At present, the most urgent thing is that we still lack a basic understanding of global warming, and what will change when the temperature rises. Ding, special adviser on climate change of China Meteorological Bureau, said that climate warming will bring some beneficial effects, such as: due to rising temperature, crop yield in some parts of mid-latitude may increase; Global timber supply may increase; For residents in some water-deficient areas, the available water may increase; Due to the cold winter, the mortality rate of residents in middle and high latitudes has decreased; Because of the warm winter, the energy needed for heating is reduced. But the impact on the national economy is mainly negative.
-Planting bears the brunt. Climate warming will increase evaporation, and if the precipitation does not increase obviously, the farming-pastoral ecotone in China will expand southward. The boundary between the farming-pastoral ecotone in Northeast China and Inner Mongolia will move south by about 70 kilometers, the boundary between the farming-pastoral ecotone in North China will move south by about 150 kilometers, and the boundary between the farming-pastoral ecotone in Northwest China will move south by about 20 kilometers, thus increasing the grassland area. However, the farming-pastoral ecotone is a potential desertification area, and desertification is a huge threat.
After climate warming, the microbial decomposition of soil organic matter will accelerate, which will lead to the decline of soil fertility and the need to apply more fertilizers; Climate warming is also beneficial to insects and weeds, which makes the application of pesticides and herbicides increase.
-the cost of agricultural production will be greatly increased. By 2030, affected by global warming, the crop yield in China may be reduced by about 5% ~ 10%, mainly wheat, rice and corn. When the annual average temperature increases by 1℃, the number of days with national accumulated temperature greater than 10℃ will be extended by 15 days on average. The northern boundary of safe planting of winter wheat will also be moved from the current Great Wall Line to Shenyang-Zhangjiakou-Baotou-Urumqi Line. By 2050, climate warming will move the northern boundary of triple cropping system 500 kilometers north, from the Yangtze River basin to the Yellow River basin; However, the double-cropping rice area will be moved northward to the middle of the current single-cropping area, and the area of single-cropping area will be reduced by 23. 1%.
Water will become less and less and dirtier. Global warming will affect the whole water cycle, which may increase evaporation, change regional precipitation and its distribution pattern, increase the occurrence of extreme precipitation events, increase the frequency and intensity of floods and droughts, and change surface runoff.
The natural annual runoff of seven major river basins in China shows a decreasing trend. Among them, the annual runoff of the Yangtze River and its south area changes little; The Huaihe River and its north area have the largest change, the Liaohe River basin has the largest increase, followed by the upper reaches of the Yellow River, and the Songhua River is the smallest. Global warming will also increase the annual average evaporation in various river basins in China, and the evaporation in the Yellow River and inland rivers will probably increase by about 15%.
In dry years, the water shortage caused by climate warming will greatly aggravate the water shortage situation in North China and Northwest China, and the impact on agricultural irrigation water is far greater than that on industrial water and domestic water, especially in areas where precipitation decreases and evaporation increases. It is estimated that the water shortage in the western region will be about 20 billion cubic meters from 20 10 to 2030, and it will be10 billion cubic meters in 2050. Global warming will make precipitation variability change with the increase of average precipitation, and evaporation will also increase with the increase of global average temperature, which may mean that the frequency of droughts and floods will increase in the future.
Due to the increase of evaporation, the river flow tends to decrease, and the original pollution degree of the river may increase, especially in the dry season. At the same time, the rise of river water temperature will also promote the deposition of pollutants in the river and the decomposition of waste, thus reducing water quality.
-personal quality of life will decline. The direct impact of climate warming on human health will be more obvious. High temperature makes viruses, bacteria, parasites and allergens more active, and it will also damage people's spirit, human immunity and disease resistance. The increase of high temperature and heat wave will increase heat-related diseases and deaths. The adverse effects of global warming on human health have the greatest impact on the population in poor areas.
Climate warming has an impact on human settlements. Floods and landslides are the most common and direct threats faced by residents living in riverside and coastal areas. At present, human habitation is facing environmental problems including water and energy shortage, garbage disposal and traffic, which are aggravated by high temperature and rainy weather. Cities in low-altitude coastal areas with high population density are often threatened by extreme coastal climate events. In China, most residents' income comes from the primary resource industry dominated by climate, and the adverse impact of climate warming on China will be more serious.