The image below shows sea surface temperature anomalies over the Arctic on July 27, 2015.
|[ departure from 1961-1990 temperatures, click on image to enlarge ]|
|[ 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.