In 2024 global defence spending surged to a record 2.7 trillion dollars, the sharpest increase in decades, even as international efforts to mobilize adequate finance for climate action continued to falter. The contrast could not be starker. Trillions were marshalled for tanks, fleets and missile systems while entire regions faced crop failures, unrelenting floods and extreme heat with only modest resources to adapt.
This divergence is not simply a matter of different budget lines. It is a reflection of a fundamental misjudgment about what truly secures societies in the twenty first century. The global community risks investing in the wrong future by continuing to equate security with weaponry while leaving climate resilience underfunded and underprioritized.
Budgets speak louder than words. They are declarations of national intent and political priority. When governments can mobilize extraordinary resources to acquire fighter jets or submarines but struggle to fund climate adaptation or disaster preparedness the imbalance exposes how outdated the current definition of security has become.
Armed conflict between states is no longer the greatest destabiliser of societies. It is the cascading consequences of climate change that are dismantling economies, displacing populations and straining political institutions beyond their capacity. The storms, fires, floods and heatwaves of recent years have shown how fragile modern economies can be in the face of environmental breakdown. Yet global responses continue to treat militarisation as urgent and climate adaptation as negotiable.
This contradiction is unsustainable. A country may stockpile sophisticated weapons systems and fortify its borders, but these measures are powerless against prolonged droughts that devastate harvests, against rising seas that swallow coastal cities, or against relentless heatwaves that make regions uninhabitable.
Security doctrines rooted in the twentieth century were designed to respond to external threats, but the destabilising risks of the twenty first century arise from within. They emerge in the form of climate driven migration, collapsing food systems, and mounting competition for water and arable land. These risks are already fuelling instability and in many regions are more consequential than military confrontation.
The economic imbalance makes the point unavoidable. The Sustainable Development Goals require an estimated 6.4 trillion dollars annually to be achieved. Developing nations alone will need nearly 400 billion dollars a year to adapt to climate impacts. These are daunting sums, but they are within reach of a global economy that is already allocating almost three trillion dollars a year to defence. The issue is not that the money does not exist, but that political will directs it overwhelmingly to militarisation while existential threats from climate collapse are allowed to escalate unchecked. If governments can fund aircraft carriers without delay, they can also fund seawalls, resilient agriculture and renewable energy grids if they choose to.
The moral implications are equally troubling. Citizens hear their governments speak of fiscal scarcity when budgets for schools, hospitals or disaster relief are discussed. Yet when new procurement contracts for weapons are proposed, the money is suddenly available. Younger generations who are acutely aware of the climate emergency see this imbalance and conclude that leaders are not serious about protecting their future. Public trust erodes when commitments to climate goals are made on global stages but defence budgets continue to expand with little scrutiny.
Compounding this mistrust is the fact that the defence sector remains one of the least transparent when it comes to emissions. Shielded by arguments of national security, militaries rarely disclose the true environmental footprint of their operations, even though the sector is among the largest institutional consumers of fossil fuels worldwide. If militaries cannot even account for their role in the climate problem, their claim to safeguard future generations rings hollow.
The concept of security therefore requires urgent redefinition. Security cannot be measured exclusively in battalions, submarines and aircraft. True security is the resilience of societies to withstand shocks, the sustainability of ecosystems that sustain life, and the strength of institutions that maintain legitimacy and cohesion.
A nation that can deter invasion but cannot protect its citizens from climate disaster is not secure. A world that is armed to the teeth but incapable of halting ecological collapse is not stable. The old divisions between national defence, climate action and development policy no longer hold. They are inseparable and mutually reinforcing, and strategies must reflect that reality.
Middle powers such as India illustrate the stakes of this redefinition. India is simultaneously one of the largest defence spenders and among the most climate vulnerable nations. Its trajectory in the next decade will test whether robust military capabilities and climate responsibility can coexist.
Treating them as parallel agendas risks hollowing out national security, because unchecked climate disruption will undermine internal stability regardless of military strength. By contrast, pioneering a security framework that integrates resilience and sustainability into planning would not only strengthen domestic stability but also provide a global model for others to follow. The same logic applies to the United States, China and Europe. No nation however wealthy or militarised can insulate itself from accelerating climate disruption.
History offers perspective. Civilisations are rarely remembered for the size of their arsenals. They are remembered for whether they recognised the defining threats of their age and acted decisively. The defining test of this generation is not an arms race between nations but the survival race against climate breakdown. Every dollar that continues to be diverted from resilience to weapons represents a choice for short term deterrence over long term survival. The opportunity cost is profound. Investments in militarisation may deter hypothetical wars, but investments in climate resilience can prevent certain catastrophe.
Reversing this trajectory will require political courage and visionary leadership. It will require governments to acknowledge openly the environmental cost of militarisation, to rebalance budgets in ways that align with twenty first century realities, and to recognise that the defence of the future is rooted in climate resilience as much as in deterrence. Leadership in this era must not be measured in the number of aircraft procured or warships commissioned. It must be measured in the ability to safeguard the systems that make life possible. Anything less is not strategic foresight but abdication of responsibility.
The world has shifted priorities before at moments of peril. After wars, nations have redirected resources from weaponry to reconstruction. At times of global challenge, rivals have set aside competition to cooperate for survival. In moments of despair, societies have chosen renewal when the stakes were highest.
The present moment demands a similar shift. The choice facing governments is stark. They can continue pouring trillions into arsenals designed for battles that may never occur, or they can redirect resources to confront a climate crisis that is already destabilising the world. The path chosen will determine not only economic stability but the legitimacy of leadership in the decades ahead.
Weapons may secure borders, but only climate action can secure the future.
