Storms Over Arctic Ocean

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 ]

The image below shows sea surface temperature anomalies on July 28, 2015.

[ 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

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Another Heatwave Hits Arctic

As parts of Canada, Greenland and Russia are hit by -40 degrees temperatures (anomalies at the bottom end of the scale), parts of the Arctic are experiencing temperatures above freezing (anomalies at the top end of the scale), as illustrated by the image below.

[ click on image to enlarge ]

Temperatures in the Arctic are much higher than they used to be and this situation further accelerates warming in the Arctic, due to a number of feedbacks.

One such feedbacks has been coined the ‘open doors feedback’. Indeed, the situation is much like leaving the fridge door open. This allows cold air to more easily move out of the fridge, i.e. the Arctic, resulting in the cold temperatures over North America that have received extensive news coverage in the media. At the same time, warm air can move more easily into the fridge, i.e. the Arctic, and this is one of the reasons why the Arctic is hit by temperatures that are so much higher than what used to be normal.

The situation has been described in a number of earlier posts such as this one, as well in a recent interview with Jennifer Francis. As the Arctic warms more rapidly than the rest of the world, there's less temperature difference between the Arctic and the equator, resulting in the jet stream going around the globe at a lower speed with more elongated loops.

The left chart on above image shows such an elongated loop going north along the east coast of Greenland, then bending before Scandinavia and moving over the north of Greenland, then going around the North Pole and moving back to Scandinavia. This loop is not very visible on the chart, because the jet stream moves faster along straight tracks, and this chart highlights wind speed more than it highlights the path of the jet stream. Yet, the shape of this loop is very important, as it traps warmer air north of Greenland.

BTW, a weaker jet stream also elevates the chance of heat waves elsewhere, which can indirectly warm up the Arctic. Examples of this are heat waves over the Gulf Stream as it crosses the Atlantic Ocean, resulting in warmer water being carried into the Arctic Ocean, and heat waves over Siberia and North America, resulting in warming up of rivers that end in the Arctic Ocean.

Anyway, to get back to the current heatwave, there are a number of reasons why temperatures in the Arctic are so high at the moment. One of the biggest reasons is ocean heat, which has reached very high levels, especially in the North Atlantic, while the Gulf Stream keeps transporting warmer water from the North Atlantic into the Arctic Ocean (i.e. water that is warmer than the water in the Arctic Ocean). This warms up the seafloor of the Arctic Ocean, resulting in methane erupting from the seafloor, with a strong immediate local warming impact in the Arctic, thus further accelerating warming in the Arctic in another one of these self-reinforcing feedback loops, as pictured in the image below.

Further feedbacks that accelerate warming in the Arctic are discussed at the feedbacks page.

Without effective and comprehensive action, these feedbacks threaten to lead to runaway warming, i.e. abrupt climate change causing mass death and destruction, and resulting in extinction at massive scale, as depicted in the image below and as described in this earlier post.

In conclusion, the situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.

Post by Sam Carana.

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