Climate Change and Human Security: Introduction to Global Threats

Climate change has rapidly evolved from a distant environmental concern to one of the most pressing security challenges facing the world today. It affects everything from food and water supplies to national defence capabilities and global political stability. Understanding how climate change intersects with human security is essential for policymakers, researchers, and citizens alike, as the consequences touch every corner of the globe.

What is human security? 🔗

The concept of human security goes beyond traditional notions of military defence. According to the United Nations Development Programme (UNDP), human security encompasses safety from chronic threats such as hunger, disease, and repression, as well as protection from sudden disruptions to daily life-whether in homes, jobs, or communities. This holistic view recognizes that true security means more than the absence of war; it means having access to the basic necessities that allow people to live with dignity.

Human security rests on several interconnected pillars: economic stability, food access, health, environmental safety, personal safety, community wellbeing, and political freedom. Climate change threatens all of these pillars simultaneously, making it a uniquely dangerous force in the modern world.

Climate change as a global security concern 🔗

Both the UN Security Council and the Intergovernmental Panel on Climate Change (IPCC) have formally acknowledged the profound security implications of climate change. The U.S. Department of Defense recognizes climate change as a “threat multiplier” because it amplifies existing stresses such as poverty, environmental degradation, political instability, and social tensions.

In a 2021 report, Secretary of Defense Lloyd Austin stated that nearly everything the Defense Department does-from strategic planning to equipment maintenance-is jeopardized by climate change. The risks are growing, especially as the world falls behind on its Paris Agreement targets.

The IPCC’s Sixth Assessment Report (AR6) released in 2023 delivered a stark message: human activities have unequivocally caused global warming, with surface temperatures already 1.1°C above pre-industrial levels. The report emphasizes that climate change is a threat to human wellbeing and planetary health, and warns that the window of opportunity to secure a livable future is rapidly closing.

Why developing nations are most vulnerable 🔗

The impacts of climate change fall disproportionately on developing countries and low-income communities. According to the IPCC, approximately 3.3 to 3.6 billion people live in contexts highly vulnerable to climate change. These are often the populations that have contributed least to greenhouse gas emissions but lack the resources and technology needed to adapt.

Between 2010 and 2020, human mortality from floods, droughts, and storms was 15 times higher in highly vulnerable regions compared to regions with very low vulnerability. Extreme weather events have exposed millions to acute food insecurity and reduced water security, with the most severe impacts observed in Africa, Asia, Central and South America, small island developing states, and among Indigenous Peoples and small-scale food producers.

Climate change and food security 🔗

One of the most direct ways climate change threatens human security is through its impact on food systems. Droughts, floods, and unpredictable rainfall patterns disrupt agricultural production, driving up food prices and reducing access to nutrition for vulnerable populations.

Although global agricultural productivity has increased overall, climate change has slowed this growth over the past 50 years, with negative impacts concentrated in mid- and low-latitude regions. Ocean warming and acidification have also harmed fisheries and shellfish aquaculture in certain oceanic regions.

A World Food Programme analysis shows that a 2°C rise in average global temperature above pre-industrial levels could put 189 million additional people at risk of hunger. If temperatures rise by 4°C, this figure could reach 1.8 billion.

In regions like the Horn of Africa, more than 23.5 million people are enduring high levels of acute food insecurity due to prolonged drought. These conditions force people to migrate in search of food, water, and livelihoods, creating new security challenges for receiving communities and nations.

Climate-driven migration and displacement 🔗

Climate change is increasingly recognized as a major driver of human migration. When extreme weather destroys homes, livelihoods, and food sources, people are forced to move-often with few resources and uncertain destinations.

By the end of 2023, nearly 64.3 million people were internally displaced in 38 countries and territories identified as having food crises. Climate change and conflict are two of the key drivers of acute food insecurity, and the resulting displacement creates additional strain on humanitarian systems.

During climatic events, the displacement and involuntary migration of populations contributes to competition over natural resources, potentially sparking or worsening conflicts. The UN Security Council has highlighted that over 330 million people were affected by acute food insecurity in 2023, as climate-related crises multiply.

The World Bank has warned that 143 million people in South Asia, sub-Saharan Africa, and Latin America could migrate due to climate impacts. This mass movement of people puts pressure on border regions, urban centres, and social services, and can fuel political instability in both origin and destination countries.

