Carbon Dioxide In Earth's Atmosphere
The concentration of carbon dioxide (CO2) in Earth's atmosphere has reached 391 ppm (parts per million) as of October 2012 and rose by 2.0 ppm/yr during 2000–2009. This current concentration is substantially higher than the 280 ppm concentration present in pre-industrial times, with the increase largely attributed to anthropogenic sources. Carbon dioxide is used in photosynthesis (in plants and other photoautotrophs), and is also a prominent greenhouse gas. Despite its relatively small overall concentration in the atmosphere, CO2 is an important component of Earth's atmosphere because it absorbs and emits infrared radiation at wavelengths of 4.26 µm (asymmetric stretching vibrational mode) and 14.99 µm (bending vibrational mode), thereby playing a role in the greenhouse effect. The present level is higher than at any time during the last 800 thousand years, and likely higher than in the past 20 million years.
Read more about Carbon Dioxide In Earth's Atmosphere: Current Concentration, Sources of Carbon Dioxide, Past Variation, Relationship With Oceanic Concentration, Irreversibility and Uniqueness of Carbon Dioxide
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