Many European countries plan to significantly increase their defence and military spending in the coming years. Replenishing weapons stockpiles and training soldiers is unlikely to contribute to a significant reduction in greenhouse gas emissions; strengthening the military power of European states will require substantial financial and political resources. Despite plans in other sectors, the German government, for instance, shows little desire to introduce climate requirements into procurement for weapons and equipment. Experts do not believe that increasing military stockpiles will significantly accelerate the development of sustainable technologies, such as the production of eco-friendly steel. At the same time, it is emphasised that a clear strategic goal could create significant indirect effects.
Will the increase in the production of tanks, artillery and ammunition, which uses thousands of tonnes of steel and other raw materials, not jeopardise emission reduction efforts?
By doubling the defence budget by 2030 and announcing the goal of building “the most powerful conventional army in Europe”, the German government has confirmed its ambition to shake off the poor reputation gained in the previous period. Germany had previously lagged far behind in European security matters and paid little attention to ensuring the combat capabilities of its army. Moving forward, the Bundeswehr budget will rise from ~€62 billion in 2025 to over €150 billion in 2029. Significantly increased spending on security naturally raises a number of questions about how it will affect the energy and climate policy of Europe's largest economy and its goal to achieve climate neutrality by 2045.
Looking at the official Bundeswehr emission data, one can roughly estimate the potential impact. In 2022, the German Ministry of Defence estimated it at ~1.7 million tonnes of CO₂, which corresponds to one large heavy-industry plant. However, the ministry's data does not include emissions from defence industry manufacturing or overseas military missions. A study by an alliance of European non-governmental organisations suggests that emissions are around 10 million tonnes per year, which could rise to 15 million tonnes or more by 2028—roughly 2% of Germany's 2024 emissions, depending on what additional funds are spent on the defence sector.
Emissions are primarily caused by buildings and transport
“It can be said that higher defence spending and greater military potential are generally associated with higher emissions,” notes Ole Adolfsen, a researcher on security and climate policy at the German Institute for International and Security Affairs (SWP), while emphasising that there is no direct link between increasing the military budget and an increase in greenhouse gas emissions. In his opinion, even higher emissions are not inevitable. O. Adolfsen points out that most military greenhouse gas sources in peacetime do not differ from civilian emission sources; therefore, substantial measures to reduce the carbon footprint reflect a country's overall goals – more renewable energy, energy-efficient renovation, more heat pumps and district heating, as well as the electrification of traditional vehicles.
Heating of barracks is the army's largest source of CO₂. These so-called stationary emissions from the more than 33,000 buildings used by the German army are included in a plan for this sector to become climate-neutral by 2030. Of course, this plan will likely increase the costs of the army's planned restructuring. Mobile emissions, on the other hand, refer to everything that allows the army to move troops or equipment, particularly aviation.
Alternatives to fossil resources in the military sphere
Currently, it is difficult to reduce carbon dioxide emissions from military vehicles. Vehicles with low-carbon technologies face many technical and logistical problems, which is why NATO has developed the so-called Single Fuel Concept. A new approach is emerging in these niche categories, even if climate action is not the main driving force, experts note. Russia's war against Ukraine has fully demonstrated that Europe is exposed to risks associated with dependence on fossil fuels.
Since 2015, European military structures have joined the European Defence Agency's Consultation Forum for Sustainable Energy, sharing experience on the energy transition and emission limitation with representatives of national military structures and other sectors to gain the benefits of renewable energy sources, such as greater energy independence. In the 2024 Defence and Climate Change Strategy, the German Ministry of Defence emphasises the need to reform energy supply by gradually introducing “new technologies that ensure the operational readiness of the armed forces in the face of climate change and energy transition, while increasing sustainable development and reducing dependence on increasingly limited resources”.
The desire to combine combat readiness with sustainable development still lags behind the real situation. The German Ministry of Defence points out that reducing emissions in military mobility remains a challenge and that climate policy must not interfere with the army's combat capabilities. Therefore, the additional €100 billion, which was allocated for military needs following Germany's 2022 announcement of the “Zeitenwende” (turning point) security policy change, was used to improve the Bundeswehr's operational capabilities and implement commitments within NATO without stopping the use of fossil resources.
The Ministry of Defence emphasises that the priority will remain unchanged. The German government's main goal is to increase the deterrent and defence capabilities of the Bundeswehr.
Will defence ensure the development of eco-friendly technologies?
Could the development of low-carbon technologies receive a new impetus thanks to the military sector, which is introducing and expanding the use of new technologies?
Former Bulgarian Environment Minister Julian Popov, now a researcher at the Brussels-based think tank Strategic Perspectives, warned in early 2025 that Europe cannot afford ambiguity in aligning military spending with climate change mitigation and adaptation measures to limit costs and capture co-benefits. European Union defence plans, which envisage investing up to €800 billion by 2030, would be a “significant stimulus for European industrial sectors”, such as steel and aluminium production, satellite and drone technologies, battery production, or the production of eco-friendly hydrogen as a climate-neutral synthetic fuel.
