A paper posted today by Proceedings of the National Academy of Sciences spells out human-induced climate changes that will be irreversible for as much as 1,000 years after greenhouse gas emissions stop. The findings are not notably new, but are sharper and more precise, and have extra weight especially because of the scientific prestige of the lead author, the atmospheric chemist Susan Solomon. Solomon is famous for elucidating the dynamics of the Antarctic ozone hole and was the leader of the IPCC''s most recent Working Group 1, which reported on the physical science basis of climate change.
''Following cessation of emissions,'' says the abstract of the PNAS paper, ''removal of carbon dioxide reduces radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop for at least 1,000 years.'' If atmospheric CO2 rises from 385 parts per million today to levels between 450 and 600 ppm in the coming century, as expected, we can expect to see ''irreversible dry season rain reductions in several regions comparable to the ''dust bowl'' era [in the United States] and inexorable sea level rise.''