Chemistry Forum

The EPA's action marks a major shift in the government's approach to global warming and could trigger a series of federal regulations affecting polluters like vehicles and coal-fired power plants. In the past, the EPA had avoided identifying such emissions as pollutants, and the Bush Administration had opposed putting mandatory limits on carbon dioxide and other greenhouse gases because it believed doing so would hurt business. The agency's finding will most likely increase pressure on Congress to pass legislation limiting greenhouse gases, something Obama supports but many Republicans deem too costly.

In other science news, the Administration issues a new set of embryonic-stem-cell-research guidelines through the National Institutes of Health. The rules allow for a vast expansion of research but stop short of permitting creation of human embryos for research or cloning.