The interrelation of climate change and national security

Kim Sung-woo

The Korea Meteorological Administration reported that 2024 was the hottest since modern meteorological observations started in 1973, setting a series of alarming new records.

Korea’s national average temperature soared to approximately 3 degrees Celsius above normal starting in April. The summer was marked by 20 tropical nights — a stark triple the average — while 15 autumn typhoons caused extensive damage, and heavy snow and torrential rain battered the peninsula in November.

Unsettling trends continue this year, with a sweltering heat wave approaching 40 degrees Celsius, followed by flash floods from torrential rains of up to 400 millimeters. In July alone, a staggering 23 consecutive tropical nights surpassed last year’s record. This volatile pattern of extreme weather shows that economic damage and social instability are deeply intertwined with national security.

This perspective is supported by a report titled “The National Security Rationale for Japan’s Transition to Renewable Energy,” published in May by the Council on Strategic Risks, an American nonprofit security policy institute. The report argues that Japan’s overwhelming reliance on foreign imports for 97 percent of its energy, with 83 percent of that coming from fossil fuels, creates significant geopolitical risks and economic vulnerabilities.

It compellingly argues that a strategic and rapid shift to renewable energy is a crucial pathway to enhancing energy self-sufficiency and strengthening national security. Given Korea’s similar circumstances, this analysis reveals three specific connections between climate change and national security.

The first and most immediate link is the concept of climate resilience, a society’s capacity to adapt to and recover from impacts of climate change. Extreme weather events, such as those Korea has recently experienced, directly affect a nation’s economic and social stability.

A prime example is “climateflation.” When floods or prolonged heat waves devastate agricultural regions, crop yields plummet, causing a sharp increase in food prices. This would not only affect household budgets but also the entire value chain of industries that depend on those ingredients. A stark example in Korea is how the price of Napa cabbage, a fundamental ingredient for kimchi, skyrocketed by 31.1 percent in a single month due to persistent heavy rains and heatwaves. This illustrates the destabilizing reality of climateflation.

The transition to a decentralized energy grid with renewable sources can bolster this resilience. Unlike centralized systems susceptible to widespread outages from a single catastrophic event, a distributed network of renewable sources can limit the scope of blackouts during a climate-related disaster. This localized approach ensures that vital services continue to operate and communities recover more swiftly. This, in turn, indirectly contributes to the nation’s security by maintaining social order and economic function during times of crisis. Moreover, by reducing greenhouse gas emissions, renewable energy also addresses the root cause of climate change, serving as a fundamental form of preventative national security.

The second major connection is the pressing need for energy independence. Like Japan, Korea’s heavy reliance on energy imports presents a significant strategic weakness. In 2024, fossil fuels constituted over 80 percent of Korea’s total energy consumption. Even more concerning is the geographic concentration of these imports: In 2023, Korea sourced 72 percent of its petroleum from the Middle East and over 40 percent of its coal from Australia.

With a 94 percent import dependency, Korea is highly vulnerable to global supply chain disruptions and price volatility caused by geopolitical conflicts, natural disasters or international market shifts. If a disruption were to occur, the resulting increase in energy costs could severely degrade industrial competitiveness, cripple the national economy and create widespread social unrest.

Expanding the use of renewable energy provides a strategic alternative. By developing domestic renewable energy sources, Korea can mitigate these external risks. The global climate think tank Ember highlights this, arguing that “a $1 investment in solar panels can produce the same amount of electricity while saving $1 a year on gas imports,” demonstrating the compelling security value of this transition.

However, this shift also presents challenges. A simple substitution of dependencies — from fossil fuel imports to a reliance on China for key raw materials and components like polysilicon and rare earth elements — would merely trade one form of geopolitical vulnerability for another. Therefore, a successful transition requires both expanding the use of renewable energy and developing a robust domestic supply chain.

Finally, a stable climate and a secure energy supply are directly linked to military power. Extreme weather and energy supply disruptions pose a direct threat to a nation’s defense capabilities. Extreme weather can wreak havoc on critical military infrastructure, from naval bases on the coast to airfields and training grounds. The U.S. Navy, for example, has spent billions of dollars on mitigating evolving climate-related infrastructure risks. Economic downturns caused by climate-related disasters or energy price shocks could also force reductions in defense spending.

Therefore, strengthening climate resilience and increasing energy independence are not just civilian concerns; they are fundamental to national defense. A resilient society with a stable, self-sufficient energy supply is better equipped to support its armed forces, ensuring military operations are not compromised by environmental or economic crises.

This also brings up the often-overlooked point of the military’s own carbon footprint. A 2022 study by a U.K. nongovernmental organization revealed that military activities account for approximately 5.5 percent of the world’s annual greenhouse gas emissions — more than the combined global emissions of the aviation and shipping industries. This creates a dangerous cycle where military activities contribute to the very climate change that later threatens military infrastructure and operational capacity.

While long-term goals are vital, the immediate and necessary step is to begin reducing military-related emissions to break this cycle and make a direct contribution to both environmental and national security.

Kim Sung-woo, head of Environment & Energy Research Institute at Kim & Chang, is a member of Management Committee for National Climate Fund.