Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan


Professor Takes on Climate Change Skeptics in Upcoming Lecture

Posted: February 2, 2009

Professor Takes on Climate Change Skeptics in Upcoming Lecture

Despite scientific consensus to the contrary, a few climate change skeptics don’t believe humans are causing global warming. They blame the sun’s cycles, or they base a divergent theory on a tiny piece of the planet’s temperature history.

At an upcoming Distinguished University Professor lecture, Joyce Penner will give evidence to support and refute some of the popular criticisms of the human-caused climate change theory.

Penner is the Ralph J. Cicerone Distinguished University Professor of Atmospheric Science in the Department of Atmospheric, Oceanic and Space Sciences. Her talk is titled “Climate Change Science: Can the Skeptics Ever Be Convinced?” It takes place at 4 p.m. February 16 in the Rackham Amphitheater.

“I’ll go through some of the common arguments against climate change and what the scientific community has done to look at them,” Penner said. “I’ll discuss whether the skeptics’ arguments have validity, and some of them do. Some of the arguments are based in reality and provide future avenues for research that will eventually enable climate change science to rest on a firmer foundation.”

For example, climate change critics have recently drawn ammunition from the World Meteorological Association’s data which show that temperatures appear to be falling since 1998. It’s true, Penner says, but it’s important to look at climate cycles more broadly.

There’s also some truth in the skeptics’ claim that current computer models of climate change aren’t reliable, Penner says. She finds fault in particular with how the models predict aerosols in clouds will affect the climate. Aerosols are fine particles such as smoke and dust that affect cloud thickness.

Current models say aerosols will make clouds thicker, exacerbating future warming. But Penner says this might not be the case, and that aerosols might in some circumstances thin clouds out.

Penner’s research focuses on how atmospheric aerosols interact with clouds and the effects this has on climate change. She was the coordinating lead author for a chapter of the Intergovernmental Panel on Climate Change’s report to the United Nations in 2001 and a co-winner of the 2007 Nobel Peace Prize.
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