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The international “4 per 1,000” initiative, launched by France in 2015 at COP 21 brings together voluntary public and private actors to implement concrete measures on soil carbon storage.
Human activity is a major source of carbon dioxide, better known as CO2. The latter is one of the main contributors to the greenhouse effect, and therefore to global warming. But about 30% of the CO2 produced each year is absorbed by plants, through an extraordinary process known as photosynthesis. These plants then become carbon sinks. After their death and decomposition, they are gradually transformed into organic matter by bacteria, fungi, and earthworms present in the soil. As nothing is lost, the carbon initially trapped through photosynthesis ends up in the soil and helps to fix water, nitrogen and phosphorus essential to the growth of future plants and human food.
Increase carbon stock
At present, soils contain on average between two and three times more carbon than the earth’s atmosphere. The international “4 per 1,000” initiative is based on this observation. The objective would be to increase this carbon stock by 0.4% per year – or 4 per 1,000, hence the name of the initiative – in the first 40 centimetres of the topsoil, which would considerably offset the increase in the amount of CO2 in the atmosphere.
As agriculture seeks by all means either to trap the maximum amount of water, nitrogen, and phosphorus in the soil – by adding carbon, for example in the form of ash – or to artificially increase their quantities via organic or chemical fertilisers, it could thus play a determining role for the future of our planet.
Indeed, with agricultural soils richer in carbon, and therefore in organic matter, agricultural productivity would be greatly improved on a global scale, ensuring food security even in the poorest regions. “Our ability to feed 9.8 billion people in 2050 in a context of climate change will depend, among other things, on our ability to keep soil alive“, recall those in charge of the initiative.
To achieve this result, the States, communities, companies and NGOs involved commit to implementing a number of essential measures, starting with the adoption of agro-ecological practices, which increase the amount of carbon in the topsoil. The international “4 per 1,000” initiative recommends, for example, reducing deforestation, not leaving soils bare – as this leads to carbon loss – and restoring degraded agricultural landscapes. It is also necessary to amend soil with manure or compost and to plant trees (or legumes) that capture CO2, which have a natural tendency to fix nitrogen and which can be used for human or animal food.
In concrete terms, each actor in the “4 per 1,000” initiative commits to a target and to one or more types of actions against land degradation (from soil carbon stock management to other support measures such as index insurance or payments for ecosystem services). This initiative planned until 2050 is part of the Global Climate Action Agenda (GCAA) adopted at COP22 following the COP21 Lima-Paris Action Agenda.