In this blog post, we’ll take a step-by-step look at the concept of global warming, its causes, its various impacts, and the solutions currently being pursued.
In March of this year, the average temperature across South Korea was significantly higher than normal, making it one of the warmest Marches on record. This phenomenon is not unique to South Korea. Over the past few decades, the global average temperature has been steadily rising, and the World Meteorological Organization (WMO) and the Intergovernmental Panel on Climate Change (IPCC) predict that temperatures will continue to rise unless human greenhouse gas emissions are sufficiently reduced. As is widely known, global warming is becoming increasingly severe worldwide. So, what exactly does “global warming” mean, and what are its causes and effects? Furthermore, what measures can be taken to address this global warming?
“Global warming” refers to the long-term rise in average temperatures near the ocean surface and land surfaces across the entire Earth. Phenomena such as the record-breaking high temperatures mentioned earlier are closely related to this global warming. In other words, the very climate environment in which humans live is gradually changing.
Various studies have long been conducted on the causes of global warming, and numerous perspectives have been put forward. These causes can be broadly divided into natural factors and anthropogenic factors resulting from human activities. Natural factors include changes in solar activity, changes in volcanic activity, and the Earth’s long-term climate cycles of alternating glacial and interglacial periods.
First, when solar activity increases, the amount of solar energy reaching Earth may rise, which can have a certain impact on the Earth’s temperature. Sunspots are one of the primary indicators of the intensity of solar activity. Since the Sun is the Earth’s fundamental source of energy, changes in its activity also affect the Earth’s environment. However, the general consensus in current climate science is that it is difficult to explain the rapid global warming observed over the past few decades solely through solar activity.
Volcanic activity can also influence climate change. When a volcano erupts, not only lava but also fine dust and volcanic ash are released into the atmosphere; these particles reflect or block some of the sunlight, temporarily lowering Earth’s temperature. In the past, there have been instances where large-scale volcanic eruptions significantly affected the climate, and changes in volcanic activity are also being studied as one of the factors contributing to natural climate variability.
The Earth’s long-term climate cycles are also an important natural factor. The Earth’s orbital path and axial tilt change gradually over very long periods, and these changes alter the distribution of solar radiation received by the Earth. Serbian scientist Milutin Milanković explained that the interaction between these changes in orbital path, axial tilt, and precession leads to the repeated cycles of glacial and interglacial periods. While such natural climate changes do indeed exist, numerous studies have been published indicating that the rapid rise in temperature currently being observed cannot be fully explained by these long-term natural cycles alone.
Next, the anthropogenic cause of global warming is the intensification of the greenhouse effect due to rising greenhouse gas levels. First, the “greenhouse effect” refers to a natural phenomenon in which some of the energy received from the Sun is absorbed by greenhouse gases in the atmosphere rather than escaping into space, and is then re-emitted toward the Earth’s surface, thereby maintaining the Earth’s temperature.
As light energy emitted by the Sun passes through the atmosphere, some of it is absorbed by the atmosphere, while the rest reaches the Earth’s surface. The Earth’s surface absorbs this energy and re-emits it in the form of thermal energy and infrared radiation. However, rather than escaping directly into outer space, some of this energy is absorbed by greenhouse gases in the atmosphere. The greenhouse gases referred to here include carbon dioxide, methane, nitrous oxide, water vapor, ozone, and various fluorinated gases. These greenhouse gases re-emit the absorbed thermal energy back to the Earth’s surface and into the atmosphere; as this process repeats, the Earth’s average temperature is maintained.
In fact, this greenhouse effect is a natural phenomenon essential for life on Earth. Without it, the Earth’s average temperature would be much lower than it is today, creating an environment inhospitable to life. However, if greenhouse gas concentrations increase excessively due to human activities, the greenhouse effect is amplified to an extreme degree. As a result, the Earth’s average temperature continues to rise, causing various problems for ecosystems and human society.
