Write a short passage with key words such as population growth, resource demand, environmental impact and economic development.

If the population is too fast, domestic sewage will increase, resulting in water pollution, carbon dioxide will also increase, and more people will own cars, which will emit toxic gases and destroy the atmosphere. People need to eat vegetables and use chemical fertilizers to grow vegetables. The cost will harden the land, people need housing, housing needs land, and people need meat. Eating meat will breed some livestock, destroy plants, and people will kill some wild animals, but other natural enemies will disappear and destroy the ecological chain. I have no time to write. I'll find one for you, and then you can sum it up and make it your own language. 7-3 Impact of population growth on the environment. While using the environment, human beings are also transforming the environment. With the growth and expansion of population, it has also caused many impacts on the environment. There are various ways and the scope is expanding. The impact of population growth on the environment is manifested in two aspects. 1. The pressure of population growth on the living environment is 1. The living space and carrying capacity of the universe are infinite, but the environmental space suitable for human survival is limited. This is that the weight of the earth (the only one found so far) is 5.875×1.026,5438+0.0t, and the area is 51. Throughout the history of population growth, we will find that the longer it takes for population growth 1 times (doubling period), the shorter it takes for population growth 1 times. It took about 450 years to increase the population 1 times after AD, 400 years for the second time, followed by 100 and 45 years. At present, it is about 35 years. Some people take the world population 1 970 as the base and calculate it at a fixed growth rate of 1 time every 35 years. By 2705, there will be 10 people per square meter on the whole earth surface, and by 3535, the total weight of the human body in the world will exceed the weight of the earth. This is an unimaginable scene. In addition, the population capacity of the earth refers not only to the volume of containers, but to the maximum number of people who can live permanently on the earth. The total output of plants on the earth is calculated by energy, which is 660× 10 15 calories per year. Each person needs 2,400 calories per day to maintain normal survival, and 8× 105 calories per year. Therefore, according to this calculation, the total plant output on the earth can feed 825 billion people, while human beings can only get 1% of the total plant output, so they can only feed 8.2 billion people. Besides, it is not only humans who eat plants on the earth, but also all kinds of other animals and plants eat plants directly or indirectly, and many animals and plants are beyond human consumption. 2. Impact on Climate Population growth will increase CO2, NOX and SO2 discharged into the atmosphere due to breathing, combustion and industrial development, resulting in acid rain, photochemical smog and greenhouse effect. In the past century, the global surface temperature has risen by 0.3~0.6℃. The 1980s was the hottest year in this century. 10. Compared with 1949~ 1979, the average temperature of 1988 rises by 0.34℃, the sea level rises by 14.4cm, and the China rises by110.5 cm, which is estimated to be 2030. 3. Impact on urban environment At present, the average urban population in the world is 42.2%, and that in developed countries is 79%. In China, the urban population accounts for 26.2% of 1990, about 300 million people. During the period of 1982~ 1990, it increased by 4.35% every year, higher than 49 ~ 86544. Population urbanization is an inevitable law of social development, but due to the over-concentration of population, housing is crowded (at the end of 1990s, there were more than 8 million urban households with housing and no housing in China, and according to the statistics of 1988, there are still 50,000 households with per capita living area exceeding 2m2). According to statistics in 2002, the average living area of urban residents in China is 2 1.3m2, and traffic congestion is another major problem in cities. According to statistics, the bus speed of 295 cities in the world is the lowest in Tianjin and the second in Beijing. The speed of major cities in China is decreasing year by year, and there is water shortage and environmental pollution (air, noise, garbage, sanitation, green space). The reasons are all caused by urban population expansion and overpopulation. Employment difficulties II. The impact of population growth on natural resources The total water resources of the earth is 65.438+0.38 billion km3, of which more than 96.53% is sea salt water, and the total fresh water of the earth is 35 million km3, accounting for only 2.53% of the total water resources of the world. Three quarters of them are in the ice sheets and glaciers of the North and South Poles. Therefore, the fresh water easily used by human beings accounts for about 20% of all fresh water. However, the fresh water directly obtained from rivers and lakes only accounts for 0.5% of all