In melting Arctic, warming is now
Arctic-dwelling Inuit have a word for their crazy weather - Uggianaqtuq. Pronounce it "oog-gi-a-nak-took." It means "to behave unexpectedly."
Scientists who consult Inuit for their take on climate change consider that an apt description. The Arctic, they say, is undergoing profound ecological change. It's become the poster child for global warming. Not only are average air temperatures rising, ice sheets thinning, and permafrost melting, the whole complex interconnected network of arctic life and its environment are changing in ways not reflected in the geological record or Inuit lore. This no longer is a forecast of what might happen in future decades. It is happening right now.
Even sophisticated computer-based climate simulations don't anticipate all the changes, say climate sleuths who laid out the story during a recent American Geophysical Union meeting in San Francisco. For example, there's more to melting permafrost than loss of solid ground, points out Daniel White with the University of Alaska in Fairbanks. He notes that much of the Arctic is desert. It has less precipitation than Tucson, Ariz. Impermeable permafrost holds what fresh water there is in lakes, ponds, snow, and ice. When that permafrost thaws out, the water drains away. Then affected regions are in trouble.
Loss of readily available water is only part of the trouble. As the frozen ice and soil that hold permafrost together soften, top layers of the thawing mass sometimes slide off. This can become a massive slump or landslide that does immediate damage. The long-term change involved is even more devastating, says Antoni Lewkowicz at the University of Ottawa, Ontario.
When the top layer slides off, the permafrost that remains is a salty marine deposit. That salt has been locked away for thousands of years. Now it's exposed. Because there's so little rain, it forms a salt crust. It takes a long time for that to erode away. Think Southwestern salt flats. This, Dr. Lewkowicz says, "is something we didn't expect" when his permafrost study began.
Besides thawing permafrost, there's loss of Arctic Ocean ice. Meteorologists, such as John Wallace of the University of Washington at Seattle, blame some of the loss on periodic changes in Arctic wind patterns that have been part of the normal climate. Right now, the winds tend to push the sea ice out of the Arctic Ocean at a rate that doesn't let it accumulate. If the wind pattern changes again, as it has in the past, this loss may stop.
But that explains only part of the loss. Some seems due to global warming. "The Arctic is still warming and we're still losing sea ice," says Mark Serreze with the University of Colorado in Boulder.
Whatever the cause, loss of sea ice is a disaster for animals, such as polar bears, that depend on it for habitat. Polar bears cannot live long on land, notes Ignatius Rigor from the University of Washington at Seattle. They are adapted to an ice-based ocean way of life. They have trouble reaching the ice when it is as far out as it is today. Polar bears, he says, are predicted to be extinct within 50 years.
Arctic geophysicists consider ecological effects of Arctic climate change intricate and highly variable. This makes these effects hard to predict and tricky to detect. One thing these scientists seem certain about, however, is that such changes are already under way. Lewkowicz notes that while climate simulations and forecasts are important, scientists need extensive monitoring to understand the massive changes now taking place.