August 31, 2009
Skating on the Hudson ?
FROM- New Haven County Environmental Policy Examiner-Kirtland Griffin
Will the quiet Sun leave us with summer sea ice as far south as NYC by 2120?
During the past two summers a strange thing has happened in the Arctic that is made even stranger by the alleged global warming that is occurring. The point often missed in the media and political discourse is that the extent of sea ice at the summer minima in the Arctic is growing. There has been more ice than the year before by approximately 400,000 square kilometers per year for the past 2 years. Now we know that this is likely not a linear phenomenon but often the climate is projected to follow linear progressions to illustrate the possible man-made global warming alarmist outcomes that could occur. Now, this may be a simplistic approach, but it is interesting to note how that could be turned around to illustrate the point.
At the present time, according to http://www.cryospheretoday.com/ the current sea ice extent is approximately 3.6 million square kilometers. This is approximately 0.4 million square kilometers more than 2008 at this time last year and the same larger than the 2007 minimum. Thus we have a 0.4 square kilometer per year growth rate. The area of the Earth north of the latitude of New York City is approximately 47.5 million square kilometers. Subtracting the current ice area, 3.6 million square kilometers, the net difference comes to 43.9 million square kilometers. This represents the area of ice that would have to grow to have a frozen Hudson River in New York City. Dividing by the rate of increase of the Arctic Ice Cap of 0.4million square kilometers per annum we get a figure of 110 years plus or minus. So under these assumptions, Summer Sea Ice extent could engulf New York by 2120. That would likely mean that winter ice could extend further South but the data are not clear on that outcome. The formula for determining the surface area was 2piR^2(1-Cos A) for an included angle of 120 degrees. This is actually a conservative estimate since there is substantial land within this area that would not have to freeze. Also, once the ice reached a certain point, the ice rate of increase would likely increase dramatically. We could call this a tipping point beyond which reversal would be impossible. Sound familiar? This could shorten the time by as much as 50 years.
Figuring this backwards for a decreasing sea ice, using the same practice, an ice-free Arctic could occur within 20 years or so. I have seen projections of 25 to 30 years for this to happen and I suspect the logic is similar to mine.
So is skating across the Atlantic in 110 years out of the question? I think so. But then so is an ice-free Arctic.