Party like the Paleoproterozoic

The Paleoproterozoic was an interesting time. Oxygen finally settled into the atmosphere on a permanent basis, most of the iron formations we use to make cars, bridges, skyscrapers etc. were formed, and the removal of methane from the atmosphere cooled the surface until everything froze, creating a condition known as the “snowball Earth”.

Similar conditions may have reoccurred again in the Neoproterozoic, but since then, the tropics have tended towards being ice free. But will this last? A simple extrapolation says no.


Figure 1. linear extrapolation of the last three years of sea ice minima.

As you can see, sea ice has been increasing for the last three years, by about half a million km ^2 per year. With only 360 million km^2 of ocean on the planet, a continuation of this trend will freeze the entire ocean by the year 2724! We are all doomed.