An interview with Scientist Roger Pielke Sr.

Roger Pielke Sr. is a retired professor of atmospheric science at Colorado State University...

EcoWorld: How would you say that current conventional wisdom regarding climate change has gotten it wrong?

Pielke: In terms of climate change and variability on the regional and local scale, the Intergovernmental Panel on Climate Change (IPCC) reports, the Climate Change Science Program (CCSP) report on surface and tropospheric temperature trends, and the U.S. National Assessment [of Climate Change] have overstated the role of the radiative effect of the anthropogenic increase of carbon dioxide (CO2) in relation to a diversity of other human climate- forcing mechanisms. Indeed, many research studies incorrectly oversimplify climate change by characterizing it as being dominated by the radiative effect of human-added CO2. But while prudence suggests that we work to minimize our disturbance of the climate system (since we don't fully understand it), by focusing on just one subset of forcing mechanisms, we end up seriously misleading policymakers as to the most effective way of dealing with our social and environmental vulnerability in the context of the entire spectrum of environmental risks and other threats we face today.

EcoWorld: What about experts' predictions of rising sea levels, extreme weather, melting polar ice caps, and so on?

Pielke: Global and regional climate models have not demonstrated themselves to be skillful predictors of regional and local climate change and variability over multidecadal time scales. For example, in the case of sea ice, the models are consistent with the decrease in Arctic sea ice in recent years, but they cannot explain the multiyear increase in Antarctic sea ice (including a record level this year). With respect to extreme weather, a much more important issue than how greenhouse gases are altering our climate is society's greatly increased vulnerability to extreme weather events - a direct result not of changes in weather but of increased settlement by expanding human populations into low-lying coastal regions, floodplains, and marginal arid land.

EcoWorld: But what about the northern icecap shrinking this September to possibly possibly its smallest size in history (exposing more than 1 million square miles of open water) or the comments of Robert Correll, chairman of the Arctic Climate Impact Assessment, regarding recent observations in Greenland ("We have seen a massive acceleration of the speed with which these glaciers are moving into the sea")? Is something new and alarming happening?

Pielke: These examples represent selected observations that promote the view that human-input carbon dioxide is dominating climate change. However, the climate is - and always will be - changing. Thus, although human activity certainly affects the way in which climate varies and changes, actual global observations present a much more complex picture than that represented by the two examples listed above. For example, Antarctic sea ice reached a record maximum coverage in 2007, and the globally averaged lower atmosphere has not warmed in the last nine years (and, in fact, is cooler than it was in 1998). In addition, there are regions of the world where glaciers are advancing (such as New Zealand, parts of the Himalayas, and Norway). However, this information - which conflicts with the projections of the multi-decadal global climate models and the 2007 IPCC report - has been almost completely ignored by policymakers and the media.