Today there are more active conflicts than at any time since World War II—over 50 in total, many of which are deeply entrenched and complicated by international involvement. From the humanitarian catastrophe in Gaza to the prolonged violence in Syria, the ongoing crisis in Sudan, and the war in Ukraine, global efforts to end these conflicts remain fraught with setbacks and competing interests. 

While the immediate priority is ending the violence, it is equally imperative to think about what comes next. Without a clear, forward-looking plan, the aftermath of conflict risks becoming fertile ground for future instability.

History shows that the transition from war to peace is perilous: power vacuums, unresolved grievances and fragile institutions often lead to cycles of renewed violence. Past reconstruction efforts, such as the Marshall Plan in post-war Europe or Japan’s transformation after World War II, focused on rebuilding infrastructure. But modern conflicts demand far more holistic approaches. Community security, institutional reform, economic revitalisation, refugee resettlement, reconciliation and inclusive governance are essential. Even these strategies may not be enough: nearly half of all conflicts risk recurring within a few years. To break this cycle, new ideas are needed.

One critical yet often overlooked dimension of post-conflict reconstruction is the impact of climate change. Rising temperatures, prolonged droughts and resource depletion exacerbate tensions, while severe floods, hurricanes and storms devastate already fragile communities. If ignored, these climate stresses can undermine fragile peace and leave societies vulnerable to future instability. Yemen offers a stark example, where climate impacts are compounding the devastation of war, overwhelming already weakened adaptation systems and fuelling further violence.

To build lasting peace, post-conflict reconstruction must embed climate resilience at its core. This means investing in infrastructure that can withstand future climate shocks, restoring degraded environments and fostering community engagement to rebuild social cohesion.

In Syria for instance, climate change is expected to lead to more extreme heat, intense storms, sea level rise and increased coastal flooding and erosion. Rebuilding without accounting for these looming threats risks wasting billions on infrastructure that will fail under increasingly severe weather conditions. Roads, buildings and energy systems must be designed to endure —not just the next storm, but the storms of the next century.

The environmental impacts of conflict are equally stark, making restoration a critical pillar of reconstruction.  In Gaza, for example, the World Bank estimates that the environmental costs of the conflict, including groundwater contamination, hazardous waste pollution and destruction of the coastal zone, amounted to US$411 million as of March 2024. This figure excludes the harder to quantify costs of damage to human health, agriculture and food safety. Addressing such challenges requires projects that tackle water scarcity, improve wastewater treatment and restore ecosystems. Effective debris management is also essential: in Gaza, unmanaged debris hinders humanitarian efforts and poses safety risks. A “Gaza Debris Management Framework” has been developed by humanitarian organisations, but its implementation hinges on securing the necessary financial and political support. 

Beyond infrastructure and environmental restoration, rebuilding the social fabric of post-war societies is equally critical. Community engagement and social cohesion are not just desirable—they are essential to maintaining peace. Medellín, Colombia offers a powerful example. After decades of conflict, innovative reconstruction policies leveraged community participation and strategic investments in public spaces, amenities and mobility infrastructure to rebuild trust and foster resilience. Trauma recovery and mental health services are also vital.  In Ukraine, international organisations are already providing mental health support to some communities. Expanding access to these services will be crucial for individuals striving to rebuild their lives and contribute to broader recovery efforts. 

In today’s fractured geopolitical landscape, addressing climate and environmental challenges offers an opportunity for cooperation. Initiatives that advance the Sustainable Development Goals, such as promoting decent work and sustainable livelihoods, can serve as building blocks for stability. The Organization for Security and Co-operation in Europe (OSCE) has demonstrated how climate-related security frameworks can foster collaboration in post-conflict regions. In South-Eastern Europe, the South Caucasus and Central Asia, the OSCE has facilitated partnerships to address issues such as illegal logging and wildfires, promoting sustainable livelihoods and climate resilience.

The stakes are clear: post-conflict reconstruction must evolve to address the climate crisis—or risk failure. Traditional approaches that treat environmental and climate concerns as secondary are increasingly unsustainable. The UN must embed climate expertise within peacekeeping missions, while donors need to shift from short-term projects to sustained investments in resilience. Development banks should prioritise climate-adaptive infrastructure in fragile states. Evidence from Colombia to Central Asia shows that climate-sensitive reconstruction not only prevents environmental degradation but actively contributes to peace. 

As today's conflicts eventually subside, the choice is clear: integrate climate resilience into reconstruction or face repeated cycles of rebuilding as both conflict and climate impacts worsen.