Two Weddings and a Computer Model - THE PULL - The World in 2050: Four Forces Shaping Civilization's Northern Future - Laurence C. Smith

The World in 2050: Four Forces Shaping Civilization's Northern Future - Laurence C. Smith (2010)


Chapter 5. Two Weddings and a Computer Model

My adoptive groomsman, whom I’d just met the night before, cracked open the church door and peeked anxiously out at the parking lot. It was a sorry mess of black asphalt, lingering slush, and streaming water. Some early guests were sitting in their cars, peering through their headlights for a dry way into the church. It was early afternoon but very dark. I’d expected dim—we were, after all, just three hundred miles shy of the Arctic Circle in the middle of winter—but not this. The expected reflective blanket of fluffy white snow was gone. My dress socks were wet and cold. We’d strategically timed our wedding day for the prettiest, whitest, most winter-wonderland month of the year. But instead, in the middle of February, some five hours north of Helsinki, a thousand miles northeast of London, and almost twenty degrees of latitude north of Toronto—there was only a steady downpour of rain.

More precisely it was our first wedding day, taking place across the Atlantic for my new European family and friends. Our second wedding day—for American families and friends—was a month later in the sunny desert resort of Palm Springs, California. Mid-March is peak tourist season in Palm Springs, with infallible blue skies and flawless temperatures hovering in the 70s. We had booked all outdoor venues for the day’s events. Our tremulous queries about tents and patio heaters—just in case of a weird-weather repeat—were politely but firmly dismissed. The weather here is always perfect in March, we were told. That’s why people pay twice as much to come then.

You know what happened next. A line of fat squalls sprayed cold rain onto our guests’ unprotected heads. By the time the lasagna came out, the temperature had plunged fifteen degrees. We did manage to scrounge up four patio heaters somehow, around which the jacketless masses could huddle. We were shocked and upset—again—by freaky weather. But just like our sub-Arctic celebration, the crowd’s good spirits soon prevailed. Both ceremonies went on as planned. Cakes were cut, dances were danced, and good times were had by all.

I shouldn’t have been so surprised. While there will always be some weird weather happening somewhere, my wedding experiences were consistent with everything we know about the statistics of climate change. I had described such phenomena many times (though as probabilities, not specific occurrences) to thousands of students in my lectures at UCLA. From my research and travels to the NORCs, plenty of people had told me about bizarre rains in the depths of winter. After a while I’d even become bored with it—one can only listen to so many bizarre-weather stories before it just isn’t new information anymore.

In the previous chapter, we explored how the statistical norms of flood and drought frequency are changing, and how they might become more intense in the future. Now it is time to discuss rising air temperatures in the North—even in the dead of winter and at very high latitudes. Indeed, this phenomenon is a central interest throughout the rest of this book.

Four facts about global climate change need to be made very clear.

The first is that any process of climate change—both natural and man-made—unfolds erratically over time. In fact, its behavior is not unlike that of the stock market.

As every investor knows, long-term trends in the stock market are overprinted with short-term fluctuations. We don’t normally assume that share prices will move smoothly up or smoothly down. Instead, and usually within days, we expect they will reverse, before reversing again, and so on. Wise investors accept this short-term volatility as being largely unpredictable, yet bank on the existence of an underlying long-term trend to guide their overarching portfolio strategy. They say that while short-term markets react to unpredictable things like profit-taking, news reports, and God-knows-what, a long-term trend is more fundamental. And indeed, they are right. Throughout modernity the long-term trend has been for stock values to rise. Its underlying driver is growth of the real economy, fueled by the steady rise of human population and prosperity.

The long-term trend for the Earth’s climate, for at least several centuries, is rising air temperatures in the troposphere (lower atmosphere). Its underlying driver is radiative forcing commanded by the steady rise of carbon dioxide and other greenhouse gases produced as by-products of human activity. Because carbon dioxide, in particular, can linger in the atmosphere for many centuries this buildup is, for all intents and purposes, permanent.273 Over the long haul, the world’s global average temperature must go up. As shown in Chapter 1, the physics of this has been known since Svante Arrhenius’ work in the 1890s.

