Soil Is Bigger Carbon Sink Than Previously Thought: Report

The world’s topsoils store 45% more carbon than previously estimated, making them a powerful, largely untapped carbon sink, according to a new report.

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A new report issued on “Agriculture Day” of COP30 found that soils store about 2,822 gigatons of carbon in the top one meter, up from earlier estimates of around 1,500 gigatons. It also concluded that 27% of carbon emissions needed to keep global warming below 2C can be sequestered in soils in good condition, the equivalent of about 3.38 gigatons of carbon dioxide (Gt CO2) per year. 

This carbon sink is in danger: the report explains that at current rates, soil degradation could release 4.81 billion metric tons of CO2 per year into the atmosphere, if allowed to continue. Current CO2 emissions from degrading US soils alone equate to approximately 75 million cars, while that if 1% of the carbon in Europe’s soils were to be released, it would equate to the annual emissions of 1 billion cars. 

Meanwhile, the economic value of soil’s ecosystem services are estimated at over $11 trillion annually, with every $1 of investment in soil regeneration leading to as much as $30 in economic returns, according to the report.

Despite this, only 30% of nations include soil restoration as a climate mitigation solution in their COP30 National Determined Contributions (NDCs), national climate plans mandated under the Paris Agreement. 

The report was compiled by the Aroura Soil Security Think Tank, the IUCN World Commission on Environmental Law (WCEL), and the Save Soil campaign.

“The third round of NDCs speaks about agriculture as part of the solution,” said Praveena Sridhar, Chief Science and Policy Officer of Save Soil, told Earth.Org. “But it doesn’t mention organic carbon. EU mentions it in the text of their NDC, but it’s not a commitment – only a potential. All energy and transportation commitments are quantified, but nothing is quantified with regard to soil. And if you don’t get soil into quantifiable targets, it’s all talk.” 

Soil health has come into increasing focus over the past several years, as 40% of Earth’s land is now already degraded and 90% could be degraded by 2050, according to the UN Food and Agriculture Organization.

However, this has not translated into concrete action at the policy level. “This has been going on for a decade,” said Sridhar. “There is no clear outcome from the Sharm el-Sheikh joint working group [on agriculture and food security]. There is no clarity on the plan, no clarity on the money, no clarity on the MRV [monitoring, reporting, and verification]. Everyone talks about how agriculture has huge potential [as a carbon sink], but nobody helps realize the potential.” 

MRV can be a serious barrier to realizing the carbon sink potential of topsoil, especially when it comes to establishing a baseline. “You need clear, accurate measurability,” said Sridhar. “It’s not like a factory, where you can switch on to determine the baseline – that’s not how land works. And with agrifood systems, that baseline of soils changes every few meters. But if you get the baseline right, you can outsource the MRV to machines.”

One EU project seeks to address this. ⁠A Soil Deal for Europe has an estimated investment of around 1 billion euros (US$1.15 billion) up to 2028, which involves establishing 100 Living Labs, research, innovation, and developing the monitoring framework, includes mapping. ⁠While other EU funding, like the Common Agricultural Policy (CAP), also contributes to soil management, the 1 billion euros is the most direct figure associated with the Soil Mission that underpins the new EU-wide soil health monitoring framework. Its ⁠goal is to develop a robust, harmonized EU-wide soil monitoring framework, which will contribute to assessing and achieving healthy soils by 2030 in line with the EU Green Deal’s long-term vision of healthy soils by 2050.

Unlike the UN Convention on the Law of the Sea (UNCLOS) for oceans and the Paris Agreement for the climate, soil lacks a global legal protection framework. However, the EU, the Pan-African Parliament and the International Union for Conservation of Nature (IUCN) last month took steps mandating the development of a Global Legal Instrument for Soil Security. 

At a COP30 High-Level Ministerial Event on Wednesday, Brazil’s Minister of Agriculture and Livestock Carlos Fávaro launched the Resilient Agriculture Investment for Net-Zero Land Degradation as a legacy effort to restore degraded farmland and promote sustainable agriculture.

The report introduces the Soil Security Framework, a practical model for protecting and restoring the world’s soils across five dimensions: capacity, condition, connectivity (how people value soil), capital, and codification (legal protection). This approach reframes soil from an agricultural variable to a strategic resource underpinning food, water security, climate resilience and economic stability.

Soil health is fundamental not only as a carbon sink, but also for climate adaptation. “Living soils are fundamental to agriculture,” said Sridhar. “They support you when you go through climate shocks. Healthy, living soils can absorb flood waters, and in drought they hold water like sponges. The crops are not successful because of the inputs you put on top like chemicals and pesticides – the security lies below the surface.”