Hansen and Sato 2001
, and , 2001: Trends of measured climate forcing agents. Proc. Natl. Acad. Sci., 98, 14778-14783, doi:10.1073/pnas.261553698.
The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/m2 per century. This growth rate has since declined to ~3 W/m2 per century, largely because of cooperative international actions. We argue that trends can be reduced to the level needed for the moderate "alternative" climate scenario (~2 W/m2 per century for the next 50 years) by means of concerted actions that have other benefits, but the forcing reductions are not automatic "co-benefits" of actions that slow CO2 emissions. Current trends of climate forcings by aerosols remain very uncertain. Nevertheless, practical constraints on changes in emission levels suggest that global warming at a rate +0.15±0.05°C per decade will occur over the next several decades.