Videographer Peter Sinclair has another excellent video for The Yale Forum on Climate Change & The Media featuring leading Arctic experts:
One of the featured scientists is Dr. Jennifer Francisof Rutgers’ Institute of Marine and Coastal Sciences. We’ve featured discussion of Francis’s important work here.
Francis was lead author of a 2012 Geophysical Research Letters study, “Evidence linking Arctic amplification to extreme weather in mid-latitudes,” which found that the loss of Arctic ice favors “extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.” You can find some good explanations of her findings here.
The Washington Post‘s Capital Weather Gang featured a guest post by Francis last Friday, “Shrinking Arctic ice and the wicked backlash on our weather.” Here are some key excerpts:
Heat waves. Drought. Flooding. Cold spells. Wildfires. The climate system is changing before our very eyes, and there is no more glaring proof than the record-shattering loss of Arctic sea ice this summer.
Via NASA: “The area covered by older and thicker sea ice in the Arctic diminished by almost 50 percent between 1980 and 2012.”
And, since overall the ice thinned out, the volume dropped by 75% during that time, making a reversal of this trend anytime soon exceedingly improbable. Francis notes:
Fossil fuels – such as oil, coal, and natural gas – are the main source of these added greenhouse gases, as they’re burned to provide the energy that heats our homes, lights our streets, and runs our vehicles. It now appears, however, that a gradual warming may not be the primary concern, as the gases may also fuel extreme weather around the world.
How does warming fuel extreme weather? Francis explains:
Since the fossil-fuel revolution after World War II, Arctic temperatures have increased at twice the global rate, illustrating a phenomenon called Arctic amplification. Thus, sea ice has melted at an unprecedented rate and is now caught in a vicious cycle known as the ice-albedo feedback: as sea ice retreats, sunshine that would have been reflected into space by the bright white ice is instead absorbed by the ocean, causing waters to warm and melt even more ice.
As temperatures over the Arctic Ocean fall with the approach of winter, the extra energy that was absorbed during summer must be released back into the atmosphere before the water can cool to freezing temperatures. Essentially, this loads the atmosphere with a new source of energy—one that affects weather patterns, both locally and on a larger scale. In spring, a similar phenomenon also occurs, but it involves snow cover on northern land areas. Snow has been melting progressively earlier each year; this past June and July it disappeared earlier than ever before. The underlying soil is then exposed to strong spring sun, which allows it to dry and warm earlier – contributing to Arctic amplification in summer months.
The difference in temperature between the Arctic and areas to the south is what drives the jet stream, a fast-moving river of air that encircles the northern hemisphere. As the Arctic warms faster, this temperature difference weakens, as does the west-to-east wind of the jet stream. Just as a river of water tends to meander when it reaches the gentle slopes of coastal plains, a weaker jet stream tends to have steeper north-south waves. Arctic amplification also stretches the northern tips of the waves farther northward, which favors further meandering. Meteorologists know that steeper waves are slower to shift westward.
The weather we experience at mid-latitudes is largely dictated by these waves in the jet stream. The slower the waves move, the longer the weather associated with them will persist. Essentially, “hot,” “dry,” “cold,” and “rainy” are all terms to describe very normal weather conditions. It’s only when those conditions persist in one area for too long that they are dubbed with the names of their extreme alter egos: heat waves, drought, cold spells, and floods. And these kinds of extreme events are precisely what we’ve seen more of in recent years.
Global warming now has a face and a fingerprint that directly touch each of our lives. Rather than just a gradual increase in temperature, we can recognize its influence in a shift toward more extreme weather events. A warmer atmosphere also means a moister atmosphere, so any given storm will have more moisture and energy to work with, increasing the chances of flooding or heavy snows. Arctic amplification adds another mechanism to the mix, making extreme weather more likely. The loss of ice and snow in the far north may load the dice for “stuck” weather patterns, compounding potential risks for our economy, our health, and our security.
If you really want to dive into Francis’s important work, she has a long video discussion here.
I believe the coming years will lead to more evidence and analysis backing Franicis’s work — and that Dr. Jeff Masters, Weather Underground director of meteorology and former hurricane hunter, was correct when he noted earlier this year:
“The climate has shifted to a new state capable of delivering rare & unprecedented weather events.”