Climate-neutral synthetic fuels will have a significant place in the plans of European Union countries to develop new weapon systems that would be compatible with NATO single fuel requirements, as well as with existing engines and vehicles. Defence experts emphasise that there are still supply problems in the market.
The German government's plans for the development of an eco-friendly hydrogen economy have faced uncertainty in recent months, while private companies such as Rheinmetall are increasingly focusing on new technologies. Representatives of the arms manufacturer Rheinmetall stated this May that they plan to quickly transition from fossil fuels to synthetic ones produced from renewable energy sources, calling this step a “necessity for modern defence”.
Germany has major advantages in a situation where the European Union is paying special attention to defence investments. This package of measures stipulates that 2/3 of purchased goods must be procured in Europe. Given the country's still extensive industrial base, the German government's decisions are particularly important for exploiting synergies between military spending and other policy areas, such as climate action. Allocating defence funds to create a market for eco-friendly steel and other sustainable materials would allow the fulfilment of promises included in the German coalition agreement and would align with the business call to strengthen eco-friendly procurement.
The coalition agreement promises to create so-called lead markets for climate-friendly products, for example through “low-emission steel production quotas, eco-friendly gas quotas or public procurement requirements”. The Procurement Acceleration Act, which the German government adopted in early August, would allow for the setting of eco-friendly requirements, but parliament still has to decide on the reform. Could such regulation also apply to Bundeswehr procurement? In response to this question, the German Ministry of Economy considers it too early to discuss, and the actual wording of the regulation, as well as its scope, is still to be discussed and examined... The separate bill on accelerating military procurement does not mention the possibility of introducing climate requirements, and the Ministry of Defence has shown no particular interest in it.
Does the government plan to set quotas for the procurement of climate-friendly materials, such as eco-friendly steel? A spokesperson for the Ministry of Defence replied that the goal is not to jeopardise the operational readiness of German troops. Only then will the armed forces be able to fulfil their main task – defending the country and its allies. Climate action and sustainable development measures can only work if they correspond to the mission of the armed forces. Where possible, the German Bundeswehr combines its core mission with action in the field of climate.
Rainer Bernat, an expert in defence and security sector transformation at PwC*, believes that efforts to expand synthetic fuel production for military needs are promising. At the same time, it is highly unlikely that the increase in defence spending will trigger an exceptionally rapid surge in the German military manufacturing sector and promote eco-friendly production processes. The reason is the relatively small scale when compared with other sectors. For example, the German automotive industry contributes almost €500 billion to the country's GDP annually.
If one were to add up all the investments for defence industry manufacturing earmarked in the growing budget, one could obtain €20-30 billion per year. That is only 5% of the automotive sector's economic output. If all other sectors were included, this share would decrease even further. This means that doubling or even tripling defence spending will not significantly affect Germany's economic growth, nor its overall emissions.
In Germany, funding for research and the development of the security sector is low
In Germany, the share of spending on research and development in the security sector is much lower than in other NATO member states. For example, in 2022, the USA allocated almost half (47%) of its R&D budget to defence, France slightly more than 10%, and Germany – only about 5%. This limits the transfer of the latest technologies from defence innovations to civilian sectors. Increasing research funding for defence could accelerate the development of climate-neutral fuels and other technologies and reduce dependence on US equipment.
Experts point out that as US equipment accounts for the bulk of new weapons procurement, it will be difficult for Germany to achieve sustainable economic benefits from higher military spending. The 2025 report by the Kiel Institute for the World Economy (IfW) acknowledges that higher spending on research in the military field would help to leverage the benefits created by the defence industry's development for the entire economy. Industry experts emphasise that greater investment in research and the latest technologies in Europe could reduce dependence on US-made weapons and technology and turn the defence budget into an addition to long-term economic growth.
It is clear that low-carbon technologies can play a major role in the future defence and security architecture, for example in ensuring the operation of data centres for drone warfare and cybersecurity, for which Germany must first define its military place in Europe. Specialists emphasise – before deciding on procurement, Germany must first answer the question: for what scenario is it preparing? Most likely – Germany is becoming Europe's military logistics hub, which means strengthening comprehensive logistics and transport capabilities.
* PricewaterhouseCoopers, also known as PwC, is a multinational professional services network, headquartered in London. It is the second-largest professional services network in the world and one of the Big Four accounting firms alongside Deloitte, EY and KPMG. The PwC network is overseen by PricewaterhouseCoopers International Limited, an England-based private company, which was formed in its current form in 1998. PwC firms are located in 140 countries and employ 370,000 people. The company's global revenue in the 2022 financial year was $50.3 billion, of which $18 billion was generated by its independent and professional accounting services practice, $11.6 billion by its tax and legal practice, and $20.7 billion by its consulting practice.