Why does air pollution darken the sky?

The weather is fine as long as you don't mind. Once the topic is formed, the Otawa disaster is linked.

"Man-made" Debate on Global Warming

Discover, an internationally renowned popular science magazine published in June 5438+ 10 this year, ranked Hurricane Katrina and the debate about global warming as the top science and technology news in 2005. Most meteorologists and environmental protection organizations believe that global warming is man-made, and excessive use of fossil energy (mainly oil, natural gas and coal) is the main reason for global warming.

Although this is a cliche, the hurricane in 2005 and two photos related to snow have made people have a more intuitive understanding of this problem. One of these two photos is the peak of Kilimanjaro Snow Mountain, which was taken from the air. People can clearly see that the snow on the top of the mountain has begun to melt, revealing dark brown rocks and soil layers. USA Today even listed Kilimanjaro Snow Mountain as the most immediate sight, because it predicted that the highest mountain in Africa would probably turn black forever in the near future. Another photo about snow is a comparison of photos of the Arctic ice sheet taken by satellite. As can be seen from the figure, in 2005, the area ratio of the Arctic white ice sheet 1979 decreased significantly. Those who live along the coast, especially those in some small island countries, may lose their homes forever because of the rising sea level caused by melting Arctic ice.

According to the annual report issued by the Geneva-based United Nations World Meteorological Organization (WMO), the global average surface temperature in 2005 was 0.48 degrees Celsius higher than the recorded average 196 1 ~ 1990, which was second only to 186 1.

However, the debate in the field of meteorology has long been not whether the climate is warming, but whether this change is man-made. Because, like many natural phenomena, the temperature of the earth itself changes periodically. If we want to know the real reason for the continuous high temperature in recent years, we must study the earth's past carefully.

Fortunately, everything that happens on the earth will leave some traces. The data of tree rings, polar ice cores and corals can provide indirect historical data for climate change. Michael, a meteorologist at the University of Virginia, USA? Michael mann is an expert in this field. 1998, he and two other meteorologists jointly published a research report and reconstructed a map of the earth's climate change since 600 years ago. 1999, they advanced this analysis to 1000 years ago. Finally, the three people draw the analysis results into a historical map of temperature changes. From the map, we can see that the average temperature curve of the earth is almost flat from 1000 to 1900, and it bends rapidly from 1900, that is, after the arrival of the industrialization era. International meteorologists call this famous temperature map "hockey stick".

At the end of 2004, Mann established his own website www.realclimate.org, which has now become an important platform for international meteorologists to exchange information. In 2005, Mann recruited nine collaborators to set up this website. These people are all senior experts in meteorology. They have written more than 100 meteorological research reports, covering almost all fields and hotspots of meteorology. One of the most striking is the critical novelist Michael? An article in michael crichton's new book Land of Fear.

Clackton is the author of Jurassic Park. His Country of Fear portrays environmentalists who support the "man-made" theory of global warming as a group of environmental terrorists, and implies that global warming is a big conspiracy made by environmental organizations with the aim of profiteering for environmental engineering companies. Interestingly, this accusation was originally the focus of environmental organizations' criticism of their opponents, but it was only aimed at the oil companies behind the scenes.

This original purely scientific debate is changing beyond recognition due to the intervention of politics and literature. No matter how well-founded Mann and others' scientific analysis is, their readers are doomed not to have as many fans as Bikel Cheton. The first print run of The Land of Fear reached 6.5438+0.7 million copies, which trained millions of "meteorologists" around the world. You can see more than 800 readers' messages on Amazon.com, an online bookstore, and quite a few of them support Clarkton's point of view. They are staunch supporters of Bush's environmental policy. It is precisely because of the sudden change of face of the Bush administration that the US government withdrew from the Kyoto Protocol, an agreement formulated by the United Nations to reduce greenhouse gas emissions. Although the Protocol finally came into force in early 2005 after suffering, the actual effect of Kyoto Protocol was greatly reduced because the United States, which accounts for more than 1/4 of global greenhouse gas emissions, did not participate.

Hurricane Katrina on August 29, 2005 almost razed New Orleans, which made environmental organizations see the hope of persuading the US government. The day after Katrina, journalists and government officials expressed their views and linked hurricanes with global warming. Senior reporter Ross? On August 30th, Gerbospan wrote in the Boston Globe: "The National Weather Service called it Hurricane Katrina, but its real name should be global warming."

Many people suspect that the increase of hurricane frequency in North America in recent years is related to global warming, but meteorologists generally believe that the hurricane frequency itself has a natural cycle, and the northern hemisphere is only rising, which has nothing to do with global warming. However, Kelly, a professor of meteorology at MIT? A group of meteorologists, represented by Emmanuel, believe that global warming leads to an increase in hurricane intensity. Kelly published a research report in Nature last August, claiming that the hurricane intensity in North America has more than doubled compared with that in 1970s, and this change is directly related to the rising sea level temperature. According to Emmanuel's early calculation, every time the sea level temperature rises by 65438 0 degrees Celsius, the hurricane speed will increase by 7%. The intensity of several hurricanes in North America in 2005 not only proved his point, but also was much stronger than he expected.

