What are the 5 Main Natural Carbon Sinks

What is Carbon Sinks?

Carbon sinks are the process, activity or mechanism that removes CO2 from the air. It is the carrier of carbon in nature, or simply put, it is a natural or artificial "storehouse" of carbon. As greenhouse gas emissions have increased over the years and climate problems have worsened, people have begun to realise the importance of carbon removal. The concept of carbon sinks was first defined in the United Nations Framework Convention on Climate Change (UNFCCC) in 1992 and has been recognised by many as a key mitigation measure.
 

What are 5 Natural Carbon Sinks?

Natural carbon sinks are mainly categorised into terrestrial and marine sinks.
 

Terrestrial Carbon Sinks

Forest carbon sinks: Forests absorb CO2 from the atmosphere through photosynthesis and fix it in forest vegetation and soil, while releasing oxygen, thus reducing the concentration of the gas in the atmosphere. Although some carbon is released back into the atmosphere during the natural death and decomposition of decaying wood and limbs, the overall amount of CO2 absorbed by forest vegetation is much greater than the amount of carbon released.

Grassland Carbon Sinks: Similarly, grassland vegetation stores CO2 through photosynthesis. However, the carbon sequestration effect of grassland carbon sinks is not stable enough, and is affected by a variety of factors such as climate and grassland type. In recognition of this, governments have begun to return farmland to forests and grasslands, which has led to an increase in overall carbon sequestration in grassland soils.

Cropland Carbon Sinks: Cropland carbon sinks, also known as agricultural carbon sinks, are mainly related to the carbon sequestration component of crop residues. Crop residues from agricultural production, if left to accumulate, decompose naturally or simply burned, will emit the CO2 they contain into the atmosphere. Currently, the commonly used method is to return crop residues to the field, fixing the carbon in the residues in the soil.

Soil Carbon Sinks: Microorganisms and plant root activity in the soil produce CO2 by decomposing organic matter, but can also fix carbon in the soil through adsorption and complexation. Proper soil maintenance and use regimes can also help to increase the carbon sequestration capacity of the soil.
 

Ocean Carbon Sinks

Ocean carbon sink is the process of using marine activities and marine organisms (e.g. plankton, bacteria, seagrasses, salt marsh plants and mangroves) to absorb CO2 from the atmosphere and fix it in the ocean. This includes coastal zone ecosystem carbon sinks, fisheries carbon sinks and microbial carbon sinks.
 

Biochar and Cropland Carbon Sink

Biochar is a solid product obtained by high-temperature anaerobic pyrolysis of biomass-based raw materials (rice husk, straw, bagasse, nut shells, coconut shells, etc.), which has a very high carbon content. In recent years, biochar technology has been widely recognised worldwide and is gradually expanding in scope, and has been officially recognised by the IPCC as an effective carbon sequestration and emission reduction technology.

Reducing Carbon Emissions from Agri-Waste: Using widely available agricultural waste as a raw material, biochar production can effectively convert this agricultural waste into stable carbon-containing material, mitigating CO2 emissions caused by incineration or decomposition.

Promote Soil Carbon Sequestration: Biochar is highly carbonaceous and stable, and adding it to arable land is a process of carbon sequestration. Moreover, the porous structure of biochar facilitates the growth and development of crop roots, improves the soil environment and the provision of nutrients, which in turn improves crop yields and quality, and optimises farming practices and arable land structure.

Extremely Environmentally Friendly: During the production of biochar, we do not use additional fossil fuels except for the initial ignition start-up. In addition, during the biomass pyrolysis process, a large amount of syngas and heat is generated, which can be collected and used to generate electricity or to hot water boilers or drying ovens. This also reduces the use of fossil fuels to a certain extent and reduces CO2 emissions.