U.S. Army works to cut its carbon "bootprint"

Davis questioned the notion that the U.S. military is among the world's biggest emitters of greenhouse gases.

The numbers are hard to pin down but the Army is starting to do just that, starting in June with an online program to track carbon emissions at Fort Carson in Colorado.

The system shows Fort Carson emits 205,000 tons of carbon dioxide annually, about the same as a town of 25,000 people.

Eventually this system, produced by California-based Enviance, is to be used on all Army bases. It is also in use at corporations and utilities in 45 countries to track compliance with environmental and safety regulations, Enviance's president Lawrence Goldenhersh said.

(Editing by John O'Callaghan)