A carbon dioxide (CO₂) sink is a carbon dioxide reservoir that is increasing in size, and is the opposite of a carbon dioxide "source". The main natural sinks are (1) the oceans and (2) plants and other organisms that use photosynthesis to remove carbon from the atmosphere by incorporating it into biomass and release oxygen into the atmosphere. The process by which carbon dioxide sinks (natural and artificial) remove CO₂ from the atmosphere is known as carbon sequestration. Public awareness of the significance of CO₂ sinks has grown since passage of the Kyoto Protocol, which allows their use as a form of carbon offset. Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Photosynthesis splits water to liberate O2 and fixes CO2 into sugar The leaf is the primary site of photosynthesis in plants. ... For the eco-industrial use of the term, which includes dead material used for biofuels, see biomass An Antarctic krill, whose species comprises roughly 0. ... Sequestration, the act of removing, separating or seizing anything from the possession of its owner, particularly in law, of the taking possession of property under process of law for the benefit of creditors or the state. ... Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ... Until recently, most carbon offsets were commonly done by planting trees. ...

Kyoto Protocol

Because growing vegetation absorbs carbon dioxide, the Kyoto Protocol allows countries that have large areas of forest (or other vegetation) to deduct a certain amount from their emissions, thus making it easier for them to achieve the desired net emission levels. Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ...

Some countries want to be able to trade in emission rights in carbon emission markets, to make it possible for one country to buy the benefit of carbon dioxide sinks in another country. If overall limits on greenhouse gas emission are put into place, such a "cap-and-trade" market mechanism will tend to find cost-effective ways to reduce emissions.^[1] There is as yet no carbon audit regime for all such markets globally, and none is specified in the Kyoto Protocol. Each nation is on its own to verify actual carbon emission reductions (CER), and to account for carbon sequestration using some less formal method. A carbon audit regime is an effective means of accounting for greenhouse gas control efforts. ... Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ...

In the Clean Development Mechanism, only afforestation and reforestation are eligible to produce CERs in the first commitment period of the Kyoto Protocol (2008–2012). Forest conservation activities or activities avoiding deforestation, which would result in emission reduction through the conservation of existing carbon stocks, are not eligible at this time.^[2] Also, agricultural carbon sequestration is not possible yet.^[3] CDM directs here. ... Afforestation is the process of converting open land into a forest by planting trees or their seeds. ... Biodiversity on a 15-year-old reforested plot of land. ... Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ... This article is about the process of deforestation in the environment. ...

Storage in vegetation and soils

Carbon stored in soils oxidizes rapidly; this, in addition to high rainfall levels, is the reason why tropical jungles have very thin organic soils. The forest eco-system may eventually become carbon neutral. Forest fires release absorbed carbon back into the atmosphere, as does deforestation due to rapidly increased oxidation of soil organic matter.

The dead trees, plants, and moss in peat bogs undergo slow anaerobic decomposition below the surface of the bog. This process is slow enough that in many cases the bog grows rapidly and fixes more carbon from the atmosphere than is released. Over time, the peat grows deeper. Peat bogs inter approximately one-quarter of the carbon stored in land plants and soils.^[4] Peat in Lewis, Scotland Peat is an accumulation of partially decayed vegetation matter. ... Two-stage, low-solids, UASB anaerobic digesters as part of a mechanical biological treatment system Anaerobic digestion (AD) is where the naturally occurring processes of anaerobic degradation are harnessed and contained. ... Carbon fixation is a process found in autotrophs, usually driven by photosynthesis, whereby carbon dioxide is changed into organic materials. ...

Under some conditions, forests and peat bogs may become sources of CO₂, such as when a forest is flooded by the construction of a hydroelectric dam. Unless the forests and peat are harvested before flooding, the rotting vegetation is a source of CO₂ and methane comparable in magnitude to the amount of carbon released by a fossil-fuel powered plant of equivalent power.^[5] Methane is a chemical compound with the molecular formula . ...

Oceans

Oceans are natural CO₂ sinks, and represent the largest active carbon sink on Earth. This role as a sink for CO₂ is driven by two processes, the solubility pump and the biological pump.^[6] The former is primarily a function of differential CO₂ solubility in seawater and the thermohaline circulation, while the latter is the sum of a series of biological processes that transport carbon (in organic and inorganic forms) from the surface euphotic zone to the ocean's interior. A small fraction of the organic carbon transported by the biological pump to the seafloor is buried in anoxic conditions under sediments and ultimately forms fossil fuels such as oil and natural gas. In oceanic biogeochemistry, the solubility pump is a physico-chemical process that transports carbon (as dissolved inorganic carbon) from the oceans surface to its interior. ... In oceanic biogeochemistry, the biological pump is the sum of a suite of biologically-mediated processes that transport carbon from the surface euphotic zone to the oceans interior. ... Annual mean sea surface salinity for the World Ocean. ... A simplified summary of the path of the Thermohaline Circulation. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, the halogens as... There is a rich variety of carbon chemistry that does not fall within the realm of organic chemistry and is thus called inorganic carbon chemistry. ... The photic zone is the depth of the water, whether in a lake or an ocean, that is exposed to sufficient sunlight for photosynthesis to occur. ... The seabed (also sea floor, seafloor, or ocean floor) is the bottom of the ocean. ... Anoxic sea water refers to water depleted of oxygen. ... Fossil fuels or mineral fuels are fossil source fuels, that is, hydrocarbons found within the top layer of the earth’s crust. ... Petro redirects here. ... For other uses, see Natural gas (disambiguation). ...

