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New research released on the realistic global potential of 4 per mille

20th Jan 2017

Source: Minasny et al (2017), Soil carbon 4 per mille, Geoderma 292, 59-86 

At COP21, the French minister of Agriculture Stephane Le Foll set an ambitious international research program, the '4 per mille Soils for Food Security and Climate' of the Lima - Paris Action Agenda. The 4 per mille or 4 per 1000 aspires to increase global soil organic matter stocks by 0.4 percent per year as a compensation for he global emissions of greenhouse gases by anthropogenic sources. It was launched during COP 21 in December 2015 and supported by over 150 signatories, ranging from countries, regions, international agencies, private sectors and NGOs). Stakeholders commit in a voluntary action plan to implement farming practice that maintain or enhance soil carbon stocks in agricultural soils and to preserve carbon-rich soils.

Soil organic carbon sequstration has been considered as a possible solution to mitigate climate change, to take atmospheric CO2 and convert it into soil carbon which is long lived.  As soil stores two to three times more carbon than the atmosphere, a relatively small increase in the stocks could exert a significant role in mitigating greenhouse gas emissions. The annual greenhouse gas emissions from fossil carbon are estimated at 8.9 giga tonnes. Taking the ratio of global anthropogenic C emissions and the total SOC stock results in the value of 0.4% or 4%. Increasing SOC has been proposed to mitigate climate change with an additional benefit of improving soil structure and conditions.

This paper uses country case studies to look at the potential for achieving this level of sequestration and whether its a sensive and manageable strategy, including what farming practices, and land types will be the most successful.

What did it find?

As a strategy for climate change mitigation, SOC sequestration should be implemented immediately. It buys time over the next ten years whilst other effective sequestration and low carbon technologies will become viable. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers and marketeers. Farmers and land managers primarily apply management practices to improve their soil's condition and, in doing so, can also contribute to the sequestration of C and mitigating climate change.

Scientists provide innovation tha can result in enhanced carbon sequestration, monitor the impact of cliamte change on soil organic carbon, and soil organic carbon functioning. Scientists also develop new technologies in measurement, mapping and auditing to verify SOC sequestration, which is expected by the market to provide confidence in investment. Famer's SOC sequestration effort provides compliance to the policy makers. This has to be integrated with institutional regulations and policies that facilitate market based approaches such as carbon trading. Soil C 4 per mille can make soils a sustianable resource, not a renewable source.

To read the full paper please click here.