Soil carbon sequestration
As plants grow they capture CO2 from the air through photosynthesis. The carbon is not only stored in the plant itself but also in the soil around the plant. Through using certain types of agricultural and land management practices, the amount of carbon stored in the soil can be accumulated. These methods are known as regenerative agriculture and include methods such as no-till farming (no disturbance of the soil through tillage), using cover crops, addition of plant reside and improved grazing management. Soil carbon sequestration can be easily deployed on existing agricultural land and would not require substantial amounts of extra land.
Carbon storage reversal can occur quickly if the soil is disturbed. For example if conventional farming practices are resumed after regenerative farming, the carbon that was accumulated in the soil can easily be degraded again and released to the atmosphere. Storage reversal can also occur if soils are damaged during storms, through floods or other disasters.
Readiness and scale
The farming methods needed to sequester more carbon in the soil are already developed but there is no large scale adoption of these methods – mostly due to the large industrialisation of agriculture and fear of decreasing crop yields. There are a number of projects spread world-wide that employ regenerative farming and have the carbon removal certified. Through wide-scale deployments, experts suggest that the global potential of soil carbon sequestration is over 5 Gt CO2 annually by 2050.
Co-benefits / limits
+ Regenerative agricultural practices can improve crop yields. This in turn provides economic benefits to farmers.
+ Regenerative agriculture improves the overall soil quality. Water retention, soil structure and nutrient balances can be improved. This can decrease the need for irrigation and the use of chemical fertilizers which further improves soil quality.
+ Healthy soils that deploy certain regenerative agricultural practices such as using perennials instead of annual crops, or using cover crops are more resilient to weather extremes such as droughts and heavy rainfalls.
– The carbon stored in soils is vulnerable to storage reversal through a disturbance of the soil.
– The measurement and verifiability of carbon removal through soil carbon sequestration is difficult and costly.
– Similar to other nature-based solutions, saturation of carbon removal can occur. Soils and plants can only hold a finite amount of carbon which they capture as the plants grow. Once the ecosystem has reached maturity it will no longer absorb excess amounts of carbon. This means any single plot of land can only be a limited carbon removal site.
Support projects that use soil carbon sequestration and other methods and contribute to the removal of CO2 from the atmosphere.