Friday, August 17, 2007

Current Polar Sea Ice Maps

One of my favorite sites is:

We get a map of current sea ice coverage and a second map showing current change against the twenty year average. Don’t miss the second map.

I personally think sea ice could be mostly gone within the next ten years. When I started watching this several years ago I thought I was been brave to predict as early as fifteen years. I had to wait for confirmation of the current speed of the melt. It is coming in spades.

I reasoned that you do not lose sixty percent of ice thickness over 40 years on a linear basis. Yet we only had two points of reference consisting of the 1958 international geophysical year when an ice thickness survey was conduced by submarine. This was repeated again at the turn of the century. The difference of sixty percent was unanticipated.

The majority was likely lost in the last third of those 40 years or over a period of about fifteen years. That meant that the remaining forty percent should largely disappear in the succeeding fifteen years. And at some point toward the end it should flush out very quickly like a spring breakup since most of the long term sea ice will have been eliminated.

In the mean time it is fun to watch. Note that grey areas in the strong white areas likely reflect standing water at the least and semi open water in the main. I think that the grey areas have been growing larger and more widespread each year also. We still have a month left in this season.

Won't everyone be surprised?

I am looking forward to a cruise through the sea ice to the North Pole and Northern Greenland and Ellesmere Island. Since it was this hot in 1421 writer Gavin Menzies’ speculation on Zhu Di’s Chinese expedition through this area may even have it right. I thought that prospect a complete stretch, even with the map evidence.

I also would like to note that the polar seas will be covered every winter with seasonal sea ice that will break up and almost disappear over a fairly long summer season. It will still be as inhospitable as ever.

And we seriously need a cold snap up there.


geoffwade said...

Do have a look at the veracity of Menzies's claims by reading the various posts on

Menzies did not "speculate". He used only imagination and sophistry, but lacked the facts and evidence which necessarily lies behind speculation.
The book was then written by his publishers' ghost writer

Citing him in any serious discussion is an affront to the listeners or readers.

Best wishes

Geoff Wade

arclein said...

Without question Gavin pushes the envelope generated by his principal thesis. He is a reasonable informant on the fleet's options and possible objectives. And they were incrediably well prepared for their mission.

However, the fleet operated for less than ten years and thus its impact anywhere must have been ephemeral.

Anyone who looks at the polar ice map can see that sailing on either the north Greenland coast or the middle Siberian coast is an absolute impossibility even after a decade of warm weather.

The question is will this hold true if we have several more years of this?

It cetainly was warm enough during the key decade of 1420 to 1430 and it would be one of the great coincidences of history if someone was able to take advantage of it.