Peace is under immense and multifaceted pressure in the 21st century. No longer defined solely by the absence of war, it is increasingly threatened by ecological breakdown, widening economic inequality, demographic shifts, and political fragmentation. These intersecting factors destabilize societies, erode public institutions, and undermine systems that protect population health, human dignity, and social cohesion.

As crises converge, there is an urgent need to rethink what it means to build peace and safeguard public health in an unstable world. It demands strategic investment in health equity, ecological sustainability, and gender justice, pillars that strengthen societal resilience and promote long-term human security, defending and safeguarding the rights and well-being of future generations.

Escalating armed conflicts and geopolitical tensions

The world is witnessing a resurgence of prolonged and complex conflicts. The UN Secretary-General has warned that global peace is becoming increasingly elusive, with conflicts deepening and international cooperation weakening (UN, 2024). In 2023, nearly 2 billion people lived in conflict-affected areas (UN, 2023), profoundly affecting health, social cohesion, and development. By 2024, the UN recorded around 32 million refugees and 67 million internally displaced people (IDPs) (Statista, 2025). Children in conflict zones are particularly affected, facing direct violence, malnutrition, psychological trauma, and preventable disease due to the breakdown of healthcare systems and essential services (Bhutta et al, 2021).

The scale of global militarization compounds the crisis. Global military spending reached an unprecedented $2.72 trillion in 2024, a 9.4% increase from the previous year and the steepest rise since the end of the Cold War (SIPRI, 2024, 2025). The erosion of arms control treaties and the modernization of nuclear arsenals pose an additional layer of global health risks. Key treaties such as the Intermediate-Range Nuclear Forces (INF) Treaty and the New START agreement have either collapsed or face uncertain futures, undermining decades of disarmament efforts (Arms Control Association, 2025; Brookings Institution, 2019).

As the Doomsday clock has moved to its most perilous position since its establishment in 1947, the escalation of conflict between nuclear-capable states, including the current crisis between Russia and Ukraine, and between Iran and Israel, increases the risk for global instability (Science and Security Board, 2025). As of 2024, nine countries maintain approximately 12,121 nuclear weapons, with over 2,000 on high alert (SIPRI, 2024). Beyond the existential risk of nuclear war, nuclear testing and environmental contamination have left lasting scars on communities, especially in the Pacific Islands and Central Asia, where countries are now calling for renewed WHO-led assessments to examine intergenerational health impacts and integrate nuclear preparedness into public health systems (Zarocostas, 2025).

Escalating geopolitical tensions, environmental collapse, and declining public trust are gravely testing the foundations of peace and stability. The shifting centers of influence, the politicization of global aid, and rising nationalism further complicate the collaboration on issues critical to human survival such as climate, health, and security thus weakening global governance.

Rivalries between major powers, such as the U.S.–China trade conflict, have intensified protectionism and fragmented global cooperation on sustainability and health. The UN Secretary-General has warned that existing global security arrangements are "disintegrating," with multilateral disarmament mechanisms failing to adapt to the complexities of a multipolar and climate-stressed world (Reuters, 2024).

Planetary health crisis as a conflict multiplier

Environmental degradation is no longer an ecological concern but a conflict accelerator. A planetary health perspective reveals how climate shocks, biodiversity loss, and pollution drive displacement, erode livelihoods, and deteriorate fragile governance systems. These disruptions in natural systems trigger and amplify social, economic, and political tensions, while undermining health systems and population well-being. The IPCC's Sixth Assessment Report highlights how climate-driven events such as droughts and resource scarcity are linked to food insecurity, armed conflict, and mental and physical health burdens (IPCC, 2023).

Research by Mach et al. (2019) supports this view, noting that climate factors, particularly drought and temperature extremes, affect organized armed conflict, though socioeconomic development and low capabilities of the state are judged to be more influential. Hao et al. (2023) argue that environmental disruptions not only exacerbate local resource competition but also erode state legitimacy when decision-makers fail to respond effectively, thereby fostering social unrest and violent mobilization.

Climate-induced insecurity is also spatially and socially uneven (WHO, 2023). The Climate Conflict Vulnerability Index maps hotspots where ecological stress intersects with institutional fragility and poverty, highlighting regions such as the Sahel, Horn of Africa, and parts of South Asia as particularly at risk (PIK, 2024). Women and girls face heightened vulnerabilities in climate-affected areas, including increased caregiving burdens, disruption in education, reduced access to sexual and reproductive health services, and increased risk of gender-based violence.

Violence against women remains tragically common in all parts of the world. Globally, an estimated one in three women has experienced physical and/or sexual violence in their lifetime, with significant consequences to individuals, societies, and economies (WHO, 2023; UN Women, 2024).

