Ben Holt: I think there is a sense of urgency. The Arctic is rapidly changing, faster than people might have imagined.
That was research oceanographer Ben Holt at NASA’s Jet Propulsion Laboratory in Pasadena. Earth & Sky asked Holt what’s happening to Arctic ice.
Ben Holt: Well, the two major changes that have been going are the extent of the ice cover and the thickness of the ice. And the extent has been decreasing steadily for the last 15 years with a particular decrease in the summer of 2007.
By the end of the 2007 melt season, Arctic sea ice was 39 percent below the 20-year average.
Ben Holt: And the thicknesses, which have been measured primarily by submarines placed by the U.S. Navy, have shown a general decrease in thickness, particularly in the last two decades.
What’s more, in early 2008, NASA’s Ice, Cloud, and Elevation Satellite revealed that thinner, younger sea ice in the Arctic had jumped from 35 percent in the mid-1980s to 58 percent. Holt said that the thinning and shrinking of Arctic sea ice indicates a warmer Arctic Ocean.
Ben Holt: So the more you’re heating the ocean, the more it will propagate into potentially further ice reductions, eventually leading to strong shifts in the heat balance of the polar oceans and the rest of the global climate.
The study showing that older, thicker Arctic ice is giving way to younger, thinner ice was conducted by James Maslanik and colleagues at University of Colorado, Boulder. That study indicates that the older, thicker ice is effectively melting away the Arctic Ocean’s hedge against complete summer meltdowns, according to Maslanik. These scientists said this thinning is consistent with long-term warming in the Arctic.
Thanks today to NASA, in celebration of the International Polar Year.
Our thanks to:
Benjamin Holt
Research Oceanographer
NASA Jet Propulsion Lab
Pasadena, CA, USA
20 year average? I thought yuo scientists believed the Earth was billions of years old. And you base this on 20 years.
Check out this article: http://www.nationalpost.com/opinion/columnists/story.html?id=332289
In part, it states: The ice we were told so hysterically last fall had melted to its “lowest levels on record” is back. Those records only date back as far as 1972 and that there is anthropological and geological evidence of much greater melts in the past. Gilles Langis, a senior forecaster with the Canadian Ice Service in Ottawa, says the Arctic winter has been so severe the ice has not only recovered, it is actually 10 to 20 cm thicker in many places than at this time last year.
According to Robert Toggweiler of the Geophysical Fluid Dynamics Laboratory at Princeton University and Joellen Russell, assistant professor of biogeochemical dynamics at the University of Arizona — two prominent climate modellers — the computer models that show polar ice-melt cooling the oceans, stopping the circulation of warm equatorial water to northern latitudes and triggering another Ice Age (a la the movie The Day After Tomorrow) are all wrong.
“We missed what was right in front of our eyes,” says Prof. Russell. It’s not ice melt but rather wind circulation that drives ocean currents northward from the tropics. Climate models until now have not properly accounted for the wind’s effects on ocean circulation, so researchers have compensated by over-emphasizing the role of manmade warming on polar ice melt.
But when Profs. Toggweiler and Russell rejigged their model to include the 40-year cycle of winds away from the equator (then back towards it again), the role of ocean currents bringing warm southern waters to the north was obvious in the current Arctic warming.
So it’s not the anthropogenic CO2, but normal 40-yr fluctuations in equitorial currents. Whatta ya know? Natural cycles again! Just like the sun.
The famed Northwest passage has been open two or three times in the last hundred or so years. Once in 1905, before the evil SUV could have been responsible.
As Bruce says, the ice is back. With a vengence. The radical environmental movement is the modern home of collectivism. If we will just give up capitalism (and our lifestyle) they will save us. It is pure poppycock.
The earth is old and we are small. We might find a way to erase humanity, but we won’t stop life. What is ironic, is that amid all the fear and screaming about how we have destroyed the environment and we are going to die, we are living longer with better health that at any time in history. Don’t make sense, does it?
Great news!!!!!: The ice in the arctic this year is 500,00 km sq greater than last year. And last year was 500,000 km sq than 2007!! The sky is not falling!!