How The U.S. Military Is Addressing Climate Change

aircraft in flight
The Air Force is studying ways to reduce fuel costs for the C-17, pictured, about to be refueled.
Credit: Airman 1st Class Makensie Cooper/U.S. Air Force

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The Pentagon is overhauling its approach to climate change, making environmental factors a key consideration in its strategic decisions, operational planning and spending. The upcoming budget request for the first time will explicitly outline its steps to battle a climate crisis and the associated costs.

For the U.S. Air Force, by far the American military’s largest user of fuel, the green initiatives mean more than simply reducing carbon emissions and adding a few more electric cars.

  • New legislation allows military to capitalize on fuel savings
  • Pentagon budget to specifically outline climate change spending
  • Efficient mission planning, engine wash techniques showing results

“I want to make sure that the culture is thinking about fuel and fuel logistics—not for greenhouse and gas emissions’ sake, not for saving money—but the fact that, you know, I can’t get an F-35 airborne without fuel,” says Roberto Guerrero, deputy assistant secretary of the Air Force for operational energy.

War games have shown that fuel efficiency is critical in operations in the Pacific. In a 2018 war game focused on the region, for example, a significant number of missions were canceled due to a lack of fuel, Guerrero says.

As the Pentagon releases its new high-level strategy and spending plan, the Air Force in the coming months will also roll out a climate action plan that will outline near-term emissions targets along with other plans to make the service more green. Air Force Secretary Frank Kendall says the service is looking at making the impact of climate change a bigger factor in basing decisions, along with other steps such as improved aerodynamic technologies, electric alternatives and upgraded engines for some aircraft.

“We’re taking climate change into account in a whole range of things that we’re doing,” he says.

Addressing the Costs

The Air Force spends more than $5 billion per year on fuel, and that cost will rise this year as gas prices increase and inflation stays high. The service’s Boeing C-17 fleet alone accounts for about $1 billion in fuel costs. Under the climate action plan, the service is looking at ways to conduct more missions with the same gallon of gas, beyond the second- and third-order effects of greenhouse gases.

“As you well know, the Air Force can make the biggest impact of all [Pentagon] agencies because we burn so much fuel,” Guerrero says. “If you combine all the tanks and ships and Navy helicopters, Marine Corps helicopters, Navy aviation, Marine Corps aviation—all of that is still going to be about 45% of the total [Pentagon] liquid fuel burning, and we’re doing the rest. We have the ability with some of these initiatives to make a big impact.”

The increase in funding is coming thanks to a legislative change in the fiscal 2021 defense policy bill that modifies how the military services can retain their approved operations and maintenance costs. Previously, unused fuel costs were lost at the end of a fiscal year, so the Air Force asked Congress to revise the policy.

“We want you to give us credit for the good work we’ve done in the past year, the technology and process that resulted in us having extra [operations and maintenance] funds that we couldn’t spend, right? Because in the past you just got penalized,” Guerrero says.

Now the services can highlight the cost savings of an efficiency initiative and move that unused money into a new account that will be able to pay for even more efficiency efforts. For example, a new computerized tool to plan for refueling tanker sorties in the Middle East, known as Jigsaw, resulted in $17 million in savings. That amount can now be used for other efforts across the military.

The service is undertaking a series of disparate steps to cut back fuel burn across many of its fleets. These include:

• New foam washing for the Bell-Boeing V-22 Osprey fleet. Air Force Special Operations Command is using a nucleated foam to clean Osprey engines as opposed to a simple wash. So far, 300 engines have been cleaned using this new step, which has resulted in a 7% gain in efficiency and a doubling of engine life on wing. The service is now looking at other engines being foam-washed, with the Lockheed C-130, for example, seeing a 0.75% reduction in fuel burn.

• Adding detergent to water for washes for Lockheed C-5s and Boeing KC-135s, E-3s and B-52s. This has resulted in a reduction in engine temperature, 0.65% lower fuel use and an overall cost avoidance of about $2 million. The data from this effort is informing a business-case analysis for different washing techniques for aircraft with large, high-bypass engines.

• A pilot program at two C-17 bases aimed at incentivizing more efficient mission planning. The $3 million project, the Mission Execution Excellence Program, calls on crews at Joint Base Charleston, South Carolina, and Travis AFB, California, to focus on precision fuel planning, reduced engine taxiing, less use of auxiliary power units, reduced or simultaneous engine starts, descent profile techniques and optimal cruise altitude. The service estimates that these efforts could improve mission effectiveness per gallon of fuel by 3%. If successful, the Air Force is looking at expanding the program across the service.

• Studies on drag reduction for several aircraft. For example, testing of vertically mounted wiper blades for KC-135s shows a 1% decrease in drag during cruise, potentially saving about $7 million in fuel costs.

KC-135 on runway
The KC-135 is targeted for Air Force fuel-reduction efforts. Credit: Airman 1st Class Kiaundra Miller/U.S. Air Force

While the broader aviation industry is investing heavily in the development of sustainable aviation fuel (SAF), such research has not been a focal point of the Air Force study. After initial research, the service determined that much of its equipment cannot run completely on SAF. It is tracking airline efforts, and some work will be needed to understand the energy-in and energy-out ratio of SAF for more limited operations, such as fueling small UAVs.