Meanwhile, policy backsliding, including the rollback of environmental protections and reproductive rights, signals a concerning departure from both ecological and gender justice (The Guardian, 2024; Jenkins, 2023; UN Women, 2024). These developments harm health outcomes and underscore a global democratic regression that undermines both gender equity and planetary health imperatives.

Climate-induced migration and displacement

Climate-induced migration is also a growing global concern within and across national boundaries. By 2050, as many as 216 million people could be displaced within their countries due to climate change (World Bank, 2021). Climate-induced migration often exacerbates public health challenges, particularly in regions where water, sanitation, and healthcare are already under pressure (The Lancet, 2018). These mobility patterns are not 'only' humanitarian concerns; they are also increasingly reshaping political and security dynamics.

In countries such as Italy and Greece, rising migration flows from climate-stressed regions in Africa and the Middle East are straining public services, exacerbating political polarization, and challenging social cohesion (IOM, 2023). Simultaneously, in Syria and Iraq, the compounded impacts of environmental degradation, particularly drought and desertification and protracted armed conflict are driving mass displacement. These intersecting crises underscore the urgent need for integrated policy responses that bridge public health, climate resilience, and peacebuilding to support both displaced populations and host communities.

Demographic consequences: A fractured future

Demographic shifts compound these pressures. Youth bulges, unplanned urbanization, and intergenerational tensions in fragile and climate-affected regions intensify the risk for unrest, particularly when young people lack access to health, education, and employment. Over 473 million children, more than one in six globally, live in areas affected by conflict (UNICEF, 2024). Youth climate movements emphasize the increasing frustration with inaction from older generations, underscoring how youth-led activism reshapes global justice and sustainability discourses (de Moor et.al., 2022).

Investing in women and youth is both a moral imperative and a strategic necessity. Yet they remain underrepresented in decision-making and many political and environmental institutions, and their voice and expertise continue to be overlooked when designing policies or leading negotiations (UNFCCC, 2019). UNDP (2021) reports that only 26% of national COVID-19 task forces included women. Without their voices in leadership, societies risk a demographic penalty and the erosion of hope among the very generations who must inherit and rebuild from today's crises.

Rethinking security: health for peace

Military power cannot shield populations from pandemics, heatwaves, or ecological collapse. Yet, in 2024 global military spending reached $2.72 trillion, whereas health systems and climate adaptation efforts are underfunded (SIPRI, 2024). This forces us to reconsider what peace and security mean in the 21st century and their impact on population health. The Lancet Commission on Peaceful Societies highlights the critical importance of health equity, gender equality, and inclusive governance for building resilient and peaceful societies and nudging harmful societies into beneficial ones (The Lancet, 2023). The WHO's Global Health and Peace Initiative (GHPI) launched in 2019 operationalizes this vision by integrating peacebuilding into its health programming, especially in conflict-related contexts (WHO, 2019).

Towards a peace-centered future

The Planetary Health Alliance calls for transforming development models that harm ecological and human systems. Ensuring equitable access to clean air, safe water, nutritious food, and healthcare is not merely an environmental or health priority but foundational to global stability (PHA, 2023). Incorporating the concept of quality peace further enriches this perspective. Quality peace, as articulated by Peter Wallensteen, emphasizes sustainable and inclusive peacebuilding efforts that promote long-term health and well-being. It underscores the importance of dignity, security, and the rule of law, creating a stable environment where healthcare systems can thrive (Wallensteen, 2015).

Framing peace and health through an intergenerational lens highlights the long-term stakes. Today's decisions on climate, migration, and conflict will shape life prospects for generations to come. Embedding youth voices and leadership, gender equity, and ecological stewardship at all levels of policymaking is not aspirational; it is the most rational and strategic path to a peaceful, sustainable, and equitable future for both people and planet.

Promising approaches:

• Nature-based peacebuilding: Initiatives like the UN's Peace Forests program promote ecological restoration in conflict zones to address environmental degradation and social division (UNEP, 2023). These efforts demonstrate how environmental stewardship can serve as a platform for peace.
• Health diplomacy as a peace catalyst: Collaborative health initiatives can serve as entry points for peace negotiations and confidence-building in fragile states. When created with equity and inclusion at their core, health systems can connect fractured societies and act as stabilizing institutions.
• Climate adaptation for peace: Regional and cross-border strategies, such as those explored in ASEAN and African Union frameworks, integrating health equity, climate resilience, and governance, can reduce conflict risk, enable cooperative problem-solving, and support long-term recovery.

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