In this blog post, we’ll examine the causes and effects of global warming—a problem exacerbated by human industrial activities and energy consumption—as well as the need for alternative energy sources and forest conservation to mitigate it.
As science has advanced rapidly, humans have come to enjoy a life of convenience. For example, we can cool off in the heat thanks to air conditioning, and we can travel long distances using various modes of transportation because of the supply of petroleum. However, even as we enjoy this convenient life right now, the Earth is suffering from a chronic illness known as global warming.
The effects of global warming on the Earth’s environment are already manifesting in various ways. According to NASA data, the global average sea level rose by approximately 20.3 cm between 1901 and 2015; this rise was driven by a combination of thermal expansion of seawater and the retreat of glaciers and ice sheets. This is one of the most prominent symptoms of global warming. To explain from the beginning, global warming is the phenomenon in which the Earth’s average temperature rises over the long term as a result of increased concentrations of greenhouse gases in the atmosphere caused by human activities. International concern regarding global warming and environmental issues has existed for a long time, and problems such as resource depletion, environmental pollution, and population growth were first raised in earnest through various discussions, including the Club of Rome’s 1972 report, ‘The Limits to Growth’. The most direct cause of global warming is greenhouse gases. Greenhouse gases include various gases such as carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride; among these, carbon dioxide emitted through human activities accounts for a significant portion. The reason greenhouse gases cause global warming is simple. The atmosphere allows energy from the Sun to reach Earth, and the Earth’s surface absorbs this energy and re-emits it as infrared radiation. However, greenhouse gases in the atmosphere absorb some of this energy and re-emit it, thereby slowing the escape of heat into space. This process itself is a natural greenhouse effect necessary for life on Earth; however, when greenhouse gas concentrations increase due to human activities, the Earth’s energy balance shifts, causing the temperatures of the Earth’s surface and the atmosphere to rise. This is the most fundamental process behind global warming.
While greenhouse gases are the direct cause of global warming, it can be argued that human industrial activities and energy consumption play an even greater role in the background. Greenhouse gases are also produced naturally. For example, humans and animals exhale carbon dioxide, and various greenhouse gases are emitted and absorbed within natural ecosystems. However, the reason global warming is progressing rapidly is that massive additional emissions of greenhouse gases from human activities have caused atmospheric concentrations to deviate from their natural equilibrium and continue to rise. Prior to the Industrial Revolution, atmospheric carbon dioxide concentrations were around 280 ppm, but they have now reached levels far higher than that. According to NOAA data, the global average carbon dioxide concentration in 2025 was estimated to be approximately 425.6 ppm, and levels well above 420 ppm have persisted into 2026 as well. This clearly indicates that factors exist that are driving up the concentrations of greenhouse gases, including carbon dioxide. While industrialization initially centered on certain European countries in the 1800s, it spread to various regions around the world in the 1900s. The industrialization process involves the large-scale combustion of fossil fuels such as coal, oil, and natural gas, which results in the emission of greenhouse gases like carbon dioxide. In particular, rapid industrialization and urbanization worldwide since the mid-20th century have led to massive greenhouse gas emissions. Today, numerous electronic devices—including air conditioners and refrigerators—as well as modes of transportation such as automobiles are widely used, and these activities are also directly or indirectly linked to greenhouse gas emissions. Furthermore, ongoing deforestation may weaken the ability of natural ecosystems to absorb carbon dioxide from the atmosphere. Ultimately, compared to the past, human energy consumption, industrial activities, and changes in land use have increased significantly, leading to a substantial rise in atmospheric greenhouse gas concentrations.
We occasionally see news stories about global warming, and when this happens, people often ask, “What consequences will global warming actually bring?” As mentioned earlier, the Earth’s average sea level continues to rise. This rise is influenced not only by the loss of mass from glaciers and ice sheets but also by the expansion of seawater as it warms. In fact, the global average sea level has been rising since 1900 at a rate faster than in any century over the preceding thousands of years. Rising sea levels may sound like a minor issue, but they have caused the Earth to suffer numerous “complications.” First and foremost, coastal areas and low-lying islands are the first to be affected by rising sea levels. As sea levels continue to rise, these regions face increased risks of coastal erosion and flooding, and the damage caused by storm surges can become even more severe. The IPCC assesses that if sea levels continue to rise, the risk of coastal flooding and erosion in low-lying areas will increase. Venice is currently one of the most prominent cities where these risks are already evident. Venice is a famous port city in Italy, often called the “City of Water,” and is world-renowned for its unique urban structure centered around lagoons and canals. However, it is difficult to conclude with certainty that Venice will disappear completely in the near future. The city faces a growing risk of flooding due to a combination of natural land subsidence, past groundwater extraction, and sea-level rise, and flooding and damage caused by high water levels have increased over the past few decades. Therefore, rather than simply stating that “Venice will disappear in 100 years,” it is more accurate to view the city’s future from the perspective that its urban fabric and cultural heritage could be placed at serious risk if sea-level rise and land subsidence continue.