Beyond this broad, average trend, however, the warming process gets more complicated. Our planet is not simply a dry rock with a sunlamp shining on it. The additional heat trapped by greenhouse gases is absorbed, released, and moved around the planet by sloshing ocean currents and turbulent air circulation patterns. Living things breathe air in and out, and store or release carbon—a fundamental ingredient of CO2 and CH4 greenhouse gases—in their tissues. When the ground is bare, it absorbs sunlight, causing local heating. When snow-covered it reflects, causing local cooling. Volcanic eruptions punch aerosols into the stratosphere, shading and cooling the planet for a few years until they dissipate.274 The energy output of the Sun waxes and wanes slightly. All of these little and not-so-little natural mechanisms and feedbacks are to climate change what profit-taking, insider trading, and short sellers are to the stock market. They muck up the underlying greenhouse forcing trend, overprinting it with shorter fluctuations that rise and fall, then rise again.275 If not for this natural variability, we’d have caught on to the deeper greenhouse signal even sooner than we did.

Any competent financial planner will tell you that the road to secure retirement is paved with market drops. Any competent climate scientist will tell you that our road to a hotter planet will be paved with cold snaps, even record-breakers. But unfortunately, when it comes to communicating this to the general public, we scientists have done a poorer job of it than financial planners. Perhaps it’s not surprising, therefore, that so many people will glance outside at the bitter cold and scoff at global warming—even as they log on to E-Trade to buy up the latest stock market dip.

The second important fact about climate change is that its geography is neither always global nor always warming. To be sure, it is mostly global and mostly warming. But because of the many complex natural mechanisms and feedbacks that inject themselves into the process, the final climatic manifestations of greenhouse forcing vary greatly in spatial pattern. Climate change is not only erratic in time, like the stock market, but also in geography. A globally averaged temperature increase of one degree Celsius does not mean temperatures rise everywhere around the globe by one degree Celsius. That’s just the average. Some places will heat up a great deal, others won’t or might even cool. Summing them all together gets you to the +1°C global average. But that seemingly small number masks some stunning differences around the world.

Consider the map below. It is a projection of our future temperature changes by the middle of this century. Some places are warming hugely but other places hardly at all.276 Why is this? Has some climate model gone haywire?

This map is not an oddball, but just one of a family of nine related maps released by the latest IPCC Assessment.277 They all show irregular geographic patterns and appear together on the following page in a three-by-three grid. From left to right they plot out a three-stage timeline for our century, with average, smoothed-out temperature changes apparent by 2011-2030, by 2046-2065, and by 2080-2099. Like the single map on page 126, each one is actually produced from not one but many climate models—much like a stock index—thus capturing where the models robustly agree rather than the quirks of any particular climate model over another.

Each of the three rows corresponds to a different concentration of greenhouse gas in the atmosphere. That, in turn, rests on all sorts of things, from political leadership to energy technology to gross domestic product. Rather than try to predict which outcome will actually transpire, the IPCC instead calculates outcomes for numerous possible social paths (called SRES scenarios 278), of which three are shown here. The first outcome (top row) may be described as a highly globalized world, with population stabilizing by midcentury and an aggressive transition to a modern information and service economy. This scenario (known to climate scientists as “B1”) is labeled “optimistic” on the figure.279 The second outcome also assumes a stabilizing population and fast adoption of new energy technologies, but with a balance of fossil and nonfossil fuels. That future (called “A1B” by climate scientists) is labeled “moderate.” The third outcome assumes a very divided world with high population growth, slower economic development, and slow adoption of new energy technology. This future (called “A2”) is labeled “pessimistic.”

The third important fact about global climate change is revealed by comparing these three rows of maps. They show that, regardless of technology path, we are already locked in to some degree of warming; but by century’s end, the actions or inactions taken now to curb greenhouse gas emissions really will matter enormously. By 2080-2099 the “pessimistic” world is indeed a cauldron compared to the “optimistic” one, with temperatures rising 3.5°-5.0°C (9°F) across the conterminous United States, Europe, and China, rather than 2.0°-2.5°C (4.5°F). While these numbers may seem small, in fact there is a huge difference between the two outcomes. A 2.5°C rise in average annual temperature is actually huge, equivalent to the difference between a record cool and record warm year in New York City. So even in the “optimistic” world, what is today considered an extreme warm year in New York will become the norm; and the new extremes will be unlike anything New Yorkers have ever seen.

