In this blog post, we explore various perspectives on whether global warming is caused by human greenhouse gas emissions or by natural cycles.
“The rapid pace of global warming is alarming. It is changing our way of life and affecting vegetation and ecosystems. Infectious diseases and other health issues are also becoming increasingly serious. Every sector of society must respond appropriately to these changes.” This is an excerpt from a recent newspaper article. From a young age, we have been taught that global warming is primarily caused by greenhouse gases emitted by humans and that measures must be taken to address it. The newspaper article cited above also points to human behavior as the cause of global warming and urges action. But is human influence really the only issue? Environmental issues are complex and multifaceted, so there are many limitations to viewing global warming as the result of a single cause.
Whenever I come across such articles, I find myself wondering, “Can global warming, with an average annual temperature rise of 0.6°C, really be caused solely by greenhouse gas emissions from human activities?” After watching the Channel 4 documentary *The Great Global Warming Swindle* and reading the book *Don’t Be Fooled by Global Warming*, I realized that global warming is not simply a problem caused by human behavior, as the media often portrays it, and that carbon dioxide may not be the primary cause. From here on, I will examine the gap between our knowledge of global warming and the facts, as well as the areas that could be problematic.
First of all, greenhouse gases are not the primary cause of global warming. Through various media outlets, we have heard scholars identify carbon dioxide as the main culprit behind global warming. Their logic is that when the Earth receives energy from space—particularly from the sun—and attempts to use some of it while releasing the rest back into space, greenhouse gases trap a portion of that energy, thereby causing global warming. While these greenhouse gases include not only carbon dioxide but also various other gases—such as CFCs and methane—whose greenhouse effect per molecule is greater than that of carbon dioxide, the argument is that carbon dioxide is the primary cause because it exists in far greater quantities than other greenhouse gases.
However, for this “shield effect” to occur, the concentration of carbon dioxide would need to be at least 15%, whereas the actual concentration of carbon dioxide in the atmosphere is only about 0.054%. Therefore, since the proportion of gases causing the greenhouse effect in the atmosphere is very low, and the proportion of carbon dioxide among them is particularly low, it is difficult to view it as having a significant impact on global warming. To address these doubts from another perspective, it is necessary to examine natural factors as well. Over the past hundreds of millions of years, the Earth has repeatedly experienced periods of cooling and warming, which appear to be the result of a combination of complex factors such as volcanic eruptions, changes in ocean currents, and periodic variations in solar activity.
Furthermore, the discrepancy between the timing of rising carbon dioxide emissions and the rise in global temperatures also indicates that carbon dioxide is not the primary cause. Examining global temperature trends reveals that temperatures began to rise in the late 19th century, stopped rising in the 1940s, and actually declined for about 30 years before beginning to rise again in 1975.
This demonstrates that carbon dioxide’s influence is not significant, as temperatures actually declined during the 1940s and the “post-war economic boom” following World War II—a period marked by high greenhouse gas emissions. Furthermore, since the rise in temperatures that began in the late 19th century occurred before the invention of automobiles and airplanes, this shows that the claim that carbon dioxide is the primary cause of global warming is contradictory.
Other skeptics argue that global warming was not caused by carbon dioxide emissions, but rather that global warming occurred first, leading to increased carbon dioxide emissions. Analysis of ice cores from Antarctic research stations revealed that changes in global temperature and carbon dioxide levels have matched exactly over the past several hundred thousand years. In other words, the Earth was warmer when carbon dioxide levels were high. However, a more detailed analysis revealed that global temperature rises preceded increases in carbon dioxide levels by about 600 years. In other words, temperatures rose first, causing the ocean surface to warm and release the carbon dioxide dissolved within it, which in turn increased carbon dioxide levels. Based on this evidence, it is difficult to conclude that greenhouse gases are the primary cause of global warming.
Nevertheless, even if carbon dioxide is not the primary cause, global temperatures have been steadily rising over the past few years. How, then, can this be explained?
One of the most widely accepted theories is that periodic warming periods on Earth are caused by cyclical changes in solar activity. In fact, the Sun experiences repeated peaks and troughs in its activity approximately every 12 years, marked by solar flare activity. It has already been proven that Earth’s temperatures fluctuate in line with the 12-year cycle of solar maximum and minimum, and the argument that solar activity could influence Earth’s temperatures over a long period of 1,500 years is compelling. Rather than the theory that global warming is caused by the small concentration of carbon dioxide emitted by humans into the Earth’s vast atmosphere, the theory that warming periods are occurring due to the activity of the Sun—which is far larger than Earth—is likely more convincing.
However, it is true that the theory attributing global warming to solar activity also requires more definitive evidence. On the other hand, given that melting glaciers in the Arctic and Antarctic are leading to more frequent natural disasters around the globe, it is argued that efforts toward environmental protection and the transition to sustainable energy are essential. While there are views that the impact of human activity on global warming may be limited, we must be prepared to respond to climate change.
So, even though there is no definitive evidence that the primary cause of global warming is the increase in carbon dioxide, why have we come to believe the claim that human-generated carbon dioxide is the cause of global warming? In 1988, the UNEP (United Nations Environment Programme) and the WMO (World Meteorological Organization) established the IPCC, an intergovernmental panel, to assess the risks of rising global temperatures and devise countermeasures. Subsequently, in 1997, the Kyoto Protocol was created to reduce greenhouse gas emissions among nations, setting and implementing reduction targets. Through various reports, the IPCC has highlighted the severity of global warming and emphasized that all of humanity must participate to solve it.
However, there are numerous vested interests and political relationships behind this, so we should not blindly believe the warnings about global warming. A prime example is when scientists included experimental results based on inaccurate data in IPCC reports in order to secure research funding. In a report submitted at the time, the IPCC claimed that “it is highly likely that Himalayan glaciers will disappear around 2035,” raising awareness about climate change and even winning the Nobel Peace Prize; however, this claim was proven false in 2010. The year 2035, which was predicted to be when the Himalayan glaciers would melt, was actually derived by reversing the digits of the year 2350 cited in a Russian research paper, and it was revealed that the area of the Himalayan glaciers had also been significantly exaggerated. Furthermore, the claim that “approximately 55% of the Netherlands lies below sea level” was also an exaggeration; the Dutch government has stated that only about 26% of the country is actually below sea level.
Finally, whether the exact cause of global warming is a man-made disaster or a natural cyclical phenomenon remains a subject of debate. Rather than blindly believing one side and resorting to black-and-white thinking, we must adopt a critical perspective to compare the evidence supporting both theories, examine what interests lie behind them, and consider the purpose for which they were presented. Furthermore, as exemplified by global warming, we should take a moment to reflect on whether we have been living in complacent conformity—without critical awareness—to societal issues that we have taken for granted under the influence of the media.
