Publication Abstracts

Hansen et al. 1993

Hansen, J., A. Lacis, R. Ruedy, M. Sato, and H. Wilson, 1993: How sensitive is the world's climate? Natl. Geog. Soc. Res. Exploration, 9, 142-158.

We estimate climate sensitivity from observed climate change on time scales ranging from the 100000-year periods of major ice ages to brief periods of cooling after major volcanic eruptions. The real-world data indicate that climate is very sensitive, equivalent to a warming of 3±1°C for doubled atmospheric CO2. Observed global warming of ~0.5°C in the past 140 years is consistent with anthropogenic greenhouse gases being the dominant climate-forcing in that period. But interpretation of current climate change is extraordinarily complex, because of lack of observations of several climate forcings as well as an unpredictable chaotic aspect of climate change. Climate change during the next decade may help confirm knowledge of climate sensitivity, if global climate forcings are accurately observed.