Ocean acidification
Ocean acidification is the other planetary catastrophe in the making caused by fossil fuel carbon dioxide emissions. Just like the atmospheric carbon dioxide concentration cannot totally stabilize without zero carbon emissions, the acid concentration oceans (from carbon dioxide in the air absorbed into the ocean surface water) cannot stop increasing unless industrial carbon dioxide emissions are stopped.

Despite all the attention given to atmospheric carbon dioxide emissions causing global warming and climate change until report that was issued by the Royal society in 2005, little attention has been given to ocean acidification.

Only absolute zero carbon emissions can allow ocean acidification to stop which means it will take virtual zero carbon emissions supplemented by negative emissions for the capacity to extract carbon dioxide direct from the air. The reason is for ocean acidification to stop as much carbon dioxide must diffuse out of the ocean surface water as is absorbed into the water.
 
​    ONLY ZERO CARBON ONLY ZERO CARBON ONLY ZERO CARBON ONLY ZERO CARBON ONLY ZERO CARBON ONLY ZERO