In a landmark move that countered eight years of inaction by the Bush administration, the Environmental Protection Agency determined yesterday that greenhouse gases threaten public health and welfare because they contribute to climate change.

The ruling set the stage for the agency to regulate emissions from a spectrum of sources, including automobiles, ships, airplanes, power plants, oil refineries, steel mills, and more.

The finding, which includes carbon dioxide and five other greenhouse gases, is subject to a period of public comment, after which the agency has no timetable and broad leeway in how to proceed.

“This finding confirms that greenhouse-gas pollution is a serious problem now and for future generations,” EPA Administrator Lisa Jackson said yesterday.

Sen. James Inhofe (R, Okla.), the ranking Republican on the Environment and Public Works Committee and a leading skeptic on global warming, said the decision would “unleash a torrent of regulations that will destroy jobs, harm consumers, and extend the agency’s reach into every corner of American life.”

The EPA’s analysis also found that climate change has “serious national-security implications” because of the potential for political and social upheaval related to food shortages, environmental refugees, and clashes over fuel, water, and other resources.

The Obama Admin has made a first step…..will they keep walking or is it just that …one lone step?