As the temperature rises in the Arctic, it sends a chill around the planet
BY EUGENE LINDEN/CHURCHILL
Monday, Sep. 04, 2000
Here's a tip for anyone trying to figure out when and whether global warming might arrive and what changes it will bring: hop a plane to the Arctic and look down. You'll see that climatic changes are already reworking the far-north landscape. In the past two decades, average annual temperatures have climbed as much as 7[degrees]F in Alaska, Siberia and parts of Canada. Sea ice is 40% thinner and covers 6% less area than in 1980. Permafrost--permanently frozen subsoil--is proving less permanent. And even polar tourists are returning with less than chilling tales, one of which was heard around the world last week.
Back from a cruise to the North Pole aboard the Russian icebreaker Yamal, tourists told the New York Times that a mile-wide lake had opened up at 90[degrees] north, with gulls fluttering overhead, and they had the pictures to prove it. The newspaper declared that such an opening in polar ice was possibly a first in 50 million years, though that claim was dismissed by scientists who nonetheless see other serious signs of Arctic warming (see box, page 56).
On a less cosmic level, Mike Macri, who runs nature tours in Churchill, on the western shores of Hudson Bay in Canada's Manitoba province, has had to rewrite his brochures. The old ones encouraged tourists to arrive at Churchill in mid-June to see beluga whales, which migrate up the mouth of the Churchill River following the spring ice breakup. The new brochure encourages visitors to arrive as early as May.
The ice also forms as much as two weeks later in the autumn than it used to in Hudson Bay, creating a bewildering situation for some of the local wildlife. Polar bears that ordinarily emerge from their summer dens and walk north up Cape Churchill before proceeding directly onto the ice now arrive at their customary departure point and find open water. Unable to move forward, the bears turn left and continue walking right into town, arriving emaciated and hungry. To reduce unscheduled encounters between townspeople and the carnivores, natural-resource officer Wade Roberts and his deputies tranquilize the bears with a dart gun, temporarily house them in a concrete-and-steel bear "jail" and move them 10 miles north. In years with a late freeze--most years since the late 1970s--the number of bears captured in or near town sometimes doubles, to more than 100.
Humans are feeling the heat too. In Alaska, melting permafrost (occasionally hastened by construction) has produced "roller coaster" roads, power lines tilted at crazy angles and houses sinking up to their window sashes as the ground liquefies. In parts of the wilderness, the signal is more clear: wetlands, ponds and grasslands have replaced forests, and moose have moved in as caribou have moved out. On the Mackenzie River delta in Canada's Northwest Territories, Arctic-savvy Inuit inhabitants have watched with dismay as warming ground melted the traditional freezers they cut into the permafrost for food storage. Permafrost provides stiffening for the coastline in much of the north; where thawing has occurred, wave action has caused severe erosion. Some coastal Inuit villages are virtually marooned as the ground crumbles all around them. And as the ice retreats farther from the coast, Inuit hunters are finding that prey like walrus has moved out of reach of their boats.
These isolated dramas play out far from the mid-latitudes of the planet, where the vast majority of people live, but they could soon have serious implications for all of us. What is really at risk in the Arctic is part of the thermostat of the earth itself. The difference in temperatures between the tropics and the poles drives the global climate system. The excess heat that collects in the tropics is dissipated at the poles, about half of it through what has been nicknamed the ocean conveyor, a vast deepwater current equivalent to 100 Amazon Rivers. Much of the rest of the heat is conveyed as energy in the storms that move north from the tropics. If the poles continue to warm faster than the tropics, the vigor of this planetary circulatory system may diminish, radically altering prevailing winds, ocean currents and rainfall patterns. One consequence: grain production in the breadbaskets of the U.S. and Canada could be in jeopardy if rainfall becomes less steady and predictable. Already, severe and unpredictable storms across the northern hemisphere may be a sign that the global system is changing.
Even greater climate change could be on the way. Growing numbers of scientists fear that the warming trend will so disrupt ocean circulation patterns that the Gulf Stream, the current that warms large parts of the northern hemisphere, could temporarily shut down. If that happens, global warming would, ironically, produce global cooling--and bring on a deep freeze.
