Climate Change Threats to National Sovereignty and Security

Climate change is no longer just an environmental concern-it has become a direct threat to the foundational pillars of national sovereignty and state security worldwide. As temperatures rise, ice sheets melt, and extreme weather events intensify, countries face unprecedented challenges to their territorial integrity, resource stability, and population security. For nations large and small, climate change is reshaping what it means to be a sovereign state in the 21st century.

How climate change disrupts natural resources
The water security crisis
Territorial integrity under threat
Vanishing nations
Questions of sovereignty and international law
Climate-induced migration and displacement
The human cost of displacement
Migration as a conflict multiplier
The changing geography of maritime sovereignty
Shrinking exclusive economic zones
International responses
Climate change as a national security priority
Building climate-resilient sovereignty

How climate change disrupts natural resources

The relationship between climate change and natural resources is fundamental to understanding its security implications. Climate change affects food and water security, degrades the environment, increases the spread of diseases, and disrupts essential services like electricity production. These compounding effects create cascading crises that strain government capacity and threaten human security at multiple levels.

Increasing concentrations of CO2 and other greenhouse gases are altering ecosystem balances that human societies have depended on for millennia. Agricultural lands face desertification and soil degradation. Forests that once regulated regional climates and water cycles are becoming more vulnerable to fires and pest outbreaks. Climate change produces a durable, long-term shift in the environment, forcing states and societies to take increasingly strong steps to mitigate and adapt.

The water security crisis

Water resources represent one of the most critical security concerns linked to climate change. Only about 3% of Earth’s water is fresh, and climate change is increasing unpredictability in weather patterns and leading to more extreme weather events that affect this limited supply.

India presents a stark example of this crisis. While India has about 16% of the global population, it only has 4% of total water resources, and many parts of the country already face severe water scarcity. According to NITI Aayog’s Composite Water Management Index, nearly 600 million people face high to extreme water stress, with around 200,000 people dying annually due to inadequate access to safe drinking water.

The situation is worsening. NASA’s GRACE satellites show water tables in northwestern India sinking by up to 4 cm annually. Groundwater, which sustains over 85% of rural households, is being depleted at alarming rates. India’s annual per capita water availability was 1,486 cubic meters in 2021-falling under the water stress category-and is projected to reduce to 1,341 cubic meters by 2025 and 1,140 cubic meters by 2050.

Climate change amplifies this pressure through erratic monsoons, prolonged droughts, and altered rainfall patterns. India is rated ‘high risk’ in the Climate Change Vulnerability Index, with major cities projected to experience more consecutive drought days with less rainfall. The melting of Himalayan glaciers-which feed major river systems-combined with rising sea levels affecting coastal aquifers through saltwater intrusion, creates an alarming water security scenario.

Territorial integrity under threat

Perhaps nowhere is the threat to sovereignty more existential than for small island developing states (SIDS). Sea-level rise is an existential threat for low-lying coastal states, particularly for small island developing countries whose land surfaces may be totally covered by the sea or become fully uninhabitable.

Small island developing states account for only 1% of global emissions yet suffer some of the worst climate impacts. These nations face rising seas, intensifying cyclones, coral bleaching, and ocean acidification that threaten their very existence.

Vanishing nations

The situation is already critical for several Pacific nations. Tuvalu and Kiribati have an average elevation of just two metres, with Tuvalu’s highest point reaching only five metres above sea level. Sea levels around Tuvalu are rising at a rate 1.5 times faster than the global average. Between 1947 and 2014, six islands of the Solomon Islands disappeared due to sea level rise, while another six shrunk by between 20 and 62 percent.

The Marshall Islands faces similar threats. According to a 2021 World Bank report, projected sea level rise could cost the Marshall Islands its status as a nation. By 2050, most of Tuvalu’s land area will be below high tide.

These nations are taking unprecedented steps to preserve their sovereignty. In 2012, Kiribati purchased 22 square kilometres of land in Fiji as a potential relocation site for its citizens. Tuvalu negotiated the Falepili Union with Australia, which ensures Australia will continue to recognize Tuvalu’s sovereignty regardless of climate change effects. Some nations are even exploring digital preservation of their statehood and cultural heritage.

Questions of sovereignty and international law

Climate change now threatens the very existence of small island states due to rising sea levels and severe weather events. Under international law, the recognition of a state requires a supreme authority over a territory and a population. If territory disappears beneath the waves, fundamental questions arise about continued statehood, UN membership, and the rights of displaced populations.

Human rights activists argue that the potential loss of entire atoll countries, and consequently the loss of national sovereignty, self-determination, cultures, and indigenous lifestyles, cannot be compensated for financially.

Climate-induced migration and displacement

When state systems fail to provide adequate resources, people move. The World Bank estimates that by 2050, Latin America, sub-Saharan Africa, and Southeast Asia will generate 143 million more climate migrants. This mass movement of people creates profound security challenges for both origin and destination countries.

Climate impacts can escalate tensions and conflicts over vital resources like water, fuel and arable land, threatening peaceful coexistence between displaced populations and host communities.

The human cost of displacement

Climate migrants face severe hardships. Migrants often face discrimination from host communities along with limited access to essential services such as education and healthcare. Vulnerable groups including women, children, elderly individuals, and indigenous populations are disproportionately affected during displacement.

