Carbon dioxide
hideCarbon dioxide (chemical formula: CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.
Carbon dioxide is used by plants during photosynthesis to make sugars, which may either be consumed in respiration or used as the raw material to produce other organic compounds needed for plant growth and development. It is produced during respiration by plants, and by all animals, fungi and microorganisms that depend either directly or indirectly on plants for food. It is thus a major component of the carbon cycle. Carbon dioxide is generated as a by-product of the combustion of fossil fuels or the burning of vegetable matter, among other chemical processes. Large amounts of carbon dioxide are emitted from volcanoes and other geothermal processes such as hot springs and geysers and by the dissolution of carbonates in crustal rocks.
As of March 2009[update], carbon dioxide in the Earth's atmosphere is at a concentration of 387 ppm by volume. Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Concentrations of carbon dioxide fall during the northern spring and summer as plants consume the gas, and rise during the northern autumn and winter as plants go dormant, die and decay. Carbon dioxide is a greenhouse gas as it transmits visible light but absorbs strongly in the infrared and near-infrared.
Carbon dioxide has no liquid state at pressures below 5.1 atmospheres. At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.
CO2 is an acidic oxide: an aqueous solution turns litmus from blue to pink. It is the anhydride of carbonic acid, an acid which is unstable and is known to exist only in aqueous solution.
CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy. Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.
For more information about Carbon dioxide, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with co2
Climate scientists underwhelmed by Copenhagen Accord
Dec 20, 2009 |
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Top climate scientists said Saturday that the eleventh-hour political deal hammered out at UN talks in Copenhagen falls perilously short of what is needed to stave off catastrophic global warming.
Koalas, penguins at risk of extinction: study
Dec 14, 2009 |
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Climate change threatens the survival of dozens of animal species from the emperor penguin to Australian koalas, according to a report released Monday at the UN climate summit.
New science estimates carbon storage potential of US lands
Dec 10, 2009 |
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The first phase of a groundbreaking national assessment estimates that U.S. forests and soils could remove additional quantities of carbon dioxide (CO2) from the atmosphere as a means to mitigate climate change.
Long-Term Effects of Carbon Dioxide on Plants Studied
Dec 09, 2009 |
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(PhysOrg.com) -- Long-term, open-top chamber studies of how rising carbon dioxide (CO2) could affect crops, forests, and pastures reveal a wide range of impacts, according to Agricultural Research Service ...
Elevated CO2 levels may mitigate losses of biodiversity from nitrogen pollution
Dec 03, 2009 |
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Rising levels of carbon dioxide may overheat the planet and cause other environmental problems, but fears that rising CO2 levels could directly reduce plant biodiversity can be allayed, according to a new study by a University ...
New method of measuring ocean CO2 uptake could lead to climate change 'early warning system'
Space & Earth / Earth Sciences
Dec 03, 2009 |
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An international team of scientists led by the University of East Anglia (UEA) has developed a new method of measuring the absorption of CO2 by the oceans and mapped for the first time CO2 uptake for the entire North Atlantic.
Peat fires drive temperatures up
Nov 30, 2009 |
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Peatlands, especially those in tropical regions, sequester gigantic amounts of organic carbon. Human activities are now having a considerable impact on these wetlands. For example, drainage projects, in combination with the ...
Burning coal worse for climate than clearing rain forests
Nov 26, 2009 |
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Deforestation has had a big influence on the increase of carbon dioxide (CO2) emissions in the past three centuries, but its impact is tapering off relatively. Nowadays, the burning of fossil fuels is a more crucial factor. ...
Climate experts debate strategies for reducing atmospheric carbon and future warming
Nov 25, 2009 |
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(PhysOrg.com) -- Reducing carbon dioxide to safe levels may require extracting carbon from the air, says Cornell climate researcher.
CO2 emissions continue significant climb
Nov 24, 2009 |
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The annual rate of increase in carbon dioxide emissions from fossil fuels has more than tripled in this decade, compared to the 1990s, reports an international consortium of scientists, who paint a bleak picture of the Earth's ...
Oceans absorbing carbon dioxide more slowly, scientist finds
Space & Earth / Earth Sciences
Nov 24, 2009 |
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The world's oceans are absorbing less carbon dioxide (CO2), a Yale geophysicist has found after pooling data taken over the past 50 years. With the oceans currently absorbing over 40 percent of the CO2 emitted by human activity, ...
Mankind using Earth's resources at alarming rate
Nov 24, 2009 |
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Humanity would need five Earths to produce the resources needed if everyone lived as profligately as Americans, according to a report issued Tuesday.
KLM flies world's first 'passenger flight on biofuel'
Nov 23, 2009 |
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A Boeing 747, one of four engines powered by a 50-percent biokerosene mix, circled the Netherlands for an hour on Monday for what airline KLM called the world's first passenger flight using biofuel.
Antarctic ice loss vaster, faster than thought: study
Space & Earth / Earth Sciences
Nov 22, 2009 |
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The East Antarctic icesheet, once seen as largely unaffected by global warming, has lost billions of tonnes of ice since 2006 and could boost sea levels in the future, according to a new study.
Dutch approve project to store CO2 underground
Nov 18, 2009 |
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The Dutch government said Wednesday it had approved the experimental below-ground storage of excess CO2 to curb damaging emissions, dismissing concerns of residents who live on top of the project.
