It's not just about coral reefs, oysters, and salmon anymore.
The oceans are now acidifying 10 times faster today than 55 million years ago when a mass extinction of marine species occurred. We are risking a marine biological meltdown “by end of century.”
But unrestricted carbon pollution doesn’t merely threaten to wipe out coral reefs, oysters, salmon, and other ocean species we rely on. Researchers find “Global warming amplified by reduced sulphur fluxes as a result of ocean acidification,” in a new Nature Climate Change study (subs. req’d).
As an accompanying news article in Nature explains:
"Atmospheric sulphur, most of which comes from the sea, is a check against global warming. Phytoplankton — photosynthetic microbes that drift in sunlit water — produces a compound called dimethylsulphide (DMS). Some of this enters the atmosphere and reacts to make sulphuric acid, which clumps into aerosols, or microscopic airborne particles. Aerosols seed the formation of clouds, which help cool the Earth by reflecting sunlight….
How much extra warming may occur because of ocean acidification? The study, led by scientists at the Max Planck Institute for Meteorology, concludes:
The reduced DMS emissions induce a significant additional radiative forcing, of which 83% is attributed to the impact of ocean acidification, tantamount to an equilibrium temperature response between 0.23 and 0.48 K. Our results indicate that ocean acidification has the potential to exacerbate anthropogenic warming through a mechanism that is not considered at present in projections of future climate change.
So we have up to 0.9°F warming from acidification this century that isn’t in the IPCC’s Fifth Assessment Report models. You can add that to the carbon feedback from the thawing permafrost — also unmodeled by the new IPCC report — which is projected to add up to 1.5°F to total global warming by 2100.