How do we know humans are causing global warming?

Climate scientists have said that since 1950 people have judged that human influence is the main cause of global warming. They are positive about this as tobacco smoke causes cancer

Why are they so confident? The reason is that you understand well how greenhouse gases are warming the earth, that the theory is consistent with existing evidence, and that other theories are excluded. Let's break it down in 6 steps.

1) It has long been known by scientists that greenhouse gases in the atmosphere, such as carbon dioxide, methane, water vapor, absorb infrared radiation of a specific frequency and scatter them to the earth. These gases basically prevent heat from escaping into space, capturing the radiation on the ground and keeping the earth warm.

2) Climate scientists also know that the concentration of atmospheric greenhouse gases has increased significantly since the Industrial Revolution. Carbon dioxide increased by 40%. Methane increased by 150%. Through relatively simple chemistry, scientists can track these increases to human activities such as oil, natural gas, and coal.

3) Therefore, more greenhouse gases cause more heat. In fact, with satellite measurements, it is less likely that infrared rays will escape into outer space and return to the surface of the earth over time. This is strong evidence that the greenhouse effect is rising.

4) There are other human fingerprints indicating that the increase in greenhouse gases warms the earth. For example, as early as the 1960's, a simple climate model predicted that global warming caused by more carbon dioxide would cool the upper atmosphere (as the heat was trapped in the atmosphere). Later satellite measurements confirmed this. Here are some other similar predictions that have been confirmed

5) At the same time, climate scientists excluded other explanations of average temperature rise over the past century. As an example, the solar activity will change every year, potentially affecting the global climate. However, the satellite data shows that despite global warming, the total solar irradiance declined slightly over the past 35 years.

6) Recent calculations have shown that it is impossible to explain the temperature rise seen in the past century without considering the increase of carbon dioxide and other greenhouse gases. Causes of nature such as the sun and volcano have influences, but they are not enough

Ultimately, the Intergovernmental Panel on Climate Change (IPCC) concluded that much of global warming since 1951 is due to human activity. Due to the forces of nature (including the Pacific vibration such as the El Niño phenomenon), the climate of the Earth will fluctuate every year. However, greenhouse gases are leading the rise in temperature

Details: This is a graph that summarizes various factors that affect the global average temperature. Details of IPCC report, especially here and here

Today we are discussing important issues of global warming. As an active team, we are convinced that global warming is caused by human behavior. But this is not a mere belief, but a fact. By definition, global warming is a progressive increase in the global temperature of the Earth's atmosphere, which is often due to the greenhouse effect caused by increased levels of carbon dioxide, CFCs and other pollutants. The greenhouse effect is that the transparency of the visible light to the sun is greater than the infrared emitted from the surface of the planet so that the warmth of the sun at the low pressure of the planet is captured. Simply put, it prefers pollutants emitted from the Earth, such as pollutants from factories, automobiles, etc., and carbon dioxide from these gases absorbs heat from the sun and interns warm the climate It means that you can do it.

The natural cause of global warming includes the earth's trajectory to the sun. As we get closer to the beginning, the temperature of our planet is rising. This is not something human beings can quit. Other natural causes or global warming are earthquakes and El Niño Southern Oscillation. These are also impossible to prevent. However, the cause of human beings may be influenced by our behavior and behavior. The most important cause of global warming is greenhouse gas emissions - carbon dioxide and methane. These two gases confine heat and prevent it from escaping into the atmosphere. Carbon dioxide is released by combustion of fossil fuels, combustion of coal, and combustion of natural gas. Methane is mainly emitted from areas where intensive livestock rearing and garbage dumps