Showing posts with label sea ice melt. Show all posts
Showing posts with label sea ice melt. Show all posts

Thursday, August 7, 2008

Northwest Passage may Open Again

Last year everyone was caught totally by surprise when the ice really started to disappear. This year they are all watching if this story is any indication. Right now it is about fifty - fifty to clear shipping through the Northwest Passage. It is open at the western end as of the first of August, but a wind change can ruin this picture over night. The rest of the passage should clear by melting in the next two weeks.

More interestingly, a third of the western sea ice is below forty percent coverage and is surely experiencing maximum melting. I think there a remains a chance that the final areal extent will even approach last year’s low while the gross ice out there will be surely less that last years if we only had a way to measure it.

It is amusing to watch the mathematically impaired experts tip toe to admitting that sea ice coverage is now actually crashing. And I note that no one is brave enough yet to say that it will be mostly done by 2012 which is a mere four years from now. It will actually happen on their watch and they will have to explain now seventy years became five years, particularly when it is not terribly warmer by any apparent measure.

The Northwest Passage itself is very vulnerable still to been shut down by a simple shift in wind bringing a nearby floe into Lancaster Sound. Remember the early enthusiasm for open water at the pole itself? That is why I am saying fifty - fifty for clear sailing.

However, as this trend continues, it will become possible to run shipping through for a two week period at the least every year. Maintaining an icebreaker on standby would be enough to provide a measure of safety and facilitation if winds become contrary.


Frozen Northwest Passage expected to open up

TU THANH HA

From Wednesday's Globe and Mail

Even though this summer's ice melt hasn't approached last year's record conditions, the once-frozen Northwest Passage through Canada's Arctic is expected to open again soon, for only the second time in recorded history.

Already, a shallower, more southern route has freed up, according to high-resolution sea ice charts extracted from satellite microwave imagery by German researchers at the University of Bremen's Institute of Environmental Physics.

The more traditional Northwest Passage route, further north, is still clogged but it could be ice-free later this month, said Mark Serreze, a senior researcher at the University of Colorado's National Snow and Ice Data Center.

"Our view is that it may well open in the next few weeks," he said in an interview yesterday.
Ice remains from west of Cornwallis Island in Nunavut to east of Banks Island in the Northwest Territories, he said. "There is only a fairly small plug in there right now and it's showing signs it's melting away."

Beyond questions of trade, ship navigation and Arctic sovereignty raised by the repeated unlocking of the fabled waterway, Dr. Serreze said, the phenomenon is further proof that humankind might witness an ice-free Arctic Ocean within decades, with resulting unpredictable weather patterns.

"It really is just one more indication how quickly we're losing the sea ice cover. ... The sea ice cover is in a downward spiral, it's essentially in a death spiral right now."

The polar ice cap is now so thin that, even though this summer has been somewhat cooler than the previous one, large portions will disappear. "It really almost doesn't matter any more. We know we'll get a big loss of ice this year simply because we have so much thin ice," Dr. Serreze said.

Scientists are still unclear how the disappearance of the Arctic ice will influence weather elsewhere in the world. Some studies show that the western part of North America will suffer extended drought. Others suggest there will be changes to storm tracks and precipitation patterns over Western Europe.

"It's the sort of thing that we're just starting to get a handle on. It's a new area of research because we weren't thinking we would lose sea ice this quickly. Compared to what our climate models said, we're 20, 30 years ahead of schedule in terms of ice loss. This kind of caught us by surprise and the researchers are just starting to catch up."

Saturday, September 15, 2007

Clear Sailing by 2020 at the North Pole

The press has woken up to the opening of the Northwest Passage. In the meantime, I see continuing babble over predictions on the rate of ice loss. These boys are mathematically challenged and it is becoming annoying. Let me clarify things.

We lost 60% of the ice thickness and by extension 60% of the total ice M between 1957 and 2000. If we conservatively assume that the loss rate was the same throughout this period, the annual loss rate R can be discovered by the simple equation:

C = M - 43R expressed as percentages and C been the current percentage of the original M(1957).

Therefore R = (M-C)/43 or: R = (100 - 60) /43 or: R = approx. 1% of M

The apparrent current loss rate can be calculated by dividing 1% by 40% remaining to give us 2.5%.

Except that it is obviously faster than this. If we project that the prinicipal warming only seriously started in the early eighties, we have instead R = 2% and a current effective loss rate of 5% which actually appears to match current experience. This also means that in the last seven years we have lost an additional 14% of the original M leaving a current C of 26% or only 13 more years,instead of the more sedate forty years.

On top of all that the clearing of the majority of the Arctic ocean is allowing a greater heat absorption than usual and a thinner winter icesheet this winter.

I think that we actually have as little as ten years of summer sea ice cover left and that further warming will eventually expand the clear season to early August.

As stated earlier, the only thing that is going to halt this runaway is a major cold snap, perhaps caused by an injection of SouthPolar water into the South Atlantic. A late summer cruise along the northern coast of Ellesmere Island with a short hop to the North Pole in 2016 is very appropriate and on my to do list.