The greenhouse effect

Carbon dioxide is also a by-product of the fermentation of sugar  

Carbohydrates and other complex carbon-containing molecules are consumed by animals, which respiie and release CO2 as an end product of metabolism  

As mentioned earlier, another major source of COt is volcanic activity. Carbon dioxide is removed from the atmosphere by photosynthetic plants and certain microorganisms  

After plants and animals die, the carbon in their tissues is oxidized to CO2 and returns to the atmosphere. In addition, there is a dynamic equilibrium between atmospheric CO7 and carbonates in the oceans and lakes. 

Upon receiving a photon in the IR region, a molecule of H2O or CO2 is promoted to a higher vibrational energy level  

Human activities have changed the concentration of a number of greenhouse gases. Unlike water, these gases exist in trace amounts and the relative human impact on their concentrations is significant. The primary greenhouse gases include carbon dioxide, methane (CH ), CFCs, and nitrous 

The greenhouse effect continues to be a controversial topic as the twenty-first cen- 

Country Rank 1998 Carbon Emissions (Thousand of metric tons) 

Earth s atmosphere functions in a manner analogous to a greenhouse s glass roof. A significant amount of the outgoing infrared radiation is absorbed by gases in Earth s atmosphere. From there, the radiation serves to either heat the atmosphere or is radiated back to Earth s surface, keeping Earth as a whole 33 C warmer than it would be without an atmosphere. 

Although carbon dioxide is only a trace gas in Earth s atmosphere, with a concentration of about 0.033 percent by volume (see Table 17.1), it plays a critical role in controlling our climate. The so-called effect describes the trapping of heat 

A dramatic illustration of the greenhouse effect is found on Venus, where the atmosphere is 97 percent CO2 and the atmospheric pressure is 9 X 10 Pa (equivalent to 89 atm). The surface temperature of Venus is about 730 K  

This reaction requires radiant energy (visibie iight). 

The great majority of the anthropogenic emissions from C02 are related to energy production. The current concentration of this gas is approximately 370 ppm as opposed to approximately 280 ppm at the beginning of the 19 th century. Because an increase in C02 concentration increases the greenhouse effect, some estimates indicate that by doubling the concentration of this gas, the Earth s surface temperature could increase 3.5°C. 

If the earth reradiated back to the atmosphere just as much energy as it obtained from the sun, its surface temperature would be 255 K (-18°C). This value can be calculated with Planck s radiation law. The fact that the average temperature is not -18°C but perhaps -i-15°C is due to the greenhouse ejfect. It seems to be a beneficial effect for human beings  

The atmosphere of the earth transmits the sun s radiation, which warms up the earth. The heat radiation, in the infrared, that is reflected by the earth s surface is partly absorbed by the atmosphere. The so-called greenhouse gases absorb radiation in the wavelength ranges 5-8 pm (water vapor) and 13-20 pm (carbon dioxide). These 

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Figure 10.1 Products of combustion contribute in vanous ways to the greenhouse effect, acid rain, and smog. (From Smith and Petela, Chem. Eng., 523 32, 1992 reproduced by permission of the Institution of Chemical Engineers.)...

Dealing with CO2 emissions. If CO2 emissions are of concern because of the greenhouse effect, then there are only two ways in which reductions can be made ... 

S. C. Uimasch, B. Moyer, D. D. LoweU, and M. D. Jackson, Comparing the Impacts of Different Transportation Fuels on the Greenhouse Effect, Pub. 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

Although there has been a warming trend over the past 100 years, it is not necessarily due to the greenhouse effect. The concern of the scientific community about accelerating changes in the next 40 to 50 years is based not only on the recent observations of temperature compared with past observations, but also on the physical principles related to the greenhouse effect. 

The Royal Society (London), The Greenhouse Effect the scientific basis for policy. Submission to the House of Lords Select Committee, 40 pp. (1989). See also Global Climate Change, Information Pamphlet (12 pp.) i.ssued by the American Chemical Society (1990) B. Hileman, Global Warming, Chem. Eng. News, April 27, 7-19 (1992) and references cited therein. 

Considerable energy is radiated back from Earth s surface into space as long-wave infrared radiation. The atmosphere absorbs some of this infrared radiation, preventing its loss to space. This trapping is sometimes referred to as the Greenhouse Effect. ... 

Coping with the greenhouse effect is a vei-y difficult sociopolitical problem. A greenhouse effect existed on Earth long before the Industrial Revolution. Had it not. Earth s surface would be much colder than it is now. The introduction of gases absorbing infrared radiation only enhances the greenhouse effect. Carbon dioxide is not the only gas of importance water vapor and methane, for exam-... 

Ozone forms a layer around the Earth that insulates against thermal radiation. This layer is being destroyed by pollutants (principally fluorocarbons). The effect of the depletion of the ozone layer is to warm the Earth (and hence exacerbate the greenhouse effect) and may also lead to an increase in the incidence of skin cancers. 

Among other contributions of Arrhenius, the most important were probably in chemical kinetics (Chapter 11). In 1889 he derived the relation for the temperature dependence of reaction rate. In quite a different area in 1896 Arrhenius published an article, "On the Influence of Carbon Dioxide in the Air on the Temperature of the Ground." He presented the basic idea of the greenhouse effect, discussed in Chapter 17. 

Alternative fuels, p. 246 Acid rain and the gene pool, p. 430 The ozone layer, p. 568 The greenhouse effect, p. 610 Nuclear power, p. 722 Fossil fuels, p. 745... 

The greenhouse effect is a natural phenomenon whereby the earth s atmosphere is more transparent to solar radiation than terrestrial infixed radiation (emitted by the earth s surface and atmosphere). Consequently, the planet s mean surface temperature is about 33 K higher than the planet s radiative equilibrium temperature (the temperature at which the earth comes into equilibrium with the energy received from the sun). 

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