 |
Greenhouse
gas forcing only.
 |
| Greenhouse
gas and sulfate aerosol forcing. |
By themselves, droplets of sulfuric
acid resulting from the burning of
fossil fuels are of little consequence.
But vast numbers of them form an aerosol
haze that moderates and obscures the
"greenhouse effect" caused by heat-trapping
gases. In 1995, Benjamin Santer of
Lawrence Livermore National Laboratory
was the first to quantify and explain
the link between fossil fuel emissions
and climate change, including the
role of greenhouse gases and aerosol
particles. Using a statistical pattern
detection method, Santer and colleagues
reviewed records of the past century
and identified the anthropogenic "fingerprint"
of climate change that took into account
the confounding effects of natural
variations. This work explored the
implications of earlier research by
Karl Taylor and Joyce Penner of Lawrence
Livermore, who showed that sulfate
aerosols have strong local cooling
effects and significantly modify the
climate change pattern associated
with greenhouse gases alone. Santer's
studies demonstrated that the inclusion
of sulfate aerosol effects helped
to bring model simulations in closer
statistical agreement with observations,
and that this correlation is improved
further by the inclusion of other
relevant factors, such as ozone depletion
and the effects of volcanic eruptions.
Scientific Impact:
Most climate modeling centers now
emulate the work of these scientists
by incorporating a sulfate chemistry
model within an atmospheric/ocean
climate model. The statistical technique
of fingerprinting has since become
the foundation for more complex methods
of separating signals from noise in
climate records.
Social Impact: Santer's
studies provided hard evidence that
human activities have global-scale
consequences. The internationally
acclaimed research by all three scientists
contributed to the scientific underpinning
for the Intergovernmental Panel on
Climate Change's 1996 conclusion regarding
a "discernible human influence" in
climate change.
Reference: Santer,
B.D., T.M.L. Wigley, T.P. Barnett,
and E. Anyamba, 1996: "Detection of
Climate Change and Attribution of
Causes," Climate Change 1995:
The Science Climate Change, 407-443,
United Nations Intergovernmental Panel
on Climate Change (Available Cambridge
University Press, New York).
Santer, B.D., K.E. Taylor, T.M.L.
Wigley, J.E. Penner, P.D. Jones and
U. Cubasch, 1995: "Towards Detection
and Attribution of an Anthropogenic
on Climate," Clim. Dyn.,
12, 79-100.
URL:
http://www.oar.noaa.gov/spotlite/archive/spot_ccdetect.html
Technical Contact:
Ricky Petty, Environmental Sciences
Division, 301-903-5548
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of Biological and Environmental
Research |
