The climate toll of war

While the world watches harrowing footage of the 2026 Iran–US conflict through the lens of humanitarian tragedy and geopolitical instability, a second, quieter casualty is unfolding in the atmosphere. 

Beyond the immediate horrors of the battlefield, modern warfare has become a vast emissions event—one that threatens to derail global climate goals. This conflict has already generated a carbon footprint so large that it challenges how we think about national emissions.

The staggering environmental costs

The scale of the atmospheric damage is difficult to grasp. Preliminary data suggest that the first 24 days of the Iran conflict generated an estimated 7.2 million tonnes of CO₂ equivalent (tCO₂e). Put simply, less than a month of fighting has produced more emissions than the annual total of a developed economy such as Iceland.

This surge is driven by the extreme energy intensity of high-tech warfare. The US–Israeli alliance alone conducted more than 2,500 air sorties in the first two weeks, consuming an estimated 150–270 million litres of jet fuel. 

At the same time, the destruction of roughly 20,000 buildings has released the "embodied carbon" once locked into their steel and concrete—effectively depleting the global carbon budget with no social benefit.

Toxic legacies and "black rain"

The environmental damage extends far beyond warming. The conflict has turned Tehran and the surrounding areas into what some experts describe as a "chemical event". Strikes on oil storage facilities, including the Shahran fuel depot, have triggered what is known as "black rain"—a toxic mix of oil residues and precipitation that contaminates water, soil and air, affecting millions of residents.

These pollutants do not respect borders. Disruptions in the Strait of Hormuz, through which around 20% of the world's oil passes, have forced global shipping onto longer, more carbon-intensive routes, significantly increasing emissions. Meanwhile, attacks on nuclear and uranium facilities raise the spectre of radioactive contamination, posing long-term ecological and public health risks across the Middle East.

The hidden cost of rebuilding

Perhaps the most insidious climate impact of war is the "carbon multiplier effect". While direct combat emissions are substantial, they are only the first draw on the global carbon budget. 

The emissions required to clear debris and rebuild cities are projected to be 1.5 to 3 times higher than those generated during the fighting itself. In some recent conflicts, reconstruction has produced many times the emissions of the war.

This creates a double burden: the carbon budget is depleted once during destruction and again during reconstruction—at a time when the world has only about 2.8 years of "allowable" emissions left to keep warming within 1.5°C.

The global reporting gap

One reason these costs remain overlooked is a structural lack of transparency. Reporting military emissions to the UNFCCC is currently voluntary and inconsistent. Estimates suggest that the world's militaries account for roughly 5.5% of global greenhouse gas emissions—enough to rank them as the fourth-largest emitter if treated as a single entity, behind only China, the US and India.

Yet, as institutions such as the IMF and World Bank convene, attention is shifting away from climate finance towards rising defence spending. Funds intended to support climate adaptation in the Global South risk being diverted to sustain high-intensity warfare, leaving the most vulnerable nations to bear the consequences of conflicts they did not initiate.

A turning point for energy security

The Iran–US conflict underscores a difficult truth: energy systems built on concentrated fossil fuel reserves are inherently geopolitically fragile. At the same time, it highlights a path forward. The most effective defence against the energy shocks of the 21st century is not simply a larger military budget, but a decentralised, resilient renewable energy system.

Sunlight cannot be blocked in the Strait of Hormuz, and wind cannot be held hostage by shipping routes. The transition to clean energy is no longer just an environmental aspiration; it is a matter of national and global security. If we are to preserve a habitable planet, the environment cannot remain a side note to war—it must be recognised as a central pillar of lasting security.

Kazi Ayman Awsaf is a law student and undergraduate teaching assistant at East West University. He can be reached at kaziaymanawsaf@gmail.com.

Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the opinions and views of The Business Standard.