What is the greenhouse effect? Why advocate a low-carbon life?

Global warming is a natural phenomenon. Because people burn fossil minerals to generate energy or cut down forests to burn, many greenhouse gases, such as carbon dioxide, are produced. This gas has high permeability to visible light from the sun and high absorption to long-wave radiation reflected from the earth, which is commonly called "greenhouse effect" and leads to global warming. In recent 100 years, the global average temperature has experienced two fluctuations: cold-warm-cold-warm, with an overall upward trend. Since 1980s, the global temperature has obviously increased. The consequences of global warming will redistribute global precipitation, melt glaciers and frozen soil and raise sea level, which will not only endanger the balance of natural ecosystems, but also threaten human food supply and living environment.

What is global warming?

Global warming refers to the increase of global temperature. In recent 100 years, the global average temperature has experienced two fluctuations: cold-warm-cold-warm, with an overall upward trend. Since 1980s, the global temperature has obviously increased.

198 1 ~ 1990, the global average temperature increased by 0.48℃ compared with 100 years ago. The main reason for global warming is that humans have used a lot of fossil fuels (such as coal and oil) and released a lot of greenhouse gases, such as carbon dioxide, in the past century. Because these greenhouse gases have high permeability to visible light radiated by the sun and high absorption to long-wave radiation reflected by the earth, this is commonly called "greenhouse effect", which leads to global warming.

The consequences of global warming will redistribute global precipitation, melt glaciers and frozen soil and raise sea level, which will not only endanger the balance of natural ecosystems, but also threaten human food supply and living environment.

The specific reason for the global warming trend is that people burn fossil minerals to generate energy or cut down forests and burn them to produce carbon dioxide that enters the earth's atmosphere. According to the climate model, the Intergovernmental Panel on Climate Change predicts that by 2 100, the global temperature will rise by about 1.4-5.8 degrees Celsius (2.5- 10.4 degrees Fahrenheit). According to this forecast, in the past 65,438+00,000 years, the global temperature will change dramatically, which will have a potentially significant impact on the global environment.

In order to stop the global warming trend, the United Nations specially formulated 1992 "United Nations Framework Convention on Climate Change", which was signed into effect in the Brazilian city of Rio de Janeiro in the same year. According to this convention, developed countries agreed to reduce their carbon dioxide and other "greenhouse gases" into the atmosphere to the level of 1990 by the year 2000. In addition, countries with total carbon dioxide emissions accounting for 60% of the global total carbon dioxide emissions in these years have also agreed to transfer relevant technologies and information to developing countries. These technologies and information transferred from developed countries to developing countries will help developing countries actively respond to the challenges brought by climate change. As of May 2004, 189 countries have formally ratified the above convention.

The History and Prediction of Global Warming

According to the instrument records, compared with the period from 1860 to 1900, the global land and ocean temperature rose by 0.75 degrees Celsius. Since 1979, the land temperature has risen twice as fast as the ocean temperature (the land temperature has risen by 0.25 degrees Celsius, while the ocean temperature has risen by 0. 13 degrees Celsius). According to satellite temperature detection, the troposphere temperature rises by 0. 12℃ to 0.22℃ every ten years. Before 1850 1000-2000, although there were warm periods and little ice ages in the middle ages, people thought that the global temperature was relatively stable.

According to the research report of Goddard Space Research Institute of NASA, it is estimated that 2005 is the hottest year, which is several percentage points higher than the record of 1998, because measuring instruments were widely used in 1960s. The World Meteorological Organization and the British Climate Research Group have similar estimates, and predict that 2005 will be the second hottest year after 1998.

There are only some temperature records in modern human history. These records come from different places and their accuracy and reliability are also different. A similar global thermometer was recorded only in 1860. I believe that the records of that year were rarely affected by the urban heat island effect. From the long-term prospects displayed by various records in the past thousand years, we can see the relevant discussions and differences in the past 1000 temperature records. The process of climate change in the last 50 years is very clear, which depends on detailed temperature records. By 1979, people began to use satellite temperature measurement to measure the temperature in the troposphere.

