Climate Central: Since the beginning of the Industrial Revolution to the end of the 20th century, humans put some 300 to 600 billion tons of carbon into the Earth's atmosphere from the emission of carbon dioxide and other greenhouse gases. About 200 billion tons of carbon has stayed in the atmosphere, warming it up by trapping heat -- the rest has been taken up by the oceans and ecosystems on land.
But exactly which systems are net sources of carbon and which are net sinks (which remove carbon from the atmosphere),...