How Are Wars Affecting Climate Change?

Wars have a significant and often overlooked impact on climate change, accounting for more GHG emissions than the annual emissions of many countries. Under the Paris Agreement, nations are not required to report on their emissions from military activities, which means that national inventories vastly underestimate real emissions.

by Theodora De Pasquale

War is catastrophic not only for people and places, but for the planet [1]. While the environmental devastation from conflicts, such as land mines, toxic chemicals and destroyed ecosystems, is more known, the global climate impact of warfare has long been underestimated and underreported. Recent studies conducted by climate scientists, including Rostyslav Bun and Gregg Marland, shine on a light on the climate cost of war and militaries, and emphasise the importance of accounting for this in climate mitigation strategies [1]. 

The overlooked carbon footprint of war

Unlike most sectors, defence is not required to report on its greenhouse gas emissions under the Paris Agreement. This omission is a legacy of the 1997 Kyoto Protocol, where emissions from the defence sector were deliberately exempted at the behest of the United States [2]. Although the Paris Agreement eliminated this exemption, reporting remains voluntary and, as such, very few countries disclose data on this matter [2]. 

As a result, the true climate impact of military operations and conflicts has remained largely hidden from global climate accounting. Yet, research suggests that military activities account for around 5.5% of global greenhouse gas emissions, a figure comparable to the entire aviation sector, and likely an underestimate due to data gaps [2, 3]. In the context of this article, military emissions include scope 1 and scope 2 emissions, as will be discussed later in the text.

The omission of mandatory military emissions reporting under the Paris Agreement has created significant data gaps, particularly in active conflict zones. Conflicts in Sudan have led to increased deforestation and pollution due to military activities and displacement, with over 6,126 hectares of natural vegetation lost in one state alone and widespread reliance on charcoal accelerating environmental degradation [4, 5]. 

Similarly, in Somalia and the Lake Chad region, wars have disrupted environmental governance and exacerbated resource conflicts, leading to unregulated exploitation of natural resources and further unaccounted emissions [6, 7]. Both these situations are examples of scope 3 emissions of the defence sector.

Emission accounting: Scope 1, 2 and 3 in warfare

To understand the full impact of war on accelerating emissions, it is crucial to use the three-tiered emission accounting system that has been widely adopted:

• Scope 1: Direct emissions from sources owned or controlled by the military, such as fuel burned in tanks, aircraft, and ships during operations.
• Scope 2: Indirect emissions from the generation of purchased electricity, steam, heating, and cooling consumed by military bases and installations.
• Scope 3: All other indirect emissions, including those from the production and transport of military equipment, supply chains and resource exploitation, weapons manufacturing, deforestation caused by explosions, and post-conflict reconstruction, such as the construction of new infrastructures and buildings.

Most voluntary military emission reports focus only on Scope 1 and 2 emissions, omitting Scope 3 emissions that can account for the vast majority of the military carbon footprint [1].

Human suffering and climate impact

Recent studies are beginning to fill this data gap. A 2024 analysis of Israel’s war on Gaza estimated that the first 120 days of fighting generated between 420,265 and 652,552 tonnes of CO2 emissions, which is more than the annual emissions of 26 countries combined [3]. When including emissions from pre-war construction and projected post-war reconstruction, the total rises to over 47 million tonnes, surpassing the yearly combined emissions of 135 countries [3]. 

Similarly, Russia’s invasion of Ukraine has produced at least 175 million tonnes of CO2 emissions over two years, equivalent to the annual emissions of the Netherlands. These estimates include direct military fuel use, emissions from fires, and the vast quantities of steel and cement required for rebuilding communities and cities [8].

The significant climate impact of conflict must be understood alongside its devastating human toll. 

In Gaza, over 35,000 people have died, with more than half of the territory’s buildings destroyed or damaged [3]. In Ukraine, tens of thousands have been killed and millions displaced, with environmental destruction compounding the humanitarian crisis [4]. 

As Dr. Patrick Bigger, Research Director at Climate and Community Project, notes, “The carbon emissions associated with Israel’s invasion of Gaza are not the most important reason that the global community should be pushing for a ceasefire – every single life still at risk is important. But this research demonstrates some of the long run social and environmental impacts of war, serving as a reminder that armed conflict brings us closer to the precipice of catastrophic warming” [3].

Can military emissions be reduced? 

There is growing demand for change. Environmental organizations and scientists are calling for the United Nations to mandate military emissions reporting under the UNFCCC [1, 3]. Projects like the Military Emissions Gap are working to independently track and compare reported versus actual emissions, thereby exposing the significant underestimates and data gaps [2].

True mitigation of military emissions will require systemic changes, such as decarbonising military operations, reducing the scale and frequency of armed conflict, and integrating climate considerations into national security strategies.

