Possible consequences of increased atmospheric greenhouse effect

Possible consequences of increased atmospheric greenhouse effect

The average temperature of the Eurasian and North American continents will be 6 to 8°C higher than the current actual temperature. The current global daily average temperature on the ground has increased by 0.6°C compared to before the first industrial revolution. The scale of this temperature increase is equivalent to the temperature change that can be observed during the 10,000 to 20,000 years required for the earth to transition from an ice age to an interglacial period. Human activities can produce such similar changes within a hundred years, which will cause a disaster to most of the earth’s ecosystems and human society itself. Strong ecosystem changes have taken place long before humans appeared on the earth. A large number of biological species became extinct in the process of this great change, and some extinction ratios were as high as 90%.

Climate warming will have a series of disastrous consequences, such as the frequency of hurricanes and the increase of storms and heat waves on the continent, the rise of sea levels, the disappearance of coral reefs, the increase of El Niño, and the increase in the frequency of disasters such as droughts and floods. The original fragile condition of the ecosystem will tend to produce more serious disasters. For example, the drought in agriculture is at risk of aggravation. This situation will be more pronounced especially when the rhythm of climate change accelerates. In addition, climate change will also bring health problems. Diseases such as malaria, dengue fever and hemorrhagic fever will appear in some temperate countries where these diseases have not occurred before and will spread in countries where these diseases have occurred. By the end of the 21st century, if the global temperature rises by 5°C, it will cause sea levels to rise substantially. Many cities near the coast, such as New York, Tokyo, Shanghai, Tianjin, and London, will be seriously threatened by seawater intrusion. Half of Shanghai’s urban area will become a depression below the sea level, and large areas of densely populated urban and rural areas will become Wang Yangzeguo. Some island countries in the Pacific are now at risk, and at least in Bangladesh, nearly 100 million people will be homeless. How to settle these environmental refugees and make up for the food crisis caused by the reduction of a large amount of arable land has become a serious issue before governments of all countries.

In recent decades, many scientists have come to realize that ozone in the stratospheric atmosphere is being increasingly destroyed. In 1985, British scientists Farmen et al., based on their observations at the Halley Bay Observatory (Halley Bay) in Antarctica, found that since 1975, the total ozone concentration there has been reduced by more than 30% in early spring each year. This news shocked all countries and all walks of life in the world.

The destruction of the ozone layer, like the greenhouse effect, is the result of chronic and widespread air pollution. More and more scientific evidence shows that the root cause of the destruction of the Antarctic ozone layer is caused by artificially synthesized chlorine and bromine-containing substances that escape into the atmosphere. The most representative compound is chlorofluorocarbons, namely Freon ( CFCs and Halons containing Australian compounds are another type of energy substances synthesized in the 1920s and are widely used as liquid refrigerants, sprays and foaming agents. Their life span in the atmosphere is several centuries. The chemical properties of CFCs and Halons released by human activities are very stable in the atmospheric troposphere and are not easily removed by general atmospheric chemical reactions. After a certain period of time, these compounds are mainly carried into the stratosphere by atmospheric circulation over tropical regions, and move from low latitudes to high latitudes by means of wind, and then are evenly distributed in the stratosphere.

In the stratosphere, strong ultraviolet radiation can dissociate CFCs and Halons molecules, releasing chlorine and bromine radicals in highly reactive atomic states. Chlorine atom free radicals and bromine atom free radicals are the main substances that destroy the ozone layer. Their destruction of ozone is carried out by a chain reaction in a catalytic way, which has a great impact.

Among the ultraviolet radiation from the sun, the ultraviolet ray with a wavelength of 280~315nm is called the UV-B region. Its ultraviolet radiation has high energy and causes the most serious harm to humans and other life on the earth. Ultraviolet rays in this band can be completely absorbed by the stratospheric atmosphere. The destruction of the ozone layer will greatly weaken its ability to absorb ultraviolet radiation, resulting in a significant increase in the intensity of ultraviolet radiation reaching the UV-B zone on the earth’s surface, which will cause serious harm to human health and the ecological environment. It is generally believed that the total amount of ozone in the stratosphere is reduced by 1%, and the harmful ultraviolet rays reaching the earth’s surface will increase by 2%.