Kolsänkor

Kolsänkor, or carbon sinks, are processes or reservoirs that remove carbon dioxide from the atmosphere and store it for varying lengths of time. They help lower atmospheric CO2 concentrations and thus influence the climate. The term is used internationally; in Swedish, kolsänkor specifically refers to these sinks.

Natural carbon sinks include the oceans, which absorb CO2 through gas exchange and the dissolution of carbon, aided by biological processes such as the biological pump. Terrestrial ecosystems—forests, soils, and wetlands—store carbon in biomass and soil organic matter. Coastal and marine ecosystems, often termed blue carbon habitats (mangroves, seagrasses, salt marshes), also lock away substantial amounts of carbon. Peatlands are particularly important stores due to their very high carbon density.

human activities can enhance sinks through land management and restoration. Examples include afforestation and reforestation, improved forest management, soil carbon sequestration via agricultural practices, and wetland or coastal habitat restoration. Such measures are central to nature-based climate solutions and policies aiming to increase the planet’s capacity to absorb CO2.

Measurement and dynamics: the global carbon budget tracks how much CO2 is emitted, how much is absorbed by sinks, and how much remains in the atmosphere. Sinks operate on timescales from years to centuries, varying by ecosystem and climate conditions. Their capacity is not fixed and can be affected by warming, altered precipitation, deforestation, and ecosystem degradation.

Understanding kolsänkor is essential for climate strategy, as effective protection and enhancement of sinks complement reductions in emissions and other mitigation efforts.