Causes and Effects of Global Warming _ Harm of Global Warming

Causes of global warming. The factors of population explosion.

The rapid population growth in recent years is one of the main

Causes and Effects of Global Warming _ Harm of Global Warming

Causes of global warming. The factors of population explosion.

The rapid population growth in recent years is one of the main factors leading to global warming. At the same time, it also seriously threatens the balance between the natural ecological environment. With such a large population, the annual carbon dioxide emitted by itself will be an amazing number, and the result will directly lead to the continuous increase of carbon dioxide content in the atmosphere, thus forming carbon dioxide? Greenhouse effect? Will directly affect the climate change on the earth's surface.

2. Atmospheric environmental pollution factors

At present, the increasingly serious environmental pollution has become a major global problem, and it is also one of the main factors leading to global warming. Now, the research on global climate change has clearly pointed out that the temperature of the earth's surface has started to rise since the end of last century.

3. Deteriorating factors of marine ecological environment

At present, the change of sea level is on the rise. According to the prediction of relevant experts, the sea level may rise by 50 cm by the middle of the next century. If no measures are taken, it will directly lead to the destruction and pollution of fresh water resources and other adverse consequences. In addition, a large number of toxic chemical wastes and solid wastes produced by land activities are continuously discharged into the sea; Major oil spills in seawater and the destruction of coastal ecological environment by human activities are the main factors leading to the destruction of seawater ecological environment.

4. Land erosion, desertification and other destructive factors

The main cause of soil erosion and desertification is improper agricultural production. As we all know, good vegetation can prevent soil erosion. But so far, human activities, such as excessive logging, land reclamation for agricultural production and overgrazing, are still seriously destroying vegetation. At present, on average, 20 hectares of forests are destroyed, 65,438+00 hectares of land are desertified and 47,000 tons of soil are eroded every minute in the world. Soil erosion reduces soil fertility and water retention, thus reducing soil biological productivity and its ability to maintain productivity; It may also lead to large-scale floods and sandstorms, causing huge economic losses to society and deteriorating the ecological environment.

5. Factors of sharp decline of forest resources

Worldwide, due to natural or man-made factors, the forest area is decreasing sharply.

6. Changes in the Earth's periodic orbit

The earth's periodic orbit changes from ellipse to circle, which is closer to the sun. According to a scientist's research, the temperature of the earth has been alternating between high temperature and low temperature, with certain regularity.

The Impact of Global Warming Global warming will bring complex potential impacts to the earth and human beings, both positive and negative. For example, with the increase of temperature, sub-polar regions may be more suitable for human habitation; Under appropriate conditions, higher carbon dioxide concentration can promote photosynthesis, thus making plants have higher carbon fixation rate, leading to an increase in plant growth, that is, the yield-increasing effect of carbon dioxide, which is a positive impact of global warming. However, compared with the positive impact, the negative impact of global warming on human activities will be more enormous and far-reaching. In August this year, CCTV reported that the summit of Mount Qomolangma dropped by 1.3 meters due to climate warming.

Glacier shrinkage in Qilian Mountains endangers Hexi Corridor: In recent years, the melting of glaciers in Qilian Mountains has decreased by about 654.38 billion cubic meters compared with that in 1970s, and the snow line of glaciers in some areas is rising at an average annual rate of 2-2.6 meters. According to experts' analysis, in addition to natural climate factors, glacier retreat and snow line rise are mainly caused by population expansion, overload and overgrazing, over-reclamation, deforestation and indiscriminate exploitation of groundwater. China environmental news

1, the influence of sea level rise

In the past century, the sea level has risen by 14.4cm, and in China by110.5cm. The main reason for the sea level rise is the thermal expansion of seawater. When the ocean warms, the sea level rises. Global warming will lead to the melting of icebergs in the north and south poles of the earth, which is also one of the main reasons for the rise of sea level. The direct impact of sea level rise has the following aspects:

The lowlands were flooded:

Britain heightens dams to cope with climate warming

Global warming makes the sea level rise and the frequency of storms increase, which makes it impossible for the British to raise flood control dams politically. Statistics released by British officials recently show that in the past 20 years, due to global warming, the Thames water level has risen, and local government agencies have to raise flood control dams 88 times to ensure the safety of Londoners' lives and property. It is reported that people now raise dams four times a year on average. It is estimated that before 2030, the frequency of heightening dams will reach 30 times a year. China Environment News 2004- 10- 19

(2) Coastal erosion

(3) The salt content of surface water and groundwater increases, which affects urban water supply.

