On the Drought in Yunnan
Recently, the meteorological drought in Yunnan Province has developed rapidly and the drought is serious, resulting in insufficient soil moisture, serious agricultural disasters and high meteorological level of forest fires. The occurrence and development of meteorological drought in Yunnan province has the characteristics of early appearance, long duration, wide influence and severe drought.
Deng Yiying of Songhuaba Water Conservancy Project Management Bureau said: "At present, the water level has dropped to 169.93 meters, the lowest in the same period of the previous years." By March 5th, the storage capacity of reservoirs in the whole province was only 1 1 100 million cubic meters, less than half of that in previous years and1500 million cubic meters less than that in the same period last year. 64 small and medium-sized rivers in the province have been cut off, 934 small reservoirs and mountain ponds have dried up ... The drought-affected area in the province has expanded from 27.52 million mu at the end of last year to 34.35 million mu, and the number of people with temporary drinking water difficulties has soared from more than 2 million to 6.63 million.
Water crisis. We rose up against the disaster. However, how much do we know about the water crisis? How much thought and preparation does it take to act? As the source of all things, water is not only related to the quality of human life, but also affects human survival ability. Do we really cherish water? Have we really saved water? Have we really protected water resources? Seek water, cherish water, ze electricity! Everybody, start from yourself!
Hiderigami is raging, and Yunnan is in a hurry!
Once a big province of water resources
Yunnan Province is rich in water resources, with a lake area of 3 1 1.388 square kilometers and a drainage area of 2,920 square kilometers, with an average water depth of 5.12m, the deepest point1.3m and the storage capacity15. Per capita water resources exceed 1 10,000 cubic meters, which is four times the national average. "In the past, Yunnan was a big province of water resources, but now, Yunnan is too thirsty ... we urgently need rain to save the drought."
The once-in-a-century drought has dealt a heavy blow to Yunnan, which has always been proud of its rich natural resources. Perhaps in the near future, the rain will return to this arid land, but in any case, it will not dilute the brand left by this drought in the hearts of Yunnan people.
From a scientific point of view, we can sum up this once-in-a-century drought as a "probability event": an extreme weather event that appears randomly in history. However, when we approached the mystery of this drought step by step, we found that the problem was not that simple. Besides science, we still have a lot to explore and reflect on.
According to the data provided by the Water Resources Department of Yunnan Province, at present, the storage capacity of reservoirs in Yunnan Province is only 1. 1 100 million cubic meters, which is less than half of last year and1.500 million cubic meters less than the same period last year. 64 small and medium-sized rivers were cut off, and 934 small reservoirs and ponds dried up. "Yunnan's reservoirs mainly rely on rainy season rainfall to store water. Once you miss this opportunity, the reservoirs can only eat their own old money. " But after September last year, the rain stopped, plus the high temperature and large evaporation in autumn. Basically, no reservoir can escape the bad luck of drying up.
Even the main streams and lakes with relatively rich water resources in Yunnan are not optimistic at present. In February, Shangri-La, Diqing, the Jinsha River in the upper reaches of the Yangtze River was greatly reduced. The river surface, which is usually 200-500 meters wide, is currently less than 50- 100 meters; In previous years, the source of the Pearl River, which was as deep as 40 to 50 meters, also caused the water level to drop by several meters due to large evaporation, and some river sections have dried up to the bottom.
So, what is the current situation of water conservancy facilities in Yunnan? A relevant person in charge of the Provincial Water Resources Department said that for a long time in the past, Yunnan's water conservancy facilities were all relying on old money. On the one hand, small reservoirs in Yunnan have hardly been repaired. As a result, there are14 villages and towns in Yunnan that have difficulty in drinking water. This is not the worst. Some local reservoirs, smaller than small ones, not only lack repair funds, but also have no corresponding scientific management, which leads to their depletion faster than small reservoirs in drought. For those small water pits dug by the masses spontaneously, there is no drought resistance without water supply.
