What is the relationship between global warming and the occurrence of climate phenomena?
A relatively small temperature difference may bring unexpected consequences. In Scotland, under normal circumstances, the temperature in winter will not stay below freezing point for a long time, but it was severely cold twice in 1995 and 12. The temperature in Crass, a Scottish highland village, once reached MINUS 29.9℃. This is the lowest temperature recorded in Britain. The main water supply pipe is completely frozen. When the temperature rose and the ice began to melt, the water pipe burst. 500 thousand households in Scotland are in a state of waterless. The Argentine grassland, which has always been lush, also dried up in 1995 and suffered the worst drought in history. The grassland turned into a piece of dry wood. 1at the beginning of 996, tens of thousands of acres of grassland caught fire, and the fire could not be controlled. Fernando Adoula, a senior official in charge of national park affairs, said: "We are facing the reality of very low humidity, record high temperature and zero probability of instant precipitation." The drought reduced the grain production in this area by about 30%, and thousands of cattle starved to death.
However, the abnormal weather has also brought some fun to some people. 1996 The unusually low temperature in mid-February turned Lake Ulster in Hamburg into a large skating rink, and about 500,000 people flocked to slide or pull sleds on the ice. In central Mexico, many people are rejoicing for the first real snow in decades! However, because there is no snow, the World Cup skiing competition to be held in Germany has to be cancelled.
Another consequence of global warming will be the partial melting of ice and snow in the Arctic and Antarctic, leading to sea level rise. Since 1920, the polar ice and snow have melted and the sea level has been rising. The global average sea level is more than 30 centimeters higher than in the past. This has to attract the attention of meteorological, marine, agricultural, forestry, environmental and other departments. Some scientists have pointed out that if the current carbon dioxide concentration doubles, the sea level will rise by 80 cm, and the coastal areas will lose a large area of fertile land. At present, the population living within 60 kilometers from the coastline accounts for about 1/3 of the world's total population. If the sea level rises due to climate warming, the urban residents from Bangkok to new york and the port facilities that maintain world trade will be affected, the low-lying coastal areas around the world will be submerged by seawater, and millions of coastal residents will be forced to move.
In the northwest, northeast and north China, if the temperature rises by 2-4 degrees Celsius, the land evaporation will increase by more than 20% and the cultivated land will lose 300 million mu. Some experts pointed out that areas below 4 meters above sea level are no longer suitable for investment in China, and areas above 1 to 2 meters above sea level must make long-term population migration planning.
Continued global warming will lead to high fever and drought in some areas, which will lead to forest fires. 1997 global forest fires are serious, which are related to high fever and drought. Because winter is cold or not, many crop pests will not die, which leads to the occurrence of crop pests and diseases and the decline of grain output. Similarly, whether it is cold or not can make people easily get sick.
Alaska is located in the northern part of the northern hemisphere, where the annual average temperature is very low, but in recent years, due to the global temperature rise, Alaska's forests have suffered great losses. 196 A large area of pests occurred, and about 25 million Douglas fir trees died. According to statistics, in the past 20 years, the annual average temperature has risen by 2℃, and the area of damaged forests has reached 6.5438+200,000 square kilometers, with 90 million trees. There is a forest pest, which usually takes two years from spawning to adult. After the temperature rises, it only takes one year, which leads to forest disaster.
The most serious consequence that the greenhouse effect may bring is the melting of ice and snow in the North and South poles, the increase of seawater and the rise of sea level, which makes many mulberry fields in the world become the sea. If the sea level rises by 2 meters, many islands will be submerged, and 30% of the big cities in the world will become Wang Yang, including Tianjin and Shanghai in China, new york in the United States and Tokyo in Japan. What a terrible picture this is!
The Antarctic ice sheet is the largest "natural freshwater reservoir" on the earth, with an average thickness of about 2,000 meters and a maximum thickness of 4,000 meters, and its total volume exceeds 1 1 100 million cubic kilometers, accounting for about 90% of the global ice mass. 72% of the world's fresh water is concentrated here, and its water content is roughly equivalent to that of the Atlantic Ocean. If the Antarctic ice sheet melts completely, the global sea level will rise by 50 ~ 70 meters. A group of British scientists who have been observing and investigating the Antarctic have warned people that they have definite evidence that since 1945 ~ 1996, the Antarctic temperature has increased by 2.5℃ and the Antarctic peninsula is shrinking. In the past 40 years, the melting ice has reached 4 1000 cubic kilometers. 1September 1992 to1February 1993, 78 Spanish scientists made a five-month field trip to Antarctica. They also found that the temperature in the Antarctic region was rising, the ice layer was thinning and glaciers were retreating. This summer, the temperature in Antarctica was 5 degrees higher than that in previous years, and the melting area in the whole year was about 32,000 square kilometers. Some continents that were once covered with snow and ice have also appeared.
Since the 20th century, the Arctic glaciers have also retreated by about 65,438+00 kilometers. Some American and Soviet scientists predict that the Arctic Ocean will become an ice-free ocean in/kloc-0 ~ 20 years. It seems that the view that the polar ice will not melt has been corrected by facts.
Not only the ice sheets in the polar regions are melting, but also the glaciers in the Andes in Peru, Kenya in Africa and the Alps in Europe are melting, which has been confirmed by field visits and measurements by scientists. In particular, 40% of the snow on the top of the mountain in Kenya has been wiped out. The amount of ice in Alps is only half of 1850, and the total area is reduced by 30% ~ 40%. Snow in Tibet and parts of the former Soviet Union also showed signs of accelerating melting.