According to the Royal Society.......
If human emissions of CO2 stopped altogether, it would take thousands of years for atmospheric CO2 to return to ‘pre-industrial’ levels.
Why is that?
It takes a long time for deep oceans to bury the carbon dioxide in ocean sediments.
Lifee on the abyssal sea floor (depths ranging from 4000-6000 m) near the Hudson Canyon off the coast of New Jersey. Photo taken using the Deep Submersible Research Vessel (DSRV) Alvin'scamera system. Image courtesy of Deep East 2001, NOAA/OER.
Surface temperatures would stay high for at least a thousand years.
Humans would face a warmer planet due to past and current emissions.
Ice would still be melting from places like Antarctica and Greenland.
So sea level would continue to rise for many centuries, even after temperature stopped increasing.
The current warming of the Earth can't be reversed on a human timescale.
But if fossil fuels are not phased out soon, the situation will be far worse.
The amount and rate of further warming will depend almost entirely on how much more CO2 humankind continues to emit.