Seemorerocks: Sam Carana on the disppearance of thick, multi-year ice in the Arctic

The once-thickest Arctic sea ice has gone

24 August, 2018

The image below shows Arctic sea ice north of Greenland and around Ellesmere Island. This is the area where for thousands of years the sea ice has been the thickest, in many places remaining thicker than 5 meters (16.4 ft) throughout the year.

[ The once-thickest sea ice has gone ]

The image is a compilation of NASA Worldview images over seven days, from August 14 through to August 21, 2018. The least cloudy areas have been selected from each image to get the best insight in the magnitude of this catastrophe.

The loss of this sea ice indicates that the buffer is gone. Sea ice acts as a buffer that absorbs heat, while keeping the temperature at the freezing point of water, about zero degrees Celsius. As long as there is sea ice in the water, this sea ice will keep absorbing heat, so the temperature doesn't rise at the sea surface.

Once the buffer is gone, further energy that enters the Arctic Ocean will go into heating up the water. The amount of energy absorbed by melting ice is as much as it takes to heat an equivalent mass of water from zero to 80°C.

[ The Latent Heat Buffer has gone, feedback #14 on the Feedbacks page ]

At the same time, decline of the snow and ice cover in the Arctic causes more sunlight to get reflected back into space, resulting in more energy getting absorbed in the Arctic Ocean.

[ Albedo Change, feedback #1 on the Feedbacks page ]

Numerous feedbacks are associated with sea ice loss. As the temperature difference between the Arctic and the Equator decreases, changes are taking pace to the Jet Stream that in turn trigger a multitude of further feedbacks, such as more extreme weather and a more scope for heat to enter the Arctic Ocean (see feedbacks page).

A further huge danger is that, as warming of the Arctic Ocean continues, heat will reach methane hydrates at the seafloor of the Arctic Ocean, causing them to get destabilized and release methane.

[ Seafloor methane, feedback #2 on the Feedbacks page ]

Adding up all warming elements associated with disappearance of the sea ice could result in additional global warming many times as much as the current global warming, all in a few years time.

Meanwhile, for the first time in human history, mean global methane levels as high as 1900 ppb have been recorded. The measurements were recorded by the MetOp-1 satellite on the morning of August 22, 2018, at 280 mb, 266 mb, 307 mb and 321 mb, as shown by the images below.