A losing battle for the world’s militaries?

24th November 2022


The world’s militaries are major contributors to global warming, but little is known about the exact scale of the problem. Huw Morris reports

It’s one of the world’s most polluting industries, but few people know it. Even experts scratch their heads about the true scale of this inconvenient truth. Yet the contribution of the world’s militaries to climate change is beginning to emerge.

Commentators describe it as the ‘carbon bootprint’. If the US military was a country, its fuel use alone would make it the 47th-largest greenhouse gas (GHG) emitter, nestling between Peru and Portugal, according to a 2019 study by academics at Durham and Lancaster Universities for the Institute of British Geographers. This also revealed that the US Department of Defense is the world’s largest institutional emitter and consumer of fossil fuels.

A two-part issue

The challenges for defence are twofold. The first problem is that parts of the world are becoming climate change hotspots, which is exacerbating tensions, rivalries, grudges and vulnerabilities: consider Africa’s Sahel region, where ethnic groups battle over diminishing agricultural resources against a backdrop of soaring temperatures and expanding populations. Such areas are also recruiting hotbeds for terrorist organisations like Boko Haram or Islamic State West Africa.

In another example, Russia and the US are increasingly using the Arctic as a military exercise ground for training manoeuvres and equipment trials.

Russia regards the emerging Northern Sea Route as a ‘national transportation corridor’, while China and the US see it as international waters.

In addition, most cities and conurbations around the world are near coasts, suggesting that major humanitarian rescue operations will be required in the future as sea levels rise. However, so are numerous military bases – making sea level rise a security threat as well as a humanitarian one.

The second problem is the contribution of defence to climate change – which, if the US military is anything to go by, is huge. Scientists for Global Responsibility (SGR), a network of academics specialising in this field, estimates that militaries and their defence industries contribute 5% of global emissions – more than aviation and shipping combined.

“We should take this very seriously,” says Oliver Belcher, associate professor at Durham University’s School of Government and International Affairs and co-author of the 2019 study.

“As a percentage of the US economy, the military is very small, at less than 2% – but if you think as an institutional and climate actor, it’s comparable to many countries.”

An enormous challenge

Such research is just scratching the surface. Belcher cites the example of the US Defense Logistics Agency, which manages the end-to-end global defence supply chain for the US’s five military services, 11 combatant commands, other federal, state and local agencies, and partner and allied nations. It employs 25,000 staff in multiple supply chains that contract for material and services across military classes of supply. These include food and water, clothing and textiles, bulk petroleum and other energy products, construction material and equipment, personal demand items, medical material and equipment, and repair parts for land, sea and air systems.

Linsey Cottrell, environmental policy officer at think tank and consultancy the Conflict and Environment Observatory, adds that the US military’s fuel use alone is larger than that of 140 countries. “They have a considerable dependency on fossil fuels because of the nature of their operations and their very large and complex supply chain,” she says. “You are not just talking about fuelling or moving machinery around and undertaking operations, but the whole network of the military complex.

“The accounting and transparency just isn’t there on GHG reporting for the military. There is uncertainty as to how big this problem is, with rough estimates putting it at around 5% of global emissions, but with lots of caveats because we don’t really have the data.

“That’s the usual military activities, training and procurement. Then you start thinking about a conflict setting: about GHG emissions, which aren’t considered in any reporting on how a conflict causes infrastructure damage, all the subsequent reconstruction, landscape degradation and deforestation, among others. That is not being considered at all, so the 5% figure will be even higher.”

The military emissions gap

Why do we know so little? Because militaries do not have to tell the UN. Belcher points out that while 46 countries and the EU are committed to providing annual reports on their national emissions under the UN Framework Convention on Climate Change, and the 2015 Paris Agreement removed the Kyoto Climate Accord’s military exemption, the Paris Agreement left reporting on military emissions voluntary. This has led to what he describes as a “military emissions gap”, in which under-reporting is standard and data is not accessible or is lobbed in with civilian activities – especially energy and aviation. Then there are countries with gigantic defence budgets, such as China, Israel, India and Saudi Arabia, that do not report to the UN.

“We all know the climate crisis must apply to all sectors, so why should one sector be exempt?”

Even when countries report their military emissions, there are doubts. SGR says official data published by different government bodies for UK military GHG emissions are neither consistent nor complete enough to guide policymaking. It analysed the main datasets published by the Ministry of Defence (MoD) and the Department for Business, Energy and Industrial Strategy and discovered major discrepancies. None gives a complete picture of Scope 1 and 2 GHG emissions, while ‘headline’ figures understate emissions by 36%–71%.