The majority of people forcibly displaced by persecution, conflict and violence today live in countries that are highly vulnerable to climate change. Displaced populations frequently have no option but to live in remote locations, in overcrowded camps or informal settlements. This creates cycles of vulnerability where climate impacts trigger displacement, and displaced people become more exposed to further climate shocks.

Migration as a conflict multiplier

Population displacement on this large scale leads to resource pressure on the towns, countries and communities receiving migrants and can exacerbate existing instabilities. In countries lacking institutional capacity to manage migrant influxes, or those already engaged in internal conflict, migration dramatically increases potential for violence.

The Lake Chad Basin illustrates this dynamic. The dwindling of natural resources has intensified regional tensions and led to the displacement of 3 million individuals. Similarly, the severe drought in Syria between 2007 and 2010 led to significant agricultural setbacks and prompted numerous farming households to relocate to cities, acting as a catalyst for the devastating civil war that followed.

Currently, those who leave their countries in the context of climate change or disasters do not qualify for protection under international law. The 1951 Refugee Convention offers protection only to those fleeing persecution along specific grounds-not environmental degradation. This legal gap leaves millions of climate migrants without formal protection or support.

The changing geography of maritime sovereignty

Rising sea levels don’t just threaten coastal lands-they challenge the fundamental legal frameworks that define maritime sovereignty. Under the UN Convention on the Law of the Sea (UNCLOS), coastal states’ maritime zones are measured from baselines along their coasts. These maritime zones are predominantly defined by maximum breadth limits, such as 12 nautical miles for the territorial sea and 200 nautical miles for the exclusive economic zone, measured from these baselines.

Shrinking exclusive economic zones

As coastlines recede and islands shrink or disappear, the legal implications become profound. This could cause the exclusive economic zones of small island states to shrink or disappear if international law allows maritime boundaries to move with changing coastlines.

The negative security implications linked to sea-level rise include affecting the coasts, which are pushed landward, thereby affecting the baselines and the maritime zones measured from them. This threatens coastal states’ access to vital marine resources.

For Pacific island nations, whose economies depend heavily on fishing rights within their exclusive economic zones, the stakes are enormous. The potential submergence of important base points may lead to the loss of maritime jurisdiction and the loss of jurisdictional rights over valuable resources within these maritime spaces, with disastrous economic consequences.

International responses

Pacific Island nations have taken collective action to protect their maritime rights. In 2021, the 18 members of the Pacific Islands Forum adopted the Declaration on Preserving Maritime Zones, asserting that once maritime zones are established, they will be maintained without reduction regardless of sea-level rise. The declaration argues that UNCLOS does not create an affirmative obligation to keep baselines under review.

A 2023 report by the UN International Law Commission found widespread international support for the stability of established maritime baselines notwithstanding sea-level rise. The United States has stated it will not challenge maritime zones that are not subsequently updated to reflect sea-level rise, encouraging other nations to adopt similar approaches.

Climate change as a national security priority

Climate change poses threats to national security, as effects like rising sea levels and catastrophic storms threaten both military and civilian infrastructure and can affect migration patterns. The U.S. Department of Defense has recognized climate change as a “threat multiplier” that exacerbates existing environmental stresses and security risks.

Climate-security threats are non-linear and escalating, posing profound challenges to national and international security. A 2024 report argues that cascading risks and tipping points are not adequately considered in national security risk assessments, leading to significant underestimation of the climate threat.

Military forces are already feeling the impact. Between 2016 and 2021, the number of National Guard personnel days spent fighting wildfires increased by 162,000 as droughts have lengthened fire seasons. Military installations worldwide face threats from rising seas, extreme heat, and intensified storms.

Building climate-resilient sovereignty

Addressing climate threats to sovereignty requires action at multiple levels. For water security, nations must invest in conservation, efficient irrigation, rainwater harvesting, and improved infrastructure. For territorial protection, small island states need international support for adaptation measures, sea barriers, and legal frameworks that preserve their sovereignty.

On migration, the international community must develop legal protections for climate-displaced persons and invest in building resilience in vulnerable regions to prevent displacement. For maritime boundaries, supporting the emerging consensus on fixed baselines would provide legal certainty for affected states.

Most fundamentally, addressing climate threats to sovereignty requires aggressive action on reducing greenhouse gas emissions. Every fraction of a degree of warming avoided means reduced pressure on water resources, slower sea-level rise, and fewer people displaced from their homes.

What do you think? As climate change increasingly threatens national sovereignty and security, how should the international community balance the rights of climate-displaced peoples against the sovereignty concerns of receiving nations? And should international law be reformed to explicitly protect nations whose territory may disappear beneath rising seas?

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Table of Contents

How climate change disrupts natural resources 🔗

The water security crisis 🔗

Territorial integrity under threat 🔗

Vanishing nations 🔗

Questions of sovereignty and international law 🔗

Climate-induced migration and displacement 🔗

The human cost of displacement 🔗

Migration as a conflict multiplier 🔗

The changing geography of maritime sovereignty 🔗

Shrinking exclusive economic zones 🔗

International responses 🔗

Climate change as a national security priority 🔗

Building climate-resilient sovereignty 🔗