“We know that there’s some ‘there’ there from a greenhouse gas perspective, [an] emissions perspective,” Guerrero says. “But [that is] why my office is trying to pull the Air Force toward sustainment practices and better propulsion and better aerodynamics, because in many cases there’s [about] a 20-1 difference in the amount of greenhouse gas reduction you can [achieve] by putting smart aerodynamics or propulsion or sustainment practices on aviation, as compared to buying an all-electric car.”

The upcoming climate action plan will also look at basing, in the aftermath of major climate disasters such as the 2018 Category 5 Hurricane Michael that leveled Tyndall AFB, Florida, and flooding in early 2019 that severely damaged Offutt AFB, Nebraska. Kendall says this is already a part of Air Force plans, but more needs to be done.

“We haven’t made a final decision on this, but we’re looking into [whether] strategic basing decisions should be affected more than they are today,” he says. For example, the frequency at which adverse events can shut down operations at a base should be considered before basing aircraft in the location.

Across the Pentagon

The U.S. Army in February released a strategy to address climate threats, which includes a fleet of hybrid tactical vehicles by 2035, all-electric nontactical vehicles by 2027 and carbon-free electricity at bases by 2030. Broadly, the Army wants to reduce carbon pollution—in 2020, the service was responsible for 4.1 million tons of carbon dioxide. The service will add “climate literacy” to training, which outlines impacts to bases, along with increasing the frequency of cold weather exercises as the Arctic becomes more strategically important.

“The Army is obviously the largest service, and I think we have a responsibility, given our scale, to be leading the way on how we’re adapting to climate change,” Army Secretary Christine Wormuth says.

The U.S. Navy directly faces climate threats at its installations, with many in flood- or hurricane-prone areas. “All indications are that these conditions will persist,” Navy Undersecretary nominee Erik Raven said in a March Senate hearing. Shipyards, for example, have seen extensive flooding, which has slowed work on ships. The Navy’s Facilities Engineering Systems Command has collaborated with the National Oceanic and Atmospheric Administration on a tool to help installations plan for environmental change as one step.

The Pentagon announced climate change would be a main priority immediately after the Biden administration took office. In response to a January 2021 executive order, it created a Climate Working Group, and Defense Secretary Lloyd Austin in April 2021 said the climate crisis is an existential threat. The Defense Department last October released its climate risk analysis, stating that the risks of climate change directly affect military strategies, plans, capabilities, missions and equipment. The Department of Homeland Security and the Office of the Director of National Intelligence have released similar assessments.

“Global efforts to address climate change—including actions to address the causes as well as the effects—will influence [Pentagon] strategic interests, relationships, competition and priorities,” the Defense Department’s analysis states. “To train, fight and win in this increasingly complex environment, [the Pentagon] will consider the effects of climate change at every level of the  [Pentagon] enterprise.”

Brian Everstine

Brian Everstine is the Pentagon Editor for Aviation Week, based in Washington, D.C. Before joining Aviation Week in August 2021, he covered the Pentagon for Air Force Magazine. Brian began covering defense aviation in 2011 as a reporter for Military Times.


It takes fuel to carry fuel. As a general rule of thumb, an aircraft will burn 5% of any additional fuel above the minimum required in every hour of flight. Adding 2000 pounds of additional fuel on a 10 hour flight will result in only having 1000 pounds extra on landing.
The USAF requires an alternate to be added to the flight plan and alternate fuel to be carried if within one hour of landing the ceiling will be less than 2000 feet and the visibility less than 3 miles (the 1-2-3 rule). This does not reflect advances in aircraft capabilities.
US airlines can operate, under certain restrictions, with 1-1-2 or 1-1-3 weather before an alternate must be declared and alternated fuel boarded.
Changing USAF regulation 4.16. IFR Alternate, has the potential to reduce buying, boarding and burning large quantities of alternate fuel.
Interesting the services’ priority is not really CO2 but psst…making sure fuel to operate is there. You don’t say!

What do they know that we do not? Probably nothing. Fuel cheap and plentiful is needed for war and commerce, not bunny farts. Me thanes all of this could be solved by simply deciding to allow money to be loaned again and regulations allowed to explore, frack, and pump in the US restoring energy independence. That then means the US has more than enough to then export petroleum products to other countries. Such a nice inadvertent diplomatic tool that we get paid for, instead of enriching Russia, Iran, etc. But surely there will be no strings attached to buying petroleum from Russia or Iran, right? And surely their production of said products will be done with the environment in mind, much cleaner than in the US.

Instead Putin has enjoyed having the petrocash to wage war, petrocash we should have brought here. Need help with that trade deficit? Need taxes for pet social programs? Why did we allow Putin, and maybe next Iran, to make his war money selling petroleum products when we could have sold it ourselves? CO2 has been higher and lower, and the world has been warmer and cooler many times way before humans.