|[ for earlier animations, see discussions ]|
Arctic sea ice is getting very thin rapidly, threatening the latent heat tipping point to get crossed soon.
The U.S. Navy animation on the right shows Arctic sea ice thickness (in m) for the 30 days up to July 31, 2021, with eight days of forecasts included.
|[ disappearing sea ice north of Greenland ]|
Disappearance of the buffer constituted by subsurface sea ice could be measured by a threshold of most sea ice becoming less than 0.5 meter thin. By that measure, the buffer is now virtually gone, implying that virtually no further heat arriving from the Atlantic Ocean and the Pacific Ocean in the Arctic Ocean can be absorbed in the process of melting of the sea ice.
The NASA Worldview image on the right shows the sea ice on July 29, 2021, north of Greenland, where once the thickest sea ice was located.
Albedo loss, latent heat loss, storms and changes to the jet stream can add up to dramatically amplify the temperature rise of the water in the Arctic Ocean, which comes with the danger of destabilization of hydrates at its seafloor, resulting in eruption of huge amounts of methane from hydrates and opening up pathways for release of even further amounts of free gas from underneath these hydrates, as illustrated by the image below.
And while the situation in 2021 is dire, the outlook for the years beyond 2021 is that things look set to get progressively worse.
According to James Hansen et al., the variation of solar irradiance from solar minimum to solar maximum is of the order of 0.25 W/m⁻².
So, the outlook is grim. The right thing to do now is to help avoid the worst things from happening, through immediate, comprehensive and effective action as described in the Climate Plan.
• National Institute of Polar Research (NIPR) in Japan
• The National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder
• Latent heat
• University of Bremen - sea ice
• Climate Plan