With the climate warming, how will the precipitation change?

Global warming is equivalent to reshuffling the earth's natural environment, and its main effects are as follows:

1. The global climate has been changed. In some areas, the climate has improved, in some places, the climate has deteriorated, and the frequency of extreme weather has increased. If the precipitation in the original arid area increases, the harvest of agriculture (including animal husbandry and forestry) in this area will also increase; If the precipitation in the originally humid area increases further, the agricultural harvest in this area may decrease. If the temperature in the original cold area is raised, the agricultural harvest in this area will also increase; If the temperature in the original high-heat area rises further, the agricultural harvest in this area may be reduced.

2. The sea level is rising, which is caused by a large amount of melting snow from icebergs in the North and South Poles and the Qinghai-Tibet Plateau, and the rising temperature leads to the expansion of ocean volume. Sea level rise will have many negative effects on coastal areas, including flooding coastal land and increasing salinization of coastal areas.

The distribution of life on the earth will change. Many animals will be forced to migrate to other places. Some creatures will reproduce and some will become extinct. Global warming can prolong the frost-free period for crops. Where one season is harvested in a year, one and a half seasons can be harvested, and where two seasons are harvested, three seasons can be harvested, which is conducive to increasing agricultural production.

As economic activities are closely related to climate change, a series of climate changes caused by global warming will affect the economic development of relevant countries and regions. For example, warm winter makes the sales of warm clothes in winter shrink, and the heating energy consumption also decreases; Hot summer will increase the cost of air conditioning and refrigeration, and will also reduce appetite.

Global warming helps to increase precipitation in China.

Undoubtedly, the reshuffle of the natural environment caused by global warming also applies to China. As we all know, China is located in the eastern part of Eurasia, with a land area of 9.6 million square kilometers, and its total water resources are less than a quarter of the world average. Moreover, there are regional imbalances (more in the southeast and less in the northwest) and seasonal imbalances (more in summer and less in the other three seasons) in precipitation, so the lack of water resources is the most important natural factor restricting China's development. Based on the analysis of China's natural environment, the author thinks that, on the whole, the rise of the earth's temperature is helpful to increase the precipitation in all parts of China.

1, the main source of precipitation in China.

As we all know, the precipitation on the earth's land mainly depends on the amount of water vapor from the ocean and the local temperature difference. For China, the distance between Chinese mainland and the Indian Ocean, the South Pacific and the Western Pacific is very small, but the water vapor in the Indian Ocean and the South Pacific is very abundant, so the precipitation in southern China is also rich, and the average annual precipitation is usually above 1000mm; Among them, the water vapor in the Indian Ocean can enter the southern and eastern parts of the Qinghai-Tibet Plateau through the deep valleys of the Yarlung Zangbo River, the Lancang River, the Nujiang River and the Jinsha River, and send precious water resources to the southern part of Tibet and the upper reaches of the Lancang River, the Nujiang River, the Yangtze River and the Yellow River. The above two items account for more than 80% of the total water resources in China.

In contrast, the northern region of China, especially the northwest region, is far away from the Indian Ocean and the Pacific Ocean, the Atlantic Ocean and the Arctic Ocean, and the precipitation is scarce. The annual precipitation in North China is between 600 mm and 1000 mm, the annual precipitation in Loess Plateau is less than 600 mm, and the annual precipitation in Northwest China is only 50 mm to 300 mm.

2. Rising temperatures in the Indian Ocean and the South Pacific will bring more precipitation to southern China. However, due to the abundant precipitation in the south of China, the new precipitation has little contribution to the economic growth in the south, but may increase the frequency and intensity of floods and extreme climate disasters.

3. The rising temperature in the western Pacific contributes to the increase of precipitation in the northern coastal areas of China, which is beneficial to the development of industry and agriculture in these areas.

4. The rising temperature of the Arctic Ocean can increase the precipitation in northern China. Due to the rapid melting of icebergs in the Arctic Ocean, the temperature in the Arctic Ocean has risen above zero degrees Celsius. The higher the temperature of cold air, the more water molecules it can carry, so the water vapor content of cold air from the Arctic Ocean is greatly increased (compared with warm and humid air flow, cold air rich in water vapor can be called cold and humid air flow), which is definitely good news for northern China.

Specifically, the Arctic Ocean covers an area of about 6.5438+0.3 million square kilometers. When its temperature is below zero degrees Celsius, the amount of evaporated water vapor is very small, and its contribution to water resources in northern China is also very small. However, with the melting of icebergs in the Arctic Ocean, after the temperature of the Arctic Ocean rises above zero, the evaporation of water vapor in the Arctic Ocean will increase exponentially, and its contribution to water resources in northern China will also increase exponentially. Assuming that the evaporation in the Arctic Ocean increases by 1 0mm every year, the evaporation per square kilometer increases by110,000 tons, and the total evaporation in the Arctic Ocean increases by1.300 million tons. If one tenth of the water vapor in the Arctic Ocean can be transported to the north of China, the water resources in the north of China can be increased by1300 million tons every year. In fact, as the temperature of the Arctic Ocean increases, the annual evaporation of the Arctic Ocean is much higher than 10 mm, which means that northern China is expected to get more water resources from the Arctic Ocean.

5. Similarly, the rising Atlantic temperature can also increase the precipitation in the northwest of China.

With the acceleration of global warming, the precipitation in northern China is increasing.

In September 2007, the author and his wife traveled to Xinjiang. After returning to Beijing, the author wrote in his travel book Journey to the West: Wandering with Mu: "At 7 o'clock on September 6, take K43 train, go south along the Yellow River, go west after passing Zhongwei, go along Hexi Corridor at the northern foot of Qilian Mountain, pass Wuwei, Jinchang, Zhangye and Jiuquan, and arrive at 2 1: 30 on the same day. This should be related to the massive melting of icebergs in the Arctic Ocean, so desert weeds are also green, and corn and sunflowers are growing well), but the air is obviously getting drier and drier. "

It is worth noting that in the spring of 2008, there were several light rains in Beijing (including the North China Plain), and several moderate to light rains in Shaanxi, Gansu, Shanxi and Hetao areas of Inner Mongolia on the Loess Plateau. At the same time, there are more than a dozen sandstorms, floating dust and sandstorms blowing in the north of China every spring (for example, on April 17, 2006, Beijing was hit by a strong sandstorm, and the author measured the amount of dust falling in Beijing for the first time). So far this spring, there have only been one or two sandstorms in Beijing (the meteorological department predicted that it was about1Kloc-0/time). The author thinks that this kind of turning climate change is mainly not the contribution of man-made afforestation, but a large-scale change in the natural environment, which is conducive to increasing the precipitation in northern China (it is not excluded that some people will be greedy for perfection). The most important factor is that global warming has caused a large number of icebergs in the Arctic Ocean to melt, resulting in a substantial increase in the water vapor content of cold air from the Arctic Ocean.