Climate change leadership requires more than stirring speeches. It means facing up to hard truths. One truth that governments around the world are struggling with is the immense contribution their militaries are making to the climate crisis.
For example, the US Department of Defense is the largest institutional consumer of fossil fuels in the world – and the largest institutional emitter. Two of us worked on a 2019 study that showed that if the US military were a country, its fuel usage alone would make it the 47th largest emitter of greenhouse gases in the world, sitting between Peru and Portugal. In other words, the American military is a more consequential climate actor than many of the industrialised countries gathered at the COP26 summit in Glasgow.
Despite the outsized role of militaries, we know surprisingly little about their emissions. This is remarkable given their reach and fossil fuel dependency. Some scientists estimate that, together, militaries and their supporting industries might account for up to 5% of global emissions: more than civilian aviation and shipping combined.
One reason we know so little is due to militaries being one of the last highly polluting industries whose emissions do not need to be reported to the United Nations. The US can…