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SOILS AS NATURAL CLIMATE 2017). The “4 per 1000” effort has proposed Restoring degraded lands and avoiding
CHANGE SOLUTIONS soil as a natural climate change solution and further land conversion (e.g., afforestation)
Intergovernmental Panel on Climate endeavors to increase SOC storage by 0.4% can also help mitigate climate change (Fig.
Change (IPCC) assessment reports and the annually (Rumpel et al., 2020), thereby offset- 2; Table 1). Afforestation of degraded sites
Paris Agreement have highlighted the impor- ting one third of global fossil fuel emissions. in the United States is estimated to poten-
tance of immediate action to prevent cata- Here, we provide a review of the available tially sequester 2.43 Pg C yr in the upper
–1
strophic changes to the earth system. Inclusion solutions to increase the amount of C stored in 30 cm of soil over 30 years (Cook-Patton et
of soils in local to global climate change mit- the soil C savings account through a variety of al., 2020). Although afforestation efforts
igation strategies is a proven and cost-effec- land stewardship practices, including use of can increase SOC storage on decadal time
tive strategy. Natural climate solutions can amendments such as compost, biochar, waste, scales, the effects are largely site-specific.
provide 37% of cost-effective CO mitigation and management interventions such as refor- For example, depending on the prevailing
2
necessary for a >66% chance of holding estation, inclusion of deep root perennials, climate of an area, restoring grasslands
warming below 2 °C by 2030 (Griscom et al., and cover crops. might be a better option for C sequestration

Figure 2. Various management strategies in forested, agriculture/grassland, and wetland ecosystems exhibit differing pro-
pensities to take up CO . Overall, these strategies represent a way to expand terrestrial ecosystem uptake of carbon
2
(Friedlingstein et al., 2020; Paustian et al., 2016; Griscom et al., 2017).

TABLE 1. CLIMATE MITIGATION POTENTIALS OF VARIOUS LAND USE
PRACTICES ACCORDING TO POSSIBLE AREA OF PRACTICE ADOPTION
Practice Climate Mitigation Potential Area of Practice Adoption References
(Pg CO eq yr ) (Mha)
–1
2
Forests
Reforestation 10 3665
Natural forest management 1.8 3665 1, 2
Improved forest plantations 0.5 204
Agriculture and Grasslands
Biochar 1.7 2000–3000
Conservation agriculture 0.8 750–2000
Grazing—Optimal intensity 0.4 500–2000
Cropland management 1.5 750–2000 2, 3
Rice management 0.3 20–50
Enhanced root phenotypes 0.1 1000–2000
Wetlands
Restored histosols 1.3 10–15 2, 3
1 Siry et al., 2005
2 Griscom et al., 2017
3 Paustian et al., 2016

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