A look at weather extremes and the big-picture climate connections.

Video: Extreme Weather and Rapid Arctic Warming

Recently I reported on a study showing links between rapid Arctic climate change and shifts in the jet stream throughout the Northern Hemisphere. The study, led by Jennifer Francis of Rutgers University, suggests that there may be an Arctic connection to some extreme weather events, particularly ones that result from stuck, or "blocked," weather patterns.

The study shows that by changing the temperature balance between the Arctic and mid-latitudes, rapid Arctic warming is altering the course of the jet stream, which steers weather systems from west to east around the hemisphere. The Arctic has been warming about twice as fast as the rest of the Northern Hemisphere, due to a combination of human emissions of greenhouse gases and unique feedbacks built into the Arctic climate system.

The jet stream, the study states, is becoming “wavier,” with steeper troughs and higher ridges. As a result, weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods, and heat waves. 

Over at the Yale Forum on Climate Change and the Media, Pete Sinclair — known for his "climate denial crock of the week" video series — posted a video exploring this study and other recent evidence regarding the causes of extreme weather and climate events. It's worth watching, and features interviews with Dr. Francis, Jeff Masters of Weather Underground, and several other experts. 

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