fresh water, which shows that the fresh water resources that can be directly used and easily obtained by human beings are very limited. Due to the growth of population and the improvement of living standards, the demand for water in some countries and regions has reached the limit of local supply capacity. A person's consumption of 12L water in one day BC increased to 20-40L in the Middle Ages and to 10L in the 8th century. At present, in some big cities in Europe and America, the water consumption per person per day is 500L, and the annual per capita water consumption exceeds 104m3, far exceeding the annual water resources consumption. According to statistics, the global total annual water consumption is close to 3 trillion m3, and the water shortage problem in many areas is very serious at present. The total amount of water resources in China is 28× 104 billion m3, but the per capita possession is only 2693m3, ranking/kloc-0.09 in the world and being listed as one of the water-poor countries in the world/kloc-0.3. Of the 668 cities in China, 400 are short of water, especially in Beijing. According to statistics, the average daily water shortage of cities in China is 6.5438+0.6 million m3, and Beijing, Shandong, Shenyang and Changchun are all water-deficient cities (654.38+0.984 and 654.38+0.92 cities are short of water, indicating that population growth and demand increase). Second, the food problem and the land problem With the increase of population, the human demand for food is also increasing. According to the calculation of the International Food Policy Research Institute of the United States, the world food growth can't keep up with the population growth. If the population growth rate remains unchanged after 1985, there will be a shortage of10 million tons of grain and 50 million tons of protein every year, and people in more countries will have to go hungry and suffer from malnutrition. One of the reasons for the food shortage is that the arable land in the world is limited and unevenly distributed. The most fertile and arable land has been cultivated, and the rest needs a lot of investment if it is cultivated. In fact, the amount of cultivated land per capita in each country is extremely uneven. In many countries and regions, it is almost impossible to expand cultivated land. Some areas even need to return farmland to forests and grasslands. With the growth of population and the increasing occupation of industry, cities and transportation, the area of cultivated land is shrinking. Although people can improve the yield per unit area by reforming farming techniques and increasing agricultural investment, so that grain can get a higher harvest, there is a limit to increasing grain output at present. The most fundamental measure is to control population growth. China's per capita arable land is less, the population is growing too fast, the per capita arable land area is getting less and less, and the contradiction between man and land is becoming increasingly acute. 1953, China's per capita arable land area was 0. 18 hectares, with an average of 5.5 people per hectare. At present, the annual birth population in China is more than150,000. Due to the occupation of land by industry, cities and transportation, the cultivated land area is reduced by 400,000-500,000 hectares every year, resulting in the per capita cultivated land area being less than 0. 1 hectare. On average, 9.8 people need to be fed per hectare of cultivated land. It is estimated that by 2050, each hectare of cultivated land needs to support about 12 people. The per capita arable land in Zhejiang Province is less than 0.05 hectares, while that in Fujian Province is only 0.04 hectares. It is predicted that by 2050, the population of China will reach 65.438+0.64 billion, while the cultivated land area will drop to 73 million hectares (from the current 96 million hectares). According to the per capita annual consumption of 600 kilograms of grain of 65.438+0.6 billion, China needs 984 million tons of grain, and needs to produce 654.38+0.3 tons of grain per hectare, with the highest grain yield at present. It is quite difficult to achieve this goal, and only controlling population growth is the only way out. Third, the problem of energy resources The problem of exhaustion of natural resources refers to non-renewable resources, including minerals and fossil fuels (coal, oil, natural gas, etc. The world energy consumption is increasing rapidly. At present, fossil energy such as oil and coal accounts for 38% of the total energy consumption, and there are many developed countries. For example, Japan's oil and natural gas consumption accounts for 65.8% of the total energy consumption, while coal only accounts for 18.8%. Oil and gas consumption in the United States accounts for 65.6% of the total energy consumption, and coal accounts for 29.3%, while China's energy consumption is characterized by coal. Mineral resources: China is rich in total, but its per capita possession is less than half of the world average. However, the huge population's demand for mineral resources makes China a resource-consuming country with low per capita mineral consumption. The annual ore mining capacity