Climate models without cloud formation data miss climate warming clues

Global climate is more sensitive to carbon dioxide than previously estimated, an Australian researcher says, citing the role of clouds in climate change. Climate models that show a low global temperature response to carbon dioxide do not take into account cloud formation processes and their effect on climate, Steven Sherwood from the University of New South Wales said. "Our research has shown climate models indicating a low temperature response to a doubling of carbon dioxide from preindustrial times are not reproducing the correct processes that lead to cloud formation," he said in a university release Friday. When the processes in climate models are corrected to match the observations in the real world, he said, the models produce cycles that take water vapor to a wider range of heights in the atmosphere, causing fewer clouds to form as the climate warms -- allowing more sunlight and heat to enter the atmosphere, which increases the sensitivity of climate to carbon dioxide or any other perturbation, he said. When cloud formation processes are correctly represented, the sensitivity of the climate to a doubling of carbon dioxide -- which will occur in the next 50 years -- could lead to a temperature increase of at least 7 degrees Fahrenheit by 2100, Sherwood said. "Climate skeptics like to criticize climate models for getting things wrong, and we are the first to admit they are not perfect, but what we are finding is that the mistakes are being made by those models which predict less warming, not those that predict more," he said.