Carbon dioxide deforestation

Fig. 11 -25 Release of carbon from the biota and soils globally according to various estimates. The fossil fuel flux is from data of Rotty. (Modified with permission from G. M. Woodwell et al. (1983). Global deforestation Contribution to atmospheric carbon dioxide. Science 222,1081-1086, AAAS.)...

What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions (5). For example, in 1997, the United States emitted about one-fifth of total global greenhouse gases. 

The clearing of forests in the United States early in the century, combined with a large increase in postwar tropical deforestation, where much of the wood was burned, released carbon dioxide to the air and changed the atmospheric components. 

With less than 5 percent of the worlds population, the United States ranks first in carbon dioxide emissions and is responsible for about 25 percent of global carbon dioxide emissions. Industrial nations worldwide are responsible for about 58 percent of carbon dioxide emissions, primarily from the combustion of fossil fuels. Developing nations account for the remaining 42 percent, but their sources of carbon dioxide are split between fossil fuels (19 percent) and deforestation (23 percent). 

Detoxification methods, pesticide content of fish, environmental analytical and monitoring techniques. (4 Utilization of biomass, drinking water quality, organic contaminants in lakes and rivers, and effect of deforestation on carbon dioxide and oxygen content of air. 

The carbon cycle has continued in this manner for millions of years. However, scientists have detected an imbalance in the carbon cycle due to the increase in the amount of carbon dioxide produced through burning fossil fuels and the deforestation of large areas of tropical rain forest. The Earth s climate is affected by the levels of carbon dioxide (and water vapour) in the atmosphere. If the amount of carbon dioxide, in particular, builds up in the air, it is thought that the average temperature of the Earth will rise. This effect is known as the greenhouse effect (Figure 13.14). 

The total quantity of carbon on Earth is about 41,000 billion metric tons (92% in the oceans, 6% on land, and 2% in the atmosphere). Prior to the Industrial Age, the concentration of C02 in the atmosphere was stable and balanced. Two hundred and ten billion tons of carbon dioxide entered the atmosphere and approximately the same amount was taken from the atmosphere by the photosynthesis of plants. That balance has been upset by fuel combustion, deforestation, and changing land use as the population increased. 

Miranda, A. C., H. S. Miranda, J. Lloyd, J. Grace, J. A. McIntyre, P. Meir, P. Riggan, R, Lockwood, and J. Brass. 1996a. Carbon dioxide fluxes over a cerrado sensu stricto in central Brazil. Pages 353-363. in J. H. C. Gash, C. A. Nobre, J. M. Roberts, and R. L. Victoria, editors. Amazonian deforestation and climate. Institute of Hydrology, London. 

Another approach is to increase carbon dioxide uptake by forests to reverse the effects of severe deforestation of the last 150 years. It has been estimated that a rapidly growing rainforest can remove 4-7kg/m year of carbon dioxide from the atmosphere, as compared to a typical crop uptake of 0.8-1.6kg/m year. Thus, vigorous reforestation could assist in increasing the photosynthetic removal of carbon dioxide from the atmosphere [59]. Annual crops also perform photosynthetic uptake of carbon dioxide, but consumption and metabolism of the product(s) and prompt decomposition of the plant wastes promptly return the fixed carbon dioxide to the atmosphere [60]. 

Carbon dioxide (CO2) 50 0.5 Combustion of fossil fuels, deforestation... 

The definite amount of greenhouse gases in the atmosphere has yet to be calculated. It depends on population, the per capita consumption of fossil fuel, deforestation, forestation activities and countermeasures that balance the extra carbon dioxide in the air. This could include planting more trees. Another factor is the use of alternative energy and conservation. Trades in fuel carbon will also have an effect. Transfers may occur from coal-rich to coal-poor nations. 

Growing fossil fuel use in the 20th century changed the carbon history of the earth. But deforestation also had an impact on carbon in the atmosphere. Forests serve as carbon sinks, producing oxygen while using carbon dioxide. 

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