CARBON SINKS AND SEQUESTRATION

The opposite of a GHG source is a GHG sink. A sink is any process, activity or mechanism that removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere.

Natural sinks for CO2 are for example forests, soils and oceans. It is also possible to enhance naturally occurring processes or use modern technology to remove CO2 from the atmosphere and store it in reservoirs. The uptake of CO2 in a reservoir, whether natural or artifi cial is also called carbon
sequestration.

Biological sequestration in forests
The role of forests in carbon sequestration is probably best understood and appears to offer the greatest near-term potential for human management. Unlike many plants and most crops, which have short lives or release much of their carbon at the end of each season, forest biomass accumulates carbon over decades and centuries. Furthermore, forests can accumulate large amounts of CO2 in relatively short periods, typically several decades. Afforestation and reforestation are measures that can be taken to

Afforestation refers to establishing forest by natural succession or planting trees on land where they did not formerly grow. Reforestation means re-establishing forest, either by natural regeneration or by planting in an area where forest was removed.

enhance biological carbon sequestration. The IPCC calculated that a global programme to 2050 involving reduced deforestation, enhanced natural regeneration of tropical forests and worldwide re-afforestation could sequester 60–87 thousand million tonnes of atmospheric carbon, equivalent to some 12–15 per cent of projected CO2 emissions from fossil fuel burning for that period.

As one of the countries in the CN Net, Costa Rica is focusing on its considerable potential for using forests to become climate neutral.

Geological sequestration beneath the Earth’s surface
The second option, carbon capture and storage (CCS) has been discussed for decades as a possible way of solving the climate crisis. As it stands, it