The World in 2050: Four Forces Shaping Civilization's Northern Future

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