Arctic Ice Meltdown Continues With Significantly Reduced Winter Ice Cover

[Luke_Wilbur]

As far as temperatures drop in the Arctic winter – on average to -34°C (-29°F) – a new study shows that in the last two years sea ice is shrinking on the surface of Arctic waters to record low levels. Using satellite data, scientists have observed unusually warm wintertime temperatures in the region and a resulting decline in the length of the Arctic seasonal ice.

 

The maximum amount of sea ice in the Arctic winter has fallen by six percent over each of the last two winters, as compared to a loss of merely 1.5 percent per decade on average annually since the earliest satellite monitoring in 1979. This is happening as summer sea ice continues its retreat at an average of ten percent per decade.

 

"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.

 

Sea ice cover in the Northern Hemisphere spans nearly 6.2 million square miles in the winter. Satellite sensors are the only means to observe such a large region effectively. Comiso confirmed the accuracy of satellite sea ice data by comparing it with high-resolution satellite information and data gathered from sensitive instruments aboard aircraft. Surface temperature data from satellite sensors are checked against measurements from meteorological stations in the region.

 

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.

 

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."

 

In addition to climate warming, other factors can contribute to the observed retreat of winter sea ice. Hard blowing winds can compact ice, causing it to contract, making it thicker, but covering a smaller area. Wind direction may blow ice toward warmer waters, causing it to melt. Other processes can also affect sea ice, by way of warmer oceans to the south spinning up cyclones that will introduce warmer temperatures than normal that melt ice.

 

"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.

[Guest Stephanie Renfrow]

2007 Arctic Sea Ice Shatters All Previous Record Lows

 

Arctic sea ice during the 2007 melt season plummeted to the lowest levels since satellite measurements began in 1979. The average sea ice extent for the month of September was 4.28 million square kilometers (1.65 million square miles), the lowest September on record, shattering the previous record for the month, set in 2005, by 23 percent (see Figure 1). At the end of the melt season, September 2007 sea ice was 39 percent below the long-term average from 1979 to 2000. If ship and aircraft records from before the satellite era are taken into account, sea ice may have fallen by as much as 50 percent from the 1950s. The September rate of sea ice decline since 1979 is now approximately 10 percent per decade, or 72,000 square kilometers (28,000 square miles) per year.

 

Arctic sea ice has long been recognized as a sensitive climate indicator. NSIDC Senior Scientist Mark Serreze said, “Computer projections have consistently shown that as global temperatures rise, the sea ice cover will begin to shrink. While a number of natural factors have certainly contributed to the overall decline in sea ice, the effects of greenhouse warming are now coming through loud and clear.

 

One factor that contributed to this fall's extreme decline was that the ice was entering the melt season in an already weakened state. NSIDC Research Scientist Julienne Stroeve said, "The spring of 2007 started out with less ice than normal, as well as thinner ice. Thinner ice takes less energy to melt than thicker ice, so the stage was set for low levels of sea ice this summer.

 

Another factor that conspired to accelerate the ice loss this summer was an unusual atmospheric pattern, with persistent high atmospheric pressures over the central Arctic Ocean and lower pressures over Siberia. The scientists noted that skies were fairly clear under the high-pressure cell, promoting strong melt. At the same time, the pattern of winds pumped warm air into the region. While the warm winds fostered further melt, they also helped push ice away from the Siberian shore. NSIDC Research Scientist Walt Meier said, "While the decline of the ice started out fairly slowly in spring and early summer, it accelerated rapidly in July. By mid-August, we had already shattered all previous records for ice extent."

 

Arctic sea ice receded so much that the fabled Northwest Passage completely opened for the first time in human memory. Explorers and other seafarers had long recognized that this passage, through the straits of the Canadian Arctic Archipelago, represented a potential shortcut from the Pacific to the Atlantic. Roald Amundsen began the first successful navigation of the route starting in 1903. It took his group two-and-a-half years to leapfrog through narrow passages of open water, with their ship locked in the frozen ice through two cold, dark winters. More recently, icebreakers and ice-strengthened ships have on occasion traversed the normally ice-choked route. However, by the end of the 2007 melt season, a standard ocean-going vessel could have sailed smoothly through. On the other hand, the Northern Sea Route, a shortcut along the Eurasian coast that is often at least partially open, was completely blocked by a band of ice this year.

 

In addition to the record-breaking retreat of sea ice, NSIDC scientists also noted that the date of the lowest sea ice extent, or the absolute minimum, has shifted to later in the year. This year, the five-day running minimum occurred on September 16, 2007; from 1979 to 2000, the minimum usually occurred on September 12. NSIDC Senior Scientist Ted Scambos said, "What we've seen this year fits the profile of lengthening melt seasons, which is no surprise. As the system warms up, spring melt will tend to come earlier and autumn freezing will begin later."

