Advantages and disadvantages of scientific and technological development to the environment

What is climate change?

Climate change is a reflection of long-term changes in atmospheric conditions. Climate change mainly represents the changes of air temperature, humidity and dryness over various time periods. Cold and warm or dry and wet alternate, forming different change cycles. However, the period of these changes is not strict, and the stages before and after a period are often asymmetric, and the length of different periods can vary greatly. Climate change is such a complex quasi-periodic change.

There are many different cycles of climate change, and the longer the cycle of climate change, the greater the change. Modern data can distinguish climate change in several years, and it is the basic data for studying climate variability. Historical climate historical data can reflect the climate change from decades to hundreds of years, and it is an important background of modern climate change. Geological data can reflect the climate change in tens of thousands of years and give the general trend of climate change in this period. Although geological data and historical data are ancient data, the climate change cycle they reflect has a restrictive effect on modern climate change.

Anything in the world, to know its future, must first understand its past, and so does the climate. It is very meaningful to study climate change in a long period of time. Long-term climate is the background and analytical basis of short-term climate state. If we don't know the past climate change, we can't figure out the ins and outs of the present climate, and we can't understand and evaluate the present climate and predict the future climate.

At present, we are more concerned about the climate change in the past hundred years. The climate change in the last hundred years can be expressed by meteorological observation data. The most prominent feature of global climate change in the past century is the significant warming of the temperature. Almost all temperature observation records show that from the end of 19 to the 1990s, the global average temperature rose by about 0.6℃, and the warming rate was 0.5℃/ 100 years. Climate warming causes many glaciers in the world to melt or even disappear, and the global average glacier material balance is negative; In the past century, the global sea level has also risen by 15cm on average, half of which is estimated to be caused by the thermal expansion of seawater and the other half by the melting of ice and snow. Satellite observation since 1970s shows that the snow cover area in the northern hemisphere has decreased by 10% since 1987. These indirect evidences also show that the climate is warming in the 20th century. Generally speaking, the precipitation in various places is generally fluctuating. It was the warmest period in 1930s-1940s, then declined, and rose to the second high temperature period in 1980s.

The temperature changes in China in the last hundred years are basically similar to the world average. In 1930s and 1950s, the temperature was relatively high, then decreased slightly, and rose to a new high value in 1980s. According to the recent statistics of China Meteorological Bureau, from 1950s to 1980s, the temperature in northern China increased obviously, while the temperature in the Yangtze River basin and southwest provinces decreased. The provinces with the largest temperature rise are Heilongjiang (0.7℃), Inner Mongolia (0.83℃), Beijing (0.88℃), Hebei (0.84℃), Jilin (0.65℃), Liaoning (0.64℃), Shanxi (0.65℃) and other provinces (cities). Sichuan (-0.92℃) and Hubei (-1.09℃) have the largest cooling range. Therefore, in the past hundred years, the temperature change in China is obvious in the north, but not obvious in the south, and even it gets cold in some places.

Human activities and climate change

Human activities are one of the important members of the global climate system, and they are also important influencing factors of climate change. Since 1970s, the impacts of human activities on climate change and their interrelationships have been the focus of research. Because of the trend of global warming in the last hundred years, and scientists have noticed that the concentration of trace gases emitted into the atmosphere by human beings has increased obviously, whether there is a causal relationship between them is a concern of scientists, the public and policy makers all over the world.

In the tens of thousands of years of development after human beings appeared on the earth, most of the time they passively adapted to the living environment and corresponding climatic conditions. During this period, human influence on the environment and climate is not enough, and the climate is still changing under the action of its basic factors. However, in the 200 years after the world industrial revolution, the population on the earth has increased sharply, the development of science and technology and the scale of production have expanded rapidly, and the damage to the environment and the impact on the climate by human beings have become more and more serious, and the natural state of the earth's surface and atmosphere has been destroyed. Due to deforestation and burning fossil fuels, the concentration of carbon dioxide in the atmosphere increases rapidly, which intensifies the greenhouse effect. Since the 1960s, the increase of trace gases such as chlorofluorocarbons has accelerated this process. At the same time, due to overgrazing, the destruction of virgin forests and natural vegetation has changed the physical condition of the surface, the expansion of cities has caused heat island effect and air pollution, and the destruction of stratospheric ozone has expanded the Antarctic ozone hole. These have directly or indirectly changed the climate system. At present, this kind of climate change caused by human activities has reached the level of climate change caused by natural factors in climate change for decades to one hundred years. Therefore, if it is not properly planned and controlled, the impact of human activities on the climate will be increasingly intensified, which will not only destroy the living environment on which human beings depend, but also endanger the sustainable development of society.

