Sustainability and Security

For a long time, the sustainability world and the defence world have viewed each other with caution.

One focused on protecting the planet and improving long term wellbeing. The other focused on protecting nations through military strength and strategic deterrence. They occupied different conferences, used different language and were funded by different institutions. Yet the reality emerging today is that sustainability depends on stability, and stability depends on security. This raises an important question for investors and policymakers: should those who care about environmental progress now be more open to supporting traditional areas of defence? The answer is increasingly, yes.

The starting point is simple. Environmental goals cannot be achieved in a vacuum. They need functioning institutions, stable societies and peaceful conditions. Where states face persistent insecurity, they struggle to invest in renewable energy, nature recovery or modern infrastructure. Fragile governments are repeatedly pulled back into crisis response. Regions suffering from conflict often see ecosystems degraded, water sources polluted and land mismanaged. Even the best designed sustainability programme cannot take root in environments where violence or instability disrupt daily life.

This is why security is emerging as a foundational layer of sustainability rather than its opposite. Strong early warning systems, maritime security, air defence and cyber resilience all protect the infrastructure that a low carbon economy depends upon. Without secure borders and credible deterrence, critical assets can be vulnerable to disruption through conflict or coercion. In such conditions progress towards net zero, clean power and restored ecosystems can be set back by decades.

There is also a practical reason for sustainability minded investors to engage more openly with defence. Many of the technologies that support clean energy and resilient infrastructure rely on supply chains that must be protected. Undersea interconnectors, offshore wind, solar arrays, battery minerals, long duration storage, grid power electronics and advanced recycling all depend on international trade routes and stable global logistics. Defence forces safeguard these routes. Maritime security protects shipping lanes that carry critical minerals. Air defence protects energy networks. Space and cyber capabilities protect communications and data. These services are rarely discussed in the sustainability sector but without them much of the modern green economy cannot function.

A second consideration is deterrence. Nations with credible defence capabilities are better positioned to pursue long term environmental strategies because they are less susceptible to external pressure. Countries that lack this security often find their energy transition shaped by the interests of stronger neighbours. Reliable defence allows governments to make independent choices about clean energy, land use and industrial policy. It strengthens political space for climate ambition rather than constraining it.

There is also a humanitarian dimension. Environmental harm and conflict often reinforce each other. When conflict breaks out, forests are cleared, wildlife is lost, water systems break down and emissions rise. When environmental conditions deteriorate, tensions over resources intensify. Supporting stability and reducing the likelihood of conflict therefore becomes a form of environmental protection. Defence capabilities are part of that picture. They help prevent escalation, support peacekeeping and provide rapid response when disasters strike. For communities vulnerable to climate impacts this support can be life changing.

None of this means that sustainability investors must abandon their principles or support every aspect of defence spending. On the contrary, the principles and approaches developed in sustainability investing can be applied to ensure defence businesses operate responsibly. But it does mean recognising that a stable world is a necessary condition for a sustainable one. It means understanding that traditional security capabilities underpin the systems that clean energy, nature restoration and resilient infrastructure rely on. It also means being willing to engage in a more honest conversation about how national security and environmental progress depend on each other rather than sit in opposition.

As governments rethink their approach to security, there is a growing opportunity to build alignment between environmental resilience and national capability. Sustainability and defence are parts of the same long-term challenge: how to build societies that are safe, stable and able to prosper for decades to come.