At a time when the world continues to speak about energy transition, decarbonization, and limiting global warming, one major source of emissions remains too often overlooked: the military and war. Public attention tends to focus on emissions from vehicles, industry, power generation, or households. Yet beyond that, countries are pouring ever-larger budgets into weapons, military operations, bases, combat logistics, and post-war reconstruction. The question worth asking is no longer just whether war destroys human life, but also: does rising military spending contribute to heating the planet?[1]

The answer is increasingly difficult to deny: very likely, yes. And this relationship is not merely a moral assumption or political critique—it is becoming increasingly visible in data, budget trends, and recent academic findings. The world is moving in a paradoxical direction: on one hand demanding rapid emissions reductions, while on the other continuing to expand funding for systems that are highly energy-, material-, and carbon-intensive.[1][2]

A World Is Rearming Itself

Recent data from the Stockholm International Peace Research Institute (SIPRI) shows that global military expenditure reached USD 2.718 trillion in 2024, a real increase of 9.4 percent compared to 2023. This is not only the highest level ever recorded by SIPRI, but also the sharpest annual increase since the end of the Cold War. More importantly, it marks ten consecutive years of growth in global military spending. Between 2015 and 2024, global military expenditure increased by approximately 37 percent, while the global military burden rose to 2.5 percent of global GDP.[1][3]

These figures point to something larger than a fiscal shift. They signal a shift in global priorities. At a time when the world requires massive investment in renewable energy, climate adaptation, ecosystem restoration, and social protection, trillions of dollars are instead being allocated to expanding military capacity. At this point, military spending can no longer be viewed solely as a security issue; it is also a climate issue and a question of global development direction.[1][3]

A Clearer Correlation

Recent scientific evidence strengthens this connection. A study published in Nature Communications in 2025 finds a statistically significant positive correlation between the ratio of global military spending to global GDP and global CO₂ emissions intensity over the period 1995–2023. The study notes that every 1 percent increase in the global military spending ratio is associated with an increase of about 0.04 kg/USD in CO₂ emissions intensity. Researchers estimate that this factor explains around 27 percent of the total change in global emissions intensity during that period.[2]

This finding is important because it shows that global militarization is not climate-neutral. The more the world allocates resources to military expenditure, the greater the likelihood that the global economy shifts toward a more carbon-intensive pathway. This does not mean that every dollar of military spending can be directly translated into a fixed amount of additional emissions, but the broader pattern is clear: increasing militarization makes decarbonization more difficult.[2]

War Emissions Do Not Only Come from Explosions

War’s carbon footprint is often imagined as coming from tanks, fighter jets, warships, or battlefield explosions. In reality, this picture is too narrow. Military emissions extend much further: from weapons production, base construction, and logistics supply chains, to the operation of vehicles and fleets, energy supply for military infrastructure, and post-war reconstruction that consumes large amounts of materials and energy.[4][5]

Analyses compiled by the Conflict and Environment Observatory (CEOBS) suggest that the global military is responsible for approximately 5.5 percent of global emissions. However, this figure is likely conservative, as reporting of military emissions to international climate systems remains weak, inconsistent, and often insufficiently detailed. In many cases, military emissions are mixed with civilian categories, or not adequately reported at all.[4][6]

This is where one of the biggest problems lies: the world is calculating climate targets with incomplete data. As military budgets rise, operations expand, and prolonged conflicts persist, we are dealing with a sector whose carbon transparency remains low. In other words, what is not properly recorded may in fact represent a significant portion of the problem.[4][6]

When War Ends, Its Emissions Do Not

There is a bitter irony in every war. When the fighting stops, its carbon footprint does not stop with it. Destroyed cities must be rebuilt. Roads, bridges, ports, power grids, hospitals, schools, and homes all require reconstruction. These processes depend heavily on materials such as cement and steel, which are among the most carbon-intensive commodities in modern development.[5]

UNEP’s Global Status Report for Buildings and Construction 2024/2025 notes that the building and construction sector accounts for around 34 percent of global CO₂ emissions, and relies heavily on materials like cement and steel, which together are linked to about 18 percent of global emissions. This means that war not only generates emissions during conflict, but also creates a new wave of emissions during reconstruction. The carbon footprint of conflict is therefore long-lasting and layered.[5]

A Trend That Can No Longer Be Ignored

When viewed as a trend, the pattern becomes increasingly clear. First, global military spending is rising sharply.[1][3] Second, recent scientific research shows a positive correlation between rising military expenditure and CO₂ emissions intensity.[2] Third, military emissions are likely higher than officially recorded due to weak reporting and low transparency.[4][6] Fourth, conflict increases emissions not only directly, but also through industrial systems, logistics, and post-war reconstruction.[4][5]

Taken together, these four patterns lead to a difficult conclusion: the higher global militarization rises, the more challenging it becomes for the world to meet its climate targets. This is not merely a moral issue linking war and environmental damage, but a structural feature of the global political economy, which continues to fund carbon-intensive systems while simultaneously claiming to reduce emissions.[1][2]

True Security and the Future of Climate

Climate debates have too often been framed around consumer behavior, electric vehicles, solar panels, or household efficiency. All of these are important, but they do not address the core issue if large-scale political decisions continue moving in the opposite direction. Rising military spending shows that the world faces a sharp contradiction: calling for decarbonization while continuing to expand funding for systems that are highly energy-intensive, lack carbon transparency, and are closely tied to conflicts that generate further emissions.[1][4]

Ultimately, this issue is not only about war or budgets—it is about civilizational choice. The world can continue pouring trillions of dollars into expanding military capacity, or begin to recognize that security in this century is not determined solely by weapons, but also by climate stability, water availability, food security, public health, and ecosystem resilience. If the planet continues to be heated by the systems we build, then war does not only destroy cities and lives—it also erodes the possibility of a livable future.[2][5]

Footnotes

• [1] SIPRI, “Unprecedented rise in global military expenditure as European and Middle East spending surges,” April 28, 2025. Key data: global military spending reached USD 2.718 trillion in 2024, up 9.4% in real terms from 2023, marking the fastest growth since the end of the Cold War.
• [2] W. Dong et al., “Rising military spending jeopardizes climate targets,” Nature Communications, 2025. The study finds a significant positive correlation between global military spending ratios and CO₂ emissions intensity; a 1% increase in spending ratio is associated with a 0.04 kg/USD increase in emissions intensity, explaining about 27% of variation from 1995–2023.
• [3] SIPRI, “Trends in World Military Expenditure, 2024,” Fact Sheet, April 28, 2025. Confirms ten consecutive years of rising military spending, increasing by 37% between 2015–2024 and reaching 2.5% of global GDP.
• [4] Conflict and Environment Observatory (CEOBS), “New data reveals the Military Emissions Gap is growing wider,” November 6, 2025. Estimates the military accounts for around 5.5% of global emissions, with weak and incomplete reporting to UNFCCC.
• [5] UNEP / GlobalABC, “Global Status Report for Buildings and Construction 2024/2025,” March 17, 2025. The building sector contributes 34% of global CO₂ emissions; cement and steel are linked to 18% of total emissions.
• [6] UNFCCC Global Stocktake Submission, “Military and Conflict Emissions,” civil society summary highlighting poor global military emissions data and underestimation of total impact.

Contributor:

Meiardhy Mujianto