Atmospheric Concentration of Carbon

Problems may arise when the atmospheric concentration of greenhouse gases increases. Since the beginning of the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%. These increases have enhanced the heat-trapping capability of the earth s atmosphere. 

The strong increase in atmospheric concentrations of carbon dioxide [ 127] has generated considerable interest in the global carbon cycle [ 128-130]. Techniques for determining the components of the carbonate system have been refined, new techniques have been developed, or both. Among the four measurable parameters (total inorganic carbon), pH, pC02, and total alkalinity... 

Atmospheric concentrations of carbon dioxide have varied naturally throughout Earth s history. Present C02 concentrations, however, are now higher than any seen in at least the past 450,000 years. Recent direct measurements combined with sampling of air trapped in polar ice cores shows that the recent rise in CO, correlates well with industrialization, which began in the early 1800s, as revealed in the following graph ... 

The combustion of fossil fuels produces carbon dioxide gas, a heattrapping gas. For the past 250 years (since the beginning of the Industrial Revolution), the increased use of fossil fuels has caused the atmospheric concentration of carbon dioxide to increase by a factor of about 2 5 percent. It is now generally believed that this increase has produced higher global temperatures—a phenomenon called the greenhouse effect. 

Another significant fact is that the last 10 years of the twentieth century appear to be the warmest decade on record. Although the exact relationship between the carbon dioxide concentration in the atmosphere and the earth s temperature is not known at present, one thing is clear The increase in the atmospheric concentration of carbon dioxide is quite dramatic. We must consider the implications of this increase as we consider our future energy needs. 

Brewer P. G., Past arid future atmospheric concentration of carbon dioxide. In Changing Climate . Report of the Carbon Dioxide Assessment Committee. National Research Council, National Academy Press, Washington, D.C., pp. 186-215 (1983). 

Maroulis PJ, Bandy AR. 1980. Measurements of atmospheric concentrations of carbon disulfide in the eastern United States. Geophysical Research Letters 7 681-684. 

Between 1960 and 1985, the atmosphere concentration of carbon dioxide increase from 315 ppm to 345 ppm. Measurements of carbon dioxide in bubbles of air trapped in the Antarctic ice have shown that for 10 000 years the concentration remained constant at 270 ppm and only started rising 100 years ago. Actually the rate of increase of the concentration is 1.5 ppm per year [1]. 

Interactions that can be described as a theoretical concept of a feedback mechanism in which the interacting elements are the areal extent of polar ice and snow cover, the albedo of the polar region (dependent on areal extent of ice and snow), absorption of solar radiation (dependent on the albedo), temperature (dependent on the absorption of solar radiation) and the area of ice and snow cover (dependent on temperature). Less snowfall would mean more absorption of solar radiation, therefore a surface warming would occur. Climate modeling studies indicate an amplification effect (i.e., positive feedback) of the ice and snow-albedo feedback on increased surface air temperatures caused by increases in the atmospheric concentration of carbon dioxide, ice cover... 

Precipitation incident to a plant canopy can be relatively well characterized chemically. Table I shows the composition of "unpolluted rain, based on analytical data for each of the constituents in precipitation and assuming equilibrium with atmospheric concentrations of carbon dioxide.In this system, the solution pH would be expected to be approximately pH 5.65. 

The procedure does have some limitations. It is necessary to know how the atmospheric concentration of carbon-14 has changed over thousands of years. Even with this information in hand, practical considerations dictate that the procedure may only he used to determine the age of objects in a range of about 100 years. The radiocarbon level of an object less than 100 years old will not have declined significantly enough from that of the living organism to allow an accurate determination of age. Likewise, objects older than 40,000 years (more than 7 half-lives) will have so little radioactive carbon remaining that an accurate determination will not be possible. 

Because large-scale atmospheric nuclear weapons testing stopped in 1963, a dynamic but stable condition has prevailed in the atmospheric concentrations of carbon-14, at least since 1964. In addition, carbon-14 concentrations and their variations in the atmosphere of the United States, Western Europe, and certain other locations have been reasonably well... 

In summary, the world is in the midst of a period of unprecedented and dismptive change. This is particularly evident when examining the health of the world s ecological systems. A host of human forces impinge upon coral reefs, tropical rain forests and other critical natural systems located around the world. Half the planet s wetlands are gone. Total carbon emissions and atmospheric concentrations of carbon dioxide are both accelerating and 2004 was the fourth warmest year ever recorded. Over the course of the last 120 years, the ten warmest years have all occurred since 1990. 

It can be very easily seen that the industrial revolution, which began about 150 years ago, has added significant quantities of GHGs (Green House gases) to the atmosphere. The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have grown by about 31%, 151% and 17%, respectively, between 1750 and 2000 (IPCC 2001). 

As shown in Figure 8.2, the atmospheric concentration of carbon dioxide has been increasing. During the past several decades, the increase has been around 1 ppm/year and now may be approaching 2 ppm/year. This increase has been so significant that climatologists have used it as a... 

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