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Comment: Military emissions

Comment: Military emissions must be reported

Published on: 2 November 2022

Emissions from the world’s armed forces must be counted and reported, argue Dr Oliver Heidrich and colleagues in a Comment article in Nature.

The authors highlight that the US and UK armed forces emit as much carbon dioxide per capita as many carbon-intensive countries.

The military sector’s share of global greenhouse-gas emissions is estimated to be around 1-5% — comparable to emissions from the aviation and shipping industries. However, militaries have been left out of international agreements to declare emissions since the 1997 Kyoto Protocol, on the basis of preserving national security. A lack of published data makes it hard to estimate totals, and only a handful of forces — including those of the United Kingdom and United States — have published strategy documents on climate action.

Also missing are accurate methodologies for calculating emissions from military activities. For example, recording is near impossible in hostile, fast-changing or insecure locations.

On the basis of available fuel-use data, the authors note that US forces alone — the world’s largest in terms of expenditure — emit more greenhouse gases than many countries, including Peru, Singapore and Switzerland. If it were a nation, the US military would have the highest per-capita emissions in the world (at 42 metric tonnes of CO2-eq per staff member).

Heidrich and co-authors suggest that the true total could be even higher: factoring in other energy supplies, raw materials, supply chains and equipment manufacturing could drastically increase emissions estimates. Emissions from warfare would add even more. Researchers need to calculate this to understand how armed conflicts impact the climate and to help countries to chart low-carbon recovery pathways.

Study lead author, Dr Oliver Heidrich, Senior Lecturer at Newcastle University’s School of Engineering, said: “A standardized methodology and comprehensive assessment framework for greenhouse gas emissions, including emissions embedded in products across their life cycles, are needed. Measurement is crucial for effective management.”

Study co-author, Dr Mohammad Ali Rajaeifar, Research Associate at Newcastle University’s School of Engineering, added: ‘’Militaries are high energy consumers and have locked themselves into fossil fuel-dependent operations and equipment for the next few decades. They also have broad and complex supply chains contributing to a large portion of total GHG emissions from militaries.

‘’Military emissions need to be put on the global agenda. They must be officially recognized and accurately reported in national inventories, and military operations need to be decarbonized.”


Rajaeifar, M., Belcher, O., Parkinson, S., Neimark, B., Weir, D., Ashworth, K., . . . Heidrich, O. (n.d.). Decarbonize the military — mandate emissions reporting. Nature, (611), 29-32. doi:

Adapted with thanks from Nature

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