Some countries are already taking steps in this direction. For example, Germany, the United Kingdom, and the United States all report annual military greenhouse gas emissions [9, 10]. An increasing number of countries – including Canada, Estonia, France, Germany, Japan, Luxembourg, the Netherlands, Spain, the United Arab Emirates, and the United States – have begun to acknowledge their military emissions and have laid out emission reduction plans specific to the defence sector [10, 11]. For example, New Zealand has established specific emission reduction targets for its military, while others like the UK integrate military emissions into broader government net zero targets [10, 11]. The European Parliament has also called for transparent reporting  of military emissions by member states and their inclusion in domestic net zero targets [9].

However, this progress is threatened by the unprecedented rise in military expenditure particularly in Europe. In response to heightened security challenges, the EU is rapidly increasing defence spending, with plans to double its military budget by 2035 and inject up to €800 billion into the defence sector over the next four years [12]. Sweden, for instance, is increasing its military budget to around 3% of its  GDP by 2030 [12]. This surge in military expenditure could increase annual emissions by up to 200 million tonnes, potentially derailing climate goals and diverting funds from green infrastructure, health, and education to defence [12]. 

Experts warn that unless military emissions are fully integrated into climate policy and reporting frameworks, the drive for greater security could paradoxically accelerate climate change and, in turn, the social and geopolitical risks that materialise as a result [12].

References:

[1] Rostyslav Bun and others, Tracking unaccounted greenhouse gas emissions due to the war in Ukraine since 2022, Science of The Total Environment, Volume 914, 1 March 2024, https://www.sciencedirect.com/science/article/pii/S0048969724000135, accessed on 20th June 2025. 
[2] Chelsea Harvey & E&E News, Warfare’s Climate Emissions Are Huge but Uncounted, Scientific American, 1 June 2024, https://www.scientificamerican.com/article/warfares-climate-emissions-are-huge-but-uncounted/, accessed on 20th June 2025.  
[3] New study reveals substantial carbon emissions from the ongoing Israel-Gaza conflict, Queen Mary University of London, 6 June 2024, https://www.qmul.ac.uk/media/news/2024/hss/new-study-reveals-substantial-carbon-emissions-from-the-ongoing-israel-gaza-conflict.html, accessed on 20th June 2025. 
[4] The environmental costs of the war in Sudan, Conflict and Environment Observatory, 21 May 2025, https://ceobs.org/the-environmental-costs-of-the-war-in-sudan/, accessed on 27th June 2025.
[5] Abdalftah Hamed Ali, Sudan’s Puzzle: Confronting Climate Change in a War-torn State, Middle East Council on Global Affairs, 4 April 2024, https://mecouncil.org/publication/sudans-puzzle-confronting-climate-change-in-a-war-torn-state/, accessed on 27th June 2025. 
[6] Chitra Nagarajan and others, Peace in an extreme climate: How climate-related security risks affect prospects for stability in Lake Chad, PLOS Climate, 9 October 2024, https://journals.plos.org/climate/article?id=10.1371%2Fjournal.pclm.0000314, accessed on 27th June 2025. 
[7] United Nations Environment Programme and Swedish Defense Research Agency, Environmental Impact Assessment: United Nations Support Office for AMISOM (UNSOA) AMISON Camps, Mogadishu, Somalia, 4 November 2010, https://somalia.un.org/sites/default/files/2020-04/UNEP_EIA_UNSOA_Mogadishu.pdf, accessed on 27th June 2025.  
[8] Max Hunder, Study details huge emissions resulting from Russia’s invasion of Ukraine, Reuters, 13 June 2024, https://www.reuters.com/world/europe/study-details-huge-emissions-resulting-russias-invasion-ukraine-2024-06-12/, accessed on 20th June 2025. 
[9] Does reporting military emissions data really threaten national security?, Conflict and Environment Observatory, 7 February 2024, https://ceobs.org/does-reporting-military-emissions-data-really-threaten-national-security/, accessed on 27th June 2025. 
[10] Ticking boxes: are military climate mitigation strategies fit for purpose?, Conflict and Environment Observatory, 19 February 2024, https://ceobs.org/ticking-boxes-are-military-climate-mitigation-strategies-fit-for-purpose/, accessed on 27th June 2025. 
[11] National climate action plans must include military emissions, Conflict and Environment Observatory, 4 June 2024, https://ceobs.org/national-climate-action-plans-must-include-military-emissions/, accessed on 27th June 2025. 
[12] Terek Salame, Europe’s new arms race could kill its climate goals, EuroWeekly News, 26 June 2025, https://euroweeklynews.com/2025/06/26/europes-new-arms-race-could-kill-its-climate-goals/, accessed on 27th June 2025.