Since the Industrial Revolution of the 19th century, the rapid development of industrial technologies—including the steam engine—has led to a significant increase in the use of fossil fuels such as coal and oil. As a result, large quantities of various greenhouse gases, including carbon dioxide, began to be emitted during the combustion of fossil fuels. Additionally, methane emissions have also risen sharply due to the growth of the livestock industry and the increase in waste. Meanwhile, chlorofluorocarbons (CFCs)—which were once widely used in refrigerants and aerosols—were found not only to deplete the ozone layer but also to be substances that cause a very potent greenhouse effect; consequently, their production and use are now being phased out in most countries in accordance with international agreements. In this way, human industrial activities have become a major cause of the significant increase in atmospheric greenhouse gas concentrations.
Furthermore, as industrialization, urban development, large-scale deforestation, and forest degradation have continued, the area of forests—which absorb carbon dioxide—has also decreased. While the amount of carbon that nature can absorb has decreased, greenhouse gas emissions from human activities have continued to rise; as a result, the Earth’s average temperature is showing a clear upward trend compared to pre-industrial levels. Along with these changes, various extreme weather events—such as heat waves, torrential rains, droughts, and wildfires—are occurring with increasing frequency worldwide.
We have thus examined the causes of global warming. There is currently broad consensus within the climate science community that greenhouse gases, increased by human activities, are the most significant cause of recent global warming. Of course, natural factors such as solar activity, volcanic activity, and long-term climate cycles also influence the climate; however, current research indicates that the increase in greenhouse gases resulting from human activity is the primary factor explaining the rapid rise in temperatures observed over the past few decades.
Although research into the causes of global warming is still ongoing, there is little disagreement that global warming is having serious impacts worldwide. The damage caused by global warming is extremely widespread, and the main issues are as follows.
First is the loss of life and property damage resulting from the intensification of extreme weather events. Extreme weather refers to meteorological phenomena that deviate significantly from long-term climate averages. As the Earth’s average temperature rises, the rate of seawater evaporation increases, leading to higher levels of water vapor in the atmosphere, which in turn raises the likelihood of powerful weather events such as torrential rains, typhoons, and hurricanes. Furthermore, climate change affects atmospheric circulation, causing extreme weather events—such as heat waves, droughts, and severe cold spells—to occur more frequently.
Recently, record-breaking heat waves have persisted in various regions around the world, including Europe, North America, and South Korea, and large-scale wildfires, prolonged droughts, torrential rains, and floods have been occurring in rapid succession. Tens of thousands of people lost their lives during the 2003 European heatwave, and since then, Europe has experienced record-breaking heatwaves in 2022 and 2023. Major wildfires have recurred in Australia and North America, while severe droughts have persisted in Brazil and parts of Africa. As such, extreme weather events caused by global warming—including heat waves, droughts, floods, and cold snaps—are inflicting significant damage on human lives and property across the globe.
The second issue stems from glacial melting and rising sea levels. As the Earth’s average temperature rises, glaciers in the Arctic, Antarctic, and mountainous regions are rapidly shrinking. When land-based glaciers melt and flow into the ocean, sea levels rise, exposing low-lying coastal areas and island nations to an even greater risk of flooding.
In fact, low-lying nations such as Tuvalu, Kiribati, and the Maldives are facing serious threats from rising sea levels, and in some regions, the relocation of residents is already becoming a reality.
Furthermore, as glaciers recede, changes in sea surface temperature and salinity distribution affect ocean currents and atmospheric circulation. This can serve as a factor that further exacerbates the extreme weather events described earlier. As sea ice in the Arctic and Antarctic decreases, the habitats of polar species such as polar bears, seals, and penguins are rapidly changing, and various species are facing threats to their survival.
