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
Famous quotes containing the words earth and/or atmosphere:
“The earth is not a mere fragment of dead history, stratum upon stratum like the leaves of a book, to be studied by geologists and antiquaries chiefly, but living poetry like the leaves of a tree, which precede flowers and fruit,—not a fossil earth, but a living earth; compared with whose great central life all animal and vegetable life is merely parasitic.”
—Henry David Thoreau (1817–1862)
“The life of our city is rich in poetic and marvelous subjects. We are enveloped and steeped as though in an atmosphere of the marvelous; but we do not notice it.”
—Charles Baudelaire (1821–1867)