People once again propose geoengineering to reflect sunlight into space as a way to counteract global heating.

However, ocean acidification would continue unabated, with the effect of eventually wiping out all coral, and all molluscs with shells. Many species of sea animals depend on coral reefs, and they would be wiped out too. The food supply for a billion people would be lost, just as plants are producing less protein due to the higher CO2 levels.