Interior Alaska’s permafrost has warmed in some places to the highest level since the ice age ended 10,000 years ago, its temperature now within a degree or two of thawing.
Earth frozen since woolly mammoths and bison wandered Interior steppes has been turning to mush. Lakes have been shrinking. Trees are stressed. Prehistoric ice has melted underground, leaving voids that collapse into sinkholes.
Largely concentrated where people have disturbed the surface, such damage can be expensive, even heartbreaking. It’s happening now in Fairbanks: Toppled spruce, roller-coaster bike trails, rippled pavement, homes and buildings that sag into ruin. And the meltdown is spreading in wild areas: sinkholes, dying trees, eroding lakes.
These collapses bode ill: They are omens of what scientists fear will happen on a large scale across the Arctic if water and air continue to warm as fast as climate models predict.
“So far, we have only some local places where permafrost is thawing naturally,” said expert Vladimir Romanovksy, a Russian-born geophysicist at the Geophysical Institute of the University of Alaska Fairbanks.
“But we are very, very close to this point when it (all) starts to thaw.”
After record high temperatures during the summer of 2004 and last winter’s deep insulating snow, Romanovsky said he expects Interior permafrost will again be significantly warmer than normal this year _ still closer to melting.
The Geophysical Institute and Romanovsky maintain the world’s most extensive network of permafrost “observatories” _ basically thermometers sunk deep into the frozen earth, many along the trans-Alaska oil pipeline. What they report is disconcerting.
Permafrost is shrinking: warming on the bottom from the Earth’s natural heat, warming on the top because of air temperature and deep snows.
It’s like holding an ice cream sandwich in your hand on a sunny day. While the icy center stays hard, it shrinks as the top and bottom both melt.
“Our permafrost is still stable, even though it is very, very warm,” Romanovsky said. “But the moment it starts to thaw, we will be able to say we are the warmest we have been the last 100,000 years.”
For a glimpse of that future, look no farther than the hills north of Fairbanks, near where Romanovsky lives with his wife and two of his three sons.
In a meadow on his mother-in-law’s property, weird 6-foot-deep channels and holes crisscross the ground, trenches and bomb pits from what amounts to thermal warfare.
A small hole opened up in the sod a few years ago, curving down into the earth like some gopher den. This spring, his sons and other children playing near the house discovered the bottom had fallen out. The cavity was now large enough to bury a person. No one has crawled down to see where it ends.
Romanovksy discourages his sons playing in the field. “It is not safe,” he said.
Maybe 100 yards away, other sinkholes have formed along the shoulder of Goldstream Road, the main travel route for residents of the rural valley. Romanovksy took photos of his sons by one hole in 2001 and matched them to another set taken this spring. In the successive snapshots, the boys grow taller, the hole grows deeper.
The newest chasm _ maybe 10 feet across _ had been filled with gravel by highway crews. But only a few weeks later, concentric cracks circled a depression. It looked like a bull’s eye.
As it does every summer, the hole was collapsing again.
Romanovsky is part of a small army of scientists investigating Arctic climate change. He teaches University of Alaska students, conducts research with the International Arctic Research Center and hopes to expand ground frost monitoring to other parts of the world with a grant from the National Science Foundation.
Since emigrating from Moscow in 1990, Romanovksy has found that Fairbanks offers a kind of paradise for a family man/permafrost scientist _ a middle-class paycheck in a small town surrounded by frozen ground.
Now 51 and a naturalized U.S. citizen, he still has a bulldog build from his days as a hockey defenseman for Moscow State University. He has two Ph.D.s, with training in mathematics, geology and the physics of how frozen dirt sheds heat.
Permafrost experts once labored in obscurity, he said. Graduate students were drawn to more glamorous topics, like glaciers and sea ice.
After all, he said, “permafrost is frozen dirt.”
But the importance of permafrost as an indicator of climate change _ and the realization that its thaw could alter the northern landscape and release vast stores of greenhouse gases into the air _ has ignited huge interest.
“It’s just exploded since last year,” said Romanovsky, who starred in a recent New Yorker piece on global warming. “I’m going to have to stop giving interviews.”