Quick thread on why it takes so long to get rid of carbon dioxide in our atmosphere.
Motivated by @hausfath's thread
Motivated by @hausfath's thread
There are multiple time scales on which CO2 is removed from the atmosphere. If you add a slug to the atmosphere, the first 50% is removed in 50 years, the next half (taking you down to 25% takes about 500 years, the next half (taking you down to 12.5%) takes 10,000+ years. 
The decadal time scale is due to transport to land-biosphere & mixed-layer ocean, the century time scale is due to the slower process of transport to the deep ocean, and the very long time scales are the conversion of ocean carbonate to rocks.
It takes 100,000 years to remove all of the carbon added to the atmosphere.
The key point is that the carbon you emit driving to the story today will stay in the atmosphere for 100,000 years and will be warming the climate for that entire time.
The key point is that the carbon you emit driving to the story today will stay in the atmosphere for 100,000 years and will be warming the climate for that entire time.
That's one of the key reasons that the decision we make today and in the next decade or two will decide the fate of the climate for thousands of years.
For more, this is a really sobering paper: nature.com/articles/nclim…
For more, this is a really sobering paper: nature.com/articles/nclim…
If we choose unwisely, I can imagine people in the year 2500, 3000, 4000, or 5000 being justifiably furious at us. We know what we're doing to them, but we really don't care.