After 2000, high temperature records in various places were often broken. For example, on August 1 1 day, 2003, the temperature recorded in Gronau was 4 1.5 degrees Celsius, breaking the record of 139. In August of the same year 10, the temperature in London, England reached 38. 1, breaking the record of 1990. In the same period, the lowest night temperature in southern Paris was 25.5 degrees Celsius, breaking the record since 1873. On the night of August 7, Germany also broke the record of the highest temperature in a hundred years. In the summer of 2003, Taipei, Shanghai, Hangzhou, Wuhan and Fuzhou all broke the local high temperature records, while China and Zhejiang broke the high temperature records even faster, and 40 of the 67 weather stations set new records. In July 2004, the rare high temperature in Guangzhou broke the record for 53 years. In July, 2005, 200 cities in the United States set a record high temperature. On August 6, 2006, the highest temperature in Chongqing reached 43 degrees. On July 8, 2006, the temperature in Yilan, Taiwan Province Province reached 38.8 degrees, breaking the record of 1997. 2006165438+1October1was the hottest day in Hong Kong, with the highest temperature of 29.2 degrees, which was higher than the average maximum of 19 1 to 1990.

American scientists found that prehistoric agricultural activities prevented the world from entering a new ice age.

According to Xinhua News Agency, American scientists found that ancient agricultural activities prevented the world from entering a new ice age. This shows that global warming caused by human activities may have lasted for thousands of years.

Researchers say that prehistoric farmers who cut down trees and reclaimed the first land created greenhouse gases such as methane and carbon dioxide in the atmosphere.

Great changes have taken place in the body content, so the global temperature is gradually rising.

Rudiman, a professor at the University of Virginia in the United States, said: "If it were not for the greenhouse gases brought by early agriculture, the current temperature of the earth would probably be the temperature of the Ice Age." Rudiman admits that the research results are controversial.

The National Center for Atmospheric Research of the United States said on June 5438+07 that scientists predicted through two latest studies that even if the global greenhouse gas emissions were stable at the level of 2000, the trend of global warming and sea level rise in this century would be irreversible.

Scientists from the National Center for Atmospheric Research published two papers in the journal Science on June 5438+08, predicting the trend of global climate change from different angles. Their achievements will be evaluated by the Intergovernmental Panel on Climate Change under the United Nations and included in the next Global Climate Change Report published in 2007.

In the first paper, Wei Gray of the National Center for Atmospheric Research proposed a simple mathematical model to understand global climate change. He believes that due to the "thermal inertia" of the ocean, the response to external influences such as greenhouse gases is lagging behind, and the trend of global warming in this century is only the result of previous greenhouse gas emissions.

According to Wei Gray's prediction, by 2400, the greenhouse gas components in the atmosphere will at least increase the global average temperature by 1 Celsius; The newly released greenhouse gases will cause the global average temperature to rise by another 2 to 6 degrees Celsius. These two factors will also cause the sea level to rise by10cm and 25cm respectively every century.

In his paper, he said that to curb the trend of climate warming, global greenhouse gas emissions must be controlled at a very low level now. Even so, the rising trend of sea level is hard to avoid, and the rising speed of10cm per century may be the most optimistic prediction.

The second paper published by Gerald Mayer and others predicted that even if human beings do not emit any greenhouse gases into the atmosphere in this century, by 2 100, the global average temperature will rise by at least 0.5 degrees Celsius, and the sea level will rise by more than 1 1 cm, in which the sea level will rise more than twice as fast as scientists had predicted. Mel explained that this is because the previous forecast did not take into account the impact of glacier melting.

Mel's research team used two sets of mathematical models and supercomputers to simulate the climate and sea level changes at low, medium and high global greenhouse gas emissions.

Conditions of global warming

Global warming is related to the greenhouse effect caused by a large number of greenhouse gases emitted by human beings. However, researchers in Japan and Denmark recently pointed out that the increase of greenhouse gases is not the only cause of climate warming, but the change of solar activity has also played a role in promoting it.