Severity of drought
The dry and wet seasons in Yunnan are distinct, and the distribution of precipitation in the four seasons is extremely uneven. Winter and spring 165438+ 10 to April of the following year is the dry season in Yunnan, and the precipitation accounts for only 0/0% to 20% of the annual/kloc-0, with frequent droughts in winter and spring. Especially since 2002, Yunnan has been under the climate background of less precipitation and higher temperature in summer and autumn, which also provides a dry and warm climate background for the occurrence of drought since autumn 2009.
According to meteorologists, the main causes of meteorological drought in Yunnan are continuous low precipitation, high temperature, large evaporation of water vapor and early end of rainy season. From July 1 day to February 23, 2009, the average precipitation in Yunnan Province was 52 1.6 mm, which broke the record of the least number of rainy days in the same period since June 1959.
If the once-in-a-century drought is really a simple probability problem, does it mean that such a situation cannot be avoided at all? For this question, Xu Jianchu, a climate expert at Kunming Institute of Botany, Chinese Academy of Sciences, gave an intriguing answer: "The once-in-a-century drought in Yunnan is an inevitable accident."
As for the causes of drought in Yunnan, the academic circles have given a general conclusion: global warming and the intensification of El Niñ o in the Pacific have destroyed the atmospheric structure, resulting in the inability of the marine monsoon to land and the formation of rainfall. Xu Jianchu supports this view, but the difference is that he focuses on the premise of "global warming", which leads to drought.
According to the data provided by Yunnan Meteorological Bureau, since 1980s, the regional average temperature in Yunnan has shown an obvious warming trend, especially from 20065438+0 to 2006, the regional temperature in Yunnan increased by 0.64℃, which was higher than the global and northern hemisphere average. Accordingly, since 196 1 year, the annual precipitation in Yunnan has generally shown a decreasing trend, while extreme precipitation events have begun to increase. From the time point of view, Yunnan began to show signs of warming in the middle and late 1980s, with the most obvious warming in the late 1990s, while central Yunnan was the most obvious warming area in the whole province in recent 10 years. In terms of precipitation, in recent 50 years, precipitation in Yunnan has decreased in summer and autumn, especially in summer.
In addition, by calculating the relationship between the global and northern hemisphere average temperature and the four-season precipitation in Yunnan, it is found that the increase of global and northern hemisphere average temperature is not conducive to the increase of summer, autumn and annual precipitation, which is basically consistent with the above-mentioned actual precipitation evolution trend. In order to further study the changes of precipitation in Yunnan, Xu Jian chose global cold period 196 1 ~ 1976 and global warm period 1987 ~2006. After calculating the annual average precipitation and four seasons precipitation in Yunnan during these two periods, it is found that there are more precipitation in autumn, summer and year in cold period than in warm period. "All these studies have proved that the warming temperature has reduced the rainfall in Yunnan."
Not only climatologists, but also villagers in Shuitang Village of Chenggong County have personal experience. "It is getting hotter, hotter and drier" is Zhou Hui's summary of climate change in recent years. "It has never been so hot as last year and this year. I didn't wear a sweater all winter. I didn't expect even water to be hot. " Like Zhou Hui, in the eyes of many villagers, the once-in-a-century drought is inextricably linked with rising temperatures. As early as a few years ago, some people in the village discovered this "law", and then paddy fields were replaced by dry land. At present, Shuitang Village is already a dry land.
According to Luo, vice president of Yunnan Institute of Geology and Mineral Exploration, "most of the water disappears in ponds or rivers and lakes." There has always been a contradiction in Yunnan: as a big province of water resources, the total amount of water resources ranks third in the country. However, due to the special topographical environment and climatic conditions, two-thirds of the population and one-third of the cultivated land are concentrated in the dam area, which accounts for 6% of the province's land area, but the water resources only account for 5% of the province. At present, the development and utilization rate of water resources in Yunnan is only 6.9%. These characteristics have largely led to Yunnan becoming a water-deficient province.
