Military implications of global warming

Climate change is an emerging global threat that may aggravate conflicts and undermine security in many regions of the world. Climate-related impacts and shocks could trigger military responses and absorb resources for risk reduction, disaster mitigation, and conflict resolution.

Background

Global warming not only affects the lives of individual human beings but may also have larger societal consequences. By triggering a cycle of environmental degradation, economic decline, social unrest, and political instability, climate change may become a crucial issue of geopolitical security and conflict. In some parts of the world (notably in Africa, Asia, and Latin America), the erosion of social order, state failure, and violence have traditionally gone hand in hand. In the most susceptible regions, conflicts that begin within one state or between two states may spread to other neighboring states through various means, including refugee flows, ethnic links, environmental resource flows, or arms exports. Such spillover effects can destabilize entire regions and expand the geographical extent of a crisis, overstretching global and regional governance structures.

Policy Debate on Climate Security

In 2007, the United Nations Security Council held its first discussion on the security risks of climate change, and the UN secretary general warned that climate change may pose as much of a danger as war. With its 2007 joint award of the Nobel Peace Prize to Al Gore and the Intergovernmental Panel on Climate Change (IPCC), the Nobel Prize Committee emphasized that extensive climate change could result in “increased danger of violent conflicts and wars, within and between states.” A panel of experts that included former US director of central intelligence James Woolsey and Nobel laureate Thomas Schelling, among others, asserted that climate change “has the potential to be one of the greatest national security challenges that this or any other generation of policymakers is likely to confront.”

The German Advisory Council on Global Change (WBGU) concluded in its 2007 comprehensive analysis that, without resolute counteraction, climate change will overwhelm many societies’ adaptive capacities in the near future, resulting in a level of instability that could jeopardize national and international security. In a 2008 report titled Climate Change and International Security, the Office of the European Union High Representative and the European Commission suggested that “climate change is best viewed as a threat multiplier which exacerbates existing trends, tensions and instability” and “threatens to overburden states and regions which are already fragile and conflict prone.” In particular, the warming of the Arctic region opens up new avenues for potential cooperation, but also for possible territorial disputes.

Water Stress and Conflict

Climate change will likely exacerbate water scarcity for hundreds of millions of people. Uneven water distribution may induce migration or the quest for resources from neighboring regions. Individual case studies suggest that water scarcity undermines human security and heightens competition for water and land resources. According to the Pacific Institute’s chronology, as of December 2015, water has been a factor in more than two hundred violent conflicts since the beginning of the twentieth century, ranging from interpersonal disputes to tactical assaults in war. As a counterpoint, the Basins at Risk project, conducted by Shira Yoffe for her PhD dissertation at Oregon State University, revealed no statistically significant links between water scarcity and violent international conflicts, and in fact showed that "historically, international cooperation over freshwater resources as a resource far outweighs international conflict." In other words, while freshwater resources may occasionally be a factor in international conflicts, it has rarely been the driving factor. However, if, as predicted, climate change leads to freshwater resources becoming scarcer—particularly in regions already affected by water scarcity, and particularly in combination with growing populations—this could soon change.

In the Middle East, water scarcity is intertwined with the region’s general conflicts. The arid climate, the imbalance between water demand and supply, and the ongoing confrontations between key political actors exacerbate the water crisis of the Nile, Euphrates, and Jordan Rivers. The combination of global warming, population growth, overexploitation, and pollution is projected to increase the likelihood and intensity of droughts in the region, undermining the conditions for peace and human security. However, statements on “water wars” in the Middle East have been questioned. The region’s conflicts are largely determined by political differences, where hydrological matters represent an additional dimension of conflict as well as cooperation. Further progress of the water talks is connected to the fate of the Middle East peace process.

