Traditional Culture Encyclopedia - Weather forecast - How harmful is carbon dioxide and why does it have such a huge impact on the global climate?
How harmful is carbon dioxide and why does it have such a huge impact on the global climate?
Climate is different from weather, weather forecast can be accurate to the minute level, and climate research is based on years. According to the regulations of the World Meteorological Organization, every 30 years is a standard climate measurement cycle. Simply put, climatology studies the average weather conditions around the world for many years.
Climate elements such as temperature and precipitation, as well as various statistical data such as mean value and extreme value, are the basic basis for expressing climate. For example, the 24 solar terms table is a summary of the climate made by the ancients in China on the basis of long-term experience. There are many factors that affect the earth's climate, including: solar activity, surface vegetation, atmospheric circulation, ocean currents, land and sea distribution, topography, earth movement and so on. Now there are human activities again. Because with the global expansion and industrialization of human beings, human beings have the ability to influence the earth's climate.
Solar activity is a key factor affecting climate. For example, at a certain time, when the sun is active, the climate on the earth will fluctuate greatly.
However, in a very short period of time, such as 100, the influence of human beings on the local climate of the earth has exceeded other factors above. At present, the ability of human civilization has been able to influence the distribution of vegetation on the earth's surface and turn oases into deserts. In large-scale densely populated cities, due to the accumulation of heat generated by human activities, the temperature in urban areas is several degrees higher than that in suburbs, which is the so-called heat island effect.
Schematic diagram of heat island effect
Human activities will not only produce heat island effect in some areas, but also increase the average temperature of the earth, and the main reason for the increase of the average temperature of the earth is the emission of a large number of greenhouse gases. Global warming is caused by human factors, which is not a scam or a lie. This is the conclusion reached by scientists in many countries after long-term research. Since the end of last century, the United Nations and other international organizations have expressed concern about global warming and taken concrete actions, such as reaching the Kyoto Protocol and other agreements.
What are greenhouse gases? Greenhouse gases have the function of heat preservation. Greenhouse gases have high penetrability to visible light (shorter wavelength) in sunlight and high absorbability to infrared light (longer wavelength) reflected from the ground. They can absorb a lot of infrared radiation from the sun and release it into the atmosphere, and they can also intercept the radiation reflected from the earth's surface back into space.
When sunlight hits the earth's surface, it will warm the surface, and the earth's surface will also radiate a lot of sunlight into outer space. Greenhouse gases in the atmosphere can intercept the radiation on the earth's surface, prevent the earth from dissipating heat and warm the earth's surface, just like covering the earth with a quilt. The effect that this greenhouse gas causes the earth's surface temperature to rise is called the greenhouse effect. Fourier, a French scientist and mathematician, was the first person in the world to discuss related issues.
At present, the main greenhouse gases in the earth's atmosphere are water vapor (H2O), carbon dioxide (CO2) and methane (CH4). The ability of different greenhouse gases to absorb infrared rays is related to their molecular structures.
The Kyoto Protocol to the United Nations Framework Convention on Climate Change stipulates that six greenhouse gases should be controlled, namely carbon dioxide, methane, nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). Among them, the latter three gases have the strongest greenhouse effect, but due to the high content of carbon dioxide in the air, they contribute nearly half to global warming.
Carbon dioxide is the main greenhouse gas. The earth's atmosphere is a mixture, which is mainly composed of 78% nitrogen, 2 1% oxygen, 0.94% rare gas and 0.03%~0.04% carbon dioxide, and the remaining 0.03% is atmospheric suspended particles such as water vapor, ozone and methane. It can be found that the carbon dioxide content in the earth's atmosphere is actually very small, even less than 0. 1%. However, this small increase in carbon dioxide is enough to raise the global average temperature.
Paleoclimatologists found that the carbon dioxide content in the atmosphere before the industrial revolution was about 0.0275%. According to scientists' statistics, in the 1950s, the carbon dioxide content in the earth's atmosphere reached 0.03 15%, but it increased to 0.0325% in the 1970s, and the growth rate of carbon dioxide concentration was still accelerating.
There are two main reasons for the increase of carbon dioxide concentration in the atmosphere. First, the extensive use of fossil fuels since the industrial revolution. /kloc-Since the middle of the 0/9th century, with the extensive use of fossil fuels, carbon dioxide emissions have increased year by year, with an estimated average annual growth rate of around 4%. The carbon dioxide emissions in the past century have exceeded the total carbon dioxide emissions of human beings for thousands of years, which is not only the skyrocketing global population, but also the growth of individual carbon emission demand several times.