Luo said that this contradiction often creates an illusion: I always feel that Yunnan's water is inexhaustible, but it is actually not enough. "Many areas in Yunnan are mainly karst landforms and mountainous areas. There is no water on the hillside, only water in the ravine. Therefore, when drought occurs, it is more difficult to get water. " What worries Luo more is the rocky desertification in karst areas of Yunnan. This rocky desertification is similar to the desertification in northwest China, and it is one of the extreme forms of land degradation and evolution. Because people keep reclaiming land and destroying the original vegetation, the soil layer that took thousands of years to form quickly loses, and finally there are only stones on the surface that can't grow any plants.
According to a recent survey, among the 740,000 square kilometers in the karst mountainous areas in southwest China, the rocky desertification area is 654.38+005,000 square kilometers, accounting for 654.38+04.2% of the surveyed area, of which the rocky desertification area in Yunnan Province is 28,000 square kilometers, with an annual growth rate of 2%. "It can be said that the current situation of surface water in Yunnan is not optimistic. Once the rocky desertification intensifies, the surface will completely lose its original water storage function, leading to more places starting to lack water. " Luo said to.
What causes the persistent drought in Yunnan?
Wang Xuefeng, deputy director and senior engineer of Yunnan Climate Center, is drawing a cloud picture of monsoon meteorology in front of the computer. "Because Yunnan has a monsoon climate, once the monsoon cannot reach, it is very likely to cause drought." Wang Xuefeng explained the cause of the drought in this way.
Wang Xuefeng said that Yunnan is in the southwest monsoon region in summer, and the precipitation in Yunnan is mostly related to the water vapor in the Bay of Bengal and the Indian Ocean. Because the Qinghai-Tibet high is too strong this year, extending eastward and downwards, the water vapor in the Bay of Bengal cannot be transported to Yunnan, and because Yunnan is mountainous, the foehn effect has aggravated the drought. "Another feature of Yunnan's climate is that the dry and wet seasons alternate obviously. 1 1 month is the dry season, and May to1month is the rainy season. Generally speaking, the rainy season accounts for more than 80% of the annual rainfall, so once the rainy season is insufficient, it may lead to drought throughout the year. " Last year, the rainy season ended 1 month earlier than normal, which is also one of the reasons for the drought.
The monitoring shows that from July 1 day to February 23, 2009, the average precipitation in Yunnan Province was 52 1.6 mm, which was 30% less than the multi-year average, breaking the record of average precipitation in the same period since June 1959. The average maximum temperature is 23.7℃, which is 2.0℃ higher than the average in the same period of many years, breaking the record of the average maximum temperature in the same period since 1959. From July to June, 2009, 65438+February, the average water vapor evaporation in Yunnan Province was 822.5 mm, which was higher than the average of the same period for many years 12%. From September 1 day in 2009 to February 23 this year, the average number of rainy days in Yunnan Province was 3 1 day, which was 44% less than the same period of many years, breaking the record of the minimum number of rainy days in the same period since 1959.
Drought is only one of the reasons for the heavy crop losses this year; On the other hand, the serious waste of irrigation water can not be ignored. "Agriculture is a major water user in Yunnan, with an annual water consumption of 1 1 100 million cubic meters, while the water utilization rate is only about 40%." Some scientists have calculated that according to the current irrigation method in China, 1 kg of rice will be "eaten" 1 ton of water! At present, the 1/2 irrigation channel in Yunnan is soil channel, and there is a lot of leakage in this traditional and backward irrigation method. Coupled with the constraints of various aspects during the construction period, most reservoirs in the irrigation area are seriously aging and degraded, and the field projects are not matched. There are only main canals and a few branch canals in the reservoir irrigation area, and the irrigation methods are backward, and the land is barren, which leads to serious soil and water loss.
