A figure with 4 radial bursts in the corners and a radial cloud in the middle with double headed arrows between the corners. The corners read Sci-Fi, Wishful Thinking Fantasy, and Facts and the cloud reads Models, Projection, Motivated Reasoning, Prediction, Delusion

The Big Picture

The World (and ocean) were not always full of Oxygen

Geological record for the Great Oxidation Event

Historic Anoxic Events and Mass Extinctions coincide

Climate change forces threaten ocean oxygenation and PH

This is more than just fertilizer induced dead zones

But the time scale is longer than simple climate catastrophe

Oxygen only gets in via surface mixing and photosynthesis

Photosynthesis only happens in a big way down to about 1-200 meters

Surface effects have an outsize influence

The surface is even more disproportionately effected by excess CO2 and heat

Mixing down to deeper strata takes thousands of years... until it *stops* circulating normally