At the present time, approximately one third^[7] of anthropogenic emissions are estimated to be entering the ocean. The solubility pump is the primary mechanism driving this, with the biological pump playing a negligible role. This stems from the limitation of the biological pump by ambient light and nutrients required by the phytoplankton that ultimately drive it. Total inorganic carbon is not believed to limit primary production in the oceans, so its increasing availability in the ocean does not directly affect production (the situation on land is different, since enhanced atmospheric levels of CO₂ essentially "fertilize" land plant growth). However, ocean acidification by invading anthropogenic CO₂ may affect the biological pump by negatively impacting calcifying organisms such as coccolithophores, foraminiferans and pteropods. Climate change may also affect the biological pump in the future by warming and stratifying the surface ocean, thus reducing the supply of limiting nutrients to surface waters. Look up anthropogenic in Wiktionary, the free dictionary. ... Diagrams of some typical phytoplankton Phytoplankton are the autotrophic component of plankton. ... The total inorganic carbon (CT, or TIC)is the sum of inorganic carbon species in a solution. ... Global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. ... Change in sea surface pH caused by anthropogenic CO2 between the 1700s and the 1990s Ocean acidification is the name given to the ongoing decrease in the pH of the Earths oceans, caused by their uptake of anthropogenic carbon dioxide from the atmosphere. ... Calcium carbonate is a chemical compound, with the chemical formula CaCO3. ... Coccolithophores (also called coccolithophorids) are single-celled algae, protists and phytoplankton belonging to the division haptophytes. ... Orders Allogromiida Carterinida Fusulinida - extinct Globigerinida Involutinida Lagenida Miliolida Robertinida Rotaliida Silicolocunida Spirillinida Textulariida incertae sedis    Xenophyophorea    Reticulomyxa The Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands that branch and merge to form a dynamic net. ... Families Limacinidae Cavoliniidae Clioidae Creseidae Cuvierinidae Praecuvierinidae Peraclididae Cymbuliidae Desmopteridae Sea butterflies, or flapping snails, are holoplanktonic mollusks (Mollusca, Gasteropoda), belonging to the suborder Thecosomata (Blainville, 1824). ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... Water stratification occurs when water of high and low salinity (halocline), as well as cold and warm water (thermocline), forms layers that act as barriers to water mixing. ...

Soils

Carbon as plant organic matter is sequestered in soils: Soils contain more carbon than is contained in vegetation and the atmosphere combined.^[8] Soils' organic carbon (humus) levels in many agricultural areas have been severely depleted. Organic material in the form of humus accumulates below about 25 degrees Celsius.^{[citation needed]} Above this temperature, humus is oxidized much more rapidly. This is part of the reason why tropical soils under jungles are so thin, despite the rapid accumulation of organic material on the jungle floor (the other being extensive rainfall leaching soluble components vital to organic soil structure). Areas where shifting cultivation or slash and burn agriculture are practiced are generally only fertile for 2-3 years before they are abandoned. These tropical jungles are similar to coral reefs in that they are highly efficient at conserving and circulating necessary nutrients, which explains their lushness in a nutrient desert.^{[citation needed][original research?]} This article does not cite any references or sources. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland For the American hard rock band, see SOiL. For the System of a Down song, see Soil (song). ... -1... Soil structure is determined by how individual soil granules clump or bind together and aggregate. ... This article is about the agricultural practice of slash and burn. ...

Grasslands contribute to soil organic matter, mostly in the form of their extensive fibrous root mats. Much of this organic matter can remain unoxidized for long periods of time, depending on rainfall conditions, the length of the winter season, and the frequency of naturally occurring lightning-induced grass-fires necessary to recycle inorganic compounds from existing plant material. While these fires release carbon dioxide, they improve the quality of the grass-lands overall, in turn increasing the amount of carbon retained in the retained humic material. They also deposit carbon directly to the soil in the form of char that does not significantly degrade back to carbon dioxide. The overall effect of carbon sequestration is beneficial for soil since it adds more and more organic carbon to it and leads to improved soil properties. Organic matter (or organic material) is matter which has come from a recently living organism; is capable of decay, or the product of decay; or is composed of organic compounds. ...

