What are the adverse effects of rapid population growth on the environment?

In short, the rapid growth of population will not only cause traffic jams, poor living conditions, employment difficulties, hunger and poverty, but also cause a series of problems such as increased environmental pollution, deterioration of ecological environment, reduction of various land resources such as forests, grasslands and cultivated land, and natural resources such as water resources and mineral resources (especially the sharp decline in per capita ownership). 1. Grain output From 1950 to 1984, the growth rate of world grain output far exceeded the growth rate of population, but since then, the growth rate of grain output has lagged behind the growth rate of population. According to the statistics of the United States Department of Agriculture, the per capita grain output has dropped by 7% (0.5% per year). Since 1984, the growth of world grain output has slowed down, because the newly reclaimed land is insufficient and the investment growth in irrigation and fertilizer use has decreased, so the land return rate has decreased. Because agriculture provides arable land for reclamation, the future growth of grain output will almost completely depend on improving the productivity of existing land. Unfortunately, it's getting harder and harder. When the per capita arable land area is decreasing, the per capita irrigation amount is decreasing, and the crop yield is decreasing with the excessive use of chemical fertilizers, the world agriculture is facing the challenge of reversing this decline. 2. Cultivated land Since the middle of this century, the grain-producing areas-usually synonymous with cultivated land-have increased by 19%, while the world population has increased by 132%. Population growth degrades cultivated land, reduces output and even uses it for other purposes. With the per capita grain area shrinking, more and more countries are in danger of losing their self-sufficiency in grain. The situation of the four countries with the fastest population growth in the world is very obvious, and he explained this development trend. During the period of 1960- 1998, the per capita cultivated land in Pakistan, Nigeria, Ethiopia and Iran decreased by 40-50%, and it is expected to further decrease to 60-70% by 2050-this is only a conservative estimate under the assumption that the cultivated land will not decrease. In this way, the total population of these four countries will be above 65.438+0 billion, while the per capita cultivated land area is only 300-600 square meters-less than 654.38+0.4 of the per capita cultivated land area in 654.38+0.950. 3. The shortage of fresh water is probably the most neglected resource problem in the contemporary world. However, where the population is still growing, the per capita fresh water supply is decreasing. The dryness of rivers and the decline of groundwater level are regarded as evidence of water shortage, such as the Nile, Yellow River and Colorado River, which are almost dry. At present, the groundwater level in all continents of the world, including major grain-producing areas, is declining, and the aquifers in the southern Great Plains of the United States, the North China Plain of China and most parts of India are increasingly depleted. The International Water Resources Management Institute predicts that in some countries, about 654.38 billion people will face absolute water shortage in 50 years. These countries are bound to reduce agricultural water consumption to meet the water demand of residents and industries. China and India are considered as two major irrigated agricultural countries in the world, which will greatly reduce the supply of irrigation water. 4. Marine Fishing Since 1950, the intake of seafood by human beings has increased five times, making the catch of most fishery resources reach or exceed its tolerable limit. Marine biologists believe that the world's marine waters can't bear the catch of more than 93 million tons per year. At the end of the twentieth century, overfishing has become a routine, without exception. Among the global 15 major marine fishery areas, the catch of 1 1 fishing ground has decreased. Atlantic cod has been the main food for western Europeans for a long time, and now the catch is reduced by 70% compared with the peak of 1968. Since 1970, the tuna resources in the western Atlantic have decreased by 80%. With the depletion of marine fishery resources at present, the increase in demand for seafood in the future can only be met by fishery farming. When the world turned to aquaculture to meet its demand, fish began to compete with livestock and poultry for feed, such as grain, soybean meal and fish meal. In the first half of the next century, it is likely that some fish species will be extinct in the world, and the quality of seafood caught will also decline, but its price will remain high, and the contradiction between countries competing for fishery resources will intensify. Compared with the highest per capita catch of 1988/7.2 kg (37.8 lb), the annual per capita catch of the ocean will decrease by roughly the same amount with the population growth, and will decrease to 9.9 kg (22 lb) for seafood in 2050. 