The “pessimistic” numbers are even more alarming. They approach the magnitude of average temperature contrast between the world of today and the world of twenty thousand years ago during the last ice age, when global temperatures averaged about 5°C (9°F) cooler. Many areas of North America and Europe were under ice, sea levels were more than 100 meters (330 feet) lower, and Japan was actually connected to the Asia mainland.280

All of these maps are conservative in that they awaken no hidden “climate genies” that give climate scientists nightmares.281 Instead, they chart out the plain vanilla, predictable intensification of the greenhouse effect, covering a realistic range of options lying well within control of human choices.

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.282

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 physics284 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.285 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 1985.286

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,288 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 extent289 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.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 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.297

The New Arrivals

As you might imagine, the biological response to this has been brisk. By the 1990s, a greening up of northern plant cover was spotted by satellites. Down on the ground, trees grew taller and barren tundra began sprouting up shrubs.298 All of this is consistent with the temperature increases recorded by weather stations. Not surprisingly, ecosystem models project plant growth to continue rising right alongside the projected increases in air temperature and growing season length. Even under the “optimistic” emissions scenario shown earlier, Arctic net primary productivity (a measure of overall plant biomass growth) is projected to almost double by the 2080s.299

Wildlife is also on the move. From my travels and interviews the appearance of “southern” creatures in northern places was a prevailing theme. I heard repeatedly about raccoons, white-tailed deer, beavers, and even a mountain lion spotted in places they’d never been seen before. My uncle, a longtime outdoorsman in northern New York State, noticed gray squirrels and opossums moving in, along with some crazy disruptions to the spring harvest of maple syrup. The Mountain Pine Beetle, normally kept in check by winter-kill, is now devastating Canadian forests. Other biological examples published in the scientific literature include the common buzzard Buteo buteo wintering near Moscow, nearly a thousand kilometers north of normal; a northward shift in Japan’s Greater White-fronted Goose, Anser albifrons; and Sweden’s Brown Hare, Lepus europaeus, infiltrating the territory of (and possibly hybridizing with) Lepus timidus, the Mountain Hare. Red foxes are displacing Arctic foxes. Beavers are pushing north, and model projections suggest they will also become denser inside their current range.300

By midcentury Ixodes scapularis—the Lyme-disease-carrying tick—is projected to expand northward from its current toehold in southern Ontario to much of Canada. By century’s end the smallmouth bass, today found only near the U.S. border, is projected to live all the way to the Arctic Ocean. In the North Sea—one of the world’s most productive fisheries—nearly two-thirds of all fish species have either shifted north in latitude or sunk down to cooler water depths. Even lowly plankton is on the move: In the past forty years Atlantic warm-water species have pushed northward a staggering ten degrees of latitude—almost seven hundred miles—supplanting cold-water species that are in turn retreating north.

The Displaced

The 2007 sea-ice contraction triggered a new wave of public consternation about the future of polar bears, including an environmentalist push in the United States to classify them under the Endangered Species Act. This gesture, ultimately rebuffed by both the Bush and Obama administrations, was largely symbolic (far more polar bears live offshore of Canada, Russia, and Greenland than Alaska, and these countries are certainly not beholden to the U.S. Endangered Species Act), but the concern for these magnificent animals is valid. They exist naturally only in the Arctic301 and are uniquely adapted to live out their lives roaming on top of a frozen ocean. Their home is on the floating sea ice, hunting ringed seals, napping, and occasionally cavorting or mating with one another. Some females go onto land to give birth, but they otherwise spend as much time as possible out on the ice. Unlike other bears they do not hibernate through the winter. The lean time for polar bears is in summer, when the ice disintegrates and retreats. Forced ashore, they mostly fast and wait until it returns.

