Are other gases, besides carbon dioxide, playing roles in climate change?
A. SCOTT DONEY: In addition to carbon dioxide, there are several other greenhouse gases that lead to warming: methane, nitrous oxide, and the chlorofluorocarbons that everyone’s heard so much about, which are associated with the ozone hole. There are also compounds emitted to the atmosphere that can lead to net cooling. When we burn fossil fuels, we actually release sulfates that produce small sulfate particles or aerosols. You can think of these as very bright little particles in the atmosphere that actually reflect a lot of sunlight back to space. One of the areas of considerable scientific debate concerns the balance between warming due to CO2, and cooling due to sulfates. The exact balance has not been that well quantified, and that’s one of the sensitivities of the climate models that we don’t know that well. This may be significant because as a lot of countries start to reduce their sulfate emissions, which is associated with air pollution and acid rain, we may see sulfate aeroso