Enhancing natural sequestration

Forests

Forests are carbon stores, and they are carbon dioxide sinks when they are increasing in density or area. In Canada's boreal forests as much as 80% of the total carbon is stored in the soils as dead organic matter. ^[9]Tropical reforestation can mitigate global warming until all available land has been reforested with mature forests.^{[10][11][12][13]}. In the United States in 2004 (the most recent year for which EPA statistics^[14] are available), forests sequestered 10.6% (637 teragrams^[15]) of the carbon dioxide released in the United States by the combustion of fossil fuels (coal, oil and natural gas; 5657 teragrams^[16]). Urban trees sequestered another 1.5% (88 teragrams^[15]). To further reduce U.S. carbon dioxide emissions by 7%, as stipulated by the Kyoto Protocol, would require the planting of "an area the size of Texas [8% of the area of Brazil] every 30 years", according to William H. Schlesinger, dean of the Nicholas School of the Environment and Earth Sciences at Duke University, in Durham, North Carolina. Carbon offset programs are planting millions of fast-growing trees per year to reforest tropical lands, for as little as $0.10 per tree; over their typical 40-year lifetime, one million of these trees will fix 0.9 teragrams of carbon dioxide^[17].In Canada, reducing timber harvesting would have very little impact on carbon dioxide emissions because of the combination of harvest and stored carbon in manufactured wood products along with the regrowth of the harvested forests. Additionally, the amount of carbon released from harvesting is small compared to the amount of carbon lost each year to forest fires and other natural disurbances. ^[18] Biodiversity on a 15-year-old reforested plot of land. ... Opened for signature December 11, 1997 in Kyoto, Japan Entered into force February 16, 2005. ... For other uses, see Texas (disambiguation). ... Until recently, most carbon offsets were commonly done by planting trees. ...

Former U.S. Vice President Al Gore shared the Nobel Peace Prize in 2007 with the United Nation's International Panel on Climate Change. The Panel concluded that "a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timbre fibre or energy from the forest, will generate the largest sustained mitigation benefit" ^[19]

Life expectancy of forests varies throughout the world, influenced by tree species, site conditions and natural disturbance patterns. In some forests carbon may be stored for centuries, while in other forests carbon is released with frequent stand replacing fires. Forests that are harvested prior to stand replacing events allow for the retention of carbon in manufactured forest products such as lumber. Only a portion of the carbon removed from logged forests ends up as durable goods and buildings - the remainder ends up as sawmill by-products such as pulp, paper and pallets. For instance, of the 1,692 teragrams of carbon harvested from forests in Oregon and Washington (U.S) from 1900 to 1992, only 23% is in long-term storage in forest products. ^[20] In addition to mitigating climate change, conserving forests to store carbon also helps provide valuable "ecosystem services" like clean water, soil conservation, wildlife habitat, and quality of life.

The global cooling effect of carbon sequestration by forests is partially counterbalanced in that reforestation can decrease the reflection of sunlight (albedo). Mid-to-high latitude forests have a much lower albedo during snow seasons than flat ground, thus contributing to warming. For other uses, see Albedo (disambiguation). ...

Oceans

See also: Iron fertilization

See also: Ocean nourishment

One way to increase the carbon sequestration efficiency of the oceans is to add micrometre-sized iron particles in the form of either hematite (iron oxide) or melanterite (iron sulfate) to certain regions of the ocean. This has the effect of stimulating growth of plankton. Iron is an important nutrient for phytoplankton, usually made available via upwelling along the continental shelves, inflows from rivers and streams, as well as deposition of dust suspended in the atmosphere. Natural sources of ocean iron have been declining in recent decades, contributing to an overall decline in ocean productivity (NASA, 2003). Yet in the presence of iron nutrients plankton populations quickly grow, or 'bloom', expanding the base of biomass productivity throughout the region and removing significant quantities of CO₂ from the atmosphere via photosynthesis. A test in 2002 in the Southern Ocean around Antarctica suggests that between 10,000 and 100,000 carbon atoms are sunk for each iron atom added to the water. More recent work in Germany (2005) suggests that any biomass carbon in the oceans, whether exported to depth or recycled in the euphotic zone, represents long-term storage of carbon. This means that application of iron nutrients in select parts of the oceans, at appropriate scales, could have the combined effect of restoring ocean productivity while at the same time mitigating the effects of human caused emissions of carbon dioxide to the atmosphere. It has been suggested that Ocean Nourishment be merged into this article or section. ... It has been suggested that this article or section be merged into Iron fertilization. ... For other uses, see Hematite (disambiguation). ... Iron(II) sulfate (FeSO4) is an example of an ionic compound. ... This article is about the real-life under-sea organisms. ... Diagrams of some typical phytoplankton Phytoplankton are the autotrophic component of plankton. ... The continental shelf is an area of relatively shallow sea water that is found on the edge of each continent. ... Air redirects here. ... For the use of the term in ecology, see Biomass (ecology). ... Photosynthesis splits water to liberate O2 and fixes CO2 into sugar The leaf is the primary site of photosynthesis in plants. ... The euphotic zone is the surface layer of the ocean where sufficient light is available for photosynthesis. ...

Because the effect of periodic small scale phytoplankton blooms on ocean ecosystems is unclear, more studies would be helpful. Phytoplankton have a complex effect on cloud formation via the release of substances such as dimethyl sulfide (DMS) that are converted to sulfate aerosols in the atmosphere, providing cloud condensation nuclei, or CCN. But the effect of small scale plankton blooms on overall DMS production is unknown. Dimethyl sulfide causes that distinctive smell from your St. ... Aerosol pollution over Northern India and Bangladesh - NASA Cloud condensation nuclei or CCNs (also known as cloud seeds) are small particles (typically 0. ...

Other nutrients such as nitrates, phosphates, and silica as well as iron may cause ocean fertilization. There has been some speculation that using pulses of fertilization (around 20 days in length) may be more effective at getting carbon to ocean floor than sustained fertilization.^[21]

There is some controversy over seeding the oceans with iron however, due to the potential for increased toxic phytoplankton growth (e.g. "red tide"), declining water quality due to overgrowth, and increasing anoxia in areas harming other sea-life such as zooplankton, fish, coral, etc.^[22][23] A red tide off the coast of La Jolla, California. ...