Many impacts of human activities on the climate and environment can be delayed for decades or even hundreds of years, and it is difficult to recover for a long time. How to evaluate the impact of human activities on climate and environment, and how to take effective measures to seek advantages and avoid disadvantages, so as to improve the living environment and climate of human beings and ensure the sustainable development of society, has become a major problem in front of people, and it is also an urgent problem for governments of all countries. China is located in the fragile climate zone of the world, and global warming is bound to have a great impact on China's economic and social development.

The Impact of Human Activities on Climate Change

The impact of human activities on climate change not only directly affects the warmth and dryness of the climate, but also has a wide impact on the ecological environment, economic trade and even international political relations. At the same time, environmental and economic changes will in turn affect climate change. It can be said that the current global climate change is one of the most complicated earth system science problems that human beings have encountered so far. The World Climate Impact Plan, which was formulated under the auspices of the World Meteorological Organization, put forward ten research directions of climate impact on human beings: 1. Human health and working ability; 2. Housing construction and new residential areas; 3. All kinds of agriculture; 4. Water resources development and management; 5. Forestry resources; 6. Fisheries and marine resources; 7. Energy production and consumption; 8. Commercial activities; 9. Transportation; 10. Various public services. Among them, the impact of climate change on sea level fluctuation, agriculture and food supply, environmental pollution, ecosystem change, fresh water resources and human health is the most concerned.

The intensification of greenhouse effect caused by human activities is one of the most important global environmental problems at present. In agricultural production in cold areas, in order to make vegetables and other crops grow normally in cold climate, glass (or transparent plastic) houses are often built and crops are planted in them. Using the principle that glass can let the short-wave radiation of the sun pass through, the indoor temperature can be kept warm enough during the day. Using the principle that the long-wave radiation of indoor ground returns to the ground through glass at night, the indoor temperature is kept warm at night. People call this glass house a greenhouse. Some trace gases in the atmosphere, such as water vapor, carbon dioxide, nitrous oxide, methane and so on. , can play a role similar to glass, that is, these trace gases in the atmosphere can make some bands of solar short-wave radiation penetrate to the ground, thus warming the near-surface layer; It can also make the long-wave radiation radiated from the ground return to the surface, thus continuing to maintain the temperature of the ground. People call this effect of trace gases in the atmosphere the greenhouse effect in the atmosphere, and trace gases with this greenhouse effect are called "greenhouse gases". According to research, if there were no greenhouse gases in the atmosphere, the average surface temperature would be 33℃ lower than it is now. Therefore, the existence of these greenhouse gases is very important for the formation of today's surface temperature suitable for biological survival.

Since the industrial revolution (1750), the concentrations of greenhouse gases such as carbon dioxide, methane and nitrous oxide in the atmosphere have increased by 30%, 145% and15% (190) respectively. Many greenhouse gases can exist in the atmosphere for a long time (for example, carbon dioxide and methane can exist for decades to hundreds of years), which has a warming effect. Therefore, they will be effective for a long time.

The evidence of global warming in the past century is manifested in many aspects besides temperature. The observation records in recent decades show that the land soil temperature and sea surface temperature are also warming from the surface to the middle and lower troposphere. In addition, the detection data also show that the upper troposphere and the lower stratosphere are getting cold. In addition, the daily minimum temperature in most land areas of the world is obviously warming, so the daily range is obviously reduced. In the past hundred years, the global sea level has risen by an average of 20 ~ 30 cm; The global mid-high latitude ice and snow melt, and the glacier range shrinks to high latitudes, especially in North America and northern Eurasia, and the alpine snow line also shrinks obviously.

Climate change is closely related to economic and social development. Global warming has done great harm to agricultural production. In some areas where agricultural production is fragile, the increase of pests and drought may reduce grain production, thus changing the pattern of grain trade. In addition, the impact of global warming on the natural earth ecosystem is also very obvious, and the social and economic consequences will be very serious, especially in ecologically fragile areas. The socio-economic development of these areas is strictly dependent on the natural ecosystem, and the change of the ecosystem will have an impact on food, fuel, medicine and building materials, endangering human survival.

The impact of global warming on the water cycle is more obvious in fragile arid and semi-arid areas. For example, in the past 50 years, the arid and semi-arid areas in China have obviously dried up, and some rivers and lakes have dried up. Global warming will probably make North China warm and dry, aggravate drought and make water resources even more scarce. The change of water cycle will change the way of water use in agriculture, ecosystem and other aspects, which will have serious consequences for agriculture and hydropower in already arid areas (such as sub-Saharan Africa). Some fragile and water-sensitive areas may not be able to withstand this pressure.

