Carbon Cycle

When fossil fuels are burned, their organic carbon is released into the atmosphere. During the past 100 years, fossil fuel consumption has increased dramatically, and this has led to a huge amount of carbon dioxide being released into the atmosphere. In addition, the widespread clearing of forests is resulting in the emission of huge quantities of carbon dioxide into the atmosphere (forests store large amounts of organic carbon in their biomass, most of which is emitted through decomposition and fire when deforestation occurs). The increasing concentrations of atmospheric carbon dioxide are a cause for concern, since they may be responsible for global warming and associated climatic and ecological disruptions. During the middle of the nineteenth century, the atmospheric concentration of carbon dioxide was about 270 ppm, but in 2000 it had increased to 365 ppm.