Why is it getting hotter?

First of all, after the industrial revolution began, the global temperature rose very obviously. The main reason is the rapid development of industrial revolution and the rapid progress of science and technology, which leads to a large increase in the use of chemical fuels. Some scientific and technological products, such as automobiles and airplanes, emit a lot of greenhouse gases with strong heat absorption into the atmosphere, such as carbon dioxide, methane and nitrous oxide.

Second, the concentration of these greenhouse gases in the atmosphere is getting higher and higher, which makes the atmosphere form a greenhouse gas film, thus forming the greenhouse effect. After the sun's heat radiates to the ground, it is reflected to the sky. Because of the greenhouse effect, this heat cannot be dissipated, which makes the earth's temperature higher and higher, leading to global warming.

Thirdly, according to statistics, the fossil energy burned by human beings will emit 22 billion tons of carbon dioxide into the atmosphere every year, causing the global greenhouse gas concentration to rise continuously. For example, in Beijing, the carbon dioxide concentration increases by 0.57% every year on average. So is the greenhouse effect really the chief culprit of rising humidity? Scientists don't think so. The greenhouse effect is only one factor that causes the global temperature to rise, and there are other factors.

Fourthly, another reason for global temperature rise is urbanization. Some scientists believe that urbanization is also an important factor of global temperature rise, that is, the heat island effect. Its impact may be more worthy of attention than the greenhouse effect. 1833, Lake Howard, a British climatologist, compared the temperatures in the urban area and the suburbs of London, and found that the temperature in the urban area was higher than that in the suburbs, and put forward the climate characteristics of the heat island effect for the first time.

Fifth, cement, asphalt, concrete, etc. Widely used in urban buildings and roads. These materials account for more than 70% in urban construction, and they absorb solar radiation more easily and heat up quickly. For example, the same quality of cement is heated to 1 degree Celsius, which requires much less thermal radiation than soil.