Second, the speed of human destruction of vegetation has greatly increased. The green plants on the earth's surface are a huge oxygen factory, and also have the function of carbon fixation. It is estimated that every square meter of forest can transform 1~2 kg of carbon dioxide. Due to the needs of human habitation and industrial and agricultural production, a large number of forests have been cut down. In 1970s, about 2.4 billion cubic meters of wood were cut down every year, and half of them were burned, which greatly increased the carbon dioxide content in the air. The reduction of plants will prevent the timely transformation of carbon dioxide in the atmosphere.
Research shows that the average temperature of the earth's surface has been rising since the industrial revolution, especially in the last half century, the increase of the average temperature of the earth's surface is almost synchronous with the increase of carbon dioxide concentration in the atmosphere.
The above picture shows the trend changes of the earth's surface temperature and carbon dioxide concentration.
Harm of greenhouse effect
It can be seen that if no action is taken, human carbon dioxide emissions will break the balance of carbon cycle in nature sooner or later.
According to the current growth level of carbon dioxide concentration, by 2050, the high concentration of carbon dioxide in the atmosphere will raise the average temperature of the earth's surface by several degrees. Some people may think this is nothing. Isn't the average temperature a few degrees higher? No big deal. You know, the increase of average temperature will cause extreme temperature to fluctuate greatly at a certain moment. For example, although the global average temperature has increased by 1℃, it will be several degrees hotter in summer than in the past.
The above picture shows the global average temperature change in recent 100 years.
The sharp change of temperature will increase the frequency of global extreme climate. In addition to the redistribution of global precipitation, global warming will also melt the ice sheets in mountains and polar regions and raise the sea level. Many places with low sea level will become Zeguo, and the map of the world will change accordingly. In addition, high concentration of carbon dioxide may increase the content of carbon dioxide in seawater, increase the acidity of seawater and endanger the survival of marine life. However, considering the melting of glaciers, the specific situation remains to be considered. In addition, the sharp rise of global temperature will accelerate the extinction of species on the earth. The harm caused by global warming is not limited to these, so I won't go into details.
As the picture shows, due to global warming, the ice sheet in the Arctic Circle began to melt, and polar bears lost their homes. In the future, we may only see polar bears in the zoo.
Since 1970s, American scientists have used satellites to study the sea ice coverage in the Arctic Ocean. At that time, the sea ice coverage of the Arctic Ocean was above 50%, while in 2007, the sea ice coverage was only 29%, and the lowest value in 20 12 reached 24%. Maybe it won't be long before, when summer comes in the northern hemisphere, there will be no ice on the Arctic Ocean at all.
The above picture is a satellite photo of the Arctic Circle.
Venus is the best example.
If human beings take action as soon as possible now to curb the increasing trend of carbon dioxide content in the atmosphere, the above scenario may not appear. But we can feel the terrible greenhouse effect from other planets.
Venus is a planet between Mercury and the Earth, with an average surface temperature of 475℃. Mercury, which is close to the sun, has a maximum surface temperature of 427 degrees Celsius during the day. Why is the surface temperature of planets far from the sun higher than that of planets near the sun? Carl sagan, an American scientist, was the first to explain the high temperature on the surface of Venus, which he believed was caused by the greenhouse effect produced by Venus' atmosphere.
Through the data sent back by Venus probe, we found that the atmosphere on Venus is mainly composed of carbon dioxide and contains a small amount of nitrogen. Venus is about the size of the earth, but the atmospheric density on its surface is higher than that of the earth, and the atmospheric pressure on its surface is about 92 times that of the earth. It is precisely because of the existence of a large amount of carbon dioxide that the greenhouse effect on the surface of Venus is extremely terrible. Without carbon dioxide, the average temperature on the surface of Venus would drop by more than 300 degrees.
If the carbon dioxide content in the earth's atmosphere continues to rise, the average temperature of the earth's surface will inevitably continue to rise. Although it is not as horrible as Venus, it will be a serious threat to human beings and life on earth.
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To sum up, although the content of carbon dioxide in the earth's atmosphere is less than 0. 1%, it is an important greenhouse gas and will have a great impact on the earth's climate. It has become a scientific knowledge that the rise of carbon dioxide concentration is the main cause of global warming.
Because of this, all countries in the world vigorously advocate low-carbon life and reduce carbon emissions. Facing the dilemma of economic development and reducing carbon emissions, it is still necessary to rely on technological changes to break the deadlock, and new energy is undoubtedly the focus of development.
In order to cope with global warming and cool the earth, scientists have given all kinds of fantastic ideas. There are only two ways, one is to reduce the carbon dioxide content in the atmosphere, and the other is to directly reduce the heat energy radiated by the sun to the earth's surface by physical methods. Obviously, the first method is more practical. Planting trees, improving vegetation coverage and reducing carbon dioxide emissions in production and life are exactly what responsible big countries are doing.
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