However, this research report has also attracted opposition.

William, a meteorologist at Colorado State University? Gray said publicly: "Emmanuel's article is terrible, the worst article I have ever read!" " "Another senior hurricane expert Christopher? Nancy pointed out that Emanuel's research is full of loopholes, mainly because the method of measuring hurricane wind speed has been improving. The error of the previous measurement method is too big, and the obtained data is not credible, so it can't be compared with the current data.

Scientific arguments will come out one day, but accusations based on morality are not so simple. Nancy, who now works at the National Hurricane Research Center, publicly announced her withdrawal from the Intergovernmental Panel on Climate Change (IPCC). He felt that IPCC interfered with serious scientific research. The Kaituo Institute, an independent American think tank, even published a research report, pointing out that IPCC is not a real scientific research institution, but a propaganda department led by politicians. Kaituo predicts that the United States will allocate $4 billion for climate research in the next fiscal year. In order to ensure the strength of funds, we must ensure that the red flag of "global warming" does not fall.

Who is right and who is wrong? I don't know yet. However, this debate in the meteorological field gave the Bush administration a very good excuse to refuse to sign the Kyoto Protocol.

Two recent discoveries support the "artificial" theory.

Let's put aside politics for a while and pay attention to the two most interesting discoveries in meteorological research in 2005. One is the latest report of the European Antarctic Ice Core (EPICA) project. Scientists drilled an ice core 650,000 years ago in Antarctica, 2 1000 years earlier than the previous data. This research can be traced back to 1990, when scientists began to extract ice cores from the Greenland ice sheet. Some of these huge icicles are as long as 3000 meters, and the bubbles in them completely retain the climate data of the past 1 1000 years, which is more accurate and reliable than any indirect analysis. The "European Antarctic Ice Core" project turned its attention to the older South Pole, which advanced human understanding of the earth in ancient times by hundreds of thousands of years. The analysis shows that in the past 650 thousand years, the content of carbon dioxide in the atmosphere has never exceeded 300PPM (300 parts per million), but at present, the content of carbon dioxide has reached 380PPM, which is 27% higher than the highest value before industrialization. This new discovery clearly shows how human activities affect the content of greenhouse gases.

Another new discovery is not new, but it finally caught public attention last year. As early as the early 1990s, some scientists suggested that the air pollution caused by burning fossil fuels (especially coal) would reduce the intensity of solar rays shining on the earth's surface. Aircraft exhaust can also produce the same effect. "9? The "1 1" incident gave meteorologists a golden opportunity, because all American civil aircraft were grounded for three days. Measurements show that in these three days, the temperature in the United States has risen by about 65438 0 degrees Celsius. This phenomenon is called "global darkening" and has never been known to the world. It was not until June 2005 that a special program was broadcast on BBC Discovery Channel that ordinary people first knew about it.

These two interesting new scientific discoveries are interrelated. The former points out that the excessive exploitation of fossil fuels by human beings has greatly changed the surface temperature in a short time. The latter implies that this change will also lead to global darkening, which in turn will lead to global cooling. At first glance, people may think that the two cancel each other out and there is nothing to worry about. In fact, air pollution that darkens the world will bring various diseases to people and must be treated anyway. The greenhouse gases that cause global warming are invisible and intangible, not air pollution in the ordinary sense, so ordinary people will ignore its impact. Many meteorologists believe that the record high summer temperature in Europe in 2003 was due to the efforts made by Europe in recent years to reduce air pollution and "global darkening", but it did not reduce the carbon dioxide content accordingly. In other words, the "global darkening" caused by air pollution may temporarily cover up the truth of global warming, and the degree of global warming is more serious than what has been observed so far.

These two new discoveries tell us that meteorology is an extremely complex science, involving too many factors, and it is difficult to predict accurately. For example, the severe cold in Europe that began at the end of last year made many people exclaim: Isn't it global warming? Why is it so cold this winter! In fact, in the final analysis, this cold is also caused by global warming, because the rising temperature leads to the melting of Arctic ice and snow, which reduces the salinity of seawater in the North Atlantic, thus slowing down the flow of warm seawater near the equator to the north, which is the main reason why Europe is not cold in Siberia in winter.

