Global warming caused by war

Global Military Emissions (Routine Operations, Excluding Active Warfare)

The military sector worldwide is responsible for approximately 5.5% of global GHG emissions, which includes CO₂ and other gases The NationWikipedia. In CO₂ terms alone, that amounts to around 2,050 million tonnes (MtCO₂) annually Scientists for Global Responsibilityceobs.org.
More conservative estimates put operational military emissions at about 500 MtCO₂e, or 1% of global GHG emissions, while the overall military footprint (including production, logistics, etc.) reaches 2,750 MtCO₂e, which corresponds to 5.5% of global GHG emissions ceobs.org.

U.S. Military-Specific Emissions

In fiscal year 2021, the U.S. Department of Defense (DoD) emitted 51 million metric tons of CO₂e, roughly equivalent to the entire annual emissions of Sweden The Atlantic.
From 2001 to 2018, U.S. military GHG emissions—including troop operations, infrastructure, and war zones—totaled around 1,267 MtCO₂e. Of that, more than 440 MtCO₂e stemmed specifically from war-related operations (Afghanistan, Iraq, Syria) Watson Institute.
Overall U.S. military emissions from 1979 to 2023 are estimated to be nearly 4,000 MtCO₂e, a scale comparable to the entire annual emissions of India The Guardian.

Conflict-Related Emissions: Active Warfare and Reconstruction

Ukraine (Russia–Ukraine War)

During the first two years of the conflict (Feb 2022 – Feb 2024), the war released approximately 175 Mt CO₂efrom battlefield destruction and infrastructure damage Wikipedia.
Another study estimated 77 Mt CO₂e over the first 18 months of the war ScienceDirect.

Gaza (Israel–Gaza Conflict, October 2023–February 2024)

Direct emissions from military action in the first 120 days were estimated between 420,265 and 652,552 tCO₂e (tonnes) Queen Mary University of London.
A broader estimate—including post-war reconstruction—suggests emissions between 47 and 61 Mt CO₂ in just the first 120 days The Review of Religions.
Reconstruction efforts—clearing rubble—could add over 90,000 tonnes (0.09 Mt) CO₂e, with long-term rebuilding possibly reaching 31 Mt CO₂e, which is more than the annual emissions of countries like Costa Rica and Estonia The Guardian+1.

Iraq War (2003–2011)

The nine-year Iraq War generated approximately 254 Mt CO₂, about the annual emissions of Spain in 2016 transformdefence.org.
Another source reports more than 50 billion tonnes (50 Gt!) of carbon emissions from burning Iraqi oil fields, though that figure seems likely inflated or erroneous as such a value would surpass global annual emissions by orders of magnitude Wikipedia. It's best to treat that figure with caution.

Key Figures at a Glance

Source of Emissions	Estimated CO₂ / CO₂e
Global military operations (annual)	2,050 Mt CO₂
Full military footprint (including production)	2,750 Mt CO₂e (~5.5%)
U.S. DoD (FY 2021)	51 Mt CO₂e
U.S. military (2001–2018) war operations	440 Mt CO₂e
Total U.S. military (1979–2023)	~4,000 Mt CO₂e
Ukraine War (≈2 years)	~175 Mt CO₂e
Gaza War (first 120 days, direct operations)	0.42–0.65 Mt CO₂e
Gaza War (with reconstruction)	47–61 Mt CO₂
Iraq War (2003–2011)	~254 Mt CO₂
Gaza Reconstruction (clean-up)	~0.09 Mt CO₂e

In Summary

Routine military emissions alone contribute significantly—roughly 5.5% of global GHG emissions.
Large-scale conflicts, like those in Ukraine, Iraq, or Gaza, add substantial additional emissions through burning, destruction, and rebuilding.
Even localized battles, such as the early Gaza conflict, can produce comparable CO₂ amounts to small or mid-sized nations within just a few weeks.

If you'd like, I can also break these numbers down per year, compare to specific countries' emissions, or explore how future conflicts or reconstruction efforts are projected to impact our carbon budget.

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Further reading on military emissions and conflict‑related climate impacts