1988 causes of heat and drought in America and Europe

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In the summer of 1988, a strange word that made us feel a sense of crisis suddenly became popular. It is the word "greenhouse effect". The greenhouse effect will lead to this situation: once the climate warms, heat waves will occur frequently, forest fires will emerge one after another, and hurricanes will continue to strike. 1988 in the summer, the above happened in the United States. As mentioned above, the United States suffers greatly.

First, the emergence of the greenhouse effect

It is called the "greenhouse effect" because the glass in the greenhouse has some properties similar to the atmosphere. Visible light radiation from the sun almost passes through the glass and is absorbed by the plants and soil inside. The thermal radiation emitted by plants and soil is stripped and absorbed, and some of it is emitted back to the greenhouse. Therefore, glass has become a "radiation barrier" to help the greenhouse keep warm.

Trace gases in the atmosphere, such as water vapor and carbon dioxide, absorb the thermal radiation emitted by the surface and play a certain role in this radiation, resulting in the only difference between the actual average surface temperature and the surface temperature obtained under the atmospheric conditions containing only oxygen and nitrogen. This occlusion is called "natural" greenhouse effect. These gases are called greenhouse gases. It is called "nature" because all atmospheric gases existed long before human beings appeared. Next, I will talk about "enhancing" the greenhouse effect, which is caused by gases produced in the atmosphere by human activities (such as burning fossil fuels and destroying forests).

The natural greenhouse effect is caused by natural gas such as water vapor and carbon dioxide. The amount of water in the atmosphere mainly depends on the temperature of the ocean surface. Most of the water vapor comes from sea surface evaporation and is not directly affected by human activities. Carbon dioxide is different. Since the industrial revolution, due to human industrial production and the destruction of forests, the content of carbon dioxide in the atmosphere has changed obviously-so far, it has changed by about 25%. In the absence of control factors, it is expected that the increase of carbon dioxide in the atmosphere will accelerate. Its atmospheric concentration is likely to be twice that before the industrial revolution in the next few hundred years. As the greenhouse effect of carbon dioxide is enhanced, its increase is leading to global warming. For example, let's imagine: when everything else remains the same, such as the sudden doubling of carbon dioxide content in the atmosphere, what will happen to the radiation budget I mentioned earlier? The solar radiation budget will not be affected. More carbon dioxide in it means that, on average, the radiation it emits will come from a higher and colder layer than before. The radiation budget will be reduced. The reduced amount will cause a net imbalance in the total budget, and more energy will come in. In order to restore balance, the surface and atmosphere will warm up. In other words, if there is no change except temperature,

Second, the influence of the greenhouse effect.

Impact of sea level rise

By 2030, the sea level will rise by an average of 15cm, and by the end of the next century, it will rise by about 0.5m m. These changes do not seem to be significant. Many people live in areas with high enough altitude and will not be directly affected. However, about half of the world's population lives in coastal areas. Among them, the lowest places are some areas with the most fertile land and the highest population density. For people living in these areas, even if the sea level rises by a few meters, it will have a serious impact on them. Some particularly vulnerable areas are Bangladesh and similar delta areas, the Netherlands and the Pacific Ocean, and other low-lying countries.

Sea level rise will also invade underground fresh water resources through salt water, further affecting the productivity of agricultural land. It is estimated that in some areas of Bangladesh, the seasonal extension of salt water inland has exceeded 150cm. When the sea level rises by 1cm, the area affected by ship salt water intrusion will increase by 1 times, which has a great impact on fresh water supply.

Impact on fresh water resources

For human beings, no one can make a key substance. We need drinking water, water to produce food, maintain health and health care, and carry out industrial production and transportation. Humans have learned various lifestyles to adapt to different water supply environments. The per capita water consumption in different countries varies from 1 1,000m3 to over 50000m3 annually. The average figures quoted here may mask the huge differences between extremely poor areas. The growing population demand and the desire for a high standard of living have brought about a greater demand for fresh water. In the past 50 years, the water consumption worldwide has increased fourfold, and now it has reached about 65,438+00% of the total flow of rivers and groundwater in the world. At present, two thirds of human water consumption is used for agriculture, most of it is used for irrigation, about 1/4 is used for industry, and only about 10% is used for living. At present, millions of groundwater stored in the past are being exploited and utilized more and more. With the rapid growth of demand, the fragility of water supply has also increased greatly. Because many major water sources in the world are enjoyed by * * *, there are many problems.

Impact on agriculture and food supply

Available water quantity is an important factor affecting agriculture and grain production. The vulnerability of water supply to climate change is transformed into the vulnerability of crop planting and food production. Therefore, the risk is greatest in arid or semi-arid areas. Another factor that can actually improve productivity is that the increase of co2 in the atmosphere accelerates the growth of some crops (related to the effect of co2 fertilization).

Impact on natural ecosystems

Climate change can change the adaptability of a region to different species and the competitiveness of different populations in the ecosystem. Therefore, even a small climate change can cause great changes in the composition of the ecosystem in a certain period of time. With global warming, most ecosystems cannot respond or migrate so quickly. Therefore, natural ecosystems will become increasingly unable to adapt to their environment. There are great differences in reactions between different species. Some species are more susceptible to average climate change or extreme weather events than others. However, all species will become vulnerable to diseases and pests. The positive effects of fertilization due to the increase of co2 may be greatly exceeded by the negative effects of other factors.

Trees have a long life span and it takes a long time to reproduce. Because trees are not easy to respond to climate change quickly, global forests may be seriously affected. In recent years, the decline of normal growth of many forests has attracted our attention, especially in Europe and North America, where most of the decline of forests is caused by acid rain and other pollution. However, not all the damage to trees comes from this. For example, the study of several areas in Canada shows that the withering of trees there is related to the change of climatic conditions, especially the continuous warm winter and dry summer. In some cases, this may be due to the dual effects of pollution and climate pressure. Due to the influence of pollution, the already weak trees can't cope with the coming climate pressure.

Impact on human health

What is the direct impact of subsequent changes on human health? Humans can live comfortably under very different conditions and have strong adaptability to various climates. However, the really extreme climatic conditions are unbearable, which can promote the spread of many diseases. The main difficulty in assessing the impact of climate change on health is that it is impossible to separate the impact of climate from many other factors that affect health. The main direct impact of subsequent changes on human beings is the thermal effect caused by extreme high temperature, which will become more and more frequent and common. The research based on the data of big cities where heat waves usually occur shows that the death rate will increase by 1 ~ 2 times in the days with unusually high temperature. Although there may be a period of low mortality after this incident, which means that there will always be some deaths, most of the increase in mortality seems to be directly related to the high temperature. It can be considered that the less severe cold provides compensation for the overheating period. However, research shows that the increase of mortality caused by overheating far exceeds the decrease in cold period, especially for the elderly, who are particularly difficult to adapt to high temperature.

Third, measures to slow down the greenhouse effect.

1, some possible actions to slow down climate change and finally achieve climate stability required by the United Nations Framework Convention on Climate Change.

Some actions have been taken to affect global greenhouse gas emissions, namely:

Some countries reduced their carbon dioxide emissions to the level of 1990 in 2000.

Montreal Protocol's regulations on the emission of chlorofluorocarbons and their substitutes.

2. Other actions that can be taken to mitigate climate change at present (these actions have little or no cost and are beneficial for other reasons) are as follows:

Reduce deforestation;

Significantly increase afforestation;

Take some easy-to-achieve actions to reduce methane emissions;

Actively take measures to save energy and reserve energy.