The authors would like to thank Daniel Aldana-Cohen, Alyssa Battistoni, Linsey Cottrell, Amelia Horgan, Mathew Lawrence, Sophie Monk, Benjamin Neimark, Stuart Parkinson, Raj Patel, Basav Sen and Lorah Steichen for their respective reviews, comments and contributions to this work.

Among all government institutions worldwide, the US and UK militaries bear some of the greatest responsibility for climate crisis.^[1] Despite this, emissions from military sources are not addressed in international climate agreements: as a result of US lobbying, overseas military emissions were made exempt from the 1997 Kyoto Protocol and military emissions reporting remained optional in the 2015 Paris Climate Agreement.^[2] Even if using opaque official data, the UK and US militaries have jointly emitted at least 430 million tonnes of CO2 equivalent since the year of the Paris Climate Agreement — more than the total greenhouse gas emissions produced in the UK in 2022.^[3] While several other militaries are also leading institutional emitters, this report focuses on the joint climate impact of the US and UK militaries for three reasons: first, their historic role in the development of the global fossil fuel economy; second, their current consumption of fossil fuels, associated greenhouse gas emissions and the environmental damage produced by their military infrastructure; third, the US and UK governments’ allocation of public investment towards carbon-intensive industrial sectors to supply their militaries when they could better prioritise green industrial policy.^[4]

The US and UK governments and their militaries are important architects of the modern fossil fuel economy. Throughout the twentieth century, the strategies of both militaries were intimately tied to the supply of oil. In the wake of the First World War, for instance, the British empire’s division of former Ottoman regions was explicitly designed around plans for hydrocarbon pipelines.^[5] As data presented in this briefing demonstrates, the legacy of the US and UK militaries as architects of the fossil economy lives on through their present consumption of fossil fuels — in 2017, the Pentagon produced more emissions than the country of Portugal.^[6] Accounting for the social consequences of US and UK military emissions since 2015 — using even a conservative social cost of carbon calculation as detailed below — would entail an international climate finance package of approximately $111 billion to be paid to the nations most threatened by climate crisis, far above the US and UK’s current contributions through established climate finance channels.^[7] Beyond carbon emissions, the US and UK’s overseas presence shows the various modes through which military bases, activity and infrastructure produce environmental damage and toxic waste. 

The UK and US militaries further rely on an international military industry to supply equipment and services. In both the US and the UK, the military hardware industry is the beneficiary of concentrated public investment and state capacity. In the US for instance, a single year of the Department of Defense budget — much of which is channelled to private contractors — eclipses even the most optimistic estimates of a decade of public investment through the Inflation Reduction Act (IRA) and accounts for the majority of the entire federal government’s discretionary spending.^[8] The military-focused industrial strategies of both the US and UK have benefitted from state intervention while green sectors have suffered from a lack of support.

The costs of military related pollution and environmental damage have been most sharply realised in Global South countries facing the diffuse, but increasingly intense, effects of global heating. As an initial step to redress their militaries’ historic and present contribution to ecological crisis, the US and UK should contribute alongside other leading emitters to independently-governed funds to compensate Global South countries facing both climate crisis and a dearth of climate finance contributions from the North. Reducing the US and UK’s global footprint of nearly 900 military bases and introducing a military superfund, similar to that administered by the US Environmental Protection Agency, to pay for environmental remediation for communities affected by hazardous materials, pollution and waste from military bases and infrastructure are also necessary steps to redress the full spectrum of environmental impacts. Domestic policy must also facilitate the development of a new industrial base focused on green manufacturing instead of military production, through state-led conversion plans and social programmes for workers currently in the arms sector and those reliant on its supply chains. These are essential measures to account for the history and present of US and UK military emissions although they only represent initial steps in providing a degree of compensation for their climate impact.

Policy Recommendations

[.num-list][.num-list-num]1[.num-list-num][.num-list-text]Not Just Less Pollution — Less Military[.num-list-text][.num-list]

Since 2001, the US Department of Defense (DOD) has consistently accounted for between 77 and 80 per cent of the US government’s total energy consumption while the UK Ministry of Defence (MOD) accounts for at least 40 per cent of British public sector emissions.^[9] Scaling back military operations and hardware acquisition is essential to emissions mitigation. 

[.num-list][.num-list-num]2[.num-list-num][.num-list-text]Close Bases[.num-list-text][.num-list]

There must be a reduction in the US and UK military’s sprawling infrastructural footprint. Base closure processes should include environmental assessments and financing for environmental remediation.

[.num-list][.num-list-num]3[.num-list-num][.num-list-text]Pay Countries for Past and Present Pollution[.num-list-text][.num-list]

The US and UK should make international climate finance contributions as a first step to compensate for the locked-in impacts of the direct greenhouse gas emissions associated with military activity.^[10] The minimum social cost of carbon attributable to the US and UK military’s direct emissions since the year of the Paris Agreement alone is $111 billion — $106 billion of this is attributable to US emissions and $5 billion to UK emissions.^[11]

[.num-list][.num-list-num]4[.num-list-num][.num-list-text]Create a Global Military Superfund[.num-list-text][.num-list]

Invest in remediation undertaken by local communities and local governments across the world through direct payments, technology transfer and job training at sites contaminated by US and UK military bases and operations in all territories both international and domestic. 

[.num-list][.num-list-num]5[.num-list-num][.num-list-text]Collate and Publish Transparent Point and Non-Point Source Pollution Data[.num-list-text][.num-list]

There must be robust quantification of present and historic US and UK military contributions to climate change. Both the UK and US governments should undertake a comprehensive audit of the environmental damage produced by military bases starting with the highest risk sites and places.

[.num-list][.num-list-num]6[.num-list-num][.num-list-text]Invest in a Just Transition for Arms Workers[.num-list-text][.num-list]

Repurposing industrial capacity within the arms sector offers a dual opportunity: to reduce military industrial emissions while expanding the capacity of green manufacturing. Public ownership and coordination can build on a long history of conversion and diversification projects to ensure that conversion delivers security for workers as rapid decarbonisation occurs.

[.num-list][.num-list-num]7[.num-list-num][.num-list-text]Provide Alternative Employment for Military Personnel[.num-list-text][.num-list]

The US and UK governments should invest in employment programmes to account for the reduction of military spending, bases and jobs worldwide.