The last time CO2 levels in the atmosphere were is high as they currently are was 3.3 million years ago. At this time not only were are temperatures 3 to 4 degrees higher that also sea levels where around 20m higher than they currently are.
To put this sea level rise in perspective, currently 10% of the world’s human population live 10 mm or less above sea level (around 650 million people). An estimated 47% of world residents live at 20m above sea level or less. The idea of almost half of the world’s population having a find new places to live in the space of a relatively short period of timewould destroy the world economy for years at a time.
It would have a dramatic impact on places like the UK and USA but there are many island states where this would essentially wipe them out completely.
However if we continue on our current trend then the predicted level of CO2 in the atmosphere by 2025 will take us back 15 million years.
Climate change mitigation detractors might suggest well if temperatures have been this high why do we need to worry about it happening again. The simple facts of the matter is that humans have not tried to live on earth where temperatures are this high or sea levels have gone off this much. the earth would not be capable of supporting as many humans and would not be able to support the freedoms we enjoy today. The coronavirus shut down cut CO2 emissions by about 5%, now while this is certainly temporary it shows what is possible when necessary. In theory we could shut all power plants and replace them with solar panels with huge batteries or other carbon neutral creation, as well as replacing all fossil fuel vehicles on the road – these two would have a huge impact.
Few countries are treating this as an emergency in the way that they are responding, but it is clear that with the will, we could save the planet.