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Carbon cycle

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The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.

Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to making the Earth capable of sustaining life; it describes the movement of carbon as it is recycled and reused throughout the biosphere.

The global carbon budget is the balance of the exchanges (incomes and losses) of carbon between the carbon reservoirs or between one specific loop (e.g., atmosphere <-> biosphere) of the carbon cycle. An examination of the carbon budget of a pool or reservoir can provide information about whether the pool or reservoir is functioning as a source or sink for carbon dioxide.

The carbon cycle was initially discovered by Joseph Priestley and Antoine Lavoisier, and popularized by Humphry Davy.

Carbon cycle. Relevance for the global climate.

Main components

Carbon cycle re-balancing. Biochar. Biochar created through the pyrolysis process.


History[edit] Left - a nutrient-poor oxisol; right - an oxisol transformed into fertile terra preta using biochar Pre-Columbian Amazonians are believed to have used biochar to enhance soil productivity. They produced it by smoldering agricultural waste (i.e., covering burning biomass with soil)[5] in pits or trenches.[6] European settlers called it terra preta de Indio.[7] Following observations and experiments, a research team working in French Guiana hypothesized that the Amazonian earthworm Pontoscolex corethrurus was the main agent of fine powdering and incorporation of charcoal debris to the mineral soil.[8] The term “biochar” was coined by Peter Read to describe charcoal used as a soil improvement.[9] Production[edit] Pyrolysis produces biochar, liquids, and gases from biomass by heating the biomass in a low/no oxygen environment.

Centralized, decentralized, and mobile systems[edit] Thermo-catalytic depolymerization[edit] Snowball Earth. Proterozoic snowball periods The Snowball Earth hypothesis posits that the Earth's surface became entirely or nearly entirely frozen at least once, sometime earlier than 650 Mya (million years ago).

Snowball Earth

Proponents of the hypothesis argue that it best explains sedimentary deposits generally regarded as of glacial origin at tropical paleolatitudes, and other otherwise enigmatic features in the geological record. Opponents of the hypothesis contest the implications of the geological evidence for global glaciation, the geophysical feasibility of an ice- or slush-covered ocean,[2][3] and the difficulty of escaping an all-frozen condition. A number of unanswered questions exist, including whether the Earth was a full snowball, or a "slushball" with a thin equatorial band of open (or seasonally open) water.

History[edit] In 1964, the idea of global-scale glaciation reemerged when W. Interest in the snowball Earth increased dramatically after Paul F. Permafrost carbon cycle. The Permafrost Carbon Cycle is a sub-cycle of the larger global carbon cycle.

Permafrost carbon cycle

Permafrost is defined as subsurface material that remains below 0o C (32o F) for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within their frozen framework during that time. Permafrost represents a large carbon reservoir that is seldom considered when determining global terrestrial carbon reservoirs. Recent and ongoing scientific research however, is changing this view.[1] Low carbon diet. A low carbon diet refers to making lifestyle choices to reduce the greenhouse gas emissions (GHGe) resulting from energy use.[1] It is estimated that the U.S. food system is responsible for at least 20 percent of U.S. greenhouse gases.[2] This estimate may be low, as it counts only direct sources of GHGe.

Low carbon diet

Indirect sources, such as demand for products from other countries, are often not counted. A low carbon diet minimizes the emissions released from the production, packaging, processing, transport, preparation and waste of food. Major tenets of a low carbon diet include eating less industrial meat and dairy, eating less industrially produced food in general, eating food grown locally and seasonally, eating less processed and packaged foods and reducing waste from food by proper portion size, recycling or composting.[3] Overall trends[edit] 7.19 for high meat-eaters5.63 for medium meat-eaters4.67 for low meat-eaters3.91 for fish-eaters3.81 for vegetarians2.89 for vegans.

Integrated Carbon Observation System. Integrated Carbon Observation System (ICOS) is a new strategic research infrastructure to quantify the greenhouse gas balance in Europe and adjacent regions.

Integrated Carbon Observation System

It consists of a harmonized network of ecosystem long-term observation sites, a network of atmospheric greenhouse gas concentration sites and a network of ocean observations. The network will be coordinated through a set of central facilities, including an atmospheric and an ecosystem thematic center, a central data center, an analytical laboratory and an oceanic thematic center. Global Carbon Project. Global carbon dioxide emissions, 1800 to 2007.

Global Carbon Project

Carbon dioxide in Earth's atmosphere. Carbon dioxide (CO2) is an important trace gas in Earth's atmosphere currently constituting about 0.04% (400 parts per million) of the atmosphere.[1][2] Despite its relatively small concentration, CO2 is a potent greenhouse gas and plays a vital role in regulating Earth's surface temperature through radiative forcing and the greenhouse effect.[3] Reconstructions show that concentrations of CO2 in the atmosphere have varied, ranging from as high as 7,000 parts per million during the Cambrian period about 500 million years ago to as low as 180 parts per million during the Quaternary glaciation of the last two million years.

Carbon dioxide in Earth's atmosphere

Carbon dioxide is an integral part of the carbon cycle, a biogeochemical cycle in which carbon is exchanged between the Earth's oceans, soil, rocks and biosphere. The present biosphere of Earth is dependent on atmospheric CO2 for its existence. The current episode of global warming is attributed primarily to increasing industrial CO2 emissions into Earth's atmosphere. Carbon diet. A carbon diet refers to reducing the impact on climate change by reducing greenhouse gas (principally CO2) production.

Carbon diet

Individuals and businesses produce carbon dioxide from daily activities such as driving, heating, and the consumption of products and services. Carbon footprint. The carbon footprint explained A carbon footprint is historically defined as "the total sets of greenhouse gas emissions caused by an organization, event, product or individual.

Carbon footprint

"[1] The total carbon footprint cannot be calculated because of the large amount of data required and the fact that carbon dioxide can be produced by natural occurrences. It is for this reason that Wright, Kemp, and Williams, writing in the journal Carbon Management, have suggested a more practicable definition: