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| [ departure from 1961-1990 temperatures, click on image to enlarge ] |
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| [ departure from 1971-2000 temperatures, click on image to enlarge ] |
There is a growing chance that the sea ice will collapse over the next few weeks, due to heavy melting and storms speeding up the flow of sea ice out of the Arctic Ocean into the Atlantic Ocean.
An example of such storms is shown on the animation below. This is a forecast for July 31, 2015, showing cyclonic winds at the center of the Arctic Ocean, with strong winds moving sea ice down Fram Strait.
The above situation alone is not likely to trigger sea ice collapse. It is more likely to be short-lived. However, there is a growing possibility for such storms to emerge and drive the melting sea ice out of the Arctic Ocean into the Atlantic Ocean.
As the situation in the Arctic further deteriorates, feedbacks can be expected to kick in with growing strength.
One of these feedbacks is the growing amount of heat (due to both latent heat and albedo changes) that will have to be absorbed by the Arctic Ocean as the sea ice disappears, and that will accelerate warming of the water of the Arctic Ocean.
Another feedback is a changing jet stream, as illustrated in above animation. This, in combination with the presence of more open water, can be expected to cause increasingly intense storms over the Arctic to emerge. Such storms can bring more heat into the Arctic Ocean, especially during heatwaves over North America and Russia. Such heatwaves can further cause surface heat to be mixed down to the seafloor, especially in the many places where the Arctic Ocean is very shallow. This can in turn cause destabilization of hydrates, resulting in huge amounts of methane to be abruptly released from the seafloor.
Methane itself is yet another feedback that will accelerate warming in the Arctic, in turn threatening to trigger further methane releases in a spiral of self-reinforcing positive feedback loops.
The situation is dire and calls for comprehensive and effective action as discussed at the Climate Plan.
Sea surface temperatures over the Arctic on July 27, 2015. There is a growing chance that the sea ice will collapse over...
Posted by Sam Carana on Tuesday, July 28, 2015
Does anyone know the estimate time in which the methane chimneys will start to shoot out into the world atmosphere, because it sounds to me from reading this that it could happen as early as next year.
ReplyDeleteI am under the impression that clathrates on the Arctic ocean seabed have been releasing methane constantly since 2007. Rates of release and areas affected have also increased dramatically. I think that CO2 has done its job. It has caused the Arctic to melt and from now on, methane will be the major cause of runaway warming. It wouldn't matter now if the world stopped using fossil fuels tomorrow - the furnace is already lit.
ReplyDeleteJim Hansen estimates sea level rise of around five metres by 2100. Ice sheets will float off their sea beds and be blown into warmer climes as the ice sheets behind them accelerate towards the ocean.
ReplyDeleteExpanding sea ice adjacent to East Antarctica, a result of fresh melt water, masks a warmer strata that is rapidly undermining the Antartic ice sheets.
Its all a bit concerning....
I think James Hansen is downplaying the dire situation we're in and fails to point at the comprehensive and effective action that needs to be taken in response.
DeleteThank you, Steve. And you're right-it is too late to stop the inevitable.
ReplyDelete"There is a growing chance that the sea ice will collapse over the next few weeks, due to heavy melting and storms speeding up the flow of sea ice out of the Arctic Ocean into the Atlantic Ocean."
ReplyDelete^ How much sea ice will collapse? It won't be a blue ocean event will it?
The Arctic sea ice is extremely fractured and winds would separate the ice pack making it more vulnerable. Warm air is also entering the region due to the El Niño in the Pacific.
DeleteThere may well be the first blue ocean event of the modern era. Huge climatic changes in the northern hemisphere are imminent - but it's impossible to know how any specific locale will be affected.
Another feed back involves Coriolis. As long as the Beaufort gyre, powered by clockwise air circulation over the Arctic continues, fresher water from melting ice and from streams flowing into the Arctic ocean will continue to be trapped within the gyre. This is because, in the northern hemisphere moving objects are veered toward the right and in a clockwise rotating system, to the right is into the middle. Once storms over the Arctic are frequent enough and strong enough, powered by the combination of air heated from the bottom from an ever warmer ocean and cool air over the surrounding land (especially in the fall) causing a strong pressure gradient, the Beaufort gyre will reverse and flow counter clockwise. In a counter clockwise rotating system in the Northern Hemisphere, to the right is away from the centre. This should expel more and more fresh water (and floating ice) through the Fram Straight as it is caught by the trans polar current. Below this approximately 200m deep layer of fresher water is saltier, warm water from the Atlantic. Once this comes up to the surface, more ice melt is inevitable. Interestingly, if a large gout of fresh water is expelled into the North Atlantic, this could greatly weaken the gulf stream and give Western Europe a very cold winter or two. Once some of the fresher water layer is removed, internal waves caused by these storms can mix the layers much more easily, especially when they break as they reach the continental shelf. This will bring more calories to the surface to continue the melt. Then as clathrates break down and stop holding the sediment together, tremors can cause under sea land slides which are famous for producing localized but very severe tsunamis. Not a pretty prospect if you live on the shores of the Arctic Ocean.
ReplyDeleteExcellent comment, William, thanks for sharing.
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