Is global warming and climate change caused by humans? In short, yes, the temperature increase observed for the past 150 years is caused by humans. More precisely, temperature fluctuations are natural phenomena of the Earth system and have different ranges on different time scales; for example, on the ten-year scale, the El Niño-Southern Oscillation system and the volcanic eruption (global temperature) are important. However, human greenhouse gas emissions rise above the natural fluctuations. Although we know that greenhouse gas emissions will cause global warming, it is not easy to say whether current climate warming is due to human influence. Ideally, if we want to confirm whether global warming is caused by humans, we can only conduct control experiments and compare human and human impacts. Unfortunately, we only have one earth, so there is no way to proceed. However, there is still a lot of evidence to illustrate this issue. One of the most used proofs is the curve of temperature and carbon dioxide rise; in fact, this article does not explain the problem, because everyone knows that correlation and cause and effect are two different things. It can be that the increase in temperature causes a rise in carbon dioxide, or there are other mechanisms influences. The stratosphere is above the troposphere and there is less material exchange between the two layers, and almost all human greenhouse gas emissions enter the troposphere. According to the greenhouse effect, we should observe an increase in tropospheric temperature because greenhouse gases absorb more long-wave radiation; at the same time, we should observe a decrease in the temperature of the stratosphere because greenhouse gases in the troposphere prevent long-wave radiation from entering Stratosphere heating gas. In other words, energy is transferred from the stratosphere to the troposphere. This is exactly what the satellite data observed. Climate warming is caused by the solar cycle, especially the temperature drop in the stratosphere; of course, the more direct rebuttal is the direct observation of the solar flare (which has been declining for half a century).
As a civil engineering student, I take our changing climate as a significant challenge that directly impacts the work we do and the infrastructure we build. Climate change is seen in various ways such as rising global temperatures, more frequent and extreme weather events along with rising sea