Understanding greenhouse gas emissions from defence

What are the GHG emissions of the defence sector and industry, and how they can be reduced across the lifecycles of defence-related products?

GHG emissions associated with the broader defence sector are currently not well documented and estimates vary. A recent study estimates the total carbon footprint of the defence sector to be approximately 520 MtCO2e each year or 1% of global man-made GHG emissions.1 This compares with 12% from road transport, and 2% from each the civil aviation and the maritime sectors.1 The European defence sector is estimated to contribute approximately 6% of defence emissions.2

Defence emissions

Emissions from the defence industry can be broken down as:

  • Emissions resulting from the production of military equipment (from raw material extraction to final product delivery) and its operation by the armed forces today account for 70% of the total.
  • The remaining 30% stems from military facilities and infrastructure.1

The defence industry contributes to the emissions associated with military equipment production and operation. These can be categorised in ‘scopes’, which cover industry’s own operations (scopes 1 and 2), its supply chains (scope 3 upstream), and the usage of its products by militaries (scope 3 downstream).

It is estimated that for military equipment, manufacturing accounts for 5-10% of the lifecycle carbon footprint (scope 1 and 2), emissions from the supply chain account for 20-30% (scope 3 upstream), and emissions from the operation of the product for the remaining 65-75% (scope 3 upstream; all scope percentage data from Boston Consulting Group internal report 2022).

While there are increasing efforts to reduce the carbon footprint of existing military equipment, the defence industry is also working to reduce the footprint of future products across their lifecycle. To achieve this, industry is improving manufacturing processes and future product design, and working with its suppliers to decarbonise their operations.

The challenge of decarbonising defence

What are the factors that make decarbonising defence particularly challenging?
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  1. Roland Berger, Defence Zero: Military Emissions and Potential Solutions (2023).
  2. Scientists for Global Responsibility, Estimating the Military's Global Greenhouse Gas Emissions (2022).