Such a calamity could be self-inflicted. Many scientists believe that the current warming is related to the increased burning of fossil fuels, such as gasoline and coal, which overloads the atmosphere with carbon dioxide and other greenhouse gases. That's why 160 countries signed the 1997 Kyoto Protocol, which requires industrial nations to reduce their greenhouse emissions to an average of 5.2% below 1990 levels between the years 2008 and 2012. But even that weak treaty remains controversial, and governments have made little progress toward implementing the pact. The U.S. Senate hasn't even considered ratifying it. Opponents seize on the possibility that the warming we're seeing may not be our doing but just part of the natural variation in climate.
Partly in response to this deadlock, NASA climatologist James Hansen last week unveiled an alternative strategy. Instead of pursuing the politically unpopular goal of drastically reducing consumption of fossil fuels, he suggests going after other greenhouse gases, such as methane, which he thinks has accounted for as much warming as carbon dioxide in the past century, even though it is present in the atmosphere in much smaller quantities.
Without action, major changes appear inevitable. Should surface water temperatures in the high Arctic rise just a few degrees, the sea ice could disappear entirely, but even a partial melting could devastate the northern hemisphere's climate. A combination of melting ice, increased precipitation and runoff from melting glaciers on land could leave a layer of buoyant freshwater floating atop the denser salt water, at a point in the North Atlantic where water ordinarily cools and sinks. The lighter freshwater wouldn't sink, interrupting the vertical circulation at a crucial point in the cycling of heat through the ocean--as if you're grabbing a conveyor belt and slowing it down.
So how would that produce cooling? Ordinarily the conveyor is propelled by the pull created by masses of water sinking in the North Atlantic. When this pull diminishes, the movement of warm water north in the Gulf Stream could slow or stall, driving down temperatures in Europe and North America, and possibly elsewhere.
It has happened before. Roughly 12,000 years ago, at the end of the last Ice Age, a natural warming sent freshwater from melting glaciers flowing out of the St. Lawrence River into the North Atlantic, all but shutting down the Gulf Stream and plunging Europe into a 1,300-year deep freeze. The more that becomes known about this period, named the Younger Dryas (after a tundra plant), the more scientists fear that the rapid melting of sea ice could cause the same catastrophe again. Only next time, writes geophysicist Penn State's Richard Alley in a forthcoming book, Two-Mile Time Machine, the effects would be much greater, "dropping northern temperatures and spreading droughts far larger than the changes that have affected humans through recorded history." Would this be "the end of humanity?" he asks rhetorically. "No," he replies. "An uncomfortable time for humanity? Very."
A sudden chill would shorten growing seasons, and the resulting changes in precipitation could be even more damaging. Colder air is dryer air, and Alley points out that during the Younger Dryas, the monsoon weakened in Asia and the Sahara expanded. Harvey Weiss, a Yale archaeologist who has studied the role of climate in human history, notes that it's not changes in temperature that bring down civilizations but changes in precipitation.
Protecting civilization is the goal of the Kyoto Protocol, but the treaty allows 12 more years for implementation, on the assumption that climate change will be gradual. That assumption looks shaky. Studies of deep underground ice layers in Greenland, which reveal a record of climate changes over hundreds of thousands of years, show that major climate shifts, like the onset of the Younger Dryas, can come very abruptly--within a few decades.
It probably won't be possible to avoid some climate change this century, up or down--and there's still a chance that the earth's systems will compensate for any that occurs--but the possibility that climate turns rapidly and unpredictably should spur us into doing whatever is practical to turn from fossil fuels--fast. If done right it can be a boon. Energy conservation usually increases profits. In developing nations it's often cheaper to use alternatives like wind power to electrify new areas.
At the entrance to the Churchill Northern Studies Centre, a base for investigations of regional climate change, a rusting rocket is a mute reminder of the complex's earlier life as part of defenses against Soviet nuclear attack. That threat never materialized, and now, belatedly, scientists venture from the base to study a threat that has materialized but against which no adequate defense has been mounted. Despite the danger that climate change poses, the resources currently devoted to studying this problem--and combatting it--are inconsequential compared with the trillions spent during the cold war. Twenty years from now, we may wonder how we could have miscalculated which threat represented the greater peril.