New Sea Ice Concensus Emerging

I admit that I reasonably assumed that with winter upon us that there was little going on in the world of sea ice discussion. Boy was I wrong. The quoted news story reflects the huge jolt last summer gave the experts. The wind shift has also not let up and we can expect a repeat of last year’s sea clearing conditions. And they have figured out just how much the perennial ice has already collapsed. I even saw an astounding admission that the reporting regulatory agency imposed a linear model only protocol on their scientists for reporting purposes.

If we assume merely that the perennial sea ice is been attacked by a constant heat surplus each and every year, the result is a very nonlinear collapse of the ice after a long weakening period. I had no difficulty predicting a rapid collapse once it became clear that we had lost 60% of the perennial sea ice over a forty year span for which we had only the end points.

We how have lost most of the perennial sea ice, and the winds are now shifting the remainder out of the Arctic.

In the meantime, we are having a very good freeze this winter and the maximum extent has already been reached at a level larger than last year – no surprise – and it has extended by Greenland in particular to a point not reached in fifteen years. Again this is new ice that should disappear next summer.

What is particularly clear is the confusion and surprise been experienced by the experts. A lot of this has been brought on by the very unusual reordering of the wind system which is accelerating the clearing process.

Even the obvious fact of a cold winter right on the heels of unexpectedly warm summer is not yet explained. What are the true cause and effect relationships or are we reading way too much into this?

In any event, this cold winter should slow the onset of spring this year. We need to watch by how much and what effect this has on the summer sea ice melt. My own expectation is that we will have a neutral year for the annual sea ice but if the ongoing removal of perennial sea ice continues by wind action, then the real result will still be negative.

As the news report makes clear, this process looks irreversible for anything short of a multiyear stretch of below average cold. My own sense is that this year, cold as it was, merely hit the average. Thirty years ago, it would have been considered a fairly good winter.

The ongoing direct removal of perennial sea ice means that the next warm summer or so will clear the Arctic of sea ice. I still think that it will likely occur around 2013, but conditions have been hugely accelerated and the experts are now establishing a new time frame coincident with that date.

The only question that I have is whether or not this rapid collapse is driven by the ongoing surplus heat coming into the Arctic for the past few decades or alternatively driven by the recent onset of a very new wind system. In either case we have leapt ahead of any accepted projections and are now accepting the probability of clear seas within five years. And believe me that even a linear projection today gives us five years.

(ANCHORAGE, Alaska) — Arctic sea ice next summer may shrink below the record low last year, according to a University of Washington climatologist. Ignatius Rigor spoke Monday at the Alaska Forum on the Environment and said global warming combined with natural cyclical changes likely will continue to push ice into the North Atlantic Ocean.

The last remnants of thick, old sea ice are dispersing and the unusual weather cycles that contributed to sea ice loss last year are continuing, he said.

"The buoys are streaming out," Rigor said, referring to the markers used to monitor the flushing of ice into the North Atlantic.

A similar pattern preceded sea ice loss last summer was not expected to continue so strongly.

Scientists are watching Arctic sea ice closely, trying to sort out the effects of global warming and natural cyclical changes.

Formal projections of sea ice loss will be made for another month or so but all indications are that ice loss will equal or exceed last year's "unless the winds turn around," Rigor said.

New ice now covering the polar seas is not like older, thicker sea ice that once covered the region in winter, Rigor said. In 1989, 80 percent of the ice in the Arctic was at least 10 years old, he said. Today, only about 3 percent of the ice is that old.

New ice melts more quickly, and then open water absorbs more sunlight, warming the seas and making the fall freeze-up come even later, he said.

"Have we passed the tipping point?" he said. "It's hard to see how the system may come back."

The prospect of a mostly ice-free Arctic could mean a boom in shipping through the Bering Strait, several speakers said, but is bad news for polar bears and other animals.

Polar bears prefer ice over the shallow continental shelf north of Alaska because it supports a rich food chain, said Steve Amstrup, a leading polar bear biologist with the U.S. Geological Survey. With melting last summer, some Alaska bears were on ice as much as 600 miles north of Barrow, far from their preferred habitat, Amstrup said.

Amstrup was lead federal biologist in studies released last year depicting the Alaska bear as likely to disappear by 2050 because of global warming. A decision by the Department of the Interior on whether to list the polar bear as "threatened" under the Endangered Species Act was due in January but has been postponed.

The state of Alaska, among others, opposes the listing, arguing the forecasts of declining sea ice are too speculative.

Scientists Monday said that the forecasts were, if anything, too cautious. None foresaw the shrinkage of 2007.

"Five of the 10 studies we used projected more sea ice at mid-century than we had this summer," Amstrup said.

The shrinkage is related to higher temperatures, scientists said, but also to shifts in a weather pattern known as the Arctic oscillation. When the Arctic oscillation is in a "high" cycle, as it has been recently, more ice is pushed past Greenland into the North Atlantic, Rigor said.

Climate models have linked a higher Arctic oscillation to increases in greenhouse gases, but that relationship is the subject of much study, Rigor said.

"All these changes are very consistent with a climate system trying to cool itself off from greenhouse gases," Rigor said.

No comments:

Post a Comment