Soils

Since the 1850s, a large proportion of the world's grasslands have been tilled and converted to croplands, allowing the rapid oxidation of large quantities of soil organic carbon. However, in the United States in 2004 (the most recent year for which EPA statistics are available), agricultural soils including pasture land sequestered 0.8% (46 teragrams^[15]) as much carbon as was released in the United States by the combustion of fossil fuels (5988 teragrams^[16]). The annual amount of this sequestration has been gradually increasing since 1998^[15].

Methods that significantly enhance carbon sequestration in soil include no-till farming, residue mulching, cover cropping, and crop rotation, all of which are more widely used in organic farming than in conventional farming.^[24][25] Because only 5% of US farmland currently uses no-till and residue mulching, there is a large potential for carbon sequestration.^[26] Conversion to pastureland, particularly with good management of grazing, can sequester even more carbon in the soil. No-till planting of corn near Plymouth, Iowa. ... Broadly defined, a cover crop is any annual, biennial, or perennial plant grown as a monoculture (one crop type grown together) or polyculture (multiple crop types grown together), to improve any number of conditions associated with sustainable agriculture. ... Satellite image of circular crop fields in Haskell County, Kansas in late June 2001. ... Organic farming is a form of agriculture which excludes the use of synthetic fertilizers and pesticides, plant growth regulators, livestock feed additives, and genetically modified organisms. ...

Terra preta, an anthropogenic, high-carbon soil, is also being investigated as a sequestration mechanism. By pyrolysing biomass, about half of its carbon can be reduced to charcoal, which can persist in the soil for centuries, and makes a useful soil amendment, especially in tropical soils (biochar or agrichar).^{[27] [28]} Terra preta (which means dark soil in Portuguese), refers to expanses of very dark soils found in the Amazon Basin. ... Look up anthropogenic in Wiktionary, the free dictionary. ... Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ... Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ... Biochar is a type of charcoal produced from biomass. ...

Savanna

Controlled burns on far north Australian savannas can result in an overall carbon sink. One working example is the West Arnhem Fire Management Agreement, started to bring "strategic fire management across 28,000 km² of Western Arnhem Land". Deliberately starting controlled burns early in the dry season results in a mosaic of burnt and unburnt country which reduces the area of burning compared with stronger, late dry season fires. In the early dry season there are higher moisture levels, cooler temperatures, and lighter wind than later in the dry season; fires tend to go out overnight. Early controlled burns also results in a smaller proportion of the grass and tree biomass being burnt. ^[29] Emission reductions of 256,000 tonnes of CO₂ have been made as at 2007.^[30] Firing the woods in a South Carolina forest with a custom made igniter mounted on an all terrain vehicle. ... Savannah redirects here. ...

Artificial sequestration

For carbon to be sequestered artificially (i.e. not using the natural processes of the carbon cycle) it must first be captured, or it must be significantly delayed or prevented from being re-released into the atmosphere (by combustion, decay, etc.) from an existing carbon-rich material, by being incorporated into an enduring usage (such as in construction). Thereafter it can be passively stored or remain productively utilized over time in a variety of ways.

For example, upon harvesting, wood (as a carbon-rich material) can be immediately burned or otherwise serve as a fuel, returning its carbon to the atmosphere, or it can be incorporated into construction or a range of other durable products, thus sequestering its carbon over years or even centuries. One ton of dry wood is equivalent to 1.8 tons of Carbon dioxide.

Indeed, a very carefully-designed and durable, energy-efficient and energy-capturing building has the potential to sequester (in its carbon-rich construction materials), as much as or more carbon than was released by the acquisition and incorporation of all its materials and than will be released by building-function "energy-imports" during the structure's (potentially multi-century) existence. Such a structure might be termed "carbon neutral" or even "carbon negative". Building construction and operation (electricity usage, heating, etc) are estimated to contribute nearly half of the annual human-caused carbon additions to the atmosphere.^[31]

Natural-gas purification plants often already have to remove carbon dioxide, either to avoid dry ice clogging gas tankers or to prevent carbon-dioxide concentrations exceeding the 3% maximum permitted on the natural-gas distribution grid. For other uses, see Natural gas (disambiguation). ... Small pellets of dry ice sublimating in air. ...

Beyond this, one of the most likely early applications of carbon capture is the capture of carbon dioxide from flue gases at power stations (in the case of coal, this is known as "clean coal"). A typical new 1000-MW coal-fired power station produces around 6 million tons of carbon dioxide annually. Adding carbon capture to existing plants can add significantly to the costs of energy production; scrubbing costs aside, a 1000-MW coal plant will require the storage of about 50 million barrels of carbon dioxide a year. However, scrubbing is relatively affordable when added to new plants based on coal gasification technology, where it is estimated to raise energy costs for households in the United States using only coal-fired electricity sources from 10 cents per kWh to 12 cents.^[32] Flue gas is gas that exits to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. ... For other uses, see Power station (disambiguation). ... Clean coal is the name attributed to coal chemically washed of minerals and impurities, sometimes gasified, burned and the resulting flue gases treated with steam and reburned so as to make the carbon dioxide in the flue gas economically recoverable. ... Mohave Generating Station, a 1,580 MW coal power plant near Laughlin, Nevada A fossil fuel power plant is an energy conversion center that burns fossil fuels to produce electricity, designed on a large scale for continuous operation. ... For other uses, see Barrel (disambiguation). ... ...

