develop the free DiveDeeper courses! If you have environmental work experience and interest, send a cover letter and resume to me at caroly@behaviordevelopmentsolutions.com

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