Matching policy and science: Rationale for the ‘4 per 1000 - soils for food security and climate’ initiative

Abstract

At the 21st session of the United Nations Framework Convention on Climate Change (UNFCCC, COP21), a voluntary action plan, the '4 per 1000 Initiative: Soils for Food Security and Climate' was proposed under the Agenda for Action. The Initiative underlines the role of soil organic matter (SOM) in addressing the three-fold challenge of food and nutritional security, adaptation to climate change and mitigation of human-induced greenhouse gases (GHGs) emissions. It sets an ambitious aspirational target of a 4 per 1000 (i.e. 0.4%) rate of annual increase in global soil organic carbon (SOC) stocks, with a focus on agricultural lands where farmers would ensure the carbon stewardship of soils, like they manage day-to-day multipurpose production systems in a changing environment. In this paper, the opportunities and challenges for the 4 per 1000 initiative are discussed. We show that the 4 per 1000 target, calculated relative to global top soil SOC stocks, is consistent with literature estimates of the technical potential for SOC sequestration, though the achievable potential is likely to be substantially lower given socio-economic constraints. We calculate that land-based negative emissions from additional SOC sequestration could significantly contribute to reducing the anthropogenic CO 2 equivalent emission gap identified from Nationally Determined Contributions pledged by countries to stabilize global warming levels below 2°C or even 1.5°C under the Paris agreement on climate. The 4 per 1000 target could be implemented by taking into account differentiated SOC stock baselines, reversing the current trend of huge soil CO 2 losses, e.g. from agriculture encroaching peatland soils. We further discuss the potential benefits of SOC stewardship for both degraded and healthy soils along contrasting spatial scales (field, farm, landscape and country) and temporal (year to century) horizons. Last, we present some of the implications relative to non-CO 2 GHGs emissions, water and nutrients use as well as co-benefits for crop yields and climate change adaptation. We underline the considerable challenges associated with the non-permanence of SOC stocks and show how the rates of adoption and the duration of improved soil management practices could alter the global impacts of practices under the 4 per 1000 initiative. We conclude that the 4 per 1000 initiative has potential to support multiple sustainable development goals (SDGs) of the 2030 Agenda. It can be regarded as no-regret since increasing SOC in agricultural soils will contribute to food security benefits that will enhance resilience to climate change. However, social, economic and environmental safeguards will be needed to ensure an equitable and sustainable implementation of the 4 per 1000 target.

Quantifying carbon for agricultural soil management: from the current status toward a global soil information system

“…While much of the data and many of the tools, technologies and collaborations needed already exist [85,94,95], the information is often fragmented and data availability is often limited [96]. More coordination, greater transparency and easier accessibility to the tools and data, among and between field scientists, remote sensing specialists, modelers and land managers, is needed.…”

“…assess model-associated uncertainty. Ensemble modeling has become standard practice in other fields that depend heavily on model-based predictions, such as weather forecasting and integrated assessment, but has yet to be routinely deployed for soil carbon modeling [95].…”

Facing climate variability in sub-Saharan Africa: analysis of climate-smart agriculture opportunities to manage climate-related risks

“…The 4‰ initiative "Soils for food security and climate", launched at COP 21 and which has now developed into a full-size international program, also targets climate change mitigation and adaptation through an increase of soil carbon content (Soussana et al, 2017).…”

Identifying Climate-smart agriculture research needs

“…At COP21 climate negotiations in Paris, the 4 per 1000 Initiative 'Soils for Food Security and Climate' was launched to promote the role of soil organic matter in addressing the triple challenge of food security, adaptation of agriculture to climate change, and mitigation of greenhouse gas emissions (Lal et al, 2015;Minasny et al, 2017;Soussana et al, 2018). The similarity with CSA is striking in terms of objectives, but the 4 per 1000 initiative focuses solely on soil carbon management as a means to achieve its goals.…”