Guest post: As the world warms
Originally a comment by John Wasson on Chiseling away.
Loss of glaciers and sea ice means less sunlight is reflected.
As glaciers grind over ground they free up mercury in rocks and 42 tonnes may be released from south-west Greenland ice sheet. Nature Geoscience, DOI: 10.1038/s4a561-021-99753-w
New Scientist May 29 2021 p. 21
As the world warms and the Greenland ice sheet melts, its fresh cold water is expected to slow down a dominant conveyor belt of ocean currents: the Atlantic Meridional Overturning Circulation (AMOC). An AMOC collapse would leave an excess of heat in the tropical South Atlantic, which would trigger a series of air-pressure changes that ultimately strengthen the Pacific trade winds.
The good news is that Greenland will somewhat rebound with the loss of weight of the glacier which would decrease the increase in sea level.
“There’s a plan to save Greenland glacier” (New Scientist, Oct. 29 2022, p. 8) by constructing a physical barrier of heavy, premade concrete foundations to slow the ingress of relatively warm water at the base of the glacier which would take 30 years to complete and do nothing to slow surface melting by warmer atmosphere. Geoengineering on this scale is unlikely to materialise any time soon. A green revolution for the necessary reduction in fossil fuel use must continue. (Poul Christoff, U of Cambridge).
The atmosphere-biosphere-hydrosphere-lithosphere assemblage is the most complex internally-interacting system we know about; in the entire Universe. Though I am not a great fan of Gaia theory, I nonetheless incline to the view that the system is self-correcting, and if thrown into imbalance adjusts over whatever period of time to a new stable state.
Though I am also not a climatologist, the most likely response to anthropogenic global warming I can think of involves increased oceanic evaporation, resulting in increased cloud cover, which can only serve to block incoming solar radiation, thus working to restore the stabiity of the whole system. With runaway global warming being touted by serious climatologists as a possibility, this would drive the Earth towards the condition of Venus, with reduced solar radiation reaching the surfaces of land and sea. It would also possibly involve increased frequency and severity of storms and heavy cloud cover impeding the work of astronomers. Who knows?