COP30 Climate Deal: Signed and Sealed, but Military Emissions Left on the Dock

At the closing plenary of COP30 in Belém, United Nations (UN) Climate Change Executive Secretary Simon Stiell affirmed that “climate cooperation is alive and kicking, keeping humanity in the fight for a liveable planet”. 195 Parties approved the Belém Packages, intended to strengthen global climate policy. The adopted text set ambitious financial targets and launched two new initiatives: the Global Implementation Accelerator and the Belém Mission to 1.5°C. However, taking place amidst an exceptionally tense international system, the Belém agreement was only reached due to exhaustion. Furthermore, the re-election of Donald Trump re-legitimized a stark form of climate scepticism, as reflected in the absence of a U.S. delegation in Belém. At the same time, a broader crisis of green policies has become evident across Europe and in other OECD countries such as Canada and Japan. Consequently, while expectations were never particularly high, COP30 cannot be considered a major success.

Across the previous two years of negotiations, at COP28 in Dubai and COP29 in Baku, the issue of military emissions was raised but never meaningfully addressed. COP28 announced the first-ever Relief, Recovery and Peace Day, while COP29 went even further, branding itself as the COP of Peace and presenting the Baku Call on Climate Action for Peace, Relief and Recovery. Thus, both COPs repeated the same pattern of publicly embracing peace agendas while failing to confront the role of militaries and armed conflicts in driving the climate crisis. This persistent avoidance created a pattern of stagnation that COP30 failed to break, leaving the military emissions gap intact.

How Big is the Military Carbon Footprint?

Existing studies in the field paint a stark picture. Militaries and their supply chains may account for around 5.5 per cent of annual global greenhouse gas emissions, meaning that if the world’s armed forces formed a country, they would be the fourth-largest emitter on Earth. The U.S. military is one of the largest single institutional carbon emitters on the planet, contributing more greenhouse gas emissions than over 150 countries combined. At the domestic level, the U.S. Department of Defence is the government’s largest fossil fuel consumer, accounting for most federal energy consumption since 2001.

Global military spending totalled USD 1.9 trillion in 2019. According to SIPRI, 2024 saw “an increase of 9.4 per cent in real terms from 2023 and the steepest year-on-year rise since at least the end of the Cold War”. While the data indicates a worldwide rise in defence budgets, Europe and the Middle East experienced some of the most substantial increases. Military spending, projected to reach USD 6.6 trillion by 2035, contributes substantially to CO2 emissions: it is estimated that for every spending increase of USD 100 billion, an equivalent 32 million tons of CO2 are generated. This means that militarization plays an active role in driving global warming and that money allocated to rearmament inevitably comes at the expense of climate adaptation and mitigation efforts.

According to the Costs of War project, military jets and vehicles burn petroleum-based fuels at exceptionally high rates, and equipment operating in conflict zones emits large quantities of carbon monoxide, nitrogen oxides, hydrocarbons, and sulphur dioxide, in addition to CO2. The lack of accurate, standardized methods for assessing emissions from military activities leads to several challenges. While estimating emissions from permanent bases or routine transport is manageable, doing so in active conflict areas becomes extremely difficult, if not unfeasible.

A lack of published data further complicates the efforts to assess overall military emissions, leaving it to researchers to estimate them. Recent studies emphasize that hidden wartime emissions and opaque military supply chains further obscure the actual footprint of armed forces. Crucially, these wartime impacts are layered on top of the emissions generated by „everyday militarism“. Aircraft, naval fleets and armoured vehicles are notoriously fuel-hungry, bases and logistics networks demand constant energy, while large-scale training exercises intensify consumption across all services. Procurement cycles and research programs add a further layer of emissions intensity, locking militaries into carbon-heavy systems for decades to come.

Military Emissions: The Blind Spot in Global Climate Governance

The main international instrument in global climate governance, the UN Framework Convention on Climate Change (UNFCCC), does not mandate its parties (198) to report their military emissions.

