The Antarctic Half of the Global Thermohaline Circulation Is Collapsing

The Nimbus 5 satellite made the surprising discovery of a large hole of fresh water in the sea ice near the Antarctic coast in the Weddell sea in 1974.  That hole reappeared each winter until 1976 then was never seen again.

This research study used the most advanced climate models and extensive reanalysis of oceanic and atmospheric data from the Antarctic to understand how the Weddell sea polynya worked and what caused it to fail.  The researchers discovered that the polynya was not a rare event when pre-industrial conditions were input into the models.  However, when models were run under present and future conditions affected by increasing levels of greenhouse gases from human activities, the surface water freshened, and the ocean stratified.  They found that anthropogenic global warming causes increasing precipitation and glacial melting, which puts a fresh water lid over the Weddell Sea, preventing Antarctic Bottom Water formation.

The IPCC's models have not considered the effects the collapsing production of Antarctic Bottom Water and political policy has not kept up with the IPCC.  We are moving rapidly into uncharted waters as the Arctic melts.  Global political policies are not keeping up with the rate of change and our models have, to date, underestimated the rate of change.  We are witnessing a total failure of global leadership to deal with changes we caused that are spiraling out of control.

The Antarctic Half of the Global Thermohaline Circulation Is Collapsing