Central Asia is another region vulnerable to water conflicts, and the IPCC projects a sharp temperature rise in that region. Agriculture largely relies on irrigation and accounts for 20 to 40 percent of the gross domestic product (GDP) of most Central Asian nations. Electricity in the region is based almost completely on hydroelectric power, which depends on glacier meltwater from mountain ranges. Some of the glaciers in the region have already declined in the past decades, and by 2050 about 20 percent of the glaciers in some mountains may disappear. The states of Central Asia are characterized by largely closed markets, extreme social disparities, and weak state structures, making them unable to cope with these changes. Struggles over land and water resources have already played a major role in this region, and they have been aggravated by ethnic disputes, separatist movements, and religious fundamentalist groups.

Land-Use Conflicts and Food Insecurity

Reduction of arable land, water shortages, diminishing food and fish stocks, increased flooding, and prolonged droughts already threaten food security in many parts of the world, and climate change will aggravate this trend. With global warming, a drop in agricultural productivity is anticipated that will be reinforced by desertification, soil salinization, and water scarcity. More frequent extreme weather events may trigger regional food crises and further undermine the economic performance of weak and unstable states, thereby exacerbating destabilization, the collapse of social systems, and violent conflicts.

Particularly vulnerable will be Africa’s food production, which has been in decline per capita for more than twenty years. In 2021, over 500 million Africans were living in drylands (hyperarid, arid, semiarid, and dry subhumid regions). In 2022, about 20 percent of the population of sub-Saharan Africa was undernourished. According to Agricultural Adaptation Atlas in 2024, the average temperature in sub-Saharan Africa is projected to increase by about 2 degrees Celsius (relative to preindustrial levels) by 2050. This could result in significant decreases in crop yields in sub-Saharan Africa, with median losses of between 5 and 8 percent across all crops. Food crises impair the livelihoods of subsistence farmers and increase unemployment and migration for millions of people. As a result of migration from rural to urban areas, slums in African cities grow and become breeding grounds for crime and violence. Growing numbers of marginalized people could join riots and armed rebel groups, possibly culminating in civil war and ethnic conflict.

An example of ethnic conflict aggravated by resource scarcity is the 1994 genocide in Rwanda. In Rwanda, soil degradation, population growth, and unequal land distribution gave radical forces an opportunity to escalate ethnic rivalries into a political power struggle. Elsewhere in North Africa, a series of droughts caused Arab herders to move into the more fertile areas of Darfur, where grazing cattle trampled farmers’ fields, contributing to existing clashes and tensions. The Sudan Post-Conflict Environmental Assessment, released by the United Nations Environment Programme (UNEP) in 2007, concluded that Darfur “can be considered a tragic example of the social breakdown that can result from ecological collapse.”

Natural Disasters

The IPCC projects that many areas of the globe will experience more frequent and intense extreme weather events and natural disasters, including droughts, heat waves, wildfires, flash floods, and storms. Disasters have dramatic impacts on human lives, generate rising economic and social costs, cause large numbers of fatalities, and temporarily impair or collapse state functions. Regions at high risk from storm and flood disasters generally have weak economic and political capacities, making adaptation and crisis management more difficult. Storm and flood disasters along the densely populated east coasts of India and China could cause major damage and trigger large migration processes. Developed countries are also vulnerable to natural disasters, as was seen during the 2003 heat wave in Europe, during which more than thirty-five thousand people died and agricultural losses reached $15 billion.

The record hurricane season of 2005 demonstrated that even the world’s most powerful nation is vulnerable and unable to cope with natural disasters. When Hurricane Katrina hit the US Gulf Coast with wind speeds of up to 230 kilometers per hour, it left a trail of destruction over an area as large as the British Isles. In the Gulf of Mexico, 90 percent of oil refinery capacity had to be shut down. When New Orleans was flooded, more than fifteen hundred people lost their lives, and hundreds of thousands fled their homes. Lester Brown, founder of the Earth Policy Institute in Washington, DC, called this outflux “the first massive movement of climate refugees.” The city’s entire infrastructure was devastated, including water, food, energy, transportation, communications, and sanitation. Public order broke down. Most vulnerable were those living in poor-quality housing in high-risk areas and having few financial resources and no insurance to cope with disasters.