Global warming is, quite literally, the phenomenon of the Earth’s average temperature rising. This phenomenon can also cause changes in the Earth’s climate and weather. As some may have noticed, there has recently been an increase in the number of regions experiencing more pronounced extreme weather events, such as intense heat waves and torrential downpours. However, global warming does not necessarily mean that summers will become hotter and winters colder in every region. According to the IPCC, since the 1950s, extreme heat events have occurred more frequently and with greater intensity in most land areas, while extreme cold events have tended to occur less frequently and with less severity. Furthermore, heavy precipitation events have increased in most land areas with sufficient observational data, and human-induced climate change is considered the primary cause of these changes. If these extreme weather events intensify, the risk of various climate-related disasters—such as floods, droughts, and heat waves—may also increase. In particular, as global warming progresses, the amount of water vapor in the atmosphere increases, raising the likelihood of heavy precipitation; similarly, for tropical cyclones and typhoons, there is a possibility that precipitation associated with severe storms will increase. While the IPCC notes that there is insufficient evidence to conclusively state that the frequency of all typhoons will inevitably increase globally, it assesses that there is a high likelihood that the proportion of strong tropical cyclones and the amount of precipitation associated with typhoons will increase. In South Korea as well, damage caused by torrential rains and typhoons has become a recurring problem. A prime example is Typhoon Maemi, which made landfall in South Korea in 2003.
Maemi brought strong winds, torrential rain, and storm surges, causing massive loss of life and property damage. While we cannot definitively attribute all such cases solely to global warming, climate change can exacerbate the risks and damage to coastal areas caused by tropical cyclones through sea-level rise and intense precipitation.
Global warming has caused us a great deal of suffering. Let’s now take a look at possible solutions to this phenomenon. People have conducted numerous studies to address the problem of global warming, and one of the most important areas is the energy transition. Currently, one of the primary energy sources widely used worldwide is oil. Since oil emits greenhouse gases not only during use but also during production, refining, and transportation, it is necessary to reduce our dependence on fossil fuels to address climate change. Moreover, since fossil fuels are finite resources, we must find energy sources that can replace them in the long term. Nuclear fuel has been proposed as one such energy resource to address these issues. Nuclear power generation has the advantage of very low carbon dioxide emissions during the power generation process—since it does not directly burn fossil fuels—and high energy density. However, since issues such as radioactive waste management, safety, and the risk of accidents must also be considered, nuclear power cannot simply be viewed as an energy source capable of solving all problems. The next most important area of alternative energy is electrical energy and electrification. Currently, a significant portion of transportation, such as automobiles, uses fuels derived from petroleum; however, switching to electricity can reduce the use of fossil fuels in the transportation sector. In particular, electric vehicles do not directly emit exhaust gases while driving because they use electricity stored in batteries to power their motors. However, the overall environmental impact of electric vehicles must be assessed by considering the source of the electricity used to charge them, as well as the battery production and recycling processes. Electric vehicles are currently being developed and adopted in many countries, and hybrid vehicles can also be viewed as an important transitional technology. Since hybrid vehicles use both an internal combustion engine and an electric motor, they can reduce fuel consumption and emissions compared to conventional internal combustion engine vehicles and have played a crucial role in the expansion of electrification technology.
Some argue that indiscriminate deforestation must also be halted to prevent global warming. Trees and forests are important carbon sinks that absorb and store carbon dioxide from the atmosphere, so preserving forests plays a vital role in mitigating climate change. However, humans are damaging even these natural carbon sinks, and deforestation and land-use changes can increase greenhouse gas emissions and weaken the ecosystem’s ability to store carbon. The Amazon Rainforest forms such a vast ecosystem that it is often referred to as the “lungs” of the Earth, and it plays a vital role in maintaining the Earth’s carbon cycle and biodiversity. However, statements such as “the Amazon rainforest supplies 25% of the Earth’s oxygen” are not accurate. While it is true that tropical rainforests produce large amounts of oxygen through photosynthesis, a significant amount of oxygen is subsequently consumed through respiration and the decomposition of organic matter within the ecosystem; therefore, it is inappropriate to simply describe the Amazon as the Earth’s oxygen source. Rather, the Amazon rainforest’s key value lies in its ability to store vast amounts of carbon, influence the carbon cycle, and provide habitat for a diverse array of species. Therefore, if these forests continue to be destroyed, the Earth could lose a critical carbon sink and vital ecosystem functions.
While greenhouse gases are a direct factor in global warming, human activity can be considered the primary cause of this phenomenon. In other words, global warming is the cumulative result of decades of human industrial activity, energy consumption, and changes in land use. If we were to compare it to a human illness, it could be interpreted as a kind of chronic disease. For now, we can still devise countermeasures to address rising temperatures and extreme weather events.
However, as the effects of global warming accumulate, there is a clear possibility that a major catastrophe—one that will be difficult to avoid no matter how hard we struggle—could strike at some point. Rather than categorically accepting specific predictions—such as “an extremely powerful super typhoon will inevitably cause damage to the Korean Peninsula within the next 30 years”—we need to focus on the scientific outlook that, as climate change intensifies, the risks associated with extreme weather and rising sea levels will increase. The IPCC assesses that extreme weather events, such as heat waves and torrential rains, are already changing in many regions due to human influence, and that these risks will grow even greater as global warming progresses. Furthermore, since global warming is a chronic phenomenon, attempting to devise countermeasures only after a disaster strikes may prove futile. Therefore, to prevent such disasters, we must begin protecting the environment and reducing greenhouse gas emissions now, while simultaneously working to mitigate global warming and adapt to the climate change that is already underway. The small changes and efforts we make today can serve as a crucial starting point for preventing greater damage in the future.
