Carbon-Storing Potential of Global Soils for Climate Mitigation

A collaborative study performed by The Nature Conservancy and the Kunming Institute of Botany, Chinese Academy of Sciences, estimated the carbon-storing power of soils worldwide and demonstrated techniques such as agroforestry designed to capitalize on the unexploited potential.

The new study reports that a crucial, nature-based strategy to tackle climate change has been existing, describing that soil holds up to 25% of the entire global potential for natural climate solutions (NCS). NCS represents ways to absorb CO₂ from the air and lock it into landscapes, such as croplands, peatlands, and forests.

This is the first time that the total global potential of soil for carbon-mitigation across wetlands, forests, grasslands, and agricultural lands has been jointly listed.

The study headed by researchers from The Nature Conservancy, in collaboration with Conservation International, Woods Hole Research Centre, University of Aberdeen, Yale University, and the Kunming Institute of Botany, Chinese Academy of Sciences (KIB/CAS), offered a timely reminder, in this crucial “super year” for nature, not to ignore the power of soil and several advantages these ecosystems can provide for wildlife, agriculture, and climate.

A paper related to this study, titled “The role of soil carbon in natural climate solutions,” was published in the Nature Sustainability journal. The study also claimed that investment has been restricted to date since the full scale of this opportunity and the ways to best capitalize on it are not clear.

While momentum continues to build behind the role nature can play in the global response to climate change, soils have historically enjoyed less of the limelight as a ‘natural climate solution’ compared with, say, forests or mangroves. Our study is designed to redress this situation.

Dr Deborah Bossio, Study Lead Author and Lead Soil Scientist, The Nature Conservancy

Dr Bossio continued, “By highlighting the full carbon-mitigation potential of soils across a range of landscapes, but also—crucially—exploring practical mechanisms that already exist for accelerating the uptake of these comparatively untapped approaches, including their integration into burgeoning carbon markets.”

Dr Bossio added, “This is particularly important for agriculture sector, for which more effective management of soils represents the single biggest contribution this industry can make towards mitigating climate change.”

Soils and improved soil management have a tremendous potential to store carbon. Agroforestry, and more generally just including more trees in the agricultural landscape, has been shown to be one of the most important approaches to increasing soil organic carbon with substantial global mitigation potential.

Dr Robert Zomer, Study Co-Author, Kunming Institute of Botany, Chinese Academy of Sciences

Zomer continued, “In addition, highlighting the complimentary beneficial impacts available from improved agricultural production practices aimed at improving soil health, both the increased on-farm bio-diversity and livelihood diversification can enhance farm and ecosystem resilience.”

Apart from showing that soil carbon accounts for up to 25% of total global NCS potential, the study also predicted that 40% of this potential can be availed by safeguarding the current soil carbon reserves and the remaining 60% can be availed by rebuilding stocks consumed up by practices like draining of peatlands and over-intensive arable agriculture.

The team broke down the data further and revealed the share of the overall NCS potential represented by the soil across several, climate-critical landscapes—ranging from a comparatively small 9% of forest mitigation potential, through 47% for grasslands and agricultural lands, up to 72% of total carbon sequestration potential in wetlands.

Also, the study demonstrated that agroforestry systems could have considerable positive effects on soil organic carbon over particular geographies. Furthermore, most of the alternative soil carbon pathways have been found to be “no regrets” practices that offer climate resilience, soil fertility, and other ecosystem services apart from climate mitigation.

We already know that nature has a powerful role in mitigating runaway climate change. This study showed the NCS provide pathways for sustainable development that have both climate mitigation and livelihood improvement potential. It is essential that soil health become a central pillar of agricultural production, not just for climate mitigation, but also for both environmental and food security.

XU Jianchu, Professor, Kunming Institute of Botany, Chinese Academy of Sciences

Jianchu was not associated with the research.