Carbon capture

Main article: Carbon capture and storage

Currently, capture of carbon dioxide is performed on a large scale by absorption of carbon dioxide onto various amine-based solvents. Other techniques are currently being investigated, such as pressure swing adsorption, temperature swing adsorption, gas separation membranes, and cryogenics. Recent pilot studies include flue capture and conversion to baking soda and use of algae for conversion to fuel or feed. Carbon capture and storage (CCS) is an approach to mitigating global warming by capturing carbon dioxide (CO2) from large point sources such as power plants and subsequently storing it instead of releasing it into the atmosphere. ... Amine gas treating is a means to remove organosulfur and other undesirable compounds from acid gas by contacting the gas with amine. ... Pressure Swing Adsorption (PSA) is a technology that is used to separate some species from a gas under pressure according to these species molecular characteristics and affinity for an adsorbent material. ... Gas mixtures can be effectively separated by synthetic membranes. ... Laboratory distillation set-up: 1: Heat source 2: Still pot 3: Still head 4: Thermometer/Boiling point temperature 5: Condenser 6: Cooling water in 7: Cooling water out 8: Distillate/receiving flask 9: Vacuum/gas inlet 10: Still receiver 11: Heat control 12: Stirrer speed control 13: Stirrer/heat plate... Flue gas is gas that exits to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. ... Sodium bicarbonate (NaHCO3), or sodium hydrogen carbonate, also known as baking soda and bicarbonate of soda, is a soluble white anhydrous or crystalline compound, with a slight alkaline taste resembling that of sodium carbonate. ... For the programming language, see algae (programming language). ... For the programming language, see algae (programming language). ... For the programming language, see algae (programming language). ...

In coal-fired power stations, the main alternatives to retrofitting amine-based absorbers to existing power stations are two new technologies: coal gasification combined-cycle and Oxy-fuel combustion. Gasification first produces a "syngas" primarily of hydrogen and carbon monoxide, which is burned, with carbon dioxide filtered from the flue gas. Oxy-fuel combustion burns the coal in oxygen instead of air, producing only carbon dioxide and water vapour, which are relatively easily separated. Some of the combustion products must be returned to the combustion chamber, either before or after separation, otherwise the temperatures would be too high for the turbine. Combined cycle is a term used when a power producing engine or plant employs more than one thermodynamic cycle. ... Oxy-fuel combustion is the process of firing a fossil-fueled power plant with an oxygen-enriched gas mix instead of air. ... It has been suggested that Town gas be merged into this article or section. ... This article is about the chemistry of hydrogen. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... This article is about the chemical element and its most stable form, or dioxygen. ... Look up air in Wiktionary, the free dictionary. ... Boundaries: Phase, Pressure, Temperature Evaporation/Sublimation Whenever a water molecule leaves a surface, it is said to have evaporated. ...

Another long-term option is carbon capture directly from the air using hydroxides. The air would literally be scrubbed of its CO₂ content. This idea offers an alternative to non-carbon-based fuels for the transportation sector. Hydroxide is a functional group consisting of oxygen and hydrogen: -O−H It has a charge of 1-. The term hydroxyl group is used when the functional group -OH is counted as a substituent of an organic compound. ... Fossil fuels or mineral fuels are fossil source fuels, that is, hydrocarbons found within the top layer of the earth’s crust. ...

Examples of carbon sequestration at coal plants include converting carbon from smokestacks into baking soda,^[33][34] and algae-based carbon capture, circumventing storage by converting algae into fuel or feed.^[35]

Oceans

Another proposed form of carbon sequestration in the ocean is direct injection. In this method, carbon dioxide is pumped directly into the water at depth, and expected to form "lakes" of liquid CO₂ at the bottom. Experiments carried out in moderate to deep waters (350 - 3600 m) indicate that the liquid CO₂ reacts to form solid CO₂ clathrate hydrates, which gradually dissolve in the surrounding waters. Clathrate hydrates (or alternatively gas clathrates, gas hydrates, clathrates, hydrates etc) are a class of solids in which gas molecules occupy cages made up of hydrogen-bonded water molecules. ...

This method, too, has potentially dangerous environmental consequences. The carbon dioxide does react with the water to form carbonic acid, H₂CO₃; however, most (as much as 99%) remains as dissolved molecular CO₂. The equilibrium would no doubt be quite different under the high pressure conditions in the deep ocean. In addition, if deep-sea bacterial methanogens that reduce carbon dioxide were to encounter the carbon dioxide sinks, levels of methane gas may increase, leading to the generation of an even worse greenhouse gas^[36]. The resulting environmental effects on benthic life forms of the bathypelagic, abyssopelagic and hadopelagic zones are unknown. Even though life appears to be rather sparse in the deep ocean basins, energy and chemical effects in these deep basins could have far-reaching implications. Much more work is needed here to define the extent of the potential problems. Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3. ... Methanogens are archaea that produce methane as a metabolic byproduct. ... Methane is a chemical compound with the molecular formula . ... In marine geology and biology, benthos are the organisms and habitats of the sea floor; in freshwater biology they are the organisms and habitats of the bottoms of lakes, rivers, and creeks. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ...

