Tad Anderson, Ph.D, Research Meteorologist, University of Washington

Tad Anderson is a Research Assistant Professor of Atmospheric Sciences at the University of Washington. He is the author or coauthor of more than 50 journal publications focused on the climatic effects of anthropogenic aerosol particles. He cut his teeth on instrument development and aerosol measurements, but is now moving into the arena of global assessments via satellite observations and large-scale models. He serves on the Science Team of a new aerosol-sensing satellite based on lidar technology (the CALIPSO mission) and has been invited to testify in March before a National Academy of Sciences panel charged with recommending research strategies for improving knowledge of climate forcings.

Aerosol Forcing and Causal Attribution of 20th Century Warming

Leading climate scientists and international committees have asserted with considerable confidence that the observed surface warming over the 20th century can be attributed to anthropogenic greenhouse gases. However, the attribution argument relies on basic premise that has not been subjected to careful scrutiny -- namely, that the total radiative forcing over the industrial era has been positive and substantial. (Note, a "positive" forcing is one that tends to produce warming.) The existence of large, negative forcings by anthropogenic aerosols makes it important to examine this premise. This talk will present the results of a year-long discussion of this question among a small group of climate modelers, mathematical/inverse modelers, and aerosol experimentalists. Our discussion culminated in a "Perspective" article in Science (16 May, 2003), copies of which are available. We compared two independent methods of calculating aerosol forcing: the standard "forward" method and an "inverse" method based on fitting the temperature record. This comparison revealed a large region of inconsistency and led us to conclude that the above premise cannot be asserted with high confidence. Where does that leave our understanding of 20th century climate change and our projections of changes for the 21st century? What can be done to improve this situation? Time permitting, these and other questions will be explored in this "minority report" on global warming.

Schedule

Meeting Location  

Ivar's Salmon House (Lake Union)

(please do not contact the restaurant for reservations or cancellations)

Take 1-5 to N.E. 45th Exit (#169). Go east, toward the University of Washington,

and turn right at Brooklyn Avenue. Follow Brooklyn to Pacific Street and turn

right. At stop sign, turn left. The Salmon House is one block further, on the

left, at 401 N.E. Northlake Way.

Menu

1.  King Salmon and Breast of Chicken
2.  Alder-Smoked Herb Marinated Chicken

Meeting Reservation Form

Cost

NOTES

1. Please make reservations or cancellations by the Friday before the meeting.

2. Please pay by check payable to Puget Sound Section AIChE, or bring exact change.

3. For reservations:  

4. You can cancel by calling by noon of the Friday before the meeting. Dinner reservations "no-shows" will be billed!!