Know more

Article published in October 2019 in the Annual Review of Environment and Resources.

Abstract:

Land-management options for greenhouse gas removal (GGR) include afforestation or reforestation (AR), wetland restoration, soil carbon sequestration (SCS), biochar, terrestrial enhanced weathering (TEW), and bioenergy with carbon capture and storage (BECCS). We assess the opportunities and risks associated with these options through the lens of their potential impacts on ecosystem services (Nature's Contributions to People; NCPs) and the United Nations Sustainable Development Goals (SDGs). We find that all land-based GGR options contribute positively to at least some NCPs and SDGs. Wetland restoration and SCS almost exclusively deliver positive impacts. A few GGR options, such as afforestation, BECCS, and biochar potentially impact negatively some NCPs and SDGs, particularly when implemented at scale, largely through competition for land. For those that present risks or are least understood, more research is required, and demonstration projects need to proceed with caution. For options that present low risks and provide co-benefits, implementation can proceed more rapidly following no-regrets principles.

Impacts of land-based GGR options on NCPs and the SDGs

 "Across all of the land-based GGR options considered, all GGRs contribute positively to at least some NCPs and SDGs".

The 6 different GGR options presented in this study, were assessed in isolation, however, some options can be combined and enhance their effectiveness. Fors example Soil Carbon Sequestration can be easily combined with biochar on land used or with TEW to enhance productivity of trees and other biomass. One R&D priority is, therefore, to build the evidence base on synergies and trade-offs between different GGR options so that new portfolios of GGR options can be considered in combination rather than as single, competing options.

The authors specify that GGR options efficiency strongly depends on land and context, negative impacts can be due to competition for land, water, and other resources such as nutrients. This emphasizes the need to assess impacts in a scale- and context-specific manner. 

Besides, the study pointed out that there is a need for large-scale demonstration projects to move GGR option toward implementation. In the case of practices that result in SCS, are well characterized and are already being applied, although not exploited to their full extent. "Demonstration projects are essential for scaling-up of technologies, for realizing economies of scale, for reducing the costs of GGR, and for “learning by doing”".

Soil Carbon Sequestration presents few risks and indeed can provide a range of co-benefits across many NCPs and SDGs. "These options could be implemented rapidly, with rapid rollout of demonstration projects [...] These options can be regarded as no-regrets options, given they provide a range of benefits, even if all of the GGR potential is not realized". No-regrets options could be implemented quickly, with other options going through R&D and large-scale demonstration as they progress through the technology readiness levels.

Read the full article for more details: https://www.annualreviews.org/doi/full/10.1146/annurev-environ-101718-033129#abstractSection

Figure 3:  Summary of the impact of soil carbon sequestration (SCS) on soil functions, on Nature's Contributions to People (NCPs), and on the United Nation's Sustainable Development Goals (SDGs), showing the impact of each function on each NCP, and the contribution of the NCPs to each of the SDGs.