Regularly the claim is made that, we may be adding carbon to the atmosphere but we are not changing the number by to great a degree. Well that excuse is now also gone – we have increased carbon emissions by 50%. This means that the planet is entering a condition that it has not been in for millions of years – far before humans arrived.
Why does this matter? There was life back at this time, wasn’t there? Well of course there was. However, last time the carbon dioxide concentration levels were this high, average temperatures were 2-3 degrees higher and sea levels were 15-25m above where they are now. Nowadays 634 million people live 10m above the sea level or less, approximately 10% of the human population – other studies put this number as high as 1 billion. The paper Nature communications 267 million people live on land 2m above sea level or less. Nearly 2 billion live at 100m height or less.
It is reasonable to suppose that perhaps 1 billion would be heavily effected by sea levels rising 25m- needing to move to other countries rapidly. Furthermore places like the UK would get a lot smaller and become more of an archipelago.
Last year there were less than 300 million migrants worldwide, and yet there is a great deal of worry about this. What would it be like if 1 billion people had to emigrate over a relatively short period of time – and this would be permanent – there would be no chance of these people every returning home.
This fails to take account of the fact that there would likely also be a similar number of people who would have to move from parts of the planet which are too hot to support human life any more.
Cutting carbon emissions very fast is now essential, but it is not enough. We also need to be removing billions of tonnes of carbon from the atmosphere.