Principles for Thinking about Carbon Dioxide Removal in Just Climate Policy

Abstract

Carbon dioxide removal (CDR) is rising up the climate-policy agenda. Four principles for thinking about its role in climate policy can help ensure that CDR supports the kind of robust, abatement-focused long-term climate strategy that is essential to fair and effective implementation.

Full text

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
Principles for Thinking about Carbon
Dioxide Removal in Just Climate Policy
David R. Morrow1, Michael S. Thompson2, Angela Anderson3, Maya Batres4, Holly J
Buck5, Kate Dooley6, Oliver Geden7,8, Arunabha Ghosh9, Sean Low10, Augustine
Njamnshi11, John Noël4, Olúfẹ́mi O. Táíwò12, Shuchi Talati3, Jennifer Wilcox13
1 Institute for Carbon Removal Law and Policy, American University, Washington, DC, USA
2 Carnegie Climate Governance Initiative, New York, NY, USA
3 Union of Concerned Scientists, Washington, DC, USA
4 Independent scholar, USA
5 UCLA School of Law, Los Angeles, CA, USA
6 Australian-German Climate and Energy College, University of Melbourne, Melbourne, Australia
7 German Institute for International and Security Affairs, Berlin, Germany
8 International Institute for Applied Systems Analysis, Laxenburg, Austria
9 Council on Energy, Environment and Water, New Delhi, India
10 Institute for Advanced Sustainability Studies, Potsdam, Germany
11 Pan-African Climate Justice Alliance, Nairobi, Kenya
12 Department of Philosophy, Georgetown University, Washington, DC, USA
13 Chemical Engineering Department, Worcester Polytechnic Institute, Worcester, MA, USA
Summary
Carbon dioxide removal (CDR) is rising up the climate policy agenda. Four principles for
thinking about its role in climate policy can help ensure that CDR supports the kind of robust,
abatement-focused long-term climate strategy that is essential to fair and effective
implementation.
Main Text
Carbon dioxide removal (CDR), sometimes called carbon removal or negative emissions, is the
practice of capturing carbon dioxide from the atmosphere and storing it for long periods of time.
There are many approaches to CDR, including nature-based solutions, like ecosystem
restoration, and more engineered approaches, like direct air capture with carbon storage.1
These encompass a variety of options for storing carbon, ranging from biomass and soils to
oceans and geological reservoirs to long-lived products like timber buildings or cement (Figure
1). CDR does not include fossil carbon capture and storage (CCS), such as CCS on a gas-fired
power plant, or carbon capture and use that embeds carbon in short-lived products, such as
synthetic fuels; they might reduce emissions, but neither of these technologies removes carbon
dioxide from the atmosphere.
CDR is rising rapidly up climate policy agendas because it could provide a useful—
perhaps essential—supplement to emissions abatement as the world works toward meeting the

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
Paris Agreement goals for limiting global warming.2 As a result, civil society organizations,
philanthropic funders, and government agencies are wrestling with the challenge of forming
positions on CDR, including whether to support it at all and, if so, what mix of approaches to
support, what kind of policies should govern it, and how to connect it to other elements of
climate policy. The following four principles crystallize some of the key ideas that shape our own
thinking about CDR. We present them here in the hope that others will find them useful as they
deliberate about their own positions.
Figure 1. Some Proposed Methods of Carbon Dioxide Removal. Some of the many
approaches that people have proposed for removing carbon dioxide from the atmosphere and
storing it, presented here without assessment of their respective potential for removing or
storing carbon or their social, environmental, or economic sustainability, which vary between
methods and depend on the details and context of implementation. These methods are often
divided into “natural climate solutions” and “engineered” approaches, with the precise boundary
between those categories contested and somewhat vague. Illustration by Matt Twombly.
Don’t forget the long game
First, CDR is only one part of a long-term climate strategy. Cutting greenhouse gas emissions
must remain at the center of that strategy: CDR would be too slow, expensive and technically
uncertain to replace the need for rapid emissions reductions.3 Furthermore, attempting to do so
would mean missing out on the social and environmental benefits of transitioning to clean
energy. Adaptation, both incremental and transformative, also plays an essential role, as do
measures to address loss and damage. The world needs to do all of these things to fight climate
change—a “both-and” approach, not “either-or.”
Different people and institutions will have different expectations about long-term climate
strategies. These include differences over the kinds of social, economic and technological

