Removal and storage of carbon from the atmosphere, usually in oceans and forest soils
E.g. carbon capture
Compressed CO2 is injected into porous rock formations
Mangrove forests

Sequester 1.5 metric tonnes of carbon per hectare every year
Soils contain high levels of carbon - over 10%
Grow quickly and absorb large amounts of carbon
Soils are anaerobic, meaning little of the carbon is respired back into the environment by microbes
Trapped plant matter decays, adding to carbon store
Clearing for shrimp farms releases carbon back into atmosphere
Tundras

Much of the soil in tundra biomes is permanently frozen and contains ancient carbon
Microbe activity is only present on the surface when it thaws, the rest of the time the roots and dead and decayed organic matter is frozen
Tropical forests
Tropical forests are huge carbon sinks, but can disappear quickly
Carbon is mainly stored in trees, plant litter and dead wood
Soils are thin and lack nutrients as decomposing litter is absorbed by vegetation
Tropical rainforests absorb more atmospheric CO2 than any other terrestrial biome, accounting for 30% of global net primary production, although they cover just 17% of the world's surface