Carbon storage in or under oceans may not be compatible with the London Convention (Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter) ^[37]. The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972, commonly called the London Convention or LC 72 and also abbreviated as Marine Dumping, is an agreement to control pollution of the sea by dumping and to encourage regional agreements supplementary to the Convention. ...

An additional method of long-term ocean-based sequestration is to gather crop residue such as corn stalks or excess hay into large weighted bales of biomass and deposit it in the alluvial fan areas of the deep ocean basin. Dropping these residues in alluvial fans would cause the residues to be quickly buried in silt on the sea floor, sequestering the biomass for very long time spans. Alluvial fans exist in all of the world's oceans and seas where river deltas fall off the edge of the continental shelf such as the Mississippi alluvial fan in the gulf of Mexico and the Nile alluvial fan in the Mediterranean Sea. A downside, however, would be an increase in aerobic bacteria growth due to the introduction of biomass, leading to more competition for oxygen resources in the deep sea, similar to the Oxygen Minimum Zone. There are two types of agricultural crop residues. ... A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. ... Oceanic basin can also refer to the river basins flowing into an ocean. ...  Sediment  Rock  Mantle  The global continental shelf, highlighted in cyan The continental shelf is the extended perimeter of each continent and associated coastal plain, which is covered during interglacial periods such as the current epoch by relatively shallow seas (known as shelf seas) and gulfs. ... The shared flood plain of the Yazoo and Mississippi Rivers The Mississippi Delta is the distinct northwest section of the state of Mississippi that lies between the Mississippi and Yazoo Rivers. ... Gulf of Mexico in 3D perspective. ... NASA satellite photograph of the Nile Delta (shown in false colour) The Nile Delta (Arabic:دلتا النيل) is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. ... Mediterranean redirects here. ...

Geological sequestration

The method of geo-sequestration or geological storage involves injecting carbon dioxide directly into underground geological formations. Declining oil fields, saline aquifers, and unminable coal seams have been suggested as storage sites. Caverns and old mines that are commonly used to store natural gas are not considered, because of a lack of storage safety. Drilling rig in a small oil field Near Sarnia, Ontario, 2001 An oil field is an area with an abundance of oil wells extracting petroleum (oil) from below ground. ... An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. ... Wyoming coal mine Coal mining is the extraction of coal from the Earth for use as fuel. ...

CO₂ has been injected into declining oil fields for more than 30 years, to increase oil recovery. This option is attractive because the storage costs are offset by the sale of additional oil that is recovered. Further benefits are the existing infrastructure and the geophysical and geological information about the oil field that is available from the oil exploration. All oil fields have a geological barrier preventing upward migration of oil. It is supposed that these geological barriers will also be sufficient as long-term barrier to contain the injected CO₂. Identified possible problems are the many 'leak' opportunities provided by old oil wells, the need for very high pressures (about 80 times air pressure) and low temperatures (below about 20 degrees Celsius) to keep the CO₂ liquified (only practical very deep underneath the sea) and the conversion of CO₂ into acids which can damage the geological barrier. Other disadvantages of old oil fields are their geographic distribution and their limited capacity.

Unminable coal seams can be used to store CO₂, because CO₂ absorbs to the coal surface, ensuring safe long-term storage. In the process it releases methane that was previously adsorbed to the coal surface and that may be recovered. Again the sale of the methane can be used to offset the cost of the CO₂ storage, although release or burning of methane would of course at least partially offset the obtained sequestration result.

Saline aquifers contain highly mineralized brines and have so far been considered of no benefit to humans except in a few cases where they have been used for the storage of chemical waste. Their advantages include a large potential storage volume and relatively common occurrence reducing the distance over which CO₂ has to be transported. The major disadvantage of saline aquifers is that relatively little is known about them compared to oil fields. To keep the cost of storage acceptable the geophysical exploration may be limited, resulting in larger uncertainty about the structure of a given aquifer. Unlike storage in oil fields or coal beds, no side product will offset the storage cost. Leakage of CO₂ back into the atmosphere may be a problem in saline-aquifer storage. However, current research shows that several trapping mechanisms immobilize the CO₂ underground, reducing the risk of leakage.

A major research project examining the geological sequestration of carbon dioxide is currently being performed at an oil field at Weyburn in south-eastern Saskatchewan. In the North Sea, Norway's Statoil natural-gas platform Sleipner strips carbon dioxide out of the natural gas with amine solvents and disposes of this carbon dioxide by geological sequestration. Sleipner reduces emissions of carbon dioxide by approximately one million tonnes a year. The cost of geological sequestration is minor relative to the overall running costs. As of April 2005, BP is considering a trial of large-scale sequestration of carbon dioxide stripped from power plant emissions in the Miller oilfield as its reserves are depleted. Location of Weyburn, Saskatchewan Weyburn is a city in southeastern Saskatchewan, Canada. ... For other uses, see Saskatchewan (disambiguation). ... The North Sea is a sea of the Atlantic Ocean, located between the coasts of Norway and Denmark in the east, the coast of the British Isles in the west, and the German, Dutch, Belgian and French coasts in the south. ... A Statoil petrol station sign in Estonia Statoil (OSE: STL, NYSE: STO) is a Norwegian petroleum company established in 1972. ... Odin entering Valhalla riding on Sleipnir (Ardre image stone) In Norse mythology, Sleipnir is Odins magical eight-legged steed, and the first of all horses. ... This article is about the energy corporation. ...

