The brave new world of Arctic amplification

There is news, and then there is news. Most of the news this fall has been about the U.S. political races, along with recent coverage of Superstorm Sandy thrown into the mix of stories about shootings, celebrity shenanigans and football.

But, puzzlingly, there have been very few stories about, and even less analysis of the most important event of the season – actually, the signature event, so far, of our young century. Perhaps that’s because the implications of that event are poorly grasped by most journalists. Indeed, even most of the climate scientists and environmentalists who follow such events closely are struggling with interpreting or accepting the ramifications of the occurrence in the Arctic.

The portentous event is that Arctic sea ice, the floating ice mass also known as the Polar Ice Cap, is disappearing at a record-breaking pace. In the middle of August, the 2012 summer sea ice extent (coverage of the ocean’s surface) dropped below the previous record, set in 2007, when the ice melted to 30 percent below the annual average.

The context of this event is that it is the culmination, thus far at least, of an ongoing trend that in the last few decades has seen half of the Arctic ice’s extent – and, more alarmingly, three quarters of its volume – disappear. (A warmer Arctic sea is thinning the ice from below.) This summer’s record melt has made it clear that there is no going back; the Arctic Ocean soon will be ice-free in the summer months.

How soon? One group of Arctic experts thinks it could happen in three years; many now believe it will happen by the end of this decade and even many cautious experts are saying by 2030. But the truly alarming news is that the ice-free condition is arriving about a century ahead of “schedule” – ahead of the consensus prediction made by the majority of the world’s climate scientists in their 2007 International Panel on Climate Change report, which dated the ice-free scenario at 2100 or later. That means the effects of climate change have arrived much sooner than almost anyone thought possible.

The effects are also arriving at a much lower temperature threshold than predicted. The scientific and international policy consensus is that the “safe” limit for global temperature rise is 2 degrees Celsius (3.6 F) above pre-industrial averages. The thinking is that the world’s nations should try to cut greenhouse gas emissions by 2020 to keep us from passing the 2-degree threshold by 2050. However, we are currently just nearing the 1-degree threshold, yet we are witnessing precipitate climate change.

Why is this happening? Scientists have known for decades that the Arctic region is warming two to four times as fast as the planet as a whole, a process called “Arctic amplification.” Poorly understood at first, the main cause of Arctic amplification is now known to be a simple feedback mechanism. Ice is light colored and reflects sunlight, keeping itself cool. But the water surrounding the ice is dark, so it warms relatively quickly when exposed to the sun. When the sea ice began melting as global warming caused temperatures to rise, more water was exposed and heated, melting more ice – which in turn exposed more water, in an ever-accelerating feedback loop.

The polar ice masses have been called the “planet’s air conditioners” because of their cooling effect on the atmosphere and ocean currents. Regionally, the drastic reduction of Arctic ice is related to the current onset of dangerous feedback mechanisms, especially the warming of the Arctic’s permafrost and shallow continental shelves. Both store massive quantities of the potent greenhouse gas methane in their biomass or locked in ice. As they warm, that methane could be released, possibly causing “runaway” (unstoppable) global warming. Soon.

Globally, Arctic ice regulates the flow of the jet stream, which in turn affects climate throughout the Northern Hemisphere’s temperate zones, which in turn affects flooding, droughts and our food supply. We have entered the brave new world of climate change, and we’ll explore its forbidding landscape in forthcoming columns at our ecological house.

Philip S. Wenz, who grew up in Durango and Boulder, now lives in Corvallis, Ore., where he teaches and writes about environmental issues. Reach him via e-mail through his website, www.your-ecological-house.com.