Stuart Parkinson’s study, “The global military carbon footprint” (2024), pointed out that if all the worldwide armed forces corresponded to a single country, they would be the fourth greatest greenhouse gas emitter, not considering the impacts of acquisition and military operations.
According to the Paris Agreement (2015), providing such data is voluntary, resulting in a significant data gap, as presented by the Military Emissions Gap, an interinstitutional project held in the UK. Thus, this voluntary basis, alongside the lack of a standard approach to estimate the ‘carbon bootprint’, prevents more accurate estimations of the actual impact caused by the defence in the context of climate change. For instance, carbon footprint estimations often do not acknowledge the environmental damage caused by armed conflicts and post-conflict rebuilding efforts. Lennard de Klerk points out in his policy brief “Climate damage caused by Russia’s war in Ukraine” (2024) that the conflict involving Russia and Ukraine generated US$ 32 billion in climate damage in addition to an increase of 175 million tonnes of carbon dioxide equivalent (tCO2e) in 24 months. In comparison, Brazil’s total emissions corresponded to 1469 million tonnes of tCO2e in 2021, according to the Climate Watch.
Nevertheless, the defence in several countries is not standing still. In June 2024, NATO published the third version of the “Climate Change and Security Impact Assessment Report“. The document discusses the impacts of climate change on the strategic environment, estate and military operations, comprising the need for climate adaptation and mitigation to retain operational effectiveness, as well as civilian resilience. Those actions unfolded following a recent acknowledgement by the Allied countries regarding the impacts of climate change on security, particularly during COP-26 in 2021, with the speech of the general secretary, Jens Stoltenberg. He emphasised that the armed forces in the future need to be “strong and green” at the same time, exploring alternative sources of energy to become more effective. This statement was a turnpoint so that countries such as the United States, the United Kingdom, France and Canada updated their approach to climate and energy between 2021 and 2022. Additionally, the alliance created the Climate Change and Security Centre of Excellence (CCASCOE) based in Canada, with operations to start in 2024.
Further investments are necessary to increase the technological maturity and the commercial feasibility of solutions such as the Sustainable Aviation Fuel (SAF), vehicle electrification and hybridisation. The defence industry has become an authentic experience lab for those investments in advanced commercial technologies. However, budgetary constraints and competing domestic priorities significantly affect this agenda, alongside the pressing fear of losing operational effectiveness and military readiness. Although alternatives to fossil fuels are still not as efficient, there are also considerable risks of “lagging behind” in energy transition. According to Depledge and Santos in “How can militaries decarbonise?” (2024), uncertainties about the costs and the availability of fossil fuels in a low-carbon world present challenges to the military. The authors argue that provided there is no single path to decarbonise defence and the current military capabilities amidst energy transitions, the best course of action lies in a close interaction involving the government, defence, academia, industry and society.
One way or another, to accomplish the goals established in the Paris Agreement, several countries committed to achieving net zero by 2050 and, in order to avoid the world’s heat to increase about 1.5°C, it will be required to involve defence on these global efforts. Two situations have unfolded in this context: (i) the UN Emissions Gap Report (2023) acknowledged for the first time that the military operations emissions are not trivial and have not been sufficiently accounted for; (ii) the COP-28 Declaration in 2023, which presented the need for actions on climate and financial aid for conflict-affected communities but did not mention defence’s responsibility in reducing emissions. One of the steps to advance this agenda and effectively include military emissions in the decarbonisation goals is involving the diverse different organisations in defence in those discussions, once those are generally absent from the mainstream forums discussing the theme.
Such a discussion is still scarce in Brazil. There is no consensus regarding the need to establish public policy focused on the impacts of climate change and the policies of mitigation, adaptation and resilience in Brazilian defence and the minutes of the refreshed National Defence Policy and the National Defence Strategy, presented to the Congress in July 2024, addressed few to no reflection at all regarding the impacts of climate change. Still, it is expected that the legislative power will appraise the mentioned documents according to their role and competencies established by the Complementary Law no. 136/2010, proposing discussions about the Brazilian society’s expectations regarding defence. However, during the past few years, Congress granted low priority to the refresh of defence documents, notable through the belated proceedings of those documents in 2016 and 2020 (with approval, respectively, in 2018 and 2024).
Aiming at fostering this debate, members from Centro Soberania e Clima, Escola Superior de Defesa and Loughborough University joined efforts in the project Climate, Sustainability and Defence. The project aims were promoting experience exchange and identifying international best practices regarding decarbonisation and energy transitions involving diverse stakeholders from government, defence, academia, industry and society.
Particularly considering Brazil, even though the country’s defence emissions do not significantly contribute to the global greenhouse gas emissions compared to military powers, the cost of the lack of green actions can be too high, whether for not being adequately prepared to operate in climate change-affected theatres (broadly in terms of doctrine, organisation, personnel, education, materiel, training, infrastructure and interoperability), whether for a faulty defence industrial base. Lagging behind the fast-paced innovations of a low-carbon world might increase external pressure for decarbonisation,impose technology restrictions and significant curtailment to access the competitive and politicised international market of defence products.
Mariana Nascimento Plum is the Executive Director of Centro Soberania e Clima.
Tamiris Santos is a Research Associate at the School of Social Sciences & Humanities, Loughborough University, UK.
Peterson Ferreira da Silva is an associate professor at Escola Superior de Defesa (ESD) and at Universidade da Força Aérea (UNIFA).
*Disclaimer: Any ideas and points of view expressed in the text above are purely for scholarly purposes and do not represent official statements of any governmental body or entity from the UK or the Brazilian governments.