Historically, during the Kyoto negotiations, the U.S. Department of Defense lobbied to exempt military emissions from the national greenhouse gas inventory. The primary concern was that a limitation in this regard would have had adverse impacts on military effectiveness. In 2015, with the adoption of the Paris Agreement, the exemption was lifted, but reporting in this area remains at the discretion of the parties.

According to the UNFCCC and IPCC reporting guidelines, countries can report their military emissions under two categories of fuel consumption. However, only a small number of states provide disaggregated data. The Military Emissions Gap project rated the accessibility of military fuel data as ‘fair’ (good, fair, poor, or very poor) for only six states (Germany, Hungary, Norway, Slovakia, Bulgaria, and Cyprus) in the 2025 reporting cycle. France, the United Kingdom, Japan, and Turkey were among the major military powers that failed to provide relevant data, while the United States did not submit a National Inventory Report (NIR).

Under the UNFCCC, Annex I (industrialized economies) and non-Annex I (developing economies) countries have different reporting obligations. If reporting among Annex I states is already limited, the situation for non-Annex I countries is even more challenging. This gap is especially significant given that several major military spenders—such as China, India and Saudi Arabia—are classified as non-Annex I. As a result, reporting is even weaker. None of these countries disclose their military emissions, despite collectively spending more than USD 480 billion on their armed forces in 2024.

Besides voluntary reporting, there are several major shortcomings in how military emissions are reported. For example, overseas bases fall into grey zones, with emissions often unaccounted for by either the operating or the host country. Therefore, even full compliance with current guidelines would leave much uncounted, such as effects of munitions production and disposal, supply chains, refrigeration and radar systems, construction materials, and more.

The data gap in this field seriously undermines global and regional climate targets, and the resulting lack of transparency in reporting leads to significant distortions between the actual data and what countries communicate. For instance, at the last reporting round, according to the Conflict and Environment Observatory (CEOBS), there was an 82 per cent gap between what 23 EU-NATO countries collectively reported to the UN in the latest assigned military emission categories under the UNFCCC. Moreover, opaque reporting enables large emitters to appear climate-ambitious while leaving out a sizable portion of their carbon footprint. For example, although India is the fourth-largest military spender in the world, the country ranks among the top performers in some climate indices, despite having no publicly reported military emissions.

The Environmental Costs of War

Armed conflicts carry profound climate and environmental costs that extend far beyond the battlefield. Wars generate enormous amounts of greenhouse gas through large-scale troop deployments, fuel-intensive operations, and the destruction of infrastructure. Preliminary assessment by the Initiative on GHG Accounting of War finds that emissions in the first three years from Russia’s full-scale invasion of Ukraine equal the combined annual emissions of Slovakia, Austria, Hungary and the Czech Republic. At the same time, another study from Queen Mary University of London reveals that emissions from the first 120 days of Israel’s war in Gaza exceeded the annual emissions of 26 individual countries due to intense military activity, including bombing raids, reconnaissance flights, and rocket attacks.

The legacy of conflict-related pollution is well documented; from the widespread use of Agent Orange in Vietnam, to the oil-well fires in Kuwait during the Gulf War, or the long-lasting soil and water contamination left by depleted uranium munitions in the Balkans and Iraq. Such impacts not only devastate ecosystems but also pose profound and lasting risks to human health, including increased rates of cancer, respiratory illnesses and birth defects. Despite this, the international legal framework for protecting the environment during armed conflict remains weak. Although relevant norms exist, they are often vague, difficult to enforce, and subject to strong resistance from major military powers, limiting their effectiveness. As a result, the environment continues to be an under-protected victim of war, with consequences that can endure for generations.

Conclusion: Bringing Military Emissions Out of the Shadows

Addressing military emissions is essential to credible global climate action. As one of the world’s largest and least regulated sources of greenhouse gases, the defence sector cannot remain outside the core mechanisms of transparency, reporting and mitigation. The environmental toll of armed conflict, combined with the vast carbon footprint of peacetime military activities, underscores the urgency of reform. Strengthening reporting obligations, closing data gaps and integrating military considerations into climate governance are necessary steps toward aligning security policies with environmental responsibility. Without confronting this blind spot, global efforts to limit warming and protect ecosystems will remain fundamentally incomplete.