Environmental Migration

In response to environmental degradation and weather extremes, or their indirect consequences such as economic decline and conflict, people will be forced to leave their homelands for other regions. Most vulnerable are high-risk climate hot spots, especially coastal and riverine areas and areas whose economies depend on climate-sensitive resources. Although most of the affected people in the Southern Hemisphere will remain within their national borders, industrialized regions face substantially increased migratory pressure—Europe from sub-Saharan Africa and the Arab world, and North America from the Caribbean and Central and South America.

The potential pressure on China to resettle large populations from flooded coastal regions or dry areas may put migration pressure on neighboring countries, including Russia. Migration of people can increase the likelihood of conflict in transit and target regions where migrants have to compete with the resident population for scarce resources such as land, accommodation, water, employment, and basic social services. Immigrants are perceived as competitors who change the “ethnic balance” in the region.

Populated mega-deltas in southern and eastern Asia will be at greatest risk due to increased flooding from the sea and, in some mega-deltas, from rivers as well. Climate change would significantly aggravate human insecurity in Bangladesh, one of the poorest and most densely populated countries of the world. Between 1961 and 2014, nearly six hundred thousand died in Bangladesh as a result of cyclones, storm surges, and floods. Improved warning systems and shelters have drastically lowered the number of such deaths in recent years. The impacts of projected sea-level rise could be disastrous, threatening the Bangladeshi economy and exacerbating insecurity.

According to Earth.org in 2022, about 3.5 million people are at risk of flooding every year because of sea level rise and intense monsoon season. On several occasions, the migration of impoverished people has already caused violent clashes within Bangladesh and between emigrating Bangladeshi and tribal people in northern India, where several thousand people have died. The complex interaction of both and natural trends and their socioeconomic and political implications may further lead to situations of political instability and violent clashes, undermining young democratic institutions.

The deteriorating relationships between North Atlantic Treaty Organization (NATO) countries and Russia following the latter’s invasion of Ukraine in February 2022 highlighted new areas where climate change could influence hostilities. The potential for such a situation to involve the People’s Republic of China also heightened. A potential flashpoint is the region of the Arctic Ocean. Under the current rate of ice melt, projections are that the Arctic Ocean will be ice-free and passable by ship by 2035. New shipping routes and access to natural resources have historically invited competition between countries. Confrontations between military forces have been a common occurrence in such instances.

By 2022 the US Department of Defense was devoting significant financial resources to ensure installations, equipment, and planning efforts were more attuned to the effects of climate change. These included investments to harden equipment for extreme weather conditions, research and development, and contingency funds for disaster relief.

Context

The security risks of climate change are determined by the causal links among climate stress factors, human impacts and responses, and societal instabilities. Whether societies are able to cope with the impacts and restrain the risks depends on their responses to change and their ability to solve and moderate associated instabilities and conflicts. While a gradual temperature rise of several degrees will already severely affect national and international security, abrupt and large-scale climate change beyond critical tipping points (for example, the collapse of the North Atlantic thermohaline circulation, the loss of the Amazon or of the South Asian monsoon, or the melting of the Greenland or the western Antarctic ice sheets with several meters of consequent sea-level rise) will likely have catastrophic consequences that could be comparable to major wars. Addressing the problem will require integrated approaches that combine climate and security policy in a mutually enforcing way. Adaptive strategies for mitigation and adaptation are needed that minimize security risks and mitigate conflicts by strengthening institutions, economic well-being, energy systems, and other critical infrastructures.

Key Concepts

• conflict: discord between opposing or incompatible values, interests, or actions of individual or collective actors
• crisis: a potential turning point to the worse in a difficult situation
• disaster: a drastic disruption in the functioning of a system with severe implications
• instability: a state in which one or more normally constant, essential features of a system are in flux
• risk: an indicator used to evaluate possible dangers that combines possible damages and the likelihood of their occurrence
• vulnerability: susceptibility of a social system or group to pressures and stresses

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