The carbon cycle

In short: Carbon constantly moves between atmosphere, plants, animals, soil and oceans. By burning fossil fuels humans put additional carbon into the air as CO₂.

In more detail: Plants take up CO₂ (fotosynthese); animals and microorganisms release it again through respiration and decay. Oceans dissolve CO₂ in water.

In detail

• Fast cycle: Seasons, photosynthesis and respiration exchange carbon on a scale of days and years.
• Slow cycle: Limestone, coal, oil and natural gas store carbon over millions of years.
• Disturbance: Coal, oil and gas that took millions of years to form are burned within decades.
• Sinks: Forests, bogs and oceans absorb part of the CO₂ but not all.
• Consequence: More CO₂ strengthens the greenhouse effect (treibhauseffekt).