The world’s first scientific estimate of global military emissions is here: they are not only nearly the same as the carbon emitted from all the cars in the world, but they are also higher than the world’s biggest oil and gas exporter – Russia.

Stupendous amounts of carbon dioxide emitted by the world’s militaries are playing a huge but invisible role in driving humanity toward climate catastrophe according to a new report published by Scientists for Global Responsibility (SGR) with the Conflict and Environment Observatory (CEOBS).

The research concludes that global military emissions are so high that if the world’s militaries were categorised as a country, they would be equivalent to the fourth highest carbon footprint in the world, just behind China, the United States and India – and higher than Russia’s.

The invisible war on Planet Earth

This conclusion is only an estimate. Report authors Dr Stuart Parkinson – former military engineer turned climate scientist – and chartered environmentalist Linsey Cottrell developed an innovative methodology to estimate the likely scale of military carbon emissions by gathering the sparse data available on emissions from military vehicles, bases, and industrial supply chains from a small number of nations. This data was then used to estimate totals for the world and the main geopolitical regions.

The new SGR and CEOBS report, titled Estimating the Military’s Global Greenhouse Gas Emissions, estimates global military emissions at about 5.5% – and perhaps as high as 7% – of total greenhouse gas emissions.

To get a sense of how massive this is, consider that it is about 85% of the carbon emitted by all the world’s passenger cars in 2019.

“The world’s militaries and wars are a very significant but neglected source of carbon pollution – and these emissions are almost certainly rising with the Ukraine war and the resulting international increase in military spending,”

said Dr Parkinson.

“We urgently need governments and militaries to more accurately measure their emissions and more openly report them – and, just as urgently, these need to be reduced. And the most effective way of doing this is to reduce war.”

Riding blind

Military institutions around the world inhabit a kind of ‘no man’s land’ when it comes to climate change. They do not keep track of their own carbon emissions, and there is no obligation on them to do so. As a result, data on military emissions is usually low quality, incomplete, masked by other civilian categories – or simply not even collected.

Governments have resisted committing to firm carbon accounting to avoid the prospect that climate action might entail restrictions on military activities. This has had feedback effects on the wider climate science community.

For instance, the United Nations Intergovernmental Panel on Climate Change (IPCC) has barely discussed the implications of military emissions. This means that we don’t really know how high these emissions are.

What we do know for certain is that the world’s biggest carbon polluters are also the world’s biggest military spenders. The report points out that some 60% of all global greenhouse gas emissions come from just ten countries: China, the US, India, Indonesia, Russia, Brazil, Japan, Iran, Canada and Saudi Arabia. All of them – except Indonesia – are among the top 20 countries in terms of their military expenditure.

The report’s findings are highly conservative because they exclude some key carbon emission sources such as “the impacts of warfighting”, such as fires, infrastructure and ecosystem damages, post-conflict reconstruction, and health-care for survivors; as well as “the additional heating effects which are caused by non-CO2 exhaust gases in the stratosphere”.

The urgent need for military accountability

Without understanding the still largely hidden role of the world’s militaries, we won’t be able to get meaningful control over rising global carbon emissions. There is therefore an “urgent need for all militaries to report emissions using consistent, unambiguous, transparent, and robust data collection methodologies – and to take action to reduce them”, conclude Parkinson and Cottrell.

This urgency is particularly heightened in light of the escalation of military activities since the breakout of war in Europe: “With the ongoing escalation of military expenditure – especially in the wake of the war in Ukraine – commitments by governments to tackle this largely ignored contribution to global GHG emissions are urgently needed”.

That is why the researchers are calling for policymakers at COP27 to look at strengthening reporting requirements under the United Nations Framework Convention on Climate Change (UNFCCC). “As a first step, we need the UNFCCC to strengthen its reporting protocols for governments’ militaries”, said Linsey Cottrell.