reaches 5 billion tons, with an annual per capita of 5 tons. The total exceeds the exploitation in the United States. It not only causes a shortage of resources, but also causes serious ecological and environmental problems. Many mineral products and processed products are used to meet the needs of the new population. The influence of population on the environment With the increase of population and the progress of science and technology, on the one hand, great progress has been made in using the environment and conquering nature, but at the same time, some serious problems have been brought. This is the ecological crisis that is often learned from the news media at present. This is because people have lost control of their own development and the environment has been destroyed. The severity of destruction has affected human beings and threatened the continued existence of many other species. Many scholars who care about the living environment of human beings are deeply disturbed by this amazing fact. They loudly ask people to control themselves in order to maintain the balance between themselves and the ecological environment. Although they also realize that there are many reasons for this crisis, it is very important to reduce the population growth rate and reduce the pressure on the environment, otherwise the environmental situation will continue to deteriorate. The population, that is, the population density of an area, is closely related to the environment. Since the Middle Ages, the change of vegetation in Central and Western Europe is a good example. In the past, farmers living in plains and valleys cut down forests, turning relatively flat areas into fertile farmland and forming densely populated agricultural areas. However, between the edge of the agricultural area and the agricultural area are hills and low mountains, where dense forests grow and are preserved because they are not suitable for farming. Because forest vegetation is closely related to hilly terrain, people living in hilly areas of Central and Western Europe often regard the word forest as a region with rugged terrain. The expansion and contraction of forest area in this area is closely related to the increase and decrease of population. During the period of war, epidemic disease and famine, the population decreased, and the forests on the hills expanded to low-lying and plain areas; During the period of social stability and population growth, the forest area will shrink. 1337- 1453, the century-long war between Britain and France greatly reduced the population and greatly expanded the forest area. In France, there is a saying among farmers: "The British brought the forest to France". This is also the case in the northeastern United States. After the first immigrants arrived, they cut down forests and cultivated farmland. At that time, agriculture developed at the speed of deforestation, so that a large area of forests disappeared. However, since the 20th century, many farmers have left the countryside and turned to cities, and the forest has also expanded to farmland, and the forest area is gradually expanding. The above example is only the relationship between the change of population and production mode and the growth and decline of forest area, and there is no major change in the forest environment that affects its own survival. In Cuba, the Spanish burned forests as fertilizer to grow coffee for profit, which led to more serious consequences. They didn't expect the heavy rain to wash away all the bare soil without forest cover, leaving only bare rocks. Not only can coffee not grow, but the forest is also difficult to recover. The consequences of human destruction of forests are serious, and grasslands are also affected by human activities to a considerable extent. Some evidences show that since the Roman period, the area of the desert has gradually expanded due to overgrazing on the short grass grassland on the edge of the Sahara desert. There is a similar situation in China, and some deserts in southern Inner Mongolia are also caused by unreasonable reclamation in history. In the past, it was often said that "the desert moved south" was actually improper large-scale reclamation in some places, which contributed to the expansion of desert area. The above examples fully show that population growth has brought heavy pressure on the environment and led to a serious ecological crisis. In fact, this conclusion is not entirely correct. In terms of people's consumption, the living standards of people in industrialized countries are relatively high, and they consume much more materials than those in developing countries. For example, per capita energy consumption in the United States 10 ton/person-year (1980) and meat consumption 108 kg/person-year. This figure is not several times or ten times higher than that of developing countries, but dozens of times. Generally speaking, the population of the United States accounts for about 5% of the world population and consumes about 40% of the world's resources every year. Therefore, every additional person in the United States will have a much greater impact on the world environment than every additional person in developing countries.