Related topics: climate change , nasa , greenhouse gas
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 carbon dioxide
Better-than-new LIDAR provides 24/7 atmospheric aerosol data
Space & Earth / Earth Sciences
11 hours ago |
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(PhysOrg.com) -- A team of researchers from eight institutions led by Pacific Northwest National Laboratory has solved a software and hardware problem that had perplexed scientists studying atmospheric aerosols ...
Don't Blame Cows for Climate Change
12 hours ago |
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(PhysOrg.com) -- Despite oft-repeated claims by sources ranging from the United Nations to music star Paul McCartney, it is simply not true that consuming less meat and dairy products will help stop climate ...
EPA says greenhouse gases endanger human health
Dec 07, 2009 |
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(AP) -- The Environmental Protection Agency took a major step Monday toward regulating greenhouses gases, concluding that climate changing pollution threatens the public health and the environment.
Study: Earth more sensitive to carbon dioxide than previously thought
Space & Earth / Earth Sciences
Dec 06, 2009 |
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In the long term, the Earth's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study published in Nature Geoscience this week.
Greenhouse gas carbon dioxide ramps up aspen growth
Dec 04, 2009 |
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The rising level of atmospheric carbon dioxide may be fueling more than climate change. It could also be making some trees grow like crazy.
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 ...
Blood Enzyme Could Help Realize Clean Coal
Dec 03, 2009 |
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(PhysOrg.com) -- An enzyme in our blood that enables our lungs to exhale carbon dioxide could be the key to isolating carbon dioxide emissions from coal plants in order to store them safely underground. A ...
CO2 levels rising in troposphere over rural areas
Space & Earth / Earth Sciences
Dec 03, 2009 |
2.7 / 5 (3) |
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Spanish researchers have measured CO2 levels for the past three years in the troposphere (lower atmosphere) over a sparsely inhabited rural area near Valladolid. The results, which are the first of their kind ...
A greener way to get electricity from natural gas
Dec 03, 2009 |
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(PhysOrg.com) -- A new type of natural-gas electric power plant proposed by MIT researchers could provide electricity with zero carbon dioxide emissions to the atmosphere, at costs comparable to or less than ...
Acid test: Study reveals both losers and winners of CO2-induced ocean acidification
Space & Earth / Earth Sciences
Dec 01, 2009 |
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(PhysOrg.com) -- As the world’s seawater becomes more acidic due to rising atmospheric carbon dioxide, some shelled marine creatures may actually become bigger and stronger, according to a new study.
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 ...
Australian scientists aim to reduce sheep burps
Nov 29, 2009 |
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Australian scientists are working to breed a sheep that belches less, as they look for ways to reduce harmful methane emissions from the country's woolly flocks, a researcher said Sunday.
New climate targets may not change daily life much
Nov 27, 2009 |
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(AP) -- Americans' day-to-day lives won't change noticeably if President Barack Obama achieves his newly announced goal of slashing carbon dioxide pollution by one-sixth in the next decade, experts say.
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.
Study sheds light on brain's fear processing center
Nov 25, 2009 |
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Breathing carbon dioxide can trigger panic attacks, but the biological reason for this effect has not been understood. A new study by University of Iowa researchers shows that carbon dioxide increases brain acidity, which ...