According to the Nihon Keizai Shimbun, Professor Koji Ito from the Institute of Environmental Information of Yokohama National University in Japan made a chart. As can be seen from the figure, the curve between the average temperature of the earth and the intensity of the solar magnetic field in the past 200 years is basically the same. Ito koji concluded that solar activities also have an impact on climate warming, and it may not be comprehensive to explain climate warming only by increasing greenhouse gases.

The influence of solar activity on the earth's temperature has long been concerned by experts. Generally speaking, when there are many sunspots, the solar activity is intense. For example, according to historical records, sunspots rarely appeared in the17th century, when the earth's climate was relatively cold. However, the detection information obtained on the ground also shows that the change range of solar radiation energy caused by the change of solar activity intensity is only 0. 1%, and such a small change does not seem to have much impact on the climate.

Recently, however, there has been a hypothesis in the international space science community that the change of solar activity will change the cloud cover over the earth, "amplify" the influence of the sun on the earth, and then affect climate change. Danish scientists who put forward this hypothesis speculate that cosmic rays emitted to the earth can ionize part of the atmosphere more stably, making it easy for clouds to form, thus absorbing a lot of solar radiation and lowering the temperature of the earth. However, the high-speed charged particle flow released at the peak of solar activity can interfere with cosmic rays that are directed at the earth, making it difficult for clouds to form, which in turn leads to an increase in the temperature of the earth. At present, Danish researchers are studying various factors related to cloud formation to demonstrate the above hypothesis.

Some Japanese experts also suggested that although the change of solar radiation energy is only 0. 1%, they found that this energy change can change the absorption of solar ultraviolet rays in the earth's atmosphere by several percent, and the increase of this absorption will increase the temperature of the atmospheric ozone layer. Koji Bangyan, head of the second research department of Japan Meteorological Institute, said that the change of ozone layer temperature will affect the troposphere, thus affecting the cold current and monsoon, but it is not clear how much the above mechanism will affect global warming. In order to continue to study this subject, an international research group composed of Koji Bangyan and others began to work last year.

Global warming continues.

Luo Yong, deputy director of the National Climate Center of China Meteorological Bureau, said that according to the predictions of many scientists in the world, in the next 50- 100 years, human beings will completely enter a warming world. Due to the influence of human activities, the concentration of greenhouse gases and sulfide aerosols will increase rapidly in 2 1 century, which will lead to the rapid increase of global temperature, East Asia and China in the future 100, and the global average surface temperature will rise by 1.4℃-5.8℃. By 2050, the average temperature in China will rise by 2.2℃.

"The frequent occurrence of rare foggy weather since winter is also a sign of warm winter." Luo Yong said that the foggy weather was caused by "warm winter" and the strong cold air was very weak. The reality of global warming is constantly sounding the alarm to all countries in the world. Climate warming has seriously affected the survival of human beings and the sustainable development of society. It is not only a scientific problem, but also a comprehensive problem covering politics, economy and energy. The fact of global warming has risen to the height of national security.

Temperature prediction of global warming

German researchers say that the future global temperature may be much higher than some scientists' previous predictions, if the prediction of climate change made by the new computer model is correct.

According to Reuters, the Intergovernmental Panel on Climate Change (IPCC), which is composed of meteorologists from various countries and studies global climate trends, predicts that by the end of this century, with the doubling of carbon dioxide, the global temperature will rise by 1.5 to 4.5 degrees Celsius. However, the latest calculation method of Professor Mainrath Andrea of Max Planck Institute of Chemistry in Mainz and his research team shows that the maximum range of global temperature rise can reach 6 degrees Celsius.

Professor Andrea said that this new method unifies suspended particles, greenhouse gases and biosphere effects, changing the previous prediction of climate change, even if it develops from a tolerable level to a more rapid and dangerous situation.