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
transformations that societies should or will use to decarbonize, the kinds of policies societies
should adopt to spur those transformations, and the urgency and speed with which the world
can completely decarbonize. These differences imply slightly different roles for CDR as part of
the long-term strategy or different roles for different approaches to CDR at different times. In
particular, some might see a role for CDR to mop up residual emissions while we figure out how
to decarbonize harder-to-abate sectors like construction, heavy industry, and heavy transport.
Others might prefer to limit CDR to compensating only for agriculture and land-use emissions or
to use it after complete decarbonization to draw down “legacy carbon” remaining in the
atmosphere from past emissions.
It turns out that these disagreements have relatively little impact on the question of
whether to devote time and resources to CDR research, development, and deployment now.
Even if the world can completely decarbonize quickly without CDR, almost any path to
decarbonization still leaves the world facing dangerous climate impacts.2 By cleaning up legacy
carbon, CDR could lower carbon dioxide concentrations and reduce climate risk, though
lowering concentrations significantly would require removing hundreds of billions of tonnes of
carbon dioxide.4
To reach that scale, societies can begin rolling out some approaches now, such as
ecosystem restoration, informed by decades of experience at the intersection of land
management and climate policy. Other approaches, such as enhanced mineralization, require
further research, development, demonstration, and deployment. Whatever mix of approaches
societies adopt, scaling up CDR capacity to the multi-gigaton scale, if feasible, would take
several decades.5 Therefore, if we want to remove hundreds of billions of tonnes by the end of
this century, whether as part of a net-zero strategy or to clean up legacy carbon,6 now is the
time to begin developing and adopting appropriate policies for CDR research, development, and
roll-out.
At the same time, thinking only about the long game isn’t enough. Reducing emissions
and adapting to climate change must remain top priorities in the near term.
It’s not all about the carbon
Second, social, economic, and environmental impacts matter. Different approaches to CDR
have different resource requirements and different social and environmental impacts.1,7 Whether
it is an individual farmer adopting cover crop rotations or a large corporation building a direct air
capture facility, the value of any CDR project depends not just on whether and how much
carbon it can sequester at what financial cost, but also on the project’s environmental, social,
and political impacts. In some cases, especially with natural climate solutions, positive impacts
could justify adoption independently of the climate benefits. In others, negative impacts could
outweigh any climate benefits. In all cases, those impacts depend on the context and details of
the project, not just on the particular technology or practice in question. For example, compare a
small bioenergy with carbon capture and storage (BECCS) facility fueled by local municipal
waste with a BECCS system in which huge swathes of commercially farmed land provide
switchgrass to fuel large power plants that pipe carbon dioxide long distances for sequestration.
These two approaches would have very different impacts, which could include impacts on land
use, water use, infrastructure needs, food prices, and biodiversity. Evaluating CDR at the level

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
of broad technologies or practices obscures these differences. As a result, technology-level
assessments tend to focus on things that can be calculated in the abstract, such as cost and
total carbon sequestered. Those aspects of CDR matter, but a complete assessment of CDR
requires assessing not only cost and sequestration potential, but also environmental and social
impacts.
Three questions about social and political context deserve special attention. The first is
whether a particular project, program, or policy comports with equity and the principle of
common but differentiated responsibility and respective capabilities. CDR is fundamentally
about cleaning up pollution. It makes sense for the polluters to pay for it, with excess costs
falling on those who are best able to bear them. It would be patently unfair for the Global North
to pass the responsibility for cleaning up carbon pollution to the Global South, which contributed
much less to the problem. Some observers worry the very corporations that contributed so
much to carbon pollution could use CDR to evade accountability, but it could be that assigning
these corporations responsibility to undertake or finance CDR offers a way to hold them
accountable. Thus, a key social and political question about any CDR undertaking is the extent
to which the costs and the social and environmental burdens associated with it fall on those who
bear the greatest responsibility for the problem.
The second question is about the overall political and economic context in which CDR would
be deployed in the future. Many civil society organizations argue that nothing short of radical
social transformation will enable us to stop climate change, with some fearing that CDR would
be used to delay that transformation. But a vast, decades-long carbon clean-up operation would
look very different after a radical social transformation than it would in the current political and
economic climate. Moreover, because CDR at the multi-gigaton-scale would require vast
infrastructure, and because some options, like direct air capture, assume widespread cheap
renewables, large-scale CDR implies widespread voter willingness to fund carbon clean-up and
deep decarbonization, making CDR a consequence of social transformation, changed values,
and renewables deployment, rather than an obstacle to them.8 We may need to stretch our
imaginations to envision economic and political futures in which CDR fits into the world we want,
rather than delaying or undermining it.
The third question is about the level of transparency included or required for any given
CDR undertaking. It is difficult to assess an undertaking’s social, economic, and environmental
impacts without adequate transparency, making transparency essential for effective and
legitimate decision-making.
Split, don’t lump
Third, assessing CDR requires going beyond technology-level analyses. This follows from the
second principle. Not all carbon removal is created equal in terms of social, economic, and
environmental impacts, and nuanced positions are needed to distinguish better technologies,
practices, projects, and policies from worse ones.
Broad categories, such as the ones in Figure 1, usefully convey the breadth of options
for CDR, but they also conceal important differences between specific technologies and
practices. For instance, forest restoration and monoculture tree plantations might both fall under
the heading of reforestation, but only the former can promote adaptation, preserve biodiversity

