right on the heels of what happened before.290
Ice Reflects, Oceans Absorb
The broader impacts of amplified warming—more rain and snow, and reduced summer sea ice at the top of our planet—extend far beyond the region itself. They will drive important climatic feedbacks that flow out to the rest of the world, influencing atmospheric circulation, precipitation patterns, and jet streams. Unlike land ice, melting sea ice does not directly affect sea level (in accordance with Archimedes’ Principle291), but its implications for northern shipping and logistical access are so profound they are the subject of the following chapter. Perhaps most importantly of all, an open ocean releases heat, causing milder temperatures to penetrate even the much larger frigid landmasses to the south. Indeed, the loss of sea ice is the single biggest reason why the geographic pattern of climate warming is so magnified in the northern high latitudes.
Look again at the nine maps (p. 128) charting different temperature outcomes for the coming decades. In every one, the epicenter of climate warming is the Arctic Ocean, radiating (relative) warmth southward like a giant mushrooming umbrella. You are looking at the power of the ice-albedo effect, one of the stronger self-reinforcing climate feedbacks on Earth.
Albedo is the light-reflectivity of a surface. Its values range from 0 to 1 (meaning 0% to 100% reflective). Snow and ice have high albedo, bouncing as much as 90% of incoming sunlight back out to space. Ocean water has very low albedo, reflecting less than 10% and absorbing the rest. Just as a white T-shirt feels cool in the Sun but a black T-shirt feels hot, so also does a white Arctic Ocean stay cool while a dark one heats up.
Compared to land glaciers, sea ice is thin and flimsy, an ephemeral floating membrane just 1-2 meters thick. The greenhouse effect, by melting it back somewhat, thus unleashes a self-reinforcing effect even greater than the greenhouse warming itself. It’s rather as if when struck by blazing hot sun, one discards a white shirt and puts on a black one. By responding in this way to small global temperature changes, sea ice thus amplifies them even more.292
While its global effect is small, the ice-albedo feedback is uniquely powerful in the Arctic because it is the only place on Earth where a major ocean gets coated with ephemeral floating sea ice during the summer. Antarctica, in contrast, is a continent of land, thickly buried beneath permanent, kilometers-thick glaciers. For this and several other reasons, climate warming is more amplified in the Arctic than the Antarctic. 293,294
As an ice-free Arctic Ocean warms up, it acts like a giant hot-water bottle, warming the chilly Arctic air as the Sun crawls off the horizon each winter. The sea ice that does eventually form is thin and crackly, allowing more of the ocean’s heat to seep out even during the depths of winter. Winters become milder, the autumn freeze-up happens later, and the spring thaw arrives earlier. The warming effect is highest over the ocean and from there spills southward, warming vast landscapes across some of the coldest terrain on Earth.
Dr. Smith Goes to Washington
I first met National Center for Atmospheric Research (NCAR) climate modeler David Lawrence in Washington, D.C. We had been brought to the Russell Senate Office Building to brief U.S. Senate staffers on the ramifications of thawing Arctic permafrost. It was exciting. The Russell is the Senate’s oldest building and the site of many historic events, including the Watergate hearings. Its hallways are white marble and mahogany, with important-looking people clacking around in dark power-suits. Just a few yards from our briefing room were the offices of Senator John Kerry and former senator John F. Kennedy. Moments before we got started, the moderator pulled us aside to whisper that Senator John McCain might show up. He didn’t, but it was cool just wondering if he would.
After the briefings and a pleasant lunch reception were over, Dave and I headed out to a local pub for a beer before catching our flights home. Over microbrews, he described his next big idea: figuring out how much northern landscapes might warm up, based purely on the ice-albedo feedback from reduced summer sea-ice. I told him he was on to something. It was critical to separate out the ice-dependent feedback from overall greenhouse gas forcing, I pointed out. That way, if the ice shrank faster than expected, we’d know what the immediate climate response could be—even ahead of the longer-term cumulative effect of greenhouse gas loading. We drained our pints and left. I promptly forgot all about the conversation until eighteen months later when I ran into Dave at a conference. Whipping out his laptop, he showed me a preliminary model simulation of his big idea.295
My eyes widened. I was gazing at a world with northern high latitudes plastered everywhere in vivid orange—a pool of spreading warmth as much as five, six, or seven degrees Celsius (8° to 12°F) higher—spreading southward from the Arctic Ocean. All of Alaska and Canada and Greenland were bathed in it. It grazed other northern U.S. states from Minnesota to Maine. Russia’s vast bulk was lit up from one end to the other. Only Scandinavia and Western Europe, already warmed by the Gulf Stream, were untouched. Then I looked closer and saw what time of year it was.
November . . . December . . . January . . . February. The warming effect was greatest not in summer but during the
The Siberian Curse
The Siberian Curse is the brutal, punishing winter cold that creeps across our northern continental interiors each year. Western Europe and the Nordic countries, steeped in tropical heat carried north from the Gulf Stream, are largely spared. But from Russia to Alaska, and tumbling south through Canada into the northern U.S. states, the Curse descends each winter. The name was popularized in a book by Fiona Hill and Clifford Gaddy of the Brookings Institution,296 but the concept is as ancient as life itself. When it arrives, the birds depart, the ground cracks, frogs freeze solid in their mud beds. At the extreme end, if temperatures plunge to -40°F (or -40°C, the Fahrenheit and Celsius temperature scales converge at this number) steel breaks, engines fail, and manual work becomes virtually impossible. Human enterprise grinds to a halt.
Regardless of country, all NORC northerners seem to hold something in common when it comes to this special temperature: “Minus forties,” as such days are known, are universally despised. The shutdown of activity it commands has been described to me by restaurateurs in Whitehorse, Cree trappers in Alberta, truck drivers in Russia, and retirees in Helsinki. And while they otherwise express varying opinions about the problems or benefits posed to them by climate change, the one sentiment they all seem to agree on is relief that “minus forties”are becoming increasingly rare.
The most crushing cold rolls each year through eastern Siberia. On a typical January day in the town of Verkhoyansk, temperatures average around -48°C (-54°F). That is far colder than the North Pole, even though Verkhoyansk lies fifteen hundred miles south of it. Such frigidity stirs up images of hardy Russians bundled in furs, trudging home with some fire-wood or vodka to beat back the elements. A less familiar image is Verkhoyansk in July, when average daytime temperatures soar to nearly +21°C (+70°F). Our same Russian friends now stroll in short-sleeved shirts and halter tops, licking delicious precast ice-cream cones that taste like pure vanilla cream.
“So . . . what are you doing this summer?” I am asked this question twenty or so times per year. Invariably—after responding I’m going to Siberia, or Iceland, or Alaska—I win a puzzled look, followed by a nodding smile and the advice to not forget my parka and snow boots. When I explain I’ll actually require sunscreen, DEET, and plenty of white T-shirts, I get another puzzled look.
In summer, even on the high Arctic tundra, there is muggy heat, hordes of buzzing insects, and water