In October 2007, the Bureau of Economic Geology at The University of Texas at Austin received a 10-year, $38 million subcontract to conduct the first intensively monitored, long-term project in the United States studying the feasibility of injecting a large volume of CO₂ for underground storage^[38]. The project is a research program of the [Southeast Regional Carbon Sequestration Partnership (SECARB)], funded by the National Energy Technology Laboratory of the U.S. Department of Energy (DOE). The SECARB partnership will demonstrate CO₂ injection rate and storage capacity in the Tuscaloosa-Woodbine geologic system that stretches from Texas to Florida. Beginning in fall 2007, the project will inject CO2 at the rate of one million tons per year, for up to 1.5 years, into brine up to 10,000 feet (3,000 m) below the land surface near the Cranfield oil field about 15 miles (24 km) east of Natchez, Mississippi. Experimental equipment will measure the ability of the subsurface to accept and retain CO2. University of Texas at Austin The University of Texas at Austin (full official name), often UT or Texas for short, is the flagship institution of the University of Texas System, the largest public university system in Texas, established in 1883. ... The National Energy Technology Laboratory (NETL) is a science, technology, and energy laboratory owned and operated by the U.S. Department of Energy (DOE). ... The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... Melrose, an antebellum home in Natchez, Mississippi. ...

Mineral sequestration

Mineral sequestration aims to trap carbon in the form of solid carbonate salts. This process occurs slowly in nature and is responsible for the deposition and accumulation of limestone (calcium carbonate) over geologic time. Carbonic acid in groundwater slowly reacts with complex silicates to dissolve calcium, magnesium, alkalis and silica and leave a residue of clay minerals. The dissolved calcium and magnesium react with bicarbonate to precipitate calcium and magnesium carbonates, a process that organisms use to make shells. When the organisms die, their shells are deposited as sediment and eventually turn into limestone. Limestones have accumulated over billions of years of geologic time and contain much of Earth's carbon. Ongoing research aims to speed up similar reactions involving alkali carbonates^[39]. Ball-and-stick model of the carbonate ion, CO32− For other meanings, see Carbonate (disambiguation) In chemistry, a carbonate is a salt or ester of carbonic acid. ... For other uses, see Limestone (disambiguation). ... Carbonic acid (ancient name acid of air or aerial acid) has the formula H2CO3. ... In chemistry, a silicate is a compound consisting of silicon and oxygen (SixOy), one or more metals, and possibly hydrogen. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... The word alkali can mean:- In chemistry, an alkali is the solution of a base in water. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Clay minerals are hydrous aluminium silicates, sometimes with minor amounts of iron, magnesium and other cations. ... For baking soda, see Sodium bicarbonate In inorganic chemistry, a bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. ...

One proposed reaction is that of the rock dunite, or its hydrated equivalent serpentinite with carbon dioxide to form the carbonate mineral magnesite, plus silica and iron oxide (magnetite). Dunite is an igneous, plutonic rock, of ultramafic composition, with coarse grained or phaneritic texture. ... A sample of serpentinite rock, partially made up of chrysotile Serpentinite is a rock comprised of one or more serpentine minerals. ... Magnesite is magnesium carbonate, MgCO3. ... Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. ...

Serpentinite sequestration is favored because of the non-toxic and predictable nature of magnesium carbonate. However, the ideal reaction (reaction 1) takes place only with extremely magnesium-rich olivine or serpentine minerals. The presence of iron in the olivine or serpentine will reduce the efficiency of the circuit and reactions 2 and 3 must take place, producing a slag of silica and magnetite. General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... For other uses, see Serpentine (disambiguation). ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... Slag is also an early play by David Hare. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. ...

Serpentinite reactions

Reaction 1
Mg-Olivine + Water + Carbon dioxide → Serpentine + Magnesite + Silica

(Mg)₂SiO₄ + nH₂O + CO₂ → Mg₃[Si₂O₅(OH)₄] + MgCO₃ + SiO₂ + H₂O (This is a non stoichiometric reaction just to show the principle).

Reaction 2
Fe-Olivine + Water + Carbonic acid → Serpentine + Magnetite + Magnesite + Silica

4(Fe,Mg)₂SiO₄ + nH₂O + H₂CO₃ → 2Mg₃[Si₂O₅(OH)₄] + 2Fe₃O₄ + 2MgCO₃ + SiO₂ + H₂O

Reaction 3
Serpentine + carbon dioxide → Magnesite + silica + water

Mg₃[Si₂O₅(OH)₄] + 3CO₂ → 3MgCO₃ + 2SiO₂ + 2H₂O

Zeolitic imidazolate frameworks

Main article: Zeolitic imidazolate frameworks

Zeolitic imidazolate frameworks is a metal-organic framework carbon dioxide sink which could be used to keep industrial emissions of carbon dioxide out of the atmosphere.^[40] Metal-Organic Frameworks (MOFs) are porous crystalline compounds consisting of metal ions coordinated to an often rigid organic molecule, creating holes in the structure. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Atmospheres redirects here. ...

