The World in 2050: Four Forces Shaping Civilization's Northern Future (18 page)

The fourth important fact to take from these nine maps is that the irregular geography of climate change presented in the first single map is not at all random. Important spatial patterns remain broadly preserved in all model simulations, for all carbon emissions scenarios, and across all time frames. Temperature increases are higher over land than over the oceans. A bull’s-eye over the northern Atlantic Ocean stubbornly refuses to warm up. And without fail, regardless of which emissions path is followed, or what time slice is examined, or what climate models are run, all of the model projections—and measured observations too—consistently tell us something big. Again and again, they tell us that global climate change is hugely amplified in the northern high latitudes.
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Even our “optimistic” scenario projects that the northern high latitudes will warm 1.5-2.5°C by midcentury and 3.5-6°C by century’s end, more than double the global average. Our “pessimistic” scenario suggests rises of +8°C (14.4°F) or more. Global climate change will not raise temperatures uniformly around the world. Instead, the fastest and most furious increases are under way in the North.

There is another robust trend expected for the northern high latitudes. For much of the world it is very difficult to project future precipitation patterns with confidence. Cloud physics and rainfall are more complicated and tougher to model than greenhouse physics, especially at the coarse spatial resolution of today’s climate models. To the frustration of policy makers, model projections of future rainfall often lack statistical confidence, and even disagree as to whether it will increase or decrease. But not in the North. If there is one thing that the climate models all agree on,
²⁸³
it’s that precipitation (snow and rain) will increase there, especially in winter. It
must
increase, in obedience to physics
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and rising evaporation from open lakes and seas as they become unfrozen for longer times during the year.

The plainest manifestation of this will be snowier winters and higher river flows. Across southern Europe, western North America, the Middle East, and southern Africa, river flows are projected to fall 10%-30% by 2050. However, they will
increase
by a similar amount across northern Canada, Alaska, Scandinavia, and Russia.
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This has already happened in Russia. Through statistical analysis of old Soviet hydrologic records, one of my own projects helped to confirm rising river flows there, including sharp increases in south-central Russia beginning around 1985.
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Recall the bleak future of stressed human water supply all around the planet’s dry latitudes from Chapter 4? That future is not shared by the North. It is water-rich now and, except for Canada’s south-central prairies and the Russian steppes, will become even more water-rich in the future.

Uncapping an Ocean

To most people, there is nothing visceral about computer model projections of average climate statistics decades from now. But in September 2007 we got a taste of what the real world inside those maps might look like. For the first time in human memory, nearly 40% of the floating lid of sea ice that papers over the Arctic Ocean disappeared in a matter of months. The famed “Northwest Passage”—an ice-encased explorers’ graveyard—opened up. From the northern Pacific, where the United States and Russia brush lips across the Bering Strait, open blue water stretched almost all the way to the North Pole.

There was an error-riddled media frenzy about a melting “ice cap” at the North Pole,
²⁸⁷
then the story faded. But climate scientists were shocked to the bone. The problem wasn’t that it had happened, but that it had happened
too soon
. Our climate models had been preparing us for a gradual contraction in Arctic sea ice—and perhaps even ice-free summers by 2050—but none had predicted a downward lurch of this magnitude until at least 2035. The models were too slow to match reality. Apparently, the Arctic Ocean’s sea-ice cover could retreat even faster than we thought.

Two months later several thousand of us were milling around the cavernous halls of San Francisco’s Moscone Center at our biggest yearly conference,
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nervously abuzz about the Arctic sea-ice retreat. In a keynote lecture, the University of Colorado’s brilliant, ponytailed Mark Serreze drove home the scale of the situation. When NASA first began mapping Arctic sea ice with microwave satellites in the 1970s, he intoned, flashing a political map of the lower forty-eight United States on the screen, its minimum summer sea-ice extent
²⁸⁹
hovered near 8 million square kilometers, equivalent to all of the lower forty-eight U.S. states minus Ohio. POOF! Ohio vanished from the big projection screen. Since then its minimum area had been declining gradually, up until this year when it suddenly contracted abruptly, like a giant poked sea anemone, to just 4.3 million square kilometers. POOF! POOF! POOF! Gone was the entire United States east of the Mississippi River, together with North Dakota, Minnesota, Missouri, Arkansas, Louisiana, and Iowa. A murmur rolled through the hall—even scientists enjoy a good animated graphic over tables of numbers any day.

After Serreze’s talk we milled around some more, wrangling over things like “model downscaling,” “cloud forcing,” and “nonlinear dynamics.” Some were revising the old projections for an ice-free Arctic Ocean from 2050 to 2035, or even 2013. Others—including me—argued for natural variability. We thought the 2007 retreat could just be a freak and the sea ice would recover, filling up its old territory by the following year.

We were wrong. The excursion persisted for two more years, with 2008 and 2009 also breaking records for the Arctic summer sea-ice minimum. They were the second- and third-lowest years ever seen, and had followed right on the heels of what happened before.
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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’ Principle
²⁹¹
), 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.
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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.
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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
coldest months of the year
. I was staring at a map of the relaxing grip of winter’s iron clench. It was an easing, a partial lifting, of the Siberian Curse.

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 running everywhere. Yes, there are stunted trees, tundra mosses, and no raccoons, but these things are the result of cold winters, not summers. In summer the sun circles the sky day and night. Everything is bathed in heat and light. The ground thaws, flowers bloom, and rodents teem. While driving through Fairbanks, Alaska, I noticed people starting softball games at midnight. The place simply explodes with pent-up life in fantastic overdrive.

There is now overwhelming evidence that northern winters are becoming milder and growing seasons are getting longer. From weather station data, we know that air temperatures rose throughout the northern high latitudes during most of the last century, and especially after 1966. There was a short cooling snap lasting from about 1946 to 1965, but even then large areas of southern Canada and southern Eurasia continued to warm. After 1966, temperatures took off sharply, especially in the northern Eurasian and northwestern North American interiors, where annual air temperatures have been rising at least 1° to 2°C per decade on average. That’s about
ten times faster
than the global average, and it’s being driven almost completely by warmer springs and winters.
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