The world needs to step up efforts to preserve soils since they are crucial to climate change mitigation and food security, the United Nations Food and Agriculture Organisation (FAO) has urged. “Soil is the foundation of agriculture, it is where food begins,” said FAO Deputy Director-General Maria Helena Semedo on World Soil Day which is celebrated on 5 December. “Maintaining the soil’s important functions and ecosystem services to support food production and increase resilience to a changing climate calls for sustainable soil management practices,” she stressed. Soil organic matter, with carbon as its main component, is crucial to soil health and fertility as well as water infiltration and retention. Almost 95% of food is produced on soils and worldwide, nearly 80% of the average calories consumption per person comes from crops directly grown in the soil. The world’s soils also act as the largest terrestrial carbon sink, reducing greenhouse gases in the atmosphere. According to FAO, soils can sequester around 20 000 megatonnes of carbon in 25 years, more than 10% of the greenhouse gas emissions. Intensifying this role could significantly offset the rapid rise of carbon dioxide in the atmosphere.

At the World Soil Day ceremony in Rome, FAO launched a comprehensive global map showing the amount of carbon stocks in the world’s soils. The map illustrates that globally, the first 30 centimetres of soil contains around 680 billion tonnes of carbon. This is a large amount compared with the carbon stored in the whole vegetation (560 billion tonnes). The map also shows that ten countries hold more than 60% of the total soil organic carbon stocks. Most carbon is found in Russia with 19.6% or 133 billion tonnes, followed by Canada (12.7%), the United States (8.3%), China, Brazil, Indonesia, Australia, Argentina, Kazakhstan and Democratic Republic of Congo. The map therefore reveals to decision-makers where the world’s natural carbon-rich soils are that need to be preserved to avoid further emissions and in which regions action should be taken to foster further sequestration.

FAO warned that the degradation of one third of the world’s soils has already prompted an enormous release of carbon into the atmosphere. However, by restoring these soils up to 63 billion tonnes of carbon could be removed from the atmosphere, significantly reducing the effects of climate change. “Maintaining – but especially increasing – soil carbon stocks should become an obligation as this will allow us to unlock the soil’s full potential to support mitigation and adaptation actions in a changing climate,” Semedo added. According to FAO, soils with high organic carbon content are likely to be more productive, better able to purify water and provide plants with optimal moisture conditions. Increasing soil organic carbon by improved management can help maintain productivity in drier conditions. This could be achieved through sustainable soil management, including mulching, planting cover crops, and moderate irrigation. Protecting the world’s soils is also fundamental for achieving Sustainable Development Goal 15 (Life on Land). The aim of SDG 15 is to protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss. (ab)