The link between climate and conflict 🔗

While climate change does not directly cause wars, it acts as a risk accelerator. When resources like water and arable land become scarce, competition intensifies. Communities that are already marginalized face even greater hardship, and tensions can escalate into violence.

The U.S. Department of Defense has stated that while climate change alone does not cause conflict, it may act as an accelerant of instability, placing additional burdens on regions already struggling with poverty and political fragility.

Weak governments struggling to meet their citizens’ basic needs become more susceptible to civil unrest. In some cases, these conditions contribute to state failure, requiring international intervention and stretching military resources.

Threats to military infrastructure and operations 🔗

Climate change poses direct threats to military capabilities worldwide. Extreme weather events such as flooding, drought, and wildfire pose real threats to military assets, as well as to the civilian infrastructure the military depends on, including roads, electricity, and water systems.

Rising sea levels and more frequent flooding are already putting into question the long-term viability of certain coastal military installations. Naval Station Norfolk in Virginia, the world’s largest naval base, experiences routine flooding during rainstorms and high tides, hampering the Navy’s ability to conduct operations and maintain ships.

Between 2016 and 2021, the number of National Guard personnel days spent fighting wildfires increased as droughts lengthened fire seasons. The 2018 Hurricane Michael caused damage at Tyndall Air Force Base in Florida that was estimated to cost $3.6 billion to repair.

These impacts divert military resources from core missions, increase operational costs, and compromise readiness. The U.S. military is now investing billions of dollars in resilience measures, including microgrids, renewable energy, and infrastructure upgrades.

Current assessment reports and policy frameworks 🔗

The IPCC’s assessment reports provide the scientific foundation for understanding climate risks. The Sixth Assessment Report synthesis, released in March 2023, integrates findings from three working groups covering physical science, impacts and adaptation, and mitigation.

The report confirms that climate-driven food insecurity and supply instability are projected to increase with warming, interacting with non-climatic factors such as urban expansion, pandemics, and conflict. It calls for deep, rapid, and sustained reductions in greenhouse gas emissions, combined with accelerated adaptation measures.

Effective adaptation options identified in the report include improved crop varieties, on-farm water management, agroforestry, community-based adaptation, early warning systems, and climate services. However, current global financial flows for adaptation remain insufficient, particularly for developing countries that face the greatest risks.

The importance of policy response 🔗

Addressing the security implications of climate change requires coordinated action at national and international levels. Strong policy frameworks are essential for managing climate risks, protecting vulnerable populations, and preventing conflicts over resources.

The U.S. government’s PREPARE initiative aims to help more than half a billion people in developing countries adapt to and manage climate impacts. This includes investing in early warning systems, climate-resilient agriculture, and support for displaced populations.

International cooperation is critical. Climate change crosses borders, and so must the response. Developing countries need increased financial and technical support to build resilience, while developed nations must accelerate their own emissions reductions and honour their climate finance commitments.

Policies must also address the complex interactions between climate risks and fundamental human needs. This means integrating climate considerations into food security programs, disaster risk management, urban planning, and conflict prevention strategies.

Looking ahead 🔗

The scientific evidence is clear: climate change is already affecting human security around the world, and the risks will intensify without urgent action. The most vulnerable communities-those who have contributed least to the problem-bear the greatest burden.

Military leaders, policymakers, and civil society must work together to address both the direct and indirect security implications of climate change. This includes reducing emissions, building adaptive capacity, and creating governance structures that can manage the complex, cascading risks that lie ahead.

The choices made in this decade will shape security outcomes for generations to come. The window for action is narrowing, but it remains open.

What do you think? How can nations balance the immediate costs of climate action with the long-term security benefits? And what role should international institutions play in supporting the most climate-vulnerable countries?

References

1. https://www.undp.org/publications/human-development-report-1994
2. https://news.climate.columbia.edu/2023/10/11/why-climate-change-is-a-national-security-risk/
3. https://www.eesi.org/topics/national-security/description
4. https://knowledge4policy.ec.europa.eu/publication/ar6-synthesis-report-climate-change-2023_en
5. https://www.migrationdataportal.org/food-security/drivers-of-food-insecurity
6. https://www.migrationdataportal.org/food-security
7. https://press.un.org/en/2024/sc15589.doc.htm
8. https://www.ipcc.ch/assessment-report/ar6/
9. https://2021-2025.state.gov/the-intersection-between-climate-change-food-security-migration-and-displacement/