Third is the destruction of ecosystems and the loss of biodiversity caused by climate change. This is also the result of the combined effects of the two issues described above. Global warming not only raises the Earth’s average temperature but also alters atmospheric circulation patterns and affects regional precipitation and seasonal changes. Furthermore, while raising the average sea surface temperature, it also causes localized changes in sea surface temperature and salinity distribution in areas where glaciers are melting, thereby significantly impacting marine ecosystems.
These environmental changes are forcing organisms that have long adapted to specific environments to alter their lifestyles, reproductive patterns, and migration routes. If the pace of change exceeds the organisms’ ability to adapt, some species may face extinction or even disappear entirely. Polar bears, seals, and penguins—as well as coral reefs, which are sensitive to temperature changes—are cited as prime examples.
Coral reefs are vital ecosystems that provide habitat and food for countless marine organisms. Although they account for a very small proportion of the total ocean area, it is estimated that approximately 25% of the world’s marine life depends directly or indirectly on coral reef ecosystems. Therefore, if coral reefs decline rapidly, the diverse marine life that depends on them will be affected in a chain reaction. Ultimately, the decline or extinction of a specific species is not merely a problem for that species alone but a serious issue that can disrupt the balance of the entire ecosystem. In other words, global warming can be considered a risk factor that has a significant impact on the Earth’s ecosystem as a whole.
As such, global warming is bringing about rapid changes and crises not only to human society but also to the Earth’s entire ecosystem. To address these issues, the international community has been making various efforts for a long time. In 1992, the “United Nations Framework Convention on Climate Change (UNFCCC)” was adopted, establishing a common framework for countries around the world to reduce greenhouse gas emissions and respond to climate change. Subsequently, in 1997, the “Kyoto Protocol” was adopted, imposing greenhouse gas reduction obligations primarily on certain developed countries.
However, the international community’s current climate response has moved beyond the Kyoto Protocol and is now centered on the “Paris Agreement,” adopted in 2015. The Paris Agreement is an international treaty that requires most countries to establish voluntary Nationally Determined Contributions (NDCs) and to continuously strengthen them. It also sets a shared goal of keeping the rise in global average temperature well below 2°C above pre-industrial levels and, if possible, limiting it to 1.5°C.
In parallel, countries around the world are expanding carbon emissions trading schemes and carbon neutrality policies to reduce greenhouse gas emissions, while also implementing policies to enhance nature’s carbon sequestration capacity through measures such as forest restoration and wetland conservation. Furthermore, to reduce dependence on fossil fuels, they are actively developing various low-carbon energy technologies, including solar, wind, hydro, geothermal, and hydrogen energy. Related technologies—such as energy storage systems, electric vehicles, and smart grids—are also advancing rapidly and are establishing themselves as crucial tools in the fight against climate change.
Nevertheless, many challenges remain in these efforts. Since economic conditions and industrial structures vary from country to country, the pace of greenhouse gas reduction also differs; furthermore, cooperation is often difficult due to factors such as economic growth and rising energy demand in developing countries, as well as conflicting interests within the international community. Furthermore, expanding renewable energy and transitioning to a low-carbon energy system require significant time and financial investment, and there are numerous technical challenges to overcome, such as grid infrastructure development and energy storage technology. Therefore, there is still no single, clear-cut solution to address global warming, and it is of the utmost importance that the international community, businesses, and individuals continue to work together through sustained efforts.
We have thus examined the definition of global warming, its causes, and the resulting problems and solutions. While natural factors also contribute to climate change, the rapid global warming currently underway is largely attributed to human industrial activities and rising greenhouse gas emissions. Furthermore, global warming has far-reaching effects not only on human society but also on the global ecosystem, causing various problems such as extreme weather events, rising sea levels, and a decline in biodiversity. To address these issues, the international community is continuously cooperating and implementing various measures, such as expanding the use of eco-friendly energy and adopting carbon-neutral policies. However, as there are still many challenges to overcome, the advancement of science and technology, international cooperation, and the sustained efforts of all members of society will remain critical tasks for effectively responding to global warming.