From the perspective of human factors, there are four main reasons for the drought caused by human activities:
1. The population has increased greatly, resulting in an increasing shortage of limited water resources.
2. Forest vegetation is destroyed by human beings, and the water storage function of plants is lost, resulting in the decrease of groundwater and soil moisture.
3. Human activities have caused a lot of water pollution and reduced the available water resources.
4. The serious waste of water resources in China, especially agricultural irrigation, leads to the shortage of water resources.
Drought has seriously affected the lives of Yunnan residents.
Since the autumn of 2009, there has been less and less precipitation in southwest China, and Yunnan has suffered a severe drought that has never happened in a hundred years, which has seriously affected the lives of Yunnan people.
Looking through the data, it is found that this year, the drought has not only seriously affected the social and economic life of Yunnan. In 2005, Yunnan suffered the worst early summer drought in the past 50 years, resulting in agricultural economic losses of more than 4.2 billion yuan and industrial economic losses of nearly 8 billion yuan.
Judging from the impact of the current drought, farmland crops mainly affect grain, sugar cane and natural rubber in Koharu. If the drought continues to develop, it will affect spring sowing, agricultural production will be greatly affected throughout the year, and even trigger the price trend in the second half of the year. At present, it is the sugarcane pressing season, and severe drought will lead to insufficient sugarcane yield in newly planted sugarcane. It is predicted that the drought will reduce the sugar production in Yunnan this season by about 15% year-on-year. As Yunnan is the main sugar producing area in China, if the drought continues, the sugar output in the next cropping season will also be greatly affected, and the sugar price is likely to continue to rise in the later period.
The persistent drought has also affected the production of fruits and vegetables. According to the introduction of the Planting Management Office of Yunnan Provincial Department of Agriculture, the affected area of crops planted in autumn and winter reached 210.2 million hectares (accounting for 85% of the sown area), of which the affected area of vegetables reached 262,000 hectares, resulting in disaster10.63 million hectares, and no harvest was received; Five types of economic forest fruits, such as fruit, tea, sericulture, rubber and coffee, suffered from drought, reaching 452,000 hectares, 6.5438+0.4 million hectares, with no harvest of 6.5438+0.407 million hectares, including 6.5438+0.57 million hectares, 54,000 hectares and 0.5 million hectares. Therefore, it will have a great impact on fruits and vegetables in the short term. If the drought continues, even if crops are replanted later, the annual output of fruits and vegetables in Yunnan and Guizhou provinces will drop sharply.
Residents go to the provincial capital to take a bath.
Residents in Yiliang, Xundian, Songming, Chuxiong and other cities have been having trouble using water for several months. Except that fire engines supply water from far away, they are urgently building canals to bring water to places with water. Many city residents in Xundian haven't had water to take a bath for more than a month, and some even went to Kunming to take a bath. Sticking to the people's draft bottom line is the bottom line of drought relief work in Yunnan. In order to do this, urban industrial water consumption is mostly at a standstill.
Residents haven't had soup for months.
The last time Li Shaorong and his wife in Kunming had soup was three or four months ago. They only eat simple rice, pickles and a few radishes every meal every day. Li's hometown is Shiyanzi Village, Xundian County, Yunnan Province, which suffered from the once-in-a-century drought. The broad beans and rape in the field have withered, and the grain is almost gone. From June+10, 5438, the local government provided water to every household according to the quota, but the amount of water was only enough for survival. They can't remember the last time they took a shower.
Villagers eat wild vegetables to satisfy their hunger.
Drought makes drinking water more difficult for residents in Jinning County, Yunnan Province. Tap water has long been gone, and villagers can only rely on external supply for drinking water. The villagers' food baskets are facing unprecedented embarrassment. The villagers began to pick wild vegetables from the mountains to eat. A kind of wild vegetable called "Hungry Sheep Vegetable" is soaked in a pot, which is a plant that sheep are willing to eat when they are hungry. When eating, an obvious astringency goes straight to the top of your head. My throat began to tighten and I couldn't help coughing. In the vegetable field behind Hejia, several flowering onions are still growing tenaciously. He Cai Zhong said, "You can eat chopped green onion when you wash your face." .
