The notion of a “carbon footprint”—the measurement, in units of carbon dioxide equivalents, of the greenhouse gases produced by an individual, an organization, or a state—may be a fairly recent phenomenon, but the conservation movement in the United States reaches back to the late 19th century. Today's environmental movement has expanded in numerous ways, and greenhouse gases, green living, and carbon footprints are common topics. While some industries are obviously energy intensive, such as the aluminum or petroleum industries, the fact that healthcare ranks as the second-most-energy-intensive industry in the United States, imprinting the world with a massive carbon footprint, may be surprising.

The American healthcare sector, which includes healthcare facilities, scientific research, and the production and distribution of pharmaceutical drugs, accounts for almost 10 percent ...