(4) The groundwater level rises.

(5) Tourism is endangered (the sea level rises by 50m, the coastal tourist areas of Dalian, Qinhuangdao, Qingdao, Beihai and Sanya are 365 and 438+0-366 behind, the beaches are lost by 24%, and the beaches of Beidaihe are lost by 60%. China Land and Resources Bulletin reported in 2002 that coastal tourism has become the largest industry, with an output value of 250.3 billion yuan, accounting for 34.6% of the total output value of marine industry.

(6) Affect the life of coastal and island residents (accounting for13 of the world population) and make them threatened. If the polar ice sheet melts, economically developed and densely populated coastal areas will be swallowed up by seawater, and low-lying island countries such as Maldives and Seychelles will disappear from the ground, and coastal cities such as Shanghai, Venice, Hong Kong, Rio de Janeiro, Tokyo, Bangkok and new york, as well as Bangladesh, the Netherlands and Egypt will also be doomed.

2, the impact on animals and plants

Climate is the main factor that determines the distribution of biological communities. Climate change can change the adaptability of different species in a region and the competitiveness of different populations in the ecosystem. Animals and plants in nature, especially plant communities, may adapt to the speed of global warming, thus encountering bad luck. Past climate change (such as the ice age) has made many species disappear, and the future climate will make some species disappear in some areas.

Loss, although some species benefit from climate warming, their habitats may increase, competitors and

Natural enemies may also decrease. Take oranges as an example. In the 1970s, its northernmost boundary line was the Yellow River.

On the front line of this mountain, Xuancheng tried to plant it, but it was frozen to death by a heavy snow in winter. But now I'm

The orange trees in our campus are all growing well. For example, Chinese alligators only live in Xuancheng, Jingxian and Nanling.

On a small scale, if the northern boundary moves northward, the Chinese alligator may become extinct naturally. This is from some parts of our province.

Go ahead. Nationally, China regards the winter 1℃ isotherm as the northern boundary of subtropical zone, which is currently.

In the Qinling-Huaihe region of China. It is found that the rising temperature will move this boundary northward to the north of the Yellow River.

The winter temperatures in Guangzhou and Zhengzhou will be similar to those in Hangzhou and Wuhan now.

3. Impact on agriculture

The distribution of temperature and precipitation in a year is the main factor to decide what crops to plant. The change of temperature and precipitation caused by temperature will affect the yield of food crops and the distribution type of crops. Climate change leads to great changes in biota and its spatial (latitude) distribution. For example, in 800- 1200, the average temperature in the North Atlantic was 1℃ higher than it is now, which made it possible to grow corn in Norway. But by 1500- 1800, there was a little ice age in western Europe, and the average temperature was only 1-2℃ lower than it is now, which caused. In addition, global warming will aggravate natural disasters such as high temperature, heat wave, tropical storm and tornado. Therefore, after the global temperature rises, the stability and distribution of world grain production will change greatly.

4. Impact on human health

Human health depends on a good ecological environment, and global warming will become one of the problems of human health in the next century.

Main factors. Extreme high temperature will become a human health problem in the next century, becoming more frequent and common, mainly

Reflected in the increase of morbidity and mortality, especially malaria, lymphatic filariasis, schistosomiasis, hookworm disease,

Infectious diseases such as cholera, meningitis, kala-azar and dengue fever will endanger tropical regions and countries, some of which are mainly

Diseases that occur in tropical areas may spread to mid-latitudes with climate warming.

First, we must reduce carbon dioxide emissions. The main measures to reduce carbon dioxide emissions are to reduce the burning of carbon-containing compounds, vigorously research and use new energy sources, and gradually phase out the use of fossil fuels, which can greatly reduce carbon dioxide in the air and will certainly have immediate effects.

Second, forests are commonly known as the lungs of the earth, so the second measure is to vigorously protect forests, prohibit deforestation, vigorously promote afforestation, and increase the coverage of artificial afforestation.

Thirdly, I think other methods can be used, such as purifying the air and absorbing carbon dioxide in the air by chemical means, so as to reduce the content of carbon dioxide in the air.

Fourth, all measures and methods must be based on national policies. On the government side, the state should formulate and improve some rules and regulations to raise citizens' awareness.