5. Meat products In some traditional low-wage people, when people's income begins to increase, they must first diversify their diets, which requires more animal products. Since 1950, the growth rate of meat products in the world is almost twice that of population. The growth of meat products was initially concentrated in western industrialized countries and Japan, but in the past 20 years, East Asia, the Middle East and Latin America have also grown rapidly. Beef, pork and poultry account for the vast majority of the world's meat consumption. According to the statistics of the United States Department of Agriculture, of the world grain output of18.7 million tons in 1998, it is estimated that 37% was used for raising livestock and poultry and producing milk, eggs and meat products. At present, grain is used to feed poultry and livestock, which is the main grain reserve during the world food crisis. It is predicted that the total consumption of meat food in the world will increase from 65,438+2110 million tons in 1997 to 51300,000 tons in 2050, which will increase the pressure on world food supply. Environment and resources. Nature Reserves From Buenos Aires to Bangkok, the population growth of major cities in the world is staggering-leading to unplanned expansion and pollution of cities-threatening nature reserves around cities. In all continents of the world, human encroachment not only reduces the scale of nature reserves, but also reduces their quality. In countries where the rapid population growth exceeds the carrying capacity of local natural resources, protected areas become particularly vulnerable. Although protected areas are synonymous with camping, picnics and country picnics in industrialized countries, most national parks, forests and protected areas in Asia, Africa and Latin America have always been inhabited by local people or used for natural resources. In many industrialized countries, the growth of immigrant population also endangers nature reserves. For example, as millions of new immigrants move to western Florida, Everglades National Park will be in danger of being destroyed. It is like an iceberg that a large number of long-awaited immigrants move to a scenic spot where the cost of a few immigrants is high. With the increase of immigrant population, not only the current calm and tranquility of the reserve will be broken, but also the colorful natural environment and human landscape will disappear. 7. Compared with most periods of human history, the reduction of global forest area is advancing with the growth of population. However, in the 20th century, the world forest loss will account for about 75%. In Latin America, pasture management is the most important reason for deforestation. In addition, overgrazing and excessive firewood collection-usually caused by population growth-have degraded 65,438+05% of the existing large virgin forests in the world. Tracing the deforestation caused by the demand for wood in recent ten years is closely related to the increase of per capita wood consumption. Since 196 1, the number of paper and paperboard per capita in the world has doubled. The reduction of forest area leads to the decline of forest functions, including the living environment of wildlife, carbon storage (the key to regulating climate), soil erosion control, water storage across rainy and dry seasons, and rainfall regulation. 8. Biodiversity In modern human life, species are disappearing at a natural rate of 100 ~ 1000 times, which is the largest period of animal and plant extinction since the end of Cretaceous 65 million years ago. The root cause of species extinction is that the increase of population density leads to the deterioration of the natural environment in which animals and plants live. The natural environment in coastal areas is particularly suitable for biological reproduction, but it is very fragile, and more than 60% of the world's population lives in this area. For example, coastal wetlands breed two-thirds of the world's commercially caught fish, and the biodiversity density of coral reefs ranks second in the world after tropical rainforests. However, the gradual invasion and pollution of human beings make the environment in coastal areas worse and worse. It is roughly estimated that the salt marshes and mangrove swamps in12 of the world have disappeared or been completely changed, and two-thirds of the coral reefs in the world have been degraded, among which 10 arc is "unrecognizable". With the continuous migration of coastal areas-in less than 30 years, coastal residents may account for 75% of the world population-the resulting environment. 9. Climate Change In the past half century, the growth rate of carbon emissions from fossil fuel combustion was almost twice that of population growth, which made the concentration of carbon dioxide, the main greenhouse gas in the atmosphere, increase by 30% compared with the pre-industrial period. The carbon emissions of fossil fuels account for about 3/4 of the total carbon emissions in the world. Therefore, where the economy is active and the corresponding energy consumption grows fastest, there is a tendency to increase regional carbon emissions. As China's fast-growing economy relies heavily on coal and other carbon-rich energy resources, it is predicted that the growth rate of carbon emissions in China will be three times faster than the population growth rate in the next 50 years. According to the government's estimation of the Subcommittee on Climate Change and the US Department of Energy, the carbon emissions of developing countries will triple in the next half century, while those of industrialized countries will increase by 30%. Although the annual carbon emissions of industrialized countries are still twice that of developing countries, the latter will surpass the former by 2020. 