An Introduction to Carbon Farming
Carbon farming is defined as farming in a way that reduces greenhouse gas emissions by capturing and holding carbon in vegetation and soils. It comprises the simultaneous management of land, water, plants, and animals to restore landscapes, mitigate climate change, and enhance food security.
It’s not a revolutionary idea. In fact it basically entails farming that is low-impact. That is, farming that doesn’t disturb the soil through tillage and overuse.
The name is a bit of a misnomer. Carbon farming doesn’t just result in captured carbon: it also improves soil quality and nutrient retention. This has a secondary effect of improving the efficiency of fertilizers, water, and energy applies to crop management.
It’s a crucial component of protecting global food systems because of the many unsustainable practices that are common today – deforestation, plowing, tillage, overuse of chemical fertilizers, and excessive construction on farm lands. All of these practices have led to erosion, a loss of soil fertility, and even desertification in extreme cases.
There’s only so much soil carbon available; if misused, it’s a non-renewable resource. According to one researcher, agricultural soils in the US have already lost 30 to 50 percent of their carbon content in just 200 years of farming. But the deficit is even more severe in developing countries: Southeast Asia, India, Pakistan, Central Asia, and sub-Saharan Africa have already lost as much as 70 to 80 percent of their soil carbon.
Current farming practices continue to withdraw carbon from the soils without replacing it. Eventually, soils will lose their carbon content and industrial agricultural practices as we know them today will no longer be possible.
The only way to break this cycle is to take carbon from the air and put it back into the soil through carbon farming techniques.
Carbon Farming Techniques
Carbon farming involves the following steps/principles:
- Using high amounts of manure and compost
- Causing minimal soil disturbance
- Conserving soil and water
- Improving soil structure
- Enhancing earthworm activity
No-till crop production is the most widely used carbon farming technique. Essentially, it employs the direct drilling of seeds in to the ground without disturbing the surface layer of soil through tillage.
Carbon Farming Credits
There is an opportunity for farmers to trade carbon credits for the carbon dioxide removed from the atmosphere through carbon farming. Farmers that capture and hold carbon dioxide in their soils could be compensated for the climate benefits, the maintenance fees, and the ecosystem services associated with carbon farming. The credits produced could be sold to companies that need to reduce their carbon footprint to comply with limits under cap-and-trade systems.
It is possible to measure changes in soil carbon levels through laboratory and field tests. But so far, there is no internationally agreed standard for accounting for soil carbon sequestration levels. Australia is the only country with a nationwide system for carbon credits from farming and forestry.
Theoretically, a carbon credit system for carbon farming could create a market for the restoration of depleted or even desert land. One could envision the creation of large carbon farms consisting of carefully selected plants to maximize the amount of carbon dioxide sequestered in the soil.
A recent study evaluated this possibility. The German researchers found that a shrub called Jatropha curcas (Barbados nut) could be particularly effective at absorbing carbon, especially in desert areas. The researchers estimate that if the one billion hectares of desert land in coastal areas were used for Barbados nut plantations, atmospheric carbon dioxide could be reduced by 17.5 ppm over two decades of plant growth (equivalent to about 16.6 percent of the carbon dioxide increase since the Industrial Revolution).
However, it is clear that carbon farming is not the solution to the climate problem. Human activities are resulting in emissions of about 10 gigatons per year. If all of the world’s farmers practiced carbon farming and land managers restored all depleted land, carbon could be sequestered at a rate of about 2 gigatons per year. The other 8 gigatons of emissions need to be addressed through renewable energy additions, energy efficiency, and other carbon-capture methods.