Because greenhouse gases will bring many unexpected results, the word "climate change" is popular in the international meteorological community, not "global warming". Like Richard, a professor at Pennsylvania State University? As Avery once said, there is a critical point in the balance of climate. When climate change exceeds a certain critical point, drastic changes will occur. Perhaps global warming itself is not enough to cause hurricanes in North America in summer and severe winters in Europe in 2005, but global warming is accelerating the earth's climate to approach the critical point. Once the critical point is exceeded, mankind will face not only several hurricanes, but a real catastrophe.

In order to slow down or even avoid the catastrophe, mankind must start at once. The annual United Nations Climate Conference held in Montreal, Canada at the end of June 2005 was a good start. The meeting discussed the new emission reduction plan after the Kyoto Protocol expires in 20 12 years. Although no substantive agreement was signed (it is impossible), at least this meeting brought the leaders back to the negotiating table and laid a framework for future negotiations, which is the greatest victory. China sent a huge delegation to the meeting, but unfortunately, few people went to the China media. This meeting has a lot to do with China. Whether enterprises in China can absorb hundreds of millions of dollars of environmental protection investment after 20 12 depends largely on the negotiation results at this conference.

Thanks to the CDM mechanism, China will be the biggest beneficiary of the Kyoto Protocol.

In essence, Kyoto Protocol is an environmental protection law specifically for developed countries, and it does not set emission limits for developing countries. Even the new version of xx protocol after 20 12 is unlikely to do so. However, China has a close relationship with the Kyoto Protocol, because it has a flexible mechanism called CDM. The full name of CDM is "Clean Development Mechanism", which means that developed countries pay for emission reduction projects in developing countries. Of course, developed countries do this because the CDM mechanism allows them to offset their emission reduction targets with the emission reductions obtained in developing countries, because the cost of emission reduction in developed countries is generally higher than that in developing countries.

This clean development mechanism is the result of years of hard negotiations. According to Professor Zou Ji, one of the negotiators of China delegation and vice president of School of Environmental Studies of Renmin University, Kyoto Protocol and CDM are the legacy of the older generation of negotiators in China. In particular, Mr. Zhong Shukong, the first chief negotiator of the China delegation, worked as an interpreter for Premier Zhou Enlai and was a diplomatic expert. He once said that international negotiations on global warming are not climate negotiations, but political negotiations. It seems that this sentence is very meaningful today. Because of its close relationship with the energy strategies of countries all over the world, this negotiation has become a stage for political leaders of various countries to wrestle.

Some people say that the Kyoto Protocol is a contest between developed and developing countries, but Professor Zou Ji disagrees with this statement. He believes that this negotiation is essentially a contest between developed countries, especially between the European Union and the United States. The European Union does do better than the United States in the field of environmental protection, and they want to use this advantage to compete with the United States economically. The reason why the United States is tough on this issue is not because American scientists don't believe in the harm of global warming, but because they don't want to lose to the European Union economically.

The withdrawal of the United States from Kyoto Protocol made China lose a lot in CDM projects, because the greenhouse gas emissions of the United States accounted for 1/4 of the world. If the United States joins, the total amount of funds for CDM projects will be several times more than it is now. In order to compete for limited funds, developing countries are secretly competing with each other fiercely. In order to prevent China from benefiting too much, some countries set up obstacles in the rules to block CDM projects in China. Thanks to the efforts of negotiators and scientists from China, the United Nations recently adopted the "emission reduction verification baseline method" for coalbed methane projects. Since then, the emission reduction mechanism of rational utilization of coalbed methane can be classified as CDM project. As we all know, China is a big coal producer. If the CBM project is included, China will be the biggest beneficiary of the international environmental protection fund in CDM projects. Therefore, some people call CDM "China Development Mechanism".

However, Professor Zou Ji believes that climate change is, after all, a problem of the whole planet, beyond the concept of a country. It is not wrong for the delegation of China to emphasize the interests of developing countries in international negotiations, because the population of developing countries accounts for 80% of the world's total population, and defending the interests of developing countries means defending the interests of the whole world.

In the past 50 years, the sunshine in China has decreased 10%.

Researchers at the Pacific Northwest National Laboratory in Washington recently published research results, saying that through nearly 500 ground sunlight receiving and recording instruments all over China, it was found that since 1954, the ground sunlight radiation has decreased by about 2% every 10 year. Compared with 50 years ago, the light in China decreased by 10% on average.

At the same time, the water evaporation rate in China is also decreasing, which is about 10/0 years .5 inches. Corresponding to the decrease of evaporation rate, the cloud cover in the sky of China has been decreasing for nearly 50 years, with a decrease of about 0.78% every 10 year.

Because the amount of clouds is also decreasing, it can be ruled out that the shading of clouds leads to the weakening of light. The researchers said that it was the large amount of emissions from the burning of coal and petroleum fuels that formed the fog that enveloped the land of China. This fog absorbs and reflects sunlight, making China even darker. The smog formed by this pollutant will not only block the sun, but also bring acid rain and respiratory diseases.