There is growing evidence that the waiting and fasting periods are getting longer, leading to skinny bears, strange behavior (like wandering into towns), and even cannibalism. In 2004 biologists confirmed three occurrences of polar bears deliberately hunting and eating each other. In one case a large male bear pounded its forepaws through the den roof of a female, savagely bit into her head and neck, then dragged her off in a trail of blood to be devoured. Her cubs were buried and suffocated in the rubble. Such behavior had never been seen before during the scientists’ thirty-four years of research in the area.302

The problem is that the bears’ favorite prey, ringed seals, also require sea ice. They spend their time either resting on top of it (and watching out for polar bears), or swimming beneath it looking for Arctic cod. The Arctic cod lurks under and along the edges of the ice, watching out for ringed seals while chasing amphipods, copepods, and krill. Those little creatures in turn graze on tiny flagellates and diatoms that grow on the underside of the ice, and also bloom profusely in the water alongside its melting edge. This entire food chain—from microscopic phytoplankton to a thousand-pound polar bear—is inextricably linked to the presence of sea ice. Walruses, bearded seals, and other species also use sea ice, though none so specifically as do polar bears, ringed seals, and Arctic cod.

Despite growing evidence of stress (like bear cannibalism), none of these species is in immediate risk of extinction. But there is little question that if the summertime sea-ice fades completely, then these amazing creatures will fade right along with it. Government scientists, in a report to aid the Bush administration’s decision on the proposed Endangered Species Act listing, estimate that two-thirds of the world’s polar bears will be gone by 2050.303

From these and other indications worldwide, climate change is forcing a massive ecological reorganization of the planet, with both extinctions and expansions now under way. Depending on the emission scenario used, one model projects that anywhere from 15% to 37% of the world’s species will be committed to climate-change extinction by 2050.304 If these numbers hold true, they are devastating—roughly comparable to the impacts of deforestation and other direct forms of habitat loss. When combined with all the other species extinctions since the last ice age, they will mark the sixth great mass extinction on Earth—and the first since the Cretaceous-Tertiary extinction that ended the dinosaurs some sixty-five million years ago.

The mechanisms for climate-change extinction are many. Amphibians and wetland species are especially vulnerable to droughts. As temperatures rise, polar and alpine species have literally nowhere left to go once pushed off the brink of the northernmost coast or highest mountain peak. A less direct mechanism is the decoupling of codependent species within a food web (called “match-mismatch” by ecologists) when their respective phenological cycles fall out of whack. Imagine birds migrating to their accustomed nesting area only to find that the caterpillar hatch they were planning to gorge on has already come and gone, for example. Another is that warmer temperatures tend to enable insect pests, invasive species, disease, and robust “generalized” species (like rats and raccoons) to outcompete specialized ones. Yet another is that the projected rate of climate change is so rapid that some sedentary species (like trees) may not be able to relocate quickly enough, or their escaping climatic comfort zone will shift to a place incompatible for other reasons, like terrain or soil. Some climates, especially in alpine and polar areas, will simply cease to exist. By century’s end, under a high carbon emissions scenario, 10%-48% of the world’s land surface is projected to “lose” its extant climate completely, and 12%-39% will develop new “novel” climates that don’t exist in the world today (mostly in the tropics and subtropics).305 These changes will have powerful impacts on world ecosystems and could even render some local conservation efforts obsolete. Finally, because ecosystems and food webs have so many complex interconnections, there will be rippling effects we don’t yet know about. All of this is piled on top of an ongoing raft of familiar ecological threats, including habitat destruction, invasive species, and pollution.

Compared with other places, habitat loss and pollution are less severe in Alaska, northern Canada, the Nordic countries, and eastern Russia, where vast boreal forests, tundra, and mountains hold some of the wildest and least-disturbed places left on Earth.306 However, northern ecosystems also have far simpler food chains and fewer species than, say, the Amazon rain forest. Indeed, much of it is a colonizing landscape, still in the early stages of soil formation and biological expansion after being encased and pulverized by glacier ice just eighteen thousand years ago.