Professor Andrea compares greenhouse gases to an accelerator that causes global warming, and the existence of suspended particles can slow down the temperature rise. Suspended particles are tiny particles produced by combustion, chemicals and smoke in the air. With the use of new air purification and regulation devices, the number of suspended particles will decrease, so its cooling effect will also become smaller. On the contrary, the global temperature will rise accordingly.

Suspended particles can only stay in the atmosphere for one week, while greenhouse gases can stay for about 50 years. In other words, the cooling effect of suspended particulate matter decreases rapidly, while the greenhouse gas decreases slowly. In this way, in the long-term competition, greenhouse gases will eventually overcome suspended particles, followed by scorching hot weather.

However, Professor Andrea also admitted that this situation has a high degree of scientific uncertainty, and climate change is far beyond the scope of experience and scientific understanding. If his calculation is correct, the climate change in 2 1 century will exceed the prediction of the Intergovernmental Panel on Climate Change.

The consequences of global warming

According to Xinhua News Agency, researchers at the Worldwatch Institute in the United States recently warned that global warming will lead to a reduction in global agricultural production, and food shortages may occur in the next century. The researchers came to this view after analyzing the information released by the United Nations and the National Academy of Sciences and the trend of the world rice market.

According to world observation research, global warming and the decline of groundwater level will become the direct cause of global food supply shortage, which is reflected in the rising trend of global rice prices.

According to statistics released by the US government, the price of rice rose by 30%, reaching $260 per ton, although the global grain harvest last year, the prices of wheat and corn fell.

A research report published by the National Academy of Sciences last year showed that the abnormal temperature rise in the rice growing season would reduce the harvest. In addition, the decline of groundwater level and the depletion of wells in many parts of the world will also affect food production.

How to slow down global warming

Scientists put forward a bold idea to build an artificial space ring around the earth, consisting of small particles or spaceships, to shield tropical sunlight and regulate the temperature of the earth.

However, some opponents believe that this idea will definitely have some side effects. A particle belt that can effectively scatter sunlight will make every night sky as bright as a full moon. And the budget of this project will be staggering, possibly reaching 6 trillion to 200 trillion dollars. Even NASA, the most well-funded scientific research institution in the world, cannot afford it. If the bulk particles are replaced by spacecraft, the budget may be less, and it is estimated that it can be reduced to about 500 billion US dollars.

Since the birth of the earth, the atmospheric temperature has fluctuated several times, and various factors such as solar radiation, cloud cover and greenhouse gases have affected or are affecting our climate. If you put a particle belt or spacecraft around the earth, a shadow will appear over the equator. In order to deploy these particles, you must use some special control spacecraft to look after the particle swarm like a sheepdog.

In the past century, the temperature of the earth has obviously increased, and this trend will continue in the next hundred years. Many studies have confirmed that in the next few centuries, the earth's temperature will rise by 1 to 20 degrees Fahrenheit, the sea level will rise obviously, and some coastal cities will cease to exist. Some scientists have pointed out that reducing sunlight will reduce the temperature of the earth, and some ground or space systems can completely achieve this goal. However, some scientists pointed out that it is still impossible to calculate how much sunlight the earth can absorb and how much sunlight is reflected back into space, which is a key step in implementing the above plan.

Research by American scientists shows that the activities of ancient farmers prevented the world from entering a new ice age. This result shows that global warming caused by human activities is not a new phenomenon, and it may have lasted for thousands of years. The British "Observer" recently quoted researchers as saying that prehistoric farmers who cut down trees and reclaimed the first field changed the content of greenhouse gases such as methane and carbon dioxide in the earth's atmosphere, and the global temperature gradually increased. Qian Wei Rudiman, a professor at the University of Virginia in the United States, said: "If it were not for the greenhouse gases brought by early agricultural activities, the current temperature of the earth would probably be the temperature of the Ice Age." Studies show that without human intervention, the earth will be 2 degrees Celsius lower than it is now, and the spreading ice sheets and glaciers will affect many parts of the world.