Nearly 40 years ago, Congress passed legislation to control air pollution and clean up our skies. The Clean Air Act and its subsequent revisions have been widely successful at cleaning up the atmosphere and improving the quality of the air we breathe. After nearly a half-century of new scientific inquiry and discovery, we have a better understanding of the natural world. We need to update our laws to recognize and regulate anthropogenic carbon dioxide and other greenhouse gases for what they truly are: pollutants.
Labeling carbon dioxide and other greenhouse gases as air pollutants might seem strange, but these gases have all of the characteristics associated with traditional air pollutants, such as sulfur dioxide or lead. These anthropogenic gases are emitted as a byproduct of human activity. They accumulate in the atmosphere and cause harm to humans, animals and plant life.
The latest Intergovernmental Panel on Climate Change assessment report clearly lays out the case. The world emitted 49 gigatonnes of carbon dioxide anthropogenic greenhouse gases in 2004. Carbon dioxide concentrations in the atmosphere reached 379 parts per million (ppm) in 2005 and showed no signs of slowing. Climate change is already causing problems, such as ecosystem disruption and glacial melting.