When imagining 2050, I anticipate that a globally unfair assortment of some winners and many more loser species will be very apparent by then. Already the world’s plants and animals are in the midst of their biggest extinction challenge in sixty-five million years. Out of perhaps seven million eukaryote species found on Earth, nearly half of all vascular plants and one-third of vertebrates are confined to just twenty-five imperiled “hot spots,” mostly in the tropics and comprising just 1.4% of the world’s land surface.307

Even in the far North, a specialized ecosystem adapted to frigid cold will be under attack by advancing southern competitors, pests, and disease. It is possible that the vast boreal forest—girdling the northern high latitudes from Canada to Siberia—might convert to a more open, savannah-like state.308 But total primary productivity—meaning plant biomass, the bottom of the food chain—will be ramping up. Certain mobile southern invaders will enjoy growing viability in a vast new territory that is larger, less fragmented, and less polluted than where they came from. Longer, deeper penetration of sunlight into the sea (owing to less shading by sea ice) will trigger more algal photosynthesis, again increasing primary productivity and reverberating throughout the Arctic marine food web. The end result of this can only be greater overall ocean biomass, more complex food webs, and the invasion of southern marine species at the expense of northern ones.

The ecology of the North is imperiled and changing. But it will be anything but lifeless.

Hunters on Thin Ice

People rely on sea ice too. For millennia the Inuit and Yupik (Eskimo) peoples have lived along the shores of the Arctic Ocean and even out on the ice itself, hunting seals, polar bears, whales, walruses, and fish. It is the platform upon which they travel, whether by snowmobile, dogsled, or on foot. It is the foundation on which they build hunting camps to live in for weeks or months at a time.

These hunters have watched in astonishment as their sea-ice travel platform—dangerous even in good times—has thinned, become less predictable, and even disappeared. People’s snowmobiles and ATVs are crashing through into the freezing ocean. Farther south, they are crashing through the ice covering rivers and lakes. In Sanikiluaq, Canada, I learned that weaker ice and a two- to three-month shorter ice season is impairing people’s ability to catch seals and Arctic char. In Pangnirtung a traditional New Year’s Day bash celebrated out on the ice has become unsafe. In Barrow, two thousand miles west on the northernmost tip of Alaska, I learned hunters are now taking boats many miles offshore, hoping to find bits of ice with a walrus or bearded seal.309

This is a serious matter. In the high Arctic, eating wild animals is an essential part of human survival and culture. In Barrow I was welcomed into the home of an Inuit elder, who explained that three-quarters of his community relies on wild-caught food.310 I was struck by this because Barrow is one of the most prosperous and modernized northern towns I have seen. There is a huge supermarket with most everything found in the supermarkets of Los Angeles. But groceries are two or three times more expensive because there is no road or rail to Barrow, so everything must be flown or barged in. Most people at least supplement their diet with wild food; many crucially depend on it. Alongside Pepe’s Mexican Restaurant (which has surprisingly good food and is apparently visited by members of the Chicago Bulls basketball team) I saw plenty of bushmeat in Barrow. My host’s kitchen and backyard were festooned with racks of drying meat and fish; in his driveway was a dead caribou. Another driveway had two seals, yet another a massive walrus. In the Arctic, obtaining “country food” is not for sport—it is as important to people’s diet as thin-crust pizza is to New Yorkers.

Of all northern peoples, the marine mammal-hunters living along the Arctic Ocean coast are suffering the most from climate change. Less sea ice means more accidents and fewer ice-loving animals to eat. It means faster shoreline erosion from pounding by the waves and storms of the open ocean. The Alaskan village of Shishmaref has lost this battle and will need to be relocated farther inland. But even in coastal towns, nearly everyone I meet bristles at the notion of being cast as a hapless climate-change refugee.

Even as they express frustration at having their lives damaged by people living thousands of miles away—and think it only fair that those damages be repatriated—they also point to their long history of adaptation and resilience in one of the world’s most extreme environments. They are not sitting around idly in despair, or gazing forlornly out at the unfamiliar sea. They are buying boats, and organizing workshops, and setting about catching the fat salmon that are increasingly moving into their seas.

There is more to this story than climate change. Later, we will discuss some profound demographic, political, and economic trends now under way that promise to be just as important to northerners’ lives in the coming decades.

