The following University of Michigan scientists are currently conducting research on questions related to the effects of global warming, climate change and increasing levels of carbon dioxide and other greenhouse gases in Earth’s atmosphere. They are available for interviews at the telephone numbers and e-mail addresses listed at the end of each item.

WARMING COULD BE THE LEAST OF OUR WORRIES, according to U-M biologist James A. Teeri. Teeri believes that increased amounts of carbon dioxide in the atmosphere

TWENTIETH-CENTURY WARMING HAS EXCEEDED that of any century since 1500, according to Henry N. Pollack, U-M professor of geological sciences. Pollack compiled temperature readings from 300 boreholes in Europe, North America, Australia and South Africa. Because boreholes preserve an archive of surface temperature changes over time, they provide an important data source for periods before the last 100 years when global meteorological data is available. Borehole data show that today’s global mean temperature is about 1 degree C. (1.8 degrees F.) warmer than it was in 1500 with 0.8 degrees C. of that warming occurring after 1750. Since most of the warming has occurred after the Industrial Revolution, Pollack maintains it likely is a result of fossil fuel burning and greenhouse gases accumulating in the atmosphere. Contact Pollack at hpollack@geo.lsa.umich.edu or (313) 763-0084.

THE GREAT LAKES COULD HAVE A DRY FUTURE, says Peter Sousounis, U-M assistant professor of atmospheric sciences. Sousounis uses mathematical computer models to study how future short-term climate variability and long-term changes could affect the water cycle in the Great Lakes. His models analyze the impact of changes in the amount of heat and moisture coming from the Earth’s surface, lake surface temperatures and the amount of precipitation falling on the lakes. According to Sousounis, climate fluctuations could cause drier conditions in the Great Lakes region by shifting the balance between evaporation and precipitation. Understanding the dynamics of water in the Great Lakes region is important, because the lakes account for 95 percent of the nation’s freshwater supply, Sousounis says. If global warming produces summer droughts in certain parts of the United States, as some climate models suggest, these regions

AEROSOLS PLAY A KEY ROLE IN GLOBAL WARMING, says Joyce Penner, U-M professor of atmospheric sciences, but most climate models have not considered the effects of aerosols—microscopic particles from industrial pollutants or fossil fuel emissions that remain suspended in the atmosphere for long periods of time. While greenhouse gases absorb infrared radiation and create atmospheric warming, aerosols scatter and absorb solar radiation to produce climate cooling. Aerosols also can trigger the formation of clouds with smaller droplets that scatter more solar radiation leading to further cooling. Penner has helped develop a climate model that quantifies the effects of aerosols to more accurately monitor the balance between cooling and warming. Contact Penner at penner@umich.edu or (313) 647-3660.

FOSSIL FUEL REDUCTION COST MODELS SHARE A BASIC FLAW, according to John R. Birge, U-M professor of industrial and operations engineering, who maintains that current computer simulations of the economic effects of carbon emission reductions are missing much of the picture. Instead of factoring uncertainties into the simulation, most researchers just assume them away, says Birge—an expert in the mathematical modeling of uncertainty. Without factors for uncertainty, Birge predicts that inaccurate models of changes in energy policy to meet reduced emissions levels could end up costing $1 trillion over the next 20 years. Contact Birge at jrbirge@umich.edu or (313) 764-9422.

Peter SousounisJoyce PennerJohn R. BirgeU-M News and Information ServicesUniversity of Michigan