Countermeasures to adapt to climate change

Impact of Climate Change on Ecological Environment and Human Health and Its Adaptation Countermeasures

Changes in climate extreme events. When the weather and climate in a certain place is abnormal, or the weather and climate in a certain place seriously deviates from its average state, it means "extreme events". According to the provisions of the World Meteorological Organization, if the time, day, month and year values of a certain climatic element (s) reach more than 25 years, or the "difference" of the corresponding 30-year average exceeds twice the mean square deviation, then the climatic element (s) are "abnormal" climatic values. Events with "abnormal" climate values are "extreme climate events". Events such as drought, flood, high-temperature heat wave and low-temperature chilling injury can all be regarded as extreme weather events.

After global warming, not only the average climate will change, but also the frequency of weather and climate extreme events will change. Although it is impossible to determine whether there is a consistent extreme trend of global climate in the 20th century due to the serious shortage of observation data, some important "trends" have been found on the regional scale.

The observation records show that since 1950, the frequency of extreme minimum temperature has decreased, so the "frost day" and "freezing day" marking cold events have decreased; However, the frequency of extreme maximum temperature has increased. The observation records also show that there is an increasing trend of heavy rain and extreme precipitation events in areas with increasing precipitation in the middle and high latitudes in the northern hemisphere. In the second half of the 20th century, the frequency of heavy rainfall events in mid-high latitudes in the northern hemisphere may have increased by 2% ~ 4%. However, in the areas where precipitation decreases in the middle and high latitudes in the northern hemisphere, heavy rain and extreme precipitation events have a downward trend. In some parts of Asia and Africa, the frequency and intensity of droughts and floods have increased in recent decades. Analysis shows that some parts of the continent may become drier in summer, and the threat of drought may increase accordingly. In East Asia, although precipitation tends to decrease or change little, heavy rain and extreme precipitation events have increased in some places. The changes of storm intensity and frequency in tropical and subtropical regions of the world are still largely influenced by interdecadal changes, and there is no obvious trend of increase or decrease.

In recent 40 ~ 50 years, the extreme minimum temperature and average minimum temperature in China are on the rise, especially in northern winter. At the same time, the frequency of cold wave tends to decrease, the number of low temperature days tends to decrease, and the number of rainy days decreases obviously.

(2) Future scenarios of global and China climate change.

As mentioned above, there are many factors affecting climate and the mechanism is complex. Considering the influence of various factors, the current scientific level can not give the future climate prediction. We can only take the changes of greenhouse gases and aerosol concentrations in the atmosphere caused by human activities in the future as conditions and input them into the climate model to calculate the possible changes in the future climate. Climate change scenario is the difference between the possible future climate state and the current climate state.

1. Temperature change. According to the second assessment report completed by the Intergovernmental Panel on Climate Change 1990-2 100, it is predicted that the global average surface temperature will rise by 1990 1.o ~ 3.5℃ in 2l00. This is equivalent to the global average temperature rising by 0. 10 ~ 0.35℃ every10 year.

According to the third assessment report completed by the Intergovernmental Panel on Climate Change in 20001year, it is predicted that by 2 100, the global average surface temperature will be about 1.4 ~ 5 higher than that in 1990-2 100. This is higher than the estimated value in the second assessment report, mainly because the estimated value of future increment of sulfur dioxide is far lower than that of 1995. In other words, the cooling effect caused by aerosols such as sulfur dioxide in the future is not as great as estimated in 1995. The warming rate of 0. 10 ~ 0.58℃ per10 year is much higher than that actually observed in the 20th century, which may be unprecedented in recent 1000 years and will be a severe challenge to the adaptability of the ecosystem.

The degree of warming in almost all land areas may be higher than the global average, especially in winter in high latitudes in the northern hemisphere. The simulated warming values in Alaska, Canada, Greenland, northern Asia and Qinghai-Tibet Plateau are 40% higher than the global average. However, in summer in South Asia and Southeast Asia, and in winter in southern South America, the simulated warming value is lower than the global average.

It should be pointed out that in the future, the temperature changes in different parts of the world will be different, and the impact on the land surface will be faster than that of the ocean, and the sea surface temperature around the North Atlantic and Antarctica will rise less than the global average. Because the regional climate model is not perfect, the current regional climate change scenarios mainly use the prediction results of the global model.

Scientists in China used different global climate models to study the climate change scenarios in China after the increase of carbon dioxide, and the results were slightly different. Using five models in the Third Assessment Report of the Intergovernmental Panel on Climate Change, it is shown that if carbon dioxide increases at the rate of 1% per year, it is predicted that the annual average temperature in East Asia and China will increase by about 5.0℃ by 21961-kloc-0/990. Assuming that carbon dioxide and aerosols increase at the same rate of 1% every year, it is predicted that the annual average temperature in East Asia and China will increase by about 3.9℃ in 196 l- 1990.

Author: 222.38.88. * 2005-6-2 1 20: 16 replied to this statement.

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5 the impact of climate change on the ecological environment and human health and adaptation countermeasures

2. Precipitation changes. The third assessment report of the Intergovernmental Panel on Climate Change pointed out that after global warming, the global average precipitation tends to increase in 2 1 century, the average precipitation in most tropical areas will increase, the average precipitation in most subtropical areas will decrease and the precipitation in high latitudes will also increase. In terms of seasons, the precipitation in tropical Africa will increase in the northern hemisphere in winter, but it will not change much in Southeast Asia, and it will decrease in Central America. In summer in the northern hemisphere, there is little change in precipitation in South Asia. Summer precipitation in the Mediterranean and winter precipitation in Australia will decrease. In high latitudes, precipitation tends to increase in winter and summer. After climate warming, heavy rainfall events will increase. Because the increase of precipitation is not enough to balance the rise of temperature and possible evaporation, the central part of the continent will generally dry up in summer. In addition, the interannual variation of summer monsoon precipitation in the northern hemisphere may increase after climate warming.

It is predicted that the average precipitation will increase in most areas, and the precipitation may change greatly from year to year. Small changes in precipitation will cause great changes in water resources. This means that the possibility of drought increases, and more frequent droughts and floods may occur in some places. Summer precipitation in Central America and southern Europe is expected to decrease by 65,438+00% ~ 20%, which may be due to the constant number of precipitation days and the decrease of each precipitation, and more likely to be due to the significant reduction of the number of rainy days and the significant extension of the no-rain period. The model study on the influence of climate warming on precipitation in Australia shows that the total precipitation has not changed much, but the number of light rain days has decreased, the number of heavy rain days has doubled, and the probability of flooding has at least doubled.