Global warming and a series of corresponding climate changes will also have direct or indirect effects on human health. Studies show that with global warming, the number of hot days in summer will increase obviously, and the morbidity and mortality of patients with heart disease and hypertension will increase. Sudden changes in climate, such as the outbreak of cold wave or the invasion of strong cold air in spring, will have an impact on people's health, especially some patients and weak people. The increase of pests and diseases and bacterial reproduction caused by global warming are extremely harmful to human health. For example, high temperature and humidity may lead to the breeding of mosquitoes and flies, leading to an increase in the incidence of cholera, malaria and yellow fever. High temperature and drought may lead to the increase of some infectious diseases, which are more harmful in densely populated areas. Changes in temperature and precipitation may fundamentally change the distribution of vector-borne diseases and viral diseases, make them move to higher latitudes, and expose more people to disease risks. Many developing countries are facing greater threats due to poor medical equipment and drugs.

Global warming will lead to large-scale melting of ice and snow and thermal expansion of seawater, accelerate sea level rise, change ocean circulation and marine ecosystem, and cause huge losses to social economy. Global sea level rise will directly endanger low islands, low coastal zones, low-lying areas and countries. Many cities are located along the coast, where the population is dense and the industry and agriculture are developed. As the sea level rises, seawater may flood farmland, pollute the fresh water supply and change the coastline.

Global warming will have an impact on human living environment, energy, transportation and industry. The potential response of human living environment to rapid climate change is fragile. Some deltas in the world are vulnerable to sea level rise, including the Nile Delta in Egypt, the Ganges Delta in Bangladesh, the Yangtze Delta and the Yellow River Delta in China, the Mekong Delta in Indochina Peninsula, the Amazon Delta in South America and the Mississippi Delta in the United States. Sea level rise and seawater intrusion will also cause huge losses to the economies of densely populated industrial areas along the coast of Brazil, Argentina and China. Sea level rise: the inundation of cultivated land will force large-scale migration of population and also affect fishery production.

Countermeasures to adapt to climate change

We only have one earth, and this is our common home. Protecting the earth environment on which human beings depend is a concern of people all over the world. Climate change affects human living environment and social and economic development, and human activities in turn affect climate change. Therefore, there is a complex process of interaction and mutual feedback among human activities, climate change and environmental change, which involves the intersection of many disciplines; Solving the problems related to climate warming and its effects requires the participation of multidisciplinary scientists, managers and government officials. Climate and environmental issues have no national boundaries. Only when all countries in the world actively participate and take concerted actions on a global scale to properly handle the problems of resources, environment and development can we finally realize the sustainable development of mankind through the unremitting efforts of several generations.

Facing the situation of global warming, our current countermeasures mainly include the following three aspects:

The first is to reduce the current carbon dioxide in the atmosphere. Technically, the most feasible thing is to plant trees extensively and strengthen greening; Stop deforestation. Absorb and fix a lot of carbon dioxide through the photosynthesis of sunlight. There are other ways to absorb carbon dioxide through chemical reaction, but the technology is not mature and it is difficult to implement it on a large scale economically.

The second is adaptation, which should be considered anyway. Therefore, in addition to the construction of coastal protection dams and other engineering and technical measures to prevent seawater intrusion, the types and varieties of local crops are gradually changed in a planned way to adapt to the changing climate. For example, in northern Japan, rice was not planted in the past because it was too cold in summer, or the yield was very low. However, due to the cultivation of cold-resistant and stress-resistant varieties, even the northernmost Hokkaido can not only grow rice, but also have a high yield. Because climate change is a relatively slow process, as long as the trend of climate change can be predicted as soon as possible, adaptive countermeasures can be found and implemented smoothly.

The other is to reduce carbon dioxide emissions. 1992 At the World Conference on Environment and Development held in Rio de Janeiro, Brazil, heads of state signed the Framework Convention on Climate Change, demanding that developed countries reduce their carbon dioxide emissions to the level of 2000 1990, and provide funds and technology transfer to developing countries to help them reduce their carbon dioxide emissions. Because most of the carbon dioxide in the global atmosphere was emitted by developed countries in the last century. Developing countries must first get rid of poverty and develop. Developed countries have an obligation to do so. However, since the Convention is a framework, it is not binding. Moreover, carbon dioxide emission reduction directly affects the economic interests of developed countries, so some developed countries have not only failed to reduce emissions, but even increased their emissions, and it is impossible to reduce them to the level of 2000 1990. At the Third Conference of the Parties to the United Nations Framework Convention on Climate Change (Kyoto Conference, Japan), which ended on June 5438+0997+February 1 1, developing countries and developed countries launched a sharp and intense struggle. Finally, the developed countries gave in and the dystocia Kyoto Protocol was finally passed. It stipulates that all developed countries should reduce the emissions of six greenhouse gases (carbon dioxide, nitrous oxide, methane and three chlorofluorocarbons) by 5.2% based on the level of 1990 in 20 10. Although this is far from the target of reducing emissions by 20 10/5% and 20% in 2020 required by developing countries, it is a legally binding international emission reduction agreement after all.