Carbon Dioxide

  • William W. Hay


The ultimate source of CO2 is thought to be volcanic emissions. However, most CO2 is continuously recycled as part of the carbon cycle. CO2 is taken up by plants, and through photosynthesis is fixed as organic matter. The organic matter is then used by plant or animals to obtain energy, releasing the CO2 back into the atmosphere. CO2 is a greenhouse gas, intercepting and re-emitting the radiation from Earth back into space. It is thought that CO2 has been the Earth’s major thermostat mechanism through time. Higher levels result in a greenhouse condition, lower levels an icehouse state. CO2 is ultimately removed from the system by the weathering of silicate minerals, an exceedingly slow process. Because CO2 reacts with water to form carbonate and bicarbonate ions it is thousands of times more soluble than oxygen. Although the changes in the icehouse state from glacial to interglacial are forced by variations in Earth’s orbit, atmospheric CO2 levels follow, acting as a positive feedback. Since the Industrial Era, there has been an almost exponential increase in the amount of CO2 in the atmosphere, almost all from the burning of fossil fuels. Today’s atmospheric concentrations are as much higher than pre-industrial levels as those were above the levels of the Last Glacial Maximum. CO2 is the major greenhouse gas in the polar regions, concentrating global warming in the high latitudes.


Ocean Floor Planktonic Foraminifera Calcareous Nannofossil Lomonosov Ridge Calcareous Nannoplankton 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.University of Colorado at BoulderEstes ParkUSA

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