Carbon dioxide in Earth

FIGURE 4-43 Increase in the mixing ratio of carbon dioxide in Earth s atmosphere as measured since March 1958 at the Mauna Loa Observatory (data from Keeling and Whorf, 1998). 

The concentration of carbon dioxide in Earth s atmosphere is regulated through a complex interplay of human, biological, and geological mechanisms. In a space vehicle, these mechanisms aren t available. If not controlled, carbon dioxide from the respiration of astronauts could become toxic to them. So how is air quality maintained within a space vehicle ... 

In combination, carbon is found as carbon dioxide in the atmosphere of the earth and dissolved in all natural waters. It is a component of great rock masses in the form of carbonates of calcium (limestone), magnesium, and iron. Coal, petroleum, and natural gas are chiefly hydrocarbons. 

About 51 percent of solar energy incident at the top of the atmosphere reaches Earth s surface. Energetic solar ultraviolet radiation affects the chemistry of the atmosphere, especially the stratosphere where, through a series of photochemical reactions, it is responsible for the creation of ozone (O,). Ozone in the stratosphere absorbs most of the short-wave solar ultraviolet (UV) radiation, and some long-wave infrared radiation. Water vapor and carbon dioxide in the troposphere also absorb infrared radiation. 

The atmosphere of Venus is chiefly carbon dioxide in a concentration much higher than that found on Earth. Surprisingly, no evidence has been found for carbon monoxide, though ultraviolet light decomposes CO2 to form CO. The atmosphere of Mars is thought to be largely nitrogen (around °8%) and some carbon dioxide. 

Concentration of carbon dioxide in the atmosphere, over the past 1000 The average change in surface temperature of the Earth from 185S to... 

The role of carbon dioxide in the Earth s radiation budget merits this interest in atmospheric CO2. There are, however, other changes of importance. The atmospheric methane concentration is increasing, probably as a result of increasing cattle populations, rice production, and biomass burning (Crutzen, 1983). Increasing methane concentrations are important because of the role it plays in stratospheric and... 

C3 plants Plants as, for example, cotton and wheat, in which, during the photosynthesis process, a stable compound consisting of three bonded carbon atoms is first formed during the fixation of carbon derived from carbon dioxide in the plants over 95% of the plant species on the earth are C3 plants see C4 and CAM plants. 

Water vapour makes a sizeable contribution, and probably the largest, to radiation trapping and as the temperature increases the water vapour concentration increases. Temperature rises as a result of increased water vapour concentration and hence a mechanism for a positive feedback in the greenhouse effect that might lead to a runaway greenhouse effect. When the vapour pressure for water reaches saturation, condensation occurs and water rains out of the atmosphere this is what happens on Earth and Mars. On Venus, however, the water vapour pressure never saturates and no precipitation occurs and the global warming continues to increase. Thus Venus suffers from extreme temperatures produced by both its proximity to the Sun and the presence of water vapour and carbon dioxide in its atmosphere. 

When the earth was formed about 4.5 billion years ago, 95% of the atmosphere consisted of carbon dioxide. The emergence of plant life changed the atmosphere since plants, through the process of photosynthesis, absorb carbon dioxide. Carbon from the atmosphere was absorbed into the vegetation and when the vegetable matter died, it decomposed, and formed coal and oil. This dropped the carbon dioxide in the atmosphere to less than 1%. 

The amount of carbon dioxide in the atmosphere then has been estimated to be many times greater than today. This explains how the earth s climate was warm enough for liquid water and the life that evolved from it about 4 billion years ago. As life on earth evolved, the solar output increased and photosynthetic organisms used much of this carbon dioxide. 

The increased use of hydrocarbon fuels in the last five decades is slowly increasing the concentration of carbon dioxide in the atmosphere, which produces more carbonic acid, leading to an imbalance in the natural carbon dioxide content of the atmosphere, which, in turn, leads to more acidity in the rain. In addition, there is a greenhouse effect, and the average temperature of the Earth may be increasing. 

What can lower the pH of an entire ocean An acid, of course.The earth s atmosphere naturally contains a small amount of carbon dioxide. Carbon dioxide in the atmosphere isn t an acid, but when it dissolves in water, it makes a weak acid called carbonic acid. Burning fossil fuels releases more carbon dioxide into the atmosphere to dissolve in water. 

It was there that Ramanathan and Cicerone discovered the potential of chlorofluorcarbons (CFCs) to trap atmospheric heat. Indeed, they demonstrated that some CFCs were 10,000 times as efficient as carbon dioxide in capturing infrared radiation from the Earth s surface. The announcement... 

Farmers use lime (calcium hydroxide) to sweeten" an acid soil, and make heavy, clay-laden soils more workable. Carbon dioxide in the air dissolves in water to form the very weak carbonic acid (hydrogen carbonate). The alkaline lime neutralizes any traces of carbonic acid in the earth, producing calcium carbonate (or chalk) - and some more water. 

Gigaton (Gt) A unit equal to one billion metric tons often used to measure carbon and carbon dioxide in the Earth. 

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