People in cold climates covet warmth. Not all of those “Canadians For Global Warming” bumper stickers are tongue-in-cheek. But they don’t joke like that in Alaska. To residents of this state, the prospect of even a small rise in average temperatures is a looming catastrophe. That’s because Alaska is melting. Literally.Much of Alaska is built on frozen ground called permafrost, a soil condition that results when the yearly temperature averages below freezing. But across most of the state, that criterion is just barely met, by a few degrees Celsius. Alaska lives on the edge of a phase change. A small bit of warming can make a big difference. And that’s why many Alaskans, along with plenty of outside researchers and environmentalists, are concerned about global warming and the strategies proposed to limit its rise. Even if the United States signed international treaties designed to limit climate change, they’re starting to realize, that might not be enough to keep the state from softening.
As I drove Alaska’s Highway 4 last summer, the landscape looked flat but the ride felt like I was on rolling hills. The road undulated up and down, thanks to spotty drainage from partially melted permafrost; costly road repairs must be done every summer. Along the sides were “drunken trees” (a local term), leaning on each other’s shoulders like thin inebriated giants, their shallow roots loosened by soft soil. There were also drunken homes, leaning and sinking into the ground, and sunken meadows, three meters lower than the surrounding forest. These result when trees are cleared and a little bit of extra warmth reaches the ground in the form of direct sunlight.
The ecology itself seems to melt down around zero degrees Celsius. Warm weather in Alaska in the 1990s encouraged an infestation of bark beetles that killed four million acres of spruce forest. This has been called the greatest epidemic of insect-caused tree mortality ever recorded in North America.
Many people think human activity is to blame for this warming, and that Alaska is a particularly sensitive alarm, like a canary in a mine shaft. Canaries were actually used as recently as the late 1980s to alert coal miners to whitedamp, their name for carbon monoxide. Now Alaska may now be our early warning against chokedamp-carbon dioxide.
Carbon dioxide comprises only 380 parts per million of the air that we breathe, yet this trace gas is the primary source of carbon for plants, and thus for our food. But it is also one of today’s villains. Because carbon dioxide absorbs infrared radiation emitted from the earth that would otherwise escape into space, an oversupply of the gas enhances the atmosphere’s natural greenhouse effect. The burning of fossil fuels and tropical rainforests has raised atmospheric carbon dioxide by about 20 percent since 1958 (when careful measurements began), and perhaps by as much as 35 percent since the beginning of the industrial revolution. And while you’ve probably heard it before, it bears repeating: The United States, with about 4.6 percent of the world’s population, is responsible for about 40 percent of fossil fuel emissions worldwide. That disproportionate fraction is partly a result of our great economy and productivity-but is also due to our great inefficiency, which is in turn abetted by low oil prices.
Is carbon dioxide responsible for the melting of Alaska? As I have pointed out previously, scientific discussion on this issue has become rude and nasty. Ad hominem accusations abound. Is global warming real? Are humans responsible? One side says, “Yes, and if you don’t believe that, you are not a non-scientific troglodyte.” The other side says, “It isn’t proven, and if you act prematurely you’ll kill our economy, you liberal communist tree-hugger.”