Collective need and climate change: New study evaluates carbon removal options
By IIPP Research Associate June Sekera
Reducing the concentration of CO2 in the atmosphere is a collective need, yet controversy exists over the over the best way to go about it. Last month, I published findings from a study of carbon dioxide (CO2) removal, which, coincidently, came out just before the report on 20 March 2023 by the IPCC on global warming and our options to slow it down.
While carbon ‘capture’ and mechanical carbon ‘removal’ are touted in news stories, and governments put billions into subsidies for these methods, both my research and the IPCC’s findings show that the more effective, and faster, way to remove billions of tons of CO2 from the atmosphere is to restore and expand the carbon sequestration capabilities of plants and soil. So long as biological sequestration is not connected to carbon ‘offset’ schemes, it can be a powerful tool to address climate change.
My paper Carbon dioxide removal–What’s worth doing? A biophysical and public need perspective, published 14 February 2023 in PLOS Climate, reports on the research by myself and five colleagues.
Comparative evaluation using criteria that matter in public policymaking
My team and I did a comparative evaluation of various methods of carbon capture and CO2 removal, looking at both technical/mechanical methods and biological methods (trees, soil capture and so forth). We performed an input-outcome analysis using set of criteria that combine biophysical imperatives with collective need. We called this lens “collective biophysical need”. Our analytic approach enabled an apples-to-apples comparison of mechanical and biological methods on effectiveness, efficiency and co-impacts –- criteria that matter in public policymaking. The study is focused on the US, but the approach can be used in any country.
Biological sequestration: more effective and faster than technical/mechanical carbon removal
Our findings: biological sequestration methods, including restoration of forests, grasslands, and wetlands and regenerative agriculture, are both more effective and more resource efficient in achieving a climate-relevant scale of CO2 removal than are techno-mechanical methods — which use machinery and chemicals to capture CO2. Additionally, the co-impacts of biological methods are largely positive, while those of technical/mechanical methods are negative. Biological methods are also far less expensive.
Our research found that, in the US, biological sequestration is currently removing almost a billion tons (a gigaton, Gt) of CO2 per year; mechanical methods are removing none. The data show that, with further preservation and restoration of forests, grasslands, and wetlands, amplified urban tree cover and accelerated regenerative agriculture practices, biological methods could sequester at least 2 Gt per year, or 40% of the 5 Gt of CO2 that the US emits annually. Mechanical methods cannot be scaled up from their present level of zero to even 1 Gt per year as economically, swiftly or safely.
Consistent with our findings on the US, global data in the IPCC’s Working Group III report (2022), indicate that biological sequestration is not only more effective, but also could achieve results faster. Here is Table 2, published in our paper, which reflects IPCC global data that corroborates our US findings.
Table 2. Global CO2 Removal and Sequestration/yr: Biological CDR and DACCS
For policymakers weighing options, the paper provides tools that can be helpful: a carbon sequestration calculator and a dashboard. The dashboard is a simple graphic display that summarises the assessment results on various CDR methods and addresses the following questions:
· Does the method actually remove CO2 from the atmosphere?
· What are the resource costs: how much energy and land are required for removal at climate-significant scale?
· What are the collateral consequences of each method for people and places?
The Carbon Sequestration Calculator published in the study contains data for the US, but policymakers in other countries could use this tool to evaluate biological sequestration alternatives for their nations by obtaining and inserting the applicable data.
The paper recommends that governments devote substantial direct funding to implement methods that effectively sequester carbon in biomass and soil. The report stresses that these methods must be financed directly by governments, not through carbon offsets and credits schemes, which are counterproductive.
Our research also found that, in the US, despite their disadvantages and a track record of failure to date, technical/mechanical methods continue to receive large subsidies from the government while biological sequestration methods do not.
