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 experts debate strategies for reducing atmospheric carbon and future warming
7 hours ago |
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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.
Scientists Find Ozone Levels Already Affecting Soybean Yields
Nov 17, 2009 |
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(PhysOrg.com) -- Current atmospheric ozone levels are already suppressing soybean yields, according to Agricultural Research Service (ARS) scientists and university cooperators studying the effect of global ...
Controversial new climate change results
Nov 10, 2009 |
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(PhysOrg.com) -- New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion ...
Australian scientists call for urgent 'global cooling' to save coral reefs
Nov 09, 2009 |
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(PhysOrg.com) -- Australian marine scientists have issued an urgent call for massive and rapid worldwide cuts in carbon emissions, deep enough to prevent atmospheric CO2 levels rising to 450 parts per million (ppm).
Japanese automakers rev up efforts in hydrogen cars
Oct 25, 2009 |
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Imagine a car that can be refuelled in minutes but emits only water. Sounds like science fiction? In fact it already exists -- Hollywood star Jamie Lee Curtis has one. So does Honda president Takanobu Ito.
Key new ingredient in climate model refines global predictions
Space & Earth / Earth Sciences
Oct 09, 2009 |
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For the first time, climate scientists from across the country have successfully incorporated the nitrogen cycle into global simulations for climate change, questioning previous assumptions regarding carbon feedback and potentially ...
Nitrogen deposition limits climate change impacts on carbon sequestration
Oct 07, 2009 |
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Forests are important in reducing the green house gas CO2. For the period 2000-2007, it has been estimated that from the 8.9 billion ton of carbon released by man, approximately 46% is found back in the atmosphere. ...
Europe bids to tax personal fuel consumption
Oct 02, 2009 |
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A Europe-wide tax on personal or household fuel consumption was proposed on Friday as EU finance ministers met to discuss who should pay what in the fight against global warming.
France aims for two million electric cars by 2020: minister
Oct 01, 2009 |
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France plans to invest 1.5 billion euros (2.2 billion dollars) on infrastructure for the two million electric and hybrid cars it wants on its roads by 2020, the ecology minister said Thursday.
