Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):14778-83. doi: 10.1073/pnas.261553698.
Proceedings of the National Academy of Sciences of the United States of America
J E Hansen, M Sato
PMID: 11752424 PMCID: PMC64935 DOI: 10.1073/pnas.261553698
The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/m(2) per century. This growth rate has since declined to approximately 3 W/m(2) 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 ( approximately 2 W/m(2) 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 CO(2) 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 degrees C per decade will occur over the next several decades.
