By David L. Brown
We have written before about the observed shrinking of the Arctic ice cap, and Star Phoenix Base has contended that the rate of disappearance is accelerating and threatens to become a runaway meltdown. Our reasoning for this pessimistic position is based on several factors. First, temperatures in the Arctic are rising faster than in temperate or tropical regions. In Alaska, for example, average temperatures already have risen by as much as seven degrees F. In the far north of Canada, Alaska, and Siberia, permafrost is melting and thus lending irony to its name, since it is no longer “perma.” That melting is releasing greenhouse gases long sequestered in the frozen bogs, adding impetus to the warming trend.
Furthermore, studies of the Arctic ice cap over the last few decades have pointed toward an increasing trend of melting. As more open water is exposed to the summer sun, the heating effect of insolation warm the dark water and the surrounding land and air to a much greater degree than when ice and snow are present to reflect the solar rays back into space.
Now there is evidence that our speculations were spot on, as the British say. According to the National Aeronautical and Space Administration, the wintertime extent of Arctic ice has decreased by six percent in each of the last two years. That compares with a previously observed rate of decrease of only 1.5 percent per decade, or a mere 0.15 percent per year. It is based on those previous rates that scientists as recently as one year ago were predicting that the Arctic ice cap would not completely disappear for about 100 years.
I analyzed the situation in October, 2005 and made the prediction in private correspondence that it would happen much faster, perhaps in as little as ten years. I later published some of this analysis on this weblog. Some earlier postings on this subject can be found in this site’s archives, particularly the articles “Bad News for Polar Bears — The Big Thaw,” and “Catastrophic Loss of Arctic Ice in Store.” You can find these and other articles by using the keyword search function on the sidebar.
Here are details on the latest results of satellite studies, as reported on the NASA web site (read it here):
“This amount of Arctic sea ice reduction the past two consecutive winters has not taken place before during the 27 years satellite data has been available,” said Joey Comiso, a research scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. “In the past, sea ice reduction in winter was significantly lower per decade compared to summer sea ice retreat. What’s remarkable is that we’ve witnessed sea ice reduction at six percent per year over just the last two winters, most likely a result of warming due to greenhouse gases.”
Comiso used satellite data from 1978 to 2006 to carry out the study, to be published in Geophysical Research Letters this month.
Computer simulations of the climate warming effect of greenhouse gases had predicted that winter sea ice would decline faster than summer sea ice. Satellite data has shown otherwise until two years ago, when record low winter ice cover and warmer temperatures have prevailed.
NASA confirms that the feedback effect from ice thinning and retreat will only accelerate the melting:
Adding to the plight of winter sea ice, previous research has shown a trend in which the melt period lasts about two weeks longer per year annually due to summer sea ice decline. This means that the onset of freeze-up is happening later in the fall season. As a result, the ice cover in winter never gets as extensive as it would have been if the freeze-up had begun earlier. More than that, the ice reflects the sun’s radiation much more efficiently than the ocean’s surface. As a result, as the ice cover declines, the ocean’s surface warms, causing in turn, further decline of the ice.
The continued melting of the Arctic ice, exposing the Arctic Ocean to the full force of the summer Sun, could have serious environmental effects, the NASA report says:
According to Comiso, if the winter ice retreat continues, the effect could be very profound, especially for marine animals. “The seasonal ice regions in the Arctic are among the most biologically productive regions in the world,” he said. “Some of the richest fisheries are found in the region, in part because of sea ice. Sea ice provides melt-water in spring that floats because of low density. This melt-water layer is considered by biologists as the ideal layer for phytoplankton growth because it does not sink, and there is plenty of sunlight reaching it to enable photosynthesis. Plankton are at the bottom of the food web. If their concentration goes down, animals at all tropics level would be deprived of a basic source of food.” …
“A continued reduction of the Arctic winter ice cover would be a clear indicator of the warming effect of increasing greenhouse gases in the atmosphere. It would at least confirm our current understanding of the physics of the Arctic climate system that has been incorporated in our models,” said Comiso.
This new information is ominous indeed, and confirms my earlier suspicions that Arctic thawing would proceed faster than previously believed. A feedback effect is no doubt in full swing, and a tipping point may have been reached after which the rate of acceleration will continue to increase.
From a rate of decrease in winter ice cover of only 1.5 percent per decade to a rate of 6 percent per year (and sustained for two years) indicates a ferocious acceleration. From 0.15 percent per year to 6 percent per year is an increase of 40 times. In other words, the rate of decreased ice cover observed prior to 2005 would have taken 40 years to yield the same reduction that was observed in each of the past two summers. That means that the maximum ice cover has shrunk in just the past two winters by an amount that would have been expected to have taken 80 years based on the previously observed rate of change.
Should the winter ice cover continue to shrink at even a fraction of that rate, the Arctic ice cap would soon be disappearing like an ice cube on a hot sidewalk in July. I believe that we might see the Arctic Ocean completely ice free in summer within just a few years, with continued decline in winter ice formation as global warming continues to climb exponentially. When you are riding a roller coaster that is just beginning its steepest climb, there is little to be learned from looking backwards. That is a good analogy for where we stand today, as feedback effects and tipping points kick in and put climate change into overdrive.
The loss of the Arctic ice cover is only one of the many ominous signs of trouble in our planet’s environment. There is now clear evidence that these events can be explained in large part by the increase in greenhouse gas (GHG) in our atmosphere due to human activities. Carbon dioxide is the main culprit, but melting tundra, peat bogs, and frozen lakes in the Arctic are beginning to belch forth large quantities of methane, another GHG that is more than 20 times more potent than CO2. I wrote about this problem just a few days ago in the article entitled “The Time to Act on Carbon Emissions is NOW” (September 9).
That global warming is real and taking place now has been demonstrated almost beyond any shadow of a doubt, and the most disconcerting aspect of this is that the effects of climate change are bearing down on us like an avalanche. There is little time to act if we are to even hope to turn around what could be a total environmental disaster. There are many threats in the world today, but none can even begin to compare with the threat of climate change and the possible runaway warming that could end our civilization and even threaten all life on Earth.