Power outages in some provinces and cities
The drought in southwest China has made the supply of thermal coal continuously tight, and some provinces and cities have power outages. Severe drought caused cracks in the airport runway in Kunming, the capital of Yunnan Province. Before next month, the airport runway will be closed for maintenance at 7: 30 every morning.
Why does the drought last?
Perhaps the latest research results can make Yunnan people who haven't seen rain for a long time breathe a little sigh of relief. Xu Jianchu pointed out in a study entitled "The Facts of Climate Change in Yunnan" that the rainfall in Yunnan will generally increase in the next 30 to 40 years. At the same time, it is pointed out that Yunnan has entered a new warm period since the 1990s, and the temperature in Yunnan will remain high in the next 10~20 years, and the temperature in Yunnan will be mainly high in the next 30-40 years. "If we consider the impact of human factors on climate change, the temperature rise in Yunnan will increase and precipitation will increase."
The question is, does this not contradict the previous conclusion that the increase in temperature leads to the decrease in precipitation? Xu Jianchu explained that this is because the temperature rise in Yunnan in the next few decades is slightly lower than the national average. From a national perspective, the temperature in Yunnan is still falling, which is also the reason why the rainfall in Yunnan will increase. "At the same time, according to the rainfall cycle, Yunnan will be in a very long period of increasing rainfall in the next 30 to 40 years."
Coincidentally, the National Meteorological Center used the atmospheric model developed by the Climate Center and the ocean model developed by the Institute of Atmospheric Physics of the Chinese Academy of Sciences to simulate the future temperature changes, which proved Xu Jianchu's inference. The simulation results show that the annual average temperature in Yunnan may increase by about 3.5℃ at the end of February1year, and the precipitation is mainly in multiple stages.
"That is to say, for a long time to come, the possibility of another severe drought in Yunnan will be reduced." Xu Jianchu said that many people are very excited to hear this news, because in the context of a once-in-a-century encounter, it will somewhat taste like "once bitten, twice shy." If you think calmly, you will find that the challenges faced by Yunnan have not really been alleviated. "As long as the probability of extreme weather does not decrease, the future of Yunnan is full of uncertainty. Once there is too much precipitation in a certain year in the future, the possibility of floods in Yunnan will greatly increase, and according to Yunnan's current water conservancy facilities, it is still unable to compete with nature. "
It sounds too pessimistic, but Xu Jianchu said that this does not mean giving up efforts. Xu Jianchu said that at present, the government has taken various measures to fight drought and provide disaster relief, but in fact, the most fundamental method is to establish the concept of saving water. "Although drought is inevitable, we can at least live a better life through our own efforts."
Water saving tips:
1, try to use a shower instead of a bath.
2. Wash your hands with a little water for a short time.
3, washing vegetables, washing dishes, washing dishes and so on. , time is not long, try to rinse with a small amount of water.
4. put a plastic bottle in the toilet tank, which can save 500 ml of water each time.
5. When squatting, reducing the valve pressure time can save water by more than 1 liter (the lower the floor, the smaller the pressure).
6. Washing clothes: Wash the bathroom, mop the floor and wash the corridor with the waste water from washing clothes, or even connect two plastic buckets for standby. It can save more than 100 liter per week (prepare two plastic buckets).
7. Use cold water reasonably before solar energy. The lower the floor, the more cold water. It is also a good idea to put cold water in a container for later use.
8. Comprehensive utilization of wastewater.
9. Washing toilets and squatting pits with bath waste water can save more than 80 liters of water each time.
10, vegetable washing water can be used to water flowers.
Shower saves 80% water than bathtub. So I suggest you take more baths, less baths or no baths. Avoid taking a shower for a long time when taking a bath, and turn off the water in time when scrubbing; Don't leave the water in the sprinkler on all the time, let alone turn it on.