“If lifecycle emissions were included, that understatement would be considerably larger,” says SGR executive director Stuart Parkinson.

Signs of progress?

There have been some advances. Enshrining net-zero targets into law, as the UK and Switzerland have done, offers a peek behind the curtain; indeed, last year the UK took the unusual step of unveiling a strategy for climate change and sustainability (see ‘How the MoD sees sustainability’, below). Meanwhile, NATO has promised to slash its emissions by at least 45% by 2030 and reach net-zero by 2050. There is a roadblock, though: so far it has not published its carbon counting methodology, an area in which militaries are notorious dawdlers.

“We were hoping last year, when they said they would be developing a methodology to support their members to undertake GHG reporting, that this was good news, that it would be shared and strengthen other militaries’ response to climate change – but it hasn’t been shared,” says Cottrell. “You can’t understand fully what’s been included, which is something you need to track what they’re doing. We all know the climate crisis must apply to all sectors, so why should one sector be exempt?”


How the MoD sees sustainability

Responsible for 50% of UK government’s estate emissions, the MoD took a bold step in publishing its Climate Change and Sustainability Strategy in March 2021.

The 15-page document outlines three strategic ambitions for 2050. One: the UK’s defence will have adapted to be able to fight and win in ever more hostile and unforgiving physical environments. Two: defence will have reduced its emissions and increased its sustainability activity, with the MoD contributing to the UK’s legal commitment to reach net zero.

Three: defence will act and be recognised as a global leader in response to emerging geopolitical and conflict-related threats exacerbated by climate change.

The strategy sets out an action plan covering three ‘epochs’ in the journey to achieve this: ‘setting the foundations’ from 2021–25, ‘minimising and fitting for the future’ from 2026–35, and ‘harnessing the future’ from 2036–50. Examples of initiatives include using electric vehicles with added ‘stealth’, optimising smart buildings for efficiency, recycling materials for fuel and components, and reducing waste and footprint through advanced maintenance methods.

“We have an ambition to contribute to net zero and adapt to a climate change world,” says MoD climate change and sustainability director James Clare. “It’s important to ensure climate change and sustainability are embedded in policies so we are making the most informed decisions we can, and make sure those decisions are as futureproofed as they can be. We need to ensure we have the right foundations in place.”

A key concept is for defence to become a “fast follower of industry”, using the UK’s green transition to add to its capabilities and installing technology as early as possible. “Most areas should be led by the civilian world, but we need to stay close to developments to see what we can exploit ourselves,” says Clare. He cites as an example any new technology that offers an “operational edge against adversaries, or helps us take military personnel out of harm’s way”.

While the MoD has carried out a lot of work on emissions, data is a challenge – particularly in terms of “the depth we want to get into so we have the right understanding and make better decisions,” Clare adds. “We know where we are now, but we need better knowledge on where we are going and our future trajectory.”




5 % Militaries and their respective defence industries contribute 5% of global emissions

45 % NATO has promised to slash its emissions by at least 45% by 2030

47th If the US military was a country, its fuel use alone would make it the 47th-largest greenhouse gas emitter



Huw Morris is a freelance journalist.

Image credit | Sam-FalconerI

Transform articles

The war on waste

While children starve, billions of tonnes of food are thrown away each year. David Burrows explores what’s being done about it

2nd February 2023

Read more

Members of IEMA’s policy team outline the key issues facing sustainability professionals in 2023 and beyond

2nd February 2023

Read more

A deposit return scheme for plastic bottles and cans will be introduced in England, Wales and Northern Ireland in 2025 – one year later than planned – the government has confirmed today.

20th January 2023

Read more

David Burrows delves into some of the issues with lifecycle assessment – and how brands are misusing results

24th November 2022

Read more

A new ISO standard could help to tackle greenhouse gas emissions from the freight sector, says Rick Gould

24th November 2022

Read more

Myles Allen, director of the Oxford Net Zero initiative, talks to Chris Seekings about the best way to decarbonise the world’s economy by 2050

24th November 2022

Read more

Anglian Water has been fined £1,221,000 following two court cases relating to pollution incidents that occurred in 2019.

24th November 2022

Read more

The Environment Act 2021 requires the government to set at least one long-term target in four areas: air quality, biodiversity, water quality and waste.

24th November 2022

Read more

Media enquires

Looking for an expert to speak at an event or comment on an item in the news?

Find an expert