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Rewards for sequestering carbon can help improve food security

The global food supply could be made more secure by actively encouraging smallholder farmers in countries that have an insecure food supply to sequester carbon in the soil by altering their cultivation practices. This can also improve soil quality and reduce greenhouse gas emissions.

[Translate to English:] Kontant belønning for ændret dyrkningspraksis i ulande kan være med til at sikre fødevareforsyningen og nedsætte udledningen af drivhusgasser. Foto: Janne Hansen

The images on the retina are stark:


One picture shows a tattered maize plant clinging to drought-cracked soil, thirsting for water and nutrients. If the farmer is lucky, she may reap a few edible cobs with the machete. This production provides an unstable, ineffective and inadequate food supply – often without even being low in carbon emissions because the soil is being depleted in carbon.


The other picture shows an army of giant harvesters that straight as a ruler eat their way through vast cornfields. This type of production effectively, intensively and stably supplies millions of people with food. The downside to this type of production is the large quantities of greenhouse gases emitted.


Is it possible to persuade countries that have an effective and fossil fuel-based food production to provide a production boost to countries with an inefficient production and in this way to both increase supply and reduce climate impacts? According to the four authors, one of whom is from Aarhus University, this can be done. In an article in the prestigious scientific journal Nature Climate Change, they set out a proposal for improving food security in developing countries.


The idea is to reward smallholder farmers directly for sequestering soil carbon. The focus is on carbon, since CO2 is the largest contributor to global warming. The scientists propose a system whereby developing countries with large greenhouse gas emissions can contribute financially to boost developing countries’ agricultural practices that are known to sequester carbon in the soil.


This form of carbon exchange can also encourage developing economies to bypass heavily polluting cultivation practices and instead move directly towards a more sustainable form of food production.


- Specific incentives for cultivation strategies in developing countries that store carbon in the soil will also increase crop yields. It will improve food security and ease the pressure on climate change. By increasing productivity we can also reduce the need to incorporate more land for agricultural production, which in itself will reduce greenhouse gas emissions, says one of the authors of the article, Professor Jørgen E. Olesen from Aarhus University.


Degraded soil can be reconstituted

The loss of carbon and nutrients from the soil is the main reason for the decline in soil fertility and thus productivity in sub-Saharan Africa. If nothing is done, this region has the prospect of remaining the most food-insecure in the world also in the future.


- Cropping systems that build up soil carbon can lead to larger and more secure yields through improved supply of water and nutrients, but it relies on sufficient supplies of nitrogen, phosphorus and sulphur, say the authors.


There are a number of methods that farmers in developing countries can employ in order to increase carbon sequestration in the soil. One of the methods is to combine farming with forestry, i.e., to plant trees. Not only do the trees bind carbon, some of them can also fix nitrogen, acquire key nutrients from the soil and can provide farming households with food, feed and fuel.


The farmer can also use restorative measures by keeping grazing animals out of the more degraded areas or by adding biochar to the soil. The most important thing is, however, for farmers to give the addition of organic matter has a high priority.


Proof of effect

Although changes in cultivation practices can provide larger and more reliable yields, it can still be difficult to convince farmers to change their traditions. Cash rewards for changing such management practices would be a good incentive.


This entails, however, the acquisition of evidence that the change in practice actually builds up carbon. To generate this knowledge for each individual situation would take far too long and undermine the farmer’s desire to become involved in the scheme.


The scientists therefore suggest research-based verification of the effect that change in management type has on carbon sequestration in different agroecological systems and soil types. This could help to significantly lower the costs and barriers to the restoration of higher carbon stocks and a more stable food supply.


The article ”Enabling food security by verifying agricultural carbon”can be read in Nature Climate Change, May 2014.


Further information: Professor Jørgen E. Olesen, Department of Agroecology, e-mail: jorgene.olesen@agrsci.dk, telephone: +45 8715 7778, Mobile: +45 4082 1659