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
and deliver long-term carbon storage.9 To take another example, spreading finely ground basalt
on cropland and scattering olivine pebbles on coastal seabeds both count as enhanced
weathering, but the former requires far more energy to grind the rocks, and the two approaches
involve very different social, economic, and environmental systems.
Furthermore, the social, economic, and political context in which people implement CDR
will affect its acceptance and impacts. For example, consider a direct air capture facility
financed by fossil fuel companies or a petrostate. Some would regard such a facility’s fossil fuel
financing as unforgivable. Distinguishing between different projects and different contexts,
however, allows those who oppose fossil fuel financing to take a nuanced position that opposes
that particular project while leaving open the possibility of direct air capture projects that operate
free from fossil fuel influence and in a context of transparency and good governance. That
makes it important to assess CDR on a case-specific basis, rather than just as abstract
technologies. It is only at this level that organizations can distinguish between bad technologies
or practices and bad projects, taking account of the environmental, social, political, and
governance contexts of specific projects.
In short, fine-grained analyses of carbon removal projects, programs or policies allow us
to avoid throwing the good out with the bad or allowing the bad in with the good. By analogy,
support for emissions reductions doesn’t automatically translate into support for every strategy
that would cut emissions.10 Some see some kinds of low-carbon energy as better than others,
and many outright oppose certain technologies or practices, such as nuclear power plants or
large hydroelectric dams, because of costs, risks, or impacts on vulnerable communities and
ecosystems. It is even possible to support a particular technology while opposing specific
projects. For example, an organization may support policies to incentivize development of solar
energy while opposing a specific project because it is sited on high value biodiversity land. CDR
deserves the same nuanced analysis.
Don’t bet it all on being right
Fourth, climate policy needs to be resilient against unexpected outcomes. The long-term
scenarios that the Intergovernmental Panel on Climate Change (IPCC) analyzed for their Fifth
Assessment Report in 2014 and their Special Report on Global warming of 1.5°C relied heavily
on vast plantations of bioenergy crops for BECCS to keep warming below 2°C or 1.5°C.2,11
Critics noted that counting on future CDR in this way puts future generations’ well-being at risk:
if large-scale CDR never emerges, for whatever reason, then future generations will find
themselves saddled with dangerous levels of atmospheric carbon dioxide.12 We agree that
precaution precludes us from betting it all on CDR panning out as the models project. We also
worry about making the opposite mistake by counting only on rapid emissions abatement: if the
world fails to decarbonize quickly, for whatever reason, or if we decarbonized quickly but the
climate did not respond as we expected, then future generations could find themselves saddled
with dangerous levels of carbon dioxide. Robust, flexible, precautionary climate policy requires
recognizing that, despite our best-laid plans, future generations might benefit from large-scale
CDR in the second half of this century. Ensuring that large-scale CDR is a possibility by mid-
century means beginning research and development now. Playing “wait and see” with CDR

Forthcoming in One Earth August 2020. DOI 10.1016/j.oneear.2020.07.015
could leave us with several extra decades of global heating that could have been avoided and
increased risk of crossing climate tipping points.
Why It Matters
What’s at stake in making the right call on CDR? We worry about three things with respect to
CDR: societies could do too little, they could do too much, or they could do it wrong. On the one
hand, if the world does not devote enough time and resources to developing and deploying
CDR, we will face higher carbon dioxide concentrations--and therefore a more dangerous
climate--than necessary. On the other hand, societies that pursue CDR at too large a scale,
adopt the wrong mix of approaches for their circumstances, or govern CDR ineffectively could
face serious social and environmental downsides. By engaging thoughtfully with CDR based on
the principles we have outlined, civil society organizations, funders, and government agencies
can help ensure that CDR plays a positive role in the kind of robust, abatement-focused long-
term climate strategy that is essential to fair and effective climate policy.
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Acknowledgements
The authors gratefully acknowledge helpful comments from the editor at One Earth. Note that
the views expressed in this Commentary are those of the authors and do not necessarily reflect
the views of their respective organizations.