Getting Down to the Roots: Why Soil Matters for Climate Stabilization (and More)

Guest Post by Ryan Anderson, Delta Institute
The Climate Trust’s ‘Point of View’ guest blogger initiative fosters and amplifies expert industry voices
July 26, 2016

Following 2015’s designation as the International Year of Soils by the UN Food and Agriculture Organization, soil carbon sequestration is experiencing something of a renaissance among policy and scientific circles. Farmers are also getting involved, most recently through the Climate Leaders program of the National Farmers Union. Now the challenge is to translate all this momentum to action, starting with how we approach and develop climate-smart projects.

In April 2015, USDA released the Building Blocks of Climate Smart Agriculture and Forestry to focus on 10 action areas for voluntary and incentive-based conservation, the first being soil health. Taken together, the USDA’s 10 Building Blocks are expected to reduce greenhouse gas emissions by 120 million metric tons of carbon dioxide equivalent (CO₂e) annually by 2025—more than 5 times the compliance credits issued to date through the California Air Resources Board cap-and-trade program. Then, during the Paris climate negotiations in December, a broad international partnership launched the 4 per Thousand Initiative to encourage better stewardship of soil carbon stocks for meeting long-term climate stabilization goals; an initiative aimed to improve food security around the world. Though the 0.4 percent per year increase in soil carbon sequestration they call for is aspirational, the result at a global scale would be another 4.4 billion metric tons CO₂e removed annually from the atmosphere (or nearly two-thirds of all U.S. emissions).

These initiatives have since been bolstered by several timely studies, from an exploration of what it would take to meet the 4 per Thousand goals at a national scale, to a global review of the latest soil carbon research and mitigation potentials. The former, written by Adam Chambers and colleagues of USDA’s Natural Resources Conservation Service, calculates that a $3 to $5 billion investment in U.S. cropland and grassland soils over the next decade could increase sequestration by 250 million metric tons CO₂e per year. The figure below reveals a significant gap between recent USDA efforts and this potential, which the authors estimate would require 10 million cropland acres and 20 million grassland acres (on average) to enroll each year. By 2025, then, a concerted effort by US farmers and ranchers could yield carbon benefits similar to the EPA Clean Power Plan, at roughly half its modeled annual cost in the same year. The latter study, by Keith Paustian and colleagues of Colorado State University, puts the global mitigation potential of a broader range of soil management practices, including biochar and restoring degraded lands, at 8 billion metric tons CO₂e per year (or one-fourth of global energy-related emissions).

Source: Chambers et al. 2016, Journal of Soil and Water Conservation

In another recent study, soil scientist Rattan Lal estimated that increasing sequestration on just croplands globally could help lower the atmospheric concentration of CO₂ by up to 41 parts per million (ppm) over the next 50 to 75 years. This would be akin to reversing one-third of the increase observed since the Industrial Revolution, a crucial metric for avoiding dangerous climate change. While Dr. Lal cautions that the actual potential may only be one-third to one-half of this technical total after factoring in cost and farmer adoption, soil carbon sequestration is unique among mitigation technologies. In addition to being a significant long-term emissions sink, regenerating soils provides additional benefits including increased water infiltration, improved crop yields, and more nutritious food.

When trying to translate science and policy into programs that yield these multiple benefits at the scope, scale, and speed necessary, our path forward should be clear: as important as agricultural carbon sequestration is to stemming climate change, we need to couple our existing approaches with other tools that will accelerate shifts in practice, policy, and behavior.

Since launching its first program for soil carbon sequestration credits in 2006, Delta Institute has been hard at work building pathways to a more sustainable future that involves farmers from the start. Our small pilot in Illinois quickly expanded to Michigan, then went national within a year. When the program ended in 2011, over 1,300 farmers and landowners covering nearly 400,000 acres voluntarily signed up to store more carbon on their farms, forests, and grasslands.

While the challenge has remained the same, the way that we and our partners have approached it has changed over the years. For instance, we have helped develop projects to improve water quality, but those practices inherently improve the soil and its capacity to store carbon. Our work with sustainable land investment companies aims to grow the acreage under management regimes where building soil and its organic carbon components is a top priority. We also build collaborations across the food system value chain by reconnecting many of the linkages that have been severed over the past decades, which increases demand for climate-smart food.

As we work to accelerate the uptake of more regenerative agricultural practices, it is clear that we must start with a strong foundation: the soil. We are continuing to work with partners, like The Climate Trust, to build healthy soils through interventions across the agricultural value chain, from farmers to eaters and beyond.

Image credit: Flickr/NRCS Oregon