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Looking at Land Restoration as a Carbon Removal Solution

Monday, January 29, 2018
Serena Choi

Serena Choi

Research and Publications Intern

With the Paris Climate Agreement’s goal to keep average global temperature from rising more than 2 degrees Celsius above pre-industrial levels, governments across the world are struggling to reduce carbon dioxide (CO2) emissions voluntarily and collectively. Some have described this challenge as a prisoner’s dilemma. Removing carbon from the atmosphere may be the key to escape.

A recent article in The Economist notes that “101 of the 116 models the Intergovernmental Panel on Climate Change (IPCC) uses to chart what lies ahead assume that carbon will be taken out of the air in order for the world to have a good chance of meeting the 2 degree Celsius target." So while carbon mitigation efforts are important, we must start talking about "negative emissions" technologies to reduce the total carbon stock that is already in the air. Without doing so, the Paris Climate Agreement’s goals may simply be unattainable.

While carbon dioxide mitigation techniques aim to reduce or prevent future emissions of greenhouse gases, carbon dioxide removal (CDR) technologies aim to extract excess carbon that already exists in the air. And while there are a number of technologies, they have their limitations. One technology, recognized as a key component for reaching CO2 targets in the IPCC Fourth Assessment Report (2007), is Bio-Energy With Carbon Capture and Storage (BECCS). Although BECCS is often branded as a viable engineering-based carbon "removal" solution by “capturing carbon from biomass at the conversion facility and permanently storing it in geological formations,” this technology is not carbon-free itself, as it entails burning plants and crops. BECCS also creates competition for limited land and food resources and further sacrifices the carbon storage benefit of land and food.

Another form of CDR technology is Carbon Capture Sequestration (CCS), which captures CO2 emissions from large point sources, such as power plants and other industrial facilities, and stores CO2 where it won't enter the atmosphere, mostly underground. There have been a number of studies on CCS both globally and nationally, but practical hurdles to widespread adoption of CCS remain. Legal Pathways to Widespread Carbon Capture and Sequestration, which appeared in the December issue of ELR's News & Analysis, highlights three main challenges. The first and tallest hurdle is the high cost of the technology and the uncertainty of potential liability and associated costs. The second is the absence of a strong national legislative or policy driver. And the third is economic and regulatory competition posed by natural gas, which undermines efforts to incentivize CCS. In addition, the process of transporting captured CO2 before depositing it also poses economic and practical problems.

Engineering-based CDR technologies include direct air capture (DAC) and enhanced CO2 mineralization techniques. DAC systems use chemicals that stick to CO2 in the atmosphere. Then, artificial “forests” of DAC machines sequester captured carbon underground or in materials. The “enhanced mineralization” technique uses certain types of rock that undergo a chemical reaction when met with CO2 in the air and transform pure CO2 into the carbonate rocks. But like the other CDR technologies, the availability and scalability of DAC and enhanced mineralization is uncertain, as neither has yet been commercially deployed. It is also hard to determine how much these technologies would actually cost once deployed. Cost estimates for DAC “range from around $60/ton of captured CO2 at the low end to $1,000/ton of CO2 at the high end.” Enhanced CO2 mineralization also isn’t economically viable yet, as it is expensive both to find cheap and voluminous low-energy intensity mineral sources and to transport them. These impediments have stymied significant project funding.

So, it is no wonder the 2014 IPCC Fifth Assessment Report recommended against CDR technologies, since "the availability and scale of CDR technologies and methods are uncertain" and they are "to varying degrees, associated with challenges and risks."

With government and private foundations also failing to meet the need for CDR technologies, truly what can be done? Are the promises of the Paris Agreement certain to be doomed? Nature-based CDR solutions may offer a path forward.

Restoring rainforests like El Yunque in Puerto Rico is one promising approach to carbon dioxide removal (Pixabay).

These natural “technologies” to capture and store CO2 in plants and soils revolve around changes in agriculture and forestry. Agricultural methods include agroforestry where landowners integrate forests with crops and livestock, “biochar,” and farm management to increase soil carbon stocks. There has been both academic and intergovernmental awareness on the advantages of agroforestry that is also closely related to land restoration. For example, the Food and Agriculture Organization of the United Nations (FAO) is currently implementing projects to help farmers control soil erosion and restore degraded lands in drought-prone areas like Guatemala and Honduras. CDR efforts in forestry go beyond simply curbing deforestation. Reforestation and afforestation both refer to adding trees to open lands, the difference being in how long these lands have been forest-less. Restoration efforts on damaged wetlands as well as other degraded lands also constitute nature-based CDR solutions.

While planting and anti-logging activities tend to capture more public attention and project investments, degraded-land restoration is often overlooked due to the challenge of measuring degradation and the need for complex and localized efforts. A recent ELI blog post, Rethinking Reforestation: Degradation as a Carbon Source in Tropical Forests, highlights why ensuring healthy, intact forests via land restoration and good governance is just as important as preserving forests, if not more. Recent research suggests that due to degradation, tropical forests that are often considered as carbon sinks may now be a carbon source; indeed, the study found that roughly 69% of all carbon losses are from land degradation and disturbance.

Nonetheless, land restoration and soil management may be promising alternatives to fancy engineering-based CDR technologies. According to the World Resources Institute (WRI), "there are more than 2 billion hectares (5 billion acres) of degraded land globally—an area the size of Australia—that are potentially ripe for restoration." Moreover, these natural approaches have been tested and used on a large scale before, as in WRI’s Initiative 20x20, as well as on a local scale, as in the Tigray Region, Ethiopia, where the policies successfully addressed and combatted desertification. Last but not least, land restoration and management are cost-effective. The Center for Carbon Removal places the average costs at $50/ton CO2 for wetland restoration and $55/ton CO2 for soil management. This per-ton cost of pulling one ton of CO2 out of the atmosphere aligns with moderate estimates of the social cost of carbon.

Put plainly, these figures suggest that society is likely to break even on an investment in nature-based CDR. This is promising; indeed, WRI highlighted these cutting-edge CDR technologies among its “Stories to Watch” in 2018. In order for such nature-based CDR technologies to be widely deployed, however, it is critical for policymakers to create incentives to spur project investments from public and private industry. Similarly, good governance is essential to conservation frameworks, and policymakers would do well to set clear policy goals with respect to land degradation. Against this backdrop, the upcoming 2018 IPCC report’s handling of negative emissions technologies will indeed be a story to watch.