Nature: Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0812721106 (2009) The warming, droughts and swollen seas caused by human-generated carbon dioxide are essentially irreversible, say scientists, and will not subside for at least 1,000 years even if emissions cease. It has long been known that a fraction of emitted CO2 lingers in the atmosphere and perpetuates the greenhouse effect for millennia after the bulk of emissions have been absorbed by the ocean. Now, researchers led by Susan …