References

Resources for the Future (RFF) is a nonprofit and nonpartisan organization that conducts independent research -- rooted primarily in economics and other social sciences -- on environmental, energy, and natural resource issues. ... is the 110th day of the year (111th in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday. ... McGill University is a public co-educational research university located in Montréal, Québec, Canada. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 54th day of the year in the Gregorian calendar. ... is the 55th day of the year in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... New Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 54th day of the year in the Gregorian calendar. ... For other uses, see BBC (disambiguation). ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... is the 339th day of the year (340th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... This article is about the day of the year. ... Also see: 2002 (number). ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... is the 364th day of the year (365th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... is the 194th day of the year (195th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 266th day of the year (267th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 281st day of the year (282nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 281st day of the year (282nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 281st day of the year (282nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 54th day of the year in the Gregorian calendar. ... Scientific American is a popular-science magazine, published (first weekly and later monthly) since August 28, 1845, making it the oldest continuously published magazine in the United States. ... Fairfield is a city located in Freestone County, Texas. ... Carbon dioxide pressure-temperature phase diagram Supercritical carbon dioxide refers to carbon dioxide with some unique properties. ... Sodium bicarbonate (NaHCO3), or sodium hydrogen carbonate, also known as baking soda and bicarbonate of soda, is a soluble white anhydrous or crystalline compound, with a slight alkaline taste resembling that of sodium carbonate. ... is the 185th day of the year (186th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ...

See also

Energy Portal

• Carbon capture and storage
• Carbon cycle
• Carbon flux
• Carbon offset
• CO2 sequestration
• Center for the Study of Carbon Dioxide and Global Change
• Iron fertilization
• North American Carbon Program

Image File history File links Crystal_128_energy. ... Carbon capture and storage (CCS) is an approach to mitigating global warming by capturing carbon dioxide (CO2) from large point sources such as power plants and subsequently storing it instead of releasing it into the atmosphere. ... For the thermonuclear reaction involving carbon that helps power stars, see CNO cycle. ... Carbon flux is the net difference between sequestration and respiration of carbon dioxide. ... Until recently, most carbon offsets were commonly done by planting trees. ... C02 sequestration is the capture, extraction, separation, collection, etc, of carbon dioxide and a means for its storage or use. ... The Center for the Study of Carbon Dioxide and Global Change is a non-profit organization based in Arizona. ... It has been suggested that Ocean Nourishment be merged into this article or section. ... The North American Carbon Program (NACP) is one of the major elements of the Strategic Plan for the U.S. Climate Change Science Program. ...

External links

General

• Carbon Sequestration News Recent news articles on CO₂ capture and storage.
• Gulf Coast Carbon Center University of Texas at Austin research center that investigates geologic storage of anthropogenic carbon dioxide in the Gulf Coast region.
• SinksWatch - An initiative to track and scrutinize carbon sink projects
• National Energy Technology Laboratory (NETL) Carbon Sequestration Home Page
• U.S. Department of Energy's Office of Science Carbon Sequestration Research Programs
• U.S. Department of Energy's National Energy Technology Laboratory - Carbon Sequestration Technology Roadmap
• The Carbon Offset Opportunity Program: A Tool for Collaborative Carbon Sequestration Project Development
• Carbon Capture and Sequestration Technologies Program at MIT
• International industry R&D group focussed on CO₂ sequestration
• CO₂ Capture Project
• Carbon Mitigation Initiative
• Southeast Regional Carbon Sequestration Partnership (SECARB)
• 'Catalyst' on Australian science TV on geosequestration
• The U.S. North American Carbon Program
• Collection of recent news articles on CO₂ capture and storage
• Synthetic Trees Could Purify Air
• The Consortium for Agricultural Soil Mitigation of Greenhouse Gases
• Scottish Centre for Carbon Storage Research
• Can geosequestration save the coal industry?

Research

• Short documentary on Australian research into limits on carbon uptake by trees
• FAO (2004) Carbon sequestration in dryland soils
• IEA Reports: Putting carbon back into the ground (pdf) and Ocean storage of CO₂ (pdf)
• Haszeldine (2005) Deep geological CO₂ storage: principles, and prospecting for bio-energy disposal sites (pdf)
• The Role of Carbon in Agricultural Soils in Carbon Sequestration - A Better Alternative for Climate Change? Chapter 1: Agricultural Sinks (1999) University of Maryland pdf format doc format
• Schlesinger, W.H. 1991. Biogeochemistry: An Analysis of Global Change. Academic Press, San Diego.
• Peat bogs may be soaking up 10 to 20% of the excess CO₂ generated by human activity
• DMS and Climate
• Carbon Store in U.S. Forests

FAO redirects here. ...

Action

• Collection of recent news articles on CO₂ capture and storage
• Britain entertains the idea
• Seattle Times, 20 February 2004, Canada pumps CO₂ underground (Weyburn oil field)
• United States pumps CO₂ underground
• Observer 24 April 2005 Seabed supplies a cure for global warming crisis
• Tyndall Centre - Assessing the potential for geological carbon sequestration in the UK
• "Baking soda could help save planet" - Luminant pilot in Texas