CT: A carbon sink is anything that absorbs more carbon that it releases, whilst a carbon source is anything that releases more carbon than is absorbed. Forests, soils, oceans and the atmosphere all store carbon and this carbon moves between them in a continuous cycle. This constant movement of carbon means that forests act as sources or sinks at different times.
Not all stores of carbon are naturally cursed with such fluctuations however. In the context of climate change, the most important carbon stores are fossil fuel deposits as they have the unique benefit of being buried deep inside the Earth, naturally separated from the carbon cycling in the atmosphere. This separation ends when humans burn coal, oil and natural gas, turning fossil carbon stores into atmospheric carbon. This release of carbon from fossil fuel has caused greenhouse gas (GHG) concentrations in the atmosphere to soar to levels more than 30 per cent higher than at the beginning of the industrial revolution. We are still adding roughly 6 billion tonnes of carbon per year to the atmospheric carbon cycle, significantly altering the intricate web of carbon fluxes and, as a consequence, altering the global climate.
S: http://www.fern.org/campaign/carbon-trading/what-are-carbon-sinks (last access: 28 December 2014)
N: carbon (n): non-metallic element, 1789, coined 1787 in French by Lavoisier as charbone, from Latin carbonem (nominative carbo) “a coal, glowing coal; charcoal,” from PIE root ker- “heat, fire, to burn”.
sink (n): early 15c., “cesspool, pit for reception of wastewater or sewage,” from sink (v.). Figurative sense of “place where corruption and vice abound” is from 1520s. Meaning “drain for carrying water to a sink” is from late 15c. Sense of “shallow basin (especially in a kitchen) with a drainpipe for carrying off dirty water” first recorded 1560s. In science and technical use, “place where heat or other energy is removed from a system” (opposite of source), from 1855.
2. A pool (reservoir) that absorbs or takes up released carbon from another part of the carbon cycle.
3. (…) if the net exchange between the biosphere and the atmosphere is toward the atmosphere, the biosphere is the source and the atmosphere is the sink.
4. carbon sink: The term “carbon” refers to all forms of carbon even though carbon dioxide is the form that fluctuates the most in carbon reservoirs.
5. CO2 sink: should be written CO2 sink.
6. carbon sink: term standardized by Environment Canada and the Translation Bureau for use in the National Inventory Report.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=carbon+sink&searchmode=none (last access: 28 December 2014). 2, 3, 4, 5 & 6. TERMIUM PLUS (last access: 28 December 2014).
SYN: carbon dioxide sink, CO2 sink.
S: TERMIUM PLUS (last access: 28 December 2014)