12 One water is multi-purpose, for example, rice washing water can be used to wash vegetables, which is beneficial to remove pesticides on the surface of vegetables, and vegetable washing water can also be used to flush toilets; Bath water, laundry water and foot washing water can be used to mop the floor and flush the toilet.
Don't turn on the tap for a long time to wash hands, clothes or vegetables. When washing vegetables and fruits, we should control the flow of the faucet and change the constant water washing into intermittent washing. Repair dripping faucets and other water appliances in time. The dripping faucet can consume 70 liters of water every day. It is suggested that using water-saving appliances can effectively save water.
Key points of disease prevention during drought.
Drought is a common natural disaster, which often lasts for a long time, has a wide range and is gradual. The living environment of human beings has gradually deteriorated, and health hazards have persisted and strengthened. During the drought, prevention of these diseases should be done well to maintain normal life and production activities.
First, prevent intestinal infectious diseases.
Drought leads to water shortage, coupled with high temperature weather. Pathogens in polluted water and food multiply faster, such as cholera, dysentery, typhoid fever and hepatitis A.
To prevent intestinal infectious diseases, we should keep in mind the principle of "eating cooked food, drinking boiled water and washing hands". Do not drink raw water, drink boiled water; The food should be cooked thoroughly, and the leftover food should be reheated thoroughly before eating, while it is hot. Don't eat bad food.
Second, prevent Japanese encephalitis.
Summer and autumn are the epidemic seasons of Japanese encephalitis, and mosquito bites are easy to cause the occurrence and prevalence of Japanese encephalitis. It is even more necessary to do a good job in mosquito prevention and control.
Third, prevent food poisoning.
During the drought, food is easy to rot and deteriorate, with normal appearance and normal consumption. Bacterial food poisoning often occurs suddenly with a short incubation period. Although non-bacterial food poisoning occasionally occurs, the mortality rate is high. So we should strengthen prevention. First, don't eat livestock, poultry, aquatic products or food with peculiar smell that has died of illness and unknown cause of death; Second, the food should be cooked and cooked thoroughly; Third, if you feel unwell after a meal, you should seek medical advice promptly.
Fourth, prevent heatstroke.
Prolonged exposure to sunlight and high temperature can lead to heatstroke. It is necessary to do personal protection to prevent heatstroke. People suffering from heatstroke should move to a ventilated and cool place to lie flat, unbutton their clothes, apply cold compress to their head or chest, give the patient cold saline, take Ren Danhe 10 drop of water and apply cool oil. Mild symptoms recover quickly,
Cherish every drop of water
Cherish resources and protect the environment, we can start from the small things around us, such as not littering, saving water and electricity resources and not using disposable goods. These are all ways to cherish resources. As long as we have perseverance, we will certainly become small pacesetters who cherish resources.
If most people destroy the environment, then the country needs a lot of resources to manage the environment. This requires not only a lot of manpower, but also a lot of material resources. However, if we all become ambassadors to protect the environment, then we can not only save resources, but also save manpower and material resources. If most people waste water resources, then there will be no water to drink in the future, even if there is water to drink, it is very precious. A newspaper once said that in about 70 years, water will be more expensive than oil.
Water, the basic substance on the earth, deserves our praise! She gave birth to the world and all sentient beings; It is she who provides energy for life and makes life survive; Or did she let life develop continuously and become more and more prosperous? Therefore, it is no exaggeration to say that "water is the source of life".
If people do not cherish water resources, then the last drop of water in the world is people's tears.
Is water inexhaustible? We can definitely answer: No, although 70.8% of the earth is covered with water, 97.55% of the water is seawater, which can neither be directly drunk nor irrigated. Of the remaining 2.5% fresh water, the water that humans can really use is less than 1% of the global total fresh water. It is true that from the appearance of primitive life on earth to the present, water has been serving life, working hard and never stopping. But I don't know if you have thought that there is a limit to the endurance of water, and now water resources are in short supply!