The U.S. military's elite forces have always pushed the envelope. And this summer will be no exception, as the Navy deploys SEALs with $2 million of new gear on missions to save hostages, combat pirates, and counter terrorism around the world. What sort of next-generation weaponry, armor, or transportation will the funds provide?

None.

The cash will pay for solar technology, enabling the SEALs to power up equipment and purify water while on the move, and even refrigerate medical supplies and food.

"It's really the first step in the Navy's effort to make the SEALs net-zero energy and net-zero water (use) down the road," said Thomas Hicks, the Navy's Deputy Assistant Secretary for Energy.

Making the SEALs into a leaner, greener tactical force is one of many such steps being taken by all branches as the U.S. military reduces its environmental footprint. The Army is targeting net-zero energy use at several bases, and the Navy and Air Force are experimenting with running jets on biofuels that use wood waste and algae and less petroleum. In Afghanistan, patrols now carry eco-friendly solar blankets and LED lamps.

Connecting the military's fossil-fuel and overall energy use with risks to our national security hasn't been easy in this political environment, especially with the presidential election looming. Congressional Republicans have repeatedly questioned and criticized the Armed Forces' new-energy strategies, portraying initiatives as political favors to clean-energy businesses.

But current and retired military leaders insist the policies are essential. The efforts protect soldiers and help them carry out missions. They also help curb climate change and its potential to intensify military conflicts.

"There is not a shred of political correctness in what the military is doing with energy efficiency or renewable energy," said Dennis McGinn, a retired Navy vice admiral who now serves as president of the D.C.-based American Council on Renewable Energy and as vice chair of the military advisory board for CNA, a 70-year-old think tank that began as a Naval antisubmarine research group during World War II. "From lance corporal to general, they are on board. They live with the problems from the over-reliance on fossil fuels."

Hicks, who previously worked at the U.S. Green Building Council and the Environmental Protection Agency's Energy Star program, says the green benefits are meaningful. Energy investments are not about "advancing an environmental agenda," he said. "They're about improving our combat capability, improving our mission effectiveness, and reducing our vulnerabilities to foreign sources of fossil fuel."

"It's about returning more of our brave sailors and Marines back home to their families safely."

A 2010 Defense Department review identified climate change and energy security as "prominent military vulnerabilities," noting that climate change in particular is an "accelerant of instability and conflict." It was the first time the Pentagon addressed climate in a comprehensive planning document.

A subsequent assessment by the National Research Council found that even moderate climate shifts will impact Navy operations. Sea-level rise and more severe storm surges will hit coastal military bases, and marine forces could also face more work in responding to an increase in humanitarian crises following disasters. The opening of the Arctic as sea ice disappears will likely require more patrols in harsh conditions as nations and industry interests are expected to vie for control of new trade routes and energy resources (Sidebar: The new geopolitics of global warming).

"The severe weather effects of climate change aren't going to start conflicts per se," McGinn said. But it will put added pressure on political, religious, economic and ethnic fault lines, particularly in fragile societies. "It's not a pretty picture for the United States."

Researchers suspect climate change could be an even greater catalyst than military planners have anticipated. Solomon Hsiang, a post-doctoral researcher studying social responses to climate change at Princeton University, linked large-scale climate patterns, such as El Ni–o, to a rise in civil conflicts.

Hsiang and his colleagues determined that social unrest is 6 percent more likely to deteriorate into warfare during periods of El Ni–o activity, which tends to bring drought and extreme weather, such as cyclones and floods that slam the tropics. This periodic, global climate shift, which previews projected climate transformations, has played a role in one out of every five civil conflicts since 1950, making it as significant as any geopolitical or economic factor, according to Hsiang.

McGinn says it's "huge" to include climate change in considering national security, yet he and other officials acknowledge it's just as essential to steer clear of the political morass over the issue. Climate change is politically toxic, forcing military planners to frame their concerns and efforts in terms of energy and troop security.

Attacks on fuel resupply convoys, for instance, accounted for more than one-third of the U.S. Army casualties in Afghanistan in 2007, according to the Council on Renewable Energy. By employing renewable and energy-efficient technologies and practices - such as solar blankets used to recharge new instruments or batteries - soldiers and contractors cut down on resupply missions and also lighten their loads on patrols and at bases. Solar modules at frontline bases have already significantly cut diesel use, reducing the number of convoy trips - and the potential for ambushes and roadside bombs.

"Whether there was climate change or not, we'd still want to do 90 percent of the stuff for energy and economic security and national security writ large," McGinn said.

Hicks, the Navy energy secretary, adds that volatile fossil-fuel prices also threaten military readiness. Increased oil prices will add $1 billion to the Navy's projected fuel budget for the coming year, he said. By developing and using new-energy innovations, the Armed Forces can minimize such overruns and direct funds elsewhere.

Detractors of the military's clean-energy efforts have taken another view, focusing on the immediate, higher costs and uncertainties of developing and testing technologies, like running jets on biofuels, while the Pentagon faces cuts to weapons programs and other areas. After President Obama doubled Defense Department energy efficiency spending to $1 billion in his 2012 spending plan, Republican lawmakers hauled Navy Secretary Ray Mabus before Congress in February to justify his department's programs.

Mabus told Congress that biofuel prices could be competitive with oil by 2020 - and that cost parity could be helped along as the military's different branches test alternative fuels and work with researchers and scientists.

After all, GPS, Internet, microchips and nuclear power all got a boost from the Navy's nuclear submarine program, McGinn noted. "The military had mission needs and they made investments."

"They paid more than the private sector would ever consider," he added. "But the results were benefits for larger society."

On the web:

American Council on Renewable Energy

2010 Defense Department quadrennial review

National Research Council March 2011 study (National Security Implications of Climate Change for U.S. Naval Forces)

Hsiang study

Mabus' 2011 Congressional testimony

This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.