Once more ice coats the brush and snow of Northwest Alaska, and Alaska Department of Fish and Game biologist Jim Dau wonders how the caribou will fare this time. Twice since 2005, the animals of the Western Arctic caribou herd have been hit hard by ice storms that threatened to lock their forage away beneath a layer of white pavement. After the first of those storms, large numbers of caribou suffered from starvation. Dau described them as dying "in droves."

They have not been the only animals to struggle with winter ice in Alaska's volatile climate in recent years, either. In the Chugach and Kenai mountains, Tom Lohuis, a Fish and Game biologist studying Dall sheep, has begun to examine icing as a possible cause of significant mortality. Lohuis is early in his studies but he has already found evidence in the Dall sheep population of Southcentral that is analogous to what Dau has seen in the Arctic -- animals hard pressed to survive because of a layer of ice coating the ground or the snow. Neither caribou nor sheep are well equipped for chipping through frozen surfaces to get at their food. Both Dau and Lohuis have seen ice related deaths and use the phrase "bags of bones" to describe the animals that manage to survive winters with serious ice events.

The big question now focuses on whether these ice events are a new phenomenon or an old one that has newly attracted attention. The question is simple: Is this icing related to a shift in climate or have all the discussions about "global warming" over the last decade merely caused scientists to finally notice long-existing, climate-related phenomenon, some of which have been obvious to generations of Alaskans that work the land?

Problems caused to polar bears by a demonstrably shrinking polar ice cap are hard to miss. Bears that die of exhaustion or lose their cubs on increasingly long swims between dens on the Alaska coast and the ice where they hunt seals are visible victims of global warming just as some other species are visible beneficiaries.

Likewise, the northern and westward expansions of moose and beaver in Alaska have been linked to forests migrating farther north and west since a general climatic warming began near the end of the 19th century. Booming Alaska salmon populations have been similarly linked, in part, to warming in the North Pacific Ocean and the Bering Sea. Outside the scientific community, of course, these latter events have been little noticed as climate-related because they are collectively considered as "good."

If global warming means more salmon, who in Alaska could oppose it? On the other hand, if it means extinction of the polar bear or shrinking Alaska caribou herds, who wouldn't oppose it?

And if it does both of these things, what then?

Global warming is a difficult topic to address in Alaska because it isn't just about warming. It's about climate change -- if not microclimate change.

Nature's law: Some Arctic animals win, others lose

Dau lives in Kotzebue, just north of the Arctic Circle. Reindeer herder Jimmy Noyakuk lives in Teller on the Seward Peninsula, just south of the circle. Noyakuk's reindeer and the caribou Dau studies are first cousins. The two men share concerns about the environment, and both agree that when it comes to climate change there is a fine, fine line between the good and the bad.

"We had a good thaw here," Noyakuk told Alaska Dispatch during a telephone interview from Teller the last week of January. But Noyakuk said the thaw didn't appear to result in much ice. Instead of locking away forage for his reindeer, it appeared to expose more of it. The weather went cold after the thaw, but the snow that came with it was equally cold. It was light and easy for the reindeer to brush aside with a foot to get at food.