Is the earth getting warmer or colder?

There is an alarmist story in the ancient book Liezi Tian Rui. Legend has it that there was a man in Qi who was worried all day. He is worried that the sky will fall, and he has nowhere to hide. He is too worried to sleep and eat. Later, people used alarmist to describe unnecessary or unfounded worries.

However, since 1970s, scientists have had a heated debate on the future temperature changes of the earth. The two sides have diametrically opposite views, but this is not an alarmist, but a global announcement: human beings will face the threat of abnormal climate!

What's the future climate of the earth? Is it getting warmer or colder? Is there any basis for scientists' worries?

greenhouse effect

Some meteorologists predict that by the next century, the cold winter on the earth will no longer exist and all the ice and snow will melt. Whether it's flying snow, Himalayan glaciers or polar ice and snow, it's gone forever. If anyone wants to hold a ice dancing performance, they will have to turn to the snow machine.

The disappearance of winter means warmer weather, which is really terrible. The low-lying coastal areas of the Pacific Ocean and the Indian Ocean will be submerged by seawater and become a Wang Yang. Thousands of residents who used to live there had to emigrate to other countries. It has been calculated that when all the ice and snow melt, the sea level will rise by about 60 meters, which means that any place below 60 meters above sea level, including the place below the 20 th floor of Manhattan skyscraper in new york, will be submerged by sea water. ...

The climate is warming and the sea level is rising. Is this alarmist? No, some scientists have found evidence of land subsidence caused by sea level rise. Compared with the same period of last century, Shanghai, Guangzhou, Tianjin and other big cities have sunk by about 15cm.

Global temperature records can also prove the trend of climate warming. According to the statistics of the British Meteorological Department, 1988 is the highest temperature in the last hundred years. At the end of this century, the annual average temperature rose six times, all in the 1980s. By the early 1990s, the global annual average temperature had risen by 0.59℃. It can be seen that the earth is obviously warming.

So why is the earth getting warmer? Scientists believe that the influence of human activities on climate is becoming more and more serious. The world emits as much as 654.38+0.2 billion tons of carbon dioxide into the sky every year.

Carbon dioxide has a peculiar effect. It can absorb a lot of heat in the upper and lower atmosphere and prevent it from being lost into the air, just like glass in a greenhouse, so scientists use the term greenhouse effect to explain the role of carbon dioxide. The higher the carbon dioxide content in the atmosphere, the more obvious the trend of climate warming.

More seriously, some trace gases in the atmosphere have a "greenhouse effect" far more serious than carbon dioxide. These trace gases include: methane produced by organic matter decay, exhaust gas emitted by automobiles, and nitrous oxide released by nitrogen fertilizer in soil ... Although these gases are not many at present, they have strong heat absorption capacity and can amplify the greenhouse effect of carbon dioxide.

In addition, there are more and more artificial heat effects in cities. With the increasing scale of urban construction and development, the population is increasing. The temperature in the city is 0.5 ~ 1℃ higher than that in the suburbs. This phenomenon is called the heat island effect.

The above reasons seem to be enough to prove that the earth is warming. However, while some scientists are scrambling to put forward measures to control the greenhouse effect, others have put forward tit-for-tat opinions.

Umbrella effect

In recent years, scholars who attack the climate "warming theory" have emerged one after another. Some scientists published their research results, pointing out that the earth is developing in the direction of low temperature and humidity. The view that the earth is warming is just a misunderstanding of unknown nature.

Some experts in geology, geography, paleontology and archaeology in the United States believe that the view of "warming theory" is based on the statistical data of meteorological observation stations, and 97.5% of the data of meteorological observation stations are taken from cities and their surrounding areas. It is not difficult to see that there is man-made warming around the city, so the warming theory lacks a strong basis.

Through satellite temperature measurement, NASA scientists have proved that the average temperature of the earth has not risen from 1979 to 1988, and is even falling. In the northern hemisphere, the temperature increased slightly in 10, but it decreased in the southern hemisphere. Generally speaking, the earth is getting cold.

The United States Department of Agriculture has been tracking research for many years and found that the earth is cooling down. They made a detailed analysis of the data of 1200 meteorological observation stations. From 1920, only the temperature in big cities rises, while the temperature in suburbs and rural areas drops.

Meteorologists in China also believe that the meteorological data in China also show that the temperature is dropping.

The earth is getting cold. What is its theoretical basis? Scientists have made all kinds of interesting answers.

Some people say that our earth will enter the refrigerator for some time every tens of thousands of years. This is called the ice age in the history of the earth. By then, the whole world will be wrapped in silver, even the equator is no exception. The earth has experienced a warm period of nearly 65438+100000 years, and humans seem to hear the footsteps of glaciers rushing in.

Some scientists say that cold weather is related to the "parasol effect" on the earth. What is the sunshade effect? This refers to the impact of smog in the earth's atmosphere. Since the second world war, the number of volcanic eruptions has increased from 16 ~ 18 to 37 ~ 40 times a year. From 1880 to 1970, the artificial smoke and dust in the northern hemisphere increased by three times, and more and more smoke and dust were emitted from industries, automobiles and stoves. These aerosol particles suspended in the atmosphere are like the umbrella of the earth, which can reflect and absorb solar radiation, leading to the drop of ground temperature.

Scientists have different opinions on the prediction of climate warming or cooling, and there are great differences. Ed Leont, a professor at Warren University in Australia, seems to have a point. He said: "The climate is changing, but the reason for the change is natural, not man-made." He said that the climate has become more changeable. For example, Britain has just experienced the coldest winter in history. Then comes the warmest spring and autumn. It's just the fluctuation of natural climate.

According to his point of view, whether it is the greenhouse effect or the parasol effect, although these human factors affect the temperature of the earth, they cannot control the general trend of temperature change. Is the earth getting cold or hot? This is still an interesting mystery. However, with the unremitting exploration of scientists, all mankind will be able to withstand the test of climate change and meet the challenge of bad weather.