WASHINGTON (Reuters) - What if cutting greenhouse emissions could also save the lives of soldiers in Iraq, where fuel-laden convoys make them targets? The U.S. Army says it is happening now in a push to reduce its carbon “bootprint.”

Soldiers from the Second Stryker Cavalry Regiment hold their weapons as the top U.S. Commander in Iraq, General David Petraeus, joins them for a patrol in Muqdadiyah, in the Diyala province July 26, 2008. REUTERS/Damir Sagolj

From forward areas like Iraq and Afghanistan to training ranges in the United States, the Army has been working to limit its use of fossil fuels and make its operations more environmentally sustainable.

The goal is to bring Army emissions of climate-warming carbon dioxide down by 30 percent by 2015, said Tad Davis, deputy assistant secretary for environment, safety and occupational health.

“What I’m interested in doing is finding out what the greenhouse gas emissions, this carbon bootprint, are for the Army in two to three years at the latest,” Davis said by telephone. “We want to emit less that do that, hand in hand with reducing energy consumption from fossil fuels.”

The Army has pushed for environmental sustainability at all of its bases, starting with the giant Fort Bragg in North Carolina in 2001, Davis said.

In practice, that meant changing the way training ranges were set up. Fort Bragg has long been the site of mock towns and villages used for combat training.

Each village used to cost up to $400,000 to build. Now they are made of recycled truck-sized shipping containers at a cost of about $25,000, Davis said, and the shipping containers stay out of the solid waste stream.

In the first years of the Iraq war, the long supply chain stretching from Kuwait to the battlefield put convoys at risk from makeshift bombs called IEDs. Much of the cargo was fuel, Davis said.

LESS FUEL, LESS RISK

The more vehicles in the convoy, the more soldiers were vulnerable so it made sense to cut down on the amount of fuel required on the front line.

“If we can reduce consumption on our forward operating bases by using renewable energy, let’s say wind or solar instead of a diesel generator outside the tent ... then we can reduce the number of these supply convoys that need to come forward that are getting hit by these IEDs,” Davis said.

A recent survey of U.S. forward bases in Djibouti, Kuwait, Iraq and Afghanistan showed that 85 percent or more of the power was used for air conditioning to provide comfort for sleeping but also to keep communications equipment cool.

Poorly insulated tents and temporary buildings are the norm in these areas, Davis said, and keeping them cool was a challenge. The solution? Foam insulation sprayed directly on tents cut the loss of energy by 45 percent.

Limiting greenhouse emissions from Army vehicles presents a different challenge, since making a Humvee or Bradley fighting vehicle more lightweight to save fuel would offer less protection for troops. But this could change, Davis said.

“There’s emerging technology that is providing lighter-weight armor, so I think at some point ... you’re going to see more hybrid vehicles in the tactical military fleet,” he said.

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.