Greenland’s Fine Potatoes

One of the more vivid media images of 2007 was one of happy Greenlanders tending lush green potato fields against a backdrop of icebergs melting away into the ocean. The diminished sea ice was wreaking havoc on seal hunting—Greenland’s finance and foreign affairs minister observed that subsistence hunting crashed by 75%—but people were beginning to plant potatoes, radishes, and broccoli. “Farming, an occupation all but unheard of a century ago, has never looked better,” trumpeted The Christian Science Monitor. By 2009 some fields were doing so well that Danish scientists started studying them, to learn why Greenland’s potatoes were growing even better than southern ones.311

What could be a more iconic symbol of the world in 2050 than seal hunters turned farmers in one of the coldest places on Earth? But in terms of sheer caloric output, any climate-triggered boons to agriculture will not be realized on the narrow, rocky shores of Greenland, or indeed any other place in the Arctic. Similarly to what we saw for certain wild organisms, the pressure is a gradient from south to north, not a leap to the top of the planet. Summers there will always be brief, and its soils thin or nonexistent. A short-lived vegetable garden is one thing, but when it comes to producing major crops for global markets, any significant increases will be realized at the northern margins of present-day agriculture. There will be no amber fields of grain waving along the shores of the Arctic Ocean.

In 2007 I watched some of the world’s top agronomists and plant geneticists debate how best to save our temperate crops from the rising heat, droughts, and pathogens forecast for the coming decades.312 Their solution was part biotech—genetic modifications, for example—and part ancient practice: Move over, water-guzzling corn, here come the best drought-tolerant sorghums and millets … from Ethiopia! Without adaptation, the group concluded, the prospect of food insecurity in the low latitudes was a serious threat.

I was particularly impressed with presentations by Stanford University’s Dave Lobell and Marshall Burke, who used twenty different climate models to statistically map where the food insecurities were most likely to emerge. Apparently, by the year 2030 South Asia, Southeast Asia, and southern Africa are especially vulnerable.313 By 2050, agricultural projections for sub-Saharan Africa get even worse, with average crop production losses of −22, −17, −17, −18, and −8% for corn, sorghum, millet, groundnut, and cassava, respectively.314 By century’s end, things become still rougher, with one study concluding it is more than 90% likely that future growing season temperatures in the tropics and subtropics will exceed anything we’ve ever seen before, with bad implications for food crops. “With growing season temperatures in excess of the hottest years on record … the stress on crops and livestock will become global in character,” wrote the paper’s authors. “Ignoring climate projections at this stage will only result in the worst form of triage.”315

In contrast to these studies, a broad pattern of rising crop yields in Canada, some northern U.S. states, southern Scandinavia, the United Kingdom, and parts of Russia have been repeatedly demonstrated by climate-change model simulations for years. Already these countries are major producers of wheat, barley, rye, rapeseed, and potatoes. As early as 1990 it was apparent that regardless of what climate model was used, the northern U.S. states of Michigan, Minnesota, and Wisconsin would likely benefit from rising average temperatures, even if corn, wheat, and soybean production in the rest of the country declined.316 Similar north-south asymmetries in crop yield (with gains in the north and declines in the south) were later demonstrated for Europe and Russia.317 The general idea is that in the marginal northern fringes of present-day agriculture, rising temperatures and longer growing seasons will boost current crops and perhaps allow introduction of new ones; in marginal southern fringes, rising temperatures and drought frequency should harm them.318

Other questions revolve around the relative importance of temperature versus moisture stress on plants, soil quality, strength of CO2 fertilization, and whether extreme events (heat waves, flooding) might be even more important determinants of future food supply than the long-term temperature and precipitation statistical averages produced by climate models.319 It is also an oversimplification to assert that Russian and Canadian agriculture, for example, will universally benefit from warmer air temperatures. Russia’s current agricultural heartland lies in its dry southern steppes, where crop declines may not be fully offset by gains in the north.320 The same holds true for Canada’s western prairies. But relative to the rest of the world, the NORCs—especially the northernmost U.S. states, parts of Canada and Russia, and northern Europe—count among the few places on Earth where we can reasonably expect to see rising crop production from climate change.

Please pass the potatoes.