Declaring war on the climate

Military spending rises will increase these emissions. However, the exact relationship between military spending and military carbon emissions is highly complex and not easy to predict. 

For example, will extra funding be mainly used to increase military activity, leading to rises in fossil fuel use by combat planes or warships? 

Or will the funding be used to expand the numbers of military personnel, leading to rises in energy consumption at military bases, or the construction of new bases? 

Or will extra money be mainly directed towards expanding arms production, leading to higher energy consumption in industry or in the production of high carbon raw materials? 

Emissions

Extra carbon emissions in the supply-chain could occur outside the home nation, making them harder to track. Then there is also the issue of additional global heating effects due to non-CO₂ emissions from aviation in the stratosphere. 

These complexities have led to a burst of research activity attempting to understand and predict how carbon emissions vary with military spending levels. 

A new review report – written by myself and published by Scientists for Global Responsibility – has assessed the findings of 11 studies from the past two years that have tried to estimate how military spending rises will impact carbon emissions. 

Our review concluded that a standardised spending rise of $100 billion will lead to an increase in the military carbon footprint of approximately 32 million tonnes of carbon dioxide equivalent (tCO₂e). 

However, the uncertainty in that figure is high due to limited data on military emissions and the complexities described above. Thus, the figure for the emissions increase could be as high as 59 million tCO₂e. 

Reconstruction

Applying this analysis to a specific case, we found that the increase in NATO’s military spending over the five years, 2019-24 has led to an increase in its military carbon footprint of about 64 million tCO₂e – similar to the territorial emissions of Bahrain. 

Furthermore, the planned increase to hit the 3.5 per cent GDP spending target is likely to lead to an additional rise of about 132 million tCO2e – more than the territorial emissions of Chile.  

It is important to note that these are single-year totals and so, if spending is maintained at higher levels as currently planned, there will be a major cumulative impact of emissions on the climate system. 

For example, ten years of extra spending by NATO above 2024 levels would add about 1,320 tCO2e – equivalent to the annual emissions of the whole of Brazil. 

And these estimates do not include emissions due to the impacts of war-fighting, such as destruction of carbon reservoirs or post-war reconstruction.

Abate

As mentioned, the uncertainty in these estimates is high. Hence, one key recommendation of the report is that measuring and reporting of direct and indirect military carbon emissions are greatly improved, so that the changes resulting from military spending rises can be adequately monitored.

However, despite the uncertainties, the research is unequivocal in highlighting that much stronger efforts are needed to reduce the military carbon footprint. 

This is not a message that militaries and militaristic governments want to hear. Even when they accept that there is a problem, they favour efforts to develop ‘greener’ weapons systems. 

Putting aside the serious ethical conflicts associated with this path, there are huge technical obstacles. Civilian decarbonisation researchers point to several sectors which are ‘hard-to-abate’. 

These include aviation, shipping, trucking, iron and steel, aluminium, and synthetic chemicals. The military is – in technological terms – an amalgamation of these sectors, meaning that it is the hardest of the hard-to-abate sectors.

Peace

This emphasises the urgent need to prioritise peace-building efforts in global affairs. Much greater use of diplomacy, mediation, and trust-building are essential. 

The importance of more arms control and disarmament measures is undeniable. One more hopeful finding from our report is that, when military spending is cut, emissions tend to fall at a faster rate than they grew, because the least energy-efficient technologies tend to be retired first. 

But the latest assessment by leading climate scientists is bleak. They say that the Paris 1.5°C target will be breached within a few years without “immediate, transformative action… to reduce emissions”. 

It is extremely difficult to see how the current and planned military spending increases can be reconciled with the transformative action necessary to prevent dangerous climate change. We must be louder in our calls for peace. 

This Author

Dr Stuart Parkinson is executive director of Scientists for Global Responsibility where he has co-ordinated research, education and campaigning on ethical issues across science and technology. He holds a PhD in climate change science, has been an expert reviewer for the Intergovernmental Panel on Climate Change, and has written several influential reports on military carbon emissions.