New satellite images show polar ice coverage dwindling in extent and thickness
Sea ice in the Arctic is disappearing at a far greater rate than previously expected, according to data from the first purpose-built satellite launched to study the thickness of the Earth’s polar caps.
Preliminary results from the European Space Agency’s CryoSat-2 probe indicate that 900 cubic kilometres of summer sea ice has disappeared from the Arctic ocean over the past year.
This rate of loss is 50% higher than most scenarios outlined by polar scientists and suggests that global warming, triggered by rising greenhouse gas emissions, is beginning to have a major impact on the region. In a few years the Arctic ocean could be free of ice in summer, triggering a rush to exploit its fish stocks, oil, minerals and sea routes.
Using instruments on earlier satellites, scientists could see that the area covered by summer sea ice in the Arctic has been dwindling rapidly. But the new measurements indicate that this ice has been thinning dramatically at the same time. For example, in regions north of Canada and Greenland, where ice thickness regularly stayed at around five to six metres in summer a decade ago, levels have dropped to one to three metres.
“Preliminary analysis of our data indicates that the rate of loss of sea ice volume in summer in the Arctic may be far larger than we had previously suspected,” said Dr Seymour Laxon, of the Centre for Polar Observation and Modelling at University College London (UCL), where CryoSat-2 data is being analysed. “Very soon we may experience the iconic moment when, one day in the summer, we look at satellite images and see no sea ice coverage in the Arctic, just open water.”
Their data suggest that summer ice could be lost entirely in about a decade. This is not too far from the models produced by PIOMAS at the Polar Science Center, which have enough data to see real trends. It found current summer sea ice volumes 55% lower than the average.
Because they have trend data they can produce this figure:
It is likely that if current trends continue, the Arctic will be free of sea ice in September by 2015, in August and October by 2016, in July and November by 2018 and in June by 2020. Ice free for six month of the year in just 8 years.
Not just the NW passage but the entire Arctic.
Several other simulations show slightly different results but we now have two different systems which indicate that the Arctic will be ice free very soon.
This is bad because ice-free waters push a positive feedback – water absorbs more heat than ice and reflect less back. So the more ice melts, alllowing water the absorb more heat, the less ice there will be. This means more water to heat up and even less ice.
As more and more of the Arctic now heats up, methane, normally trapped in the cold waters and beneath the tundra, will begin to be released. In greater amounts. Methane is even a greater greenhouse gas than carbon dioxide.
The release of the Arctic methane could result in a new climate, one antithetical to human life. The greatest extinction event in the Earth’s history followed a large, geologically rapid release of methane.
One of the scary things about the Permian-Triassic extinction is the disappearance of coal from degraded plants. Coal does not reappear in the rocks for 10 million years. This suggests that most plants disappeared.
We know that many animals died as did much of the life in the ocean.
Could it happen again?