/ ˈkɑːrbən ˈsaɪkl̩ /
Množina reči carbon cycle je carbon cycles.
1. A thermonuclear reaction in the interior of stars.
2. The organic circulation of carbon from the atmosphere into organisms and back again.
Sequence by which carbon circulates and is recycled through the natural world. The carbon element from carbon dioxide, released into the atmosphere by living things as a result of respiration, is taken up by plants during photosynthesis and converted into carbohydrates; the oxygen component is released back into the atmosphere. Some of this carbon becomes locked up in coal and petroleum and other sediments. The simplest link in the carbon cycle occurs when an animal eats a plant and carbon is transferred from, say, a leaf cell to the animal body. The oceans absorb 25–40% of all carbon dioxide released into the atmosphere.
Today, the carbon cycle is in danger of being disrupted by the increased consumption and burning of fossil fuels, and the burning of large tracts of tropical forests, as a result of which levels of carbon dioxide are building up in the atmosphere and probably contributing to the greenhouse effect.
The European Union has pledged to stabilize CO2 emissions at 1990 levels by the year 2000. They would otherwise rise by 11% per year over this period. Maintaining such levels will be achieved by burning less fossil fuel through increased energy efficiency.