10. Energy In the past 50 years, the growth rate of global energy demand is twice that of population. By 2050, developing countries will consume more energy due to the increase of population and the affluence of life. When the per capita energy consumption remains high, even the low population growth may have a significant impact on the total energy demand. For example. By 2050, the population of the United States is expected to increase by 75 million, and its energy demand will increase to the sum of the current energy consumption in Africa and Latin America. The world's per capita oil production reached the highest level in 1979, and then decreased by 23%. It is predicted that global oil production will reach the highest limit by 20 1 1 in 2025, which shows that as long as oil remains the leading fuel in the world, oil prices will still rise sharply in the future. In the next 50 years, the region with the largest increase in energy demand will be the most active region: in Asia, although the population growth is only 50%, energy consumption will increase by 36 1%. In Latin America and Africa, energy consumption is expected to increase by 340% and 326% respectively. The above three areas are facing great pressure in energy resources such as forests, fossil fuel reserves and water resources; 1 1. Because the world's new population will reach 3.4 billion in the next half century, the impact of waste discharge on the regional and global environment is likely to be more serious, and the hope of providing an available sanitary environment in the near and medium term is also very slim. The growth of population has increased the headache of social garbage disposal-garbage, sewage and industrial waste must be disposed of. Even in areas where the population is basically stable-many industrialized countries-garbage flows into landfills and rivers, which is usually increasing continuously. In the next few decades, many developing countries will have rapid economic development and rapid population growth at the same time, and the mountainous garbage that is difficult to handle is likely to challenge the municipal and state management agencies. Economic impact and quality of life. 12. Employment Since 1950, the world labor force population has increased by more than 1 billion-from1200 million to 2.7 billion-exceeding the growth rate of employment creation. Future population growth will increase the demand for labor (through economic activities and commodity demand), and at the same time, it will obviously promote the supply of labor. When the population growth makes the supply and demand of labor force unbalanced, the salary is excessively reduced. However, the workload will not improve rapidly because of the labor surplus environment, because employees will be forced to extend their working hours, but various allowances will be reduced and their ability to control their work activities will be reduced. Since today's children are tomorrow's workers, the interaction between population growth and employment is the most sensitive in countries with a large number of young people. Countries with more than half of the population under the age of 25, such as Poland, Mexico, Indonesia and Zambia, will feel the importance of this labor tide. In addition to giving people a sense of self-esteem and self-reliance, employment is also the key to obtaining food, housing, medical services and education. 13. The developing countries and regions with the largest population decline have the fastest income growth, including South Korea, Taiwan Province Province, China, Indonesia and Malaysia. Most African countries that neglect family planning are troubled by a large number of young people who really need education and employment. If all countries in the world can't turn their economies to the track of environmental sustainability and low population growth at the same time, economic recession will be inevitable. 14. The final result of the housing population growth exceeding the housing supply is that some people can return home. According to United Nations estimates, there are at least 654.38 billion people in the world-about the population of Mexico. The female population includes squatters and other unsafe or temporary shelters, and the total number is as high as 654.38+0 billion. If the world population growth cannot be controlled, the number of homeless people may increase alarmingly. 15. Education In countries where the proportion of children is increasing, the basic pressure on educational institutions will be very heavy. Most of the countries with the fastest population growth 10 in the world are in Africa and the Middle East, and the population of school-age children will increase by 93% on average in the next 50 years. By 2040, the school-age population in Africa will increase by 75%. If educational organizations in various countries begin to emphasize lifelong learning in view of the rapid changes in the world in the 2 1 century, then adult education needs to be widely carried out, even affecting those countries where the child population is decreasing. 16. Urban modernization develops at a relatively fast speed: in the past 130 years, the permanent population of London increased from1300,000 to 8 million, while Mexico City achieved this leap in only 30 years. In a word, the world urban population is increasing at the rate of1000000 per week, which includes the natural growth of urban population, the migration of rural population and the expansion of villages and towns to cities or being absorbed by the expansion of existing cities. If the current urban population growth momentum continues, 6.5 billion people will live in cities by 2050.