 

Changes in sea ice extent, timing, ice thickness, and seasonal fluctuations are already having an impact on the people, plants, and animals that live in the Arctic. NSIDC Research Scientist and Arctic resident Shari Gearheard said, Local people who live in the region are noticing the changes in sea ice. The earlier break up and later freeze up affect when and where people can go hunting, as well as safety for travel.

 

NSIDC scientists monitor and study Arctic sea ice year round, analyzing satellite data and seeking to understand the regional changes and complex feedbacks that we are seeing. Serreze said, The sea ice cover is in a downward spiral and may have passed the point of no return. As the years go by, we are losing more and more ice in summer, and growing back less and less ice in winter. We may well see an ice-free Arctic Ocean in summer within our lifetimes.” The scientists agree that this could occur by 2030. Serreze concluded, The implications for global climate, as well as Arctic animals and people, are disturbing."

[Guest human_*]

Okay! How long will it take if we stop polluting the atmosphere for the arctic shelf to recover?

 

Will it take decades, centuries for the pollutants to dissipate in our atmosphere, Before we can even BEGIN to see a reversal?

[Luke_Wilbur]

No one really knows how to reverse the situation yet. Just like researching a cure for cancer it takes time and money. Right now we need to find a solution to slow down the process first. There has been talk about putting iron in the ocean. But, it may kill the local plant and wild life. People are also planting trees. We need to get away from Fossil fuels. First the Poor countries will feel it. Then refugees will hit their neighbors resources to compound the problem. The chain will grow. Everyone who has money needs to donate their time or money to slow this down. This is about our survival.

 

Men are from Earth, women are from Earth. Deal with it. - George Carlin

[Soldier of God]

No one really knows how to reverse the situation yet. Just like researching a cure for cancer it takes time and money. Right now we need to find a solution to slow down the process first. There has been talk about putting iron in the ocean. But, it may kill the local plant and wild life. People are also planting trees. We need to get away from Fossil fuels. First the Poor countries will feel it. Then refugees will hit their neighbors resources to compound the problem. The chain will grow. Everyone who has money needs to donate their time or money to slow this down. This is about our survival.

 

God knows the answer.

[Guest Ice Age]

Snow cover over North America and much of Siberia, Mongolia and China is greater than at any time since 1966. The U.S. National Climatic Data Center (NCDC) reported that many American cities and towns suffered record cold temperatures in January and early February. According to the NCDC, the average temperature in January "was -0.3 F cooler than the 1901-2000 (20th century) average." China is surviving its most brutal winter in a century. Temperatures in the normally balmy south were so low for so long that some middle-sized cities went days and even weeks without electricity because once power lines had toppled it was too cold or too icy to repair them. And remember the Arctic Sea ice? The ice we were told so hysterically last fall had melted to its "lowest levels on record? Never mind that those records only date back as far as 1972 and that there is anthropological and geological evidence of much greater melts in the past. The ice is back. 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.

[Guest Ms Carine Richard-Van Maele]

The current La Niña event, characterized by a cooling of the sea surface in the central and eastern Equatorial Pacific, has strengthened slightly in recent months and is expected to continue through the first quarter of 2008, with a likelihood of persisting through to the middle of the year.

 

The ongoing La Niña event started in the third quarter of 2007 and has already influenced climate patterns during the last six months across many parts of the globe, including in the Equatorial Pacific, across the Indian Ocean, Asia, Africa and the Americas.

 

During the last three months, La Niña conditions have become slightly stronger. Sea surface temperatures are now about 1.5 to 2 degrees Celsius colder than average over large parts of the central and eastern Equatorial Pacific. This La Niña is in the mid range of past historically recorded events, but the slight further cooling in recent months will likely place it on the stronger side of the middle range.

 

During a La Niña event, sea surface temperatures in the central and eastern Equatorial Pacific become cooler than normal. Such cooling has important effects on the global weather, particularly rainfall. While sea surface temperatures cool in the central and eastern Equatorial Pacific, those in the west remain warmer. This is associated with increases in the frequency of heavy rain and thunderstorms in surrounding regions.

 

It is rare for a La Niña event to persist for two years or more, such as occurred from early 1998 to early 2000. The likelihood of the current La Niña continuing for such a period will remain unclear for some months, but will be closely monitored. Long-term statistics suggest it is more likely that in the latter part of 2008, neutral conditions will prevail, i.e., neither La Niña nor El Niño with no significant cooling or warming of Equatorial Pacific sea surface temperatures.

[Guest Henry K]

Earth is losing its atmosphere. During the rein of the dinosaurs the atmospheric pressure was around 30 pounds per square inch. Now it is down to 14.5 pounds per square inch.