“Legacy” Emissions and Beyond-Neutrality Corporate Emission Reduction Targets


  • Corporations need not only to stop emitting greenhouse gases (“GHGs”) to prevent climate change, but they also need remove and sequester “legacy” emissions from the atmosphere.
  • Corporate GHG emission reduction targets set at levels above 100% create new challenges for corporations around measuring their past emissions, setting appropriate targets, and deploying strategies to remove carbon from the atmosphere.
  • Despite the challenges, the new opportunities for value creation from carbon removal for corporations are significant.


A number of large companies have recently introduced pledges to eliminate carbon emissions entirely in their efforts to fight climate change and grow in a sustainable manner. While eliminating future emissions is an important first step on the pathway to stabilizing our climate, few companies are talking about how they can deal with the fact that a significant percentage of their emissions from previous decades of doing business still remain in the atmosphere, contribute to climate change, and affect the sustainability of their operations going forward.

Scientific context. Carbon dioxide is considered a “long-lived” pollutant, meaning that it resides in the atmosphere for centuries (on average). This leads to a pesky problem — we could decarbonize our economy entirely, and we still could face the consequences of climate change caused by pollution from decades past. As a result, it is increasingly likely that we will need to employ carbon removal solutions — i.e. processes capable of removing and sequestering carbon from the atmosphere. While there is increasing activity to develop such carbon removal solutions, proven and scaleable carbon removal solutions have yet to emerge.

Challenges for corporations. Carbon removal creates a number of challenges for corporations seeking to set meaningful GHG emission reduction targets.

  • Measurement. It is frequently difficult for companies to asses their historic contributions to carbon emissions. Companies can usually get a rough order-of-magnitude estimate of historical emissions, but it is very difficult to tell using legacy systems that might not have captured necessary data to get a more precise estimate.
  • Targeting. Even if companies have a good sense of their total historical emissions, it can be difficult to set reduction timelines. New science-based methodologies are being developed to help inform forward looking targets, but it is unclear whether they will incorporate negative emissions.  A more fundamental question is how companies might deal with legacy emissions not directly attributable to them, but that still affect how they do business in the future.
  • Action: Given the current state of development of many carbon removal approaches, companies could face challenges around generating scalable and verifiable net-negative emission levels. Many carbon removal approaches today are expensive to deploy and/or measure, so companies are unlikely to deploy these such technologies at scale without further development.

Opportunities for corporations. Despite the challenges associated with adopting greater than 100% emission reduction targets, corporations that strive for such targets stand to seize valuable business opportunities — even in the sort-term.

CDP 2012 data


Above: data from the CDP 2012 disclosure scores, with my own analysis of carbon removal potential. 

For one, carbon removal offers new growth opportunities for companies thinking about providing carbon-negative products and services. Today, startups like Newlight Technologies are developing carbon-negative plastics that can substitute directly for carbon-emitting products — similar carbon-removing products could provide a great way for companies in commoditized industries for differentiating their offerings.

Above: AirCarbon packaging used by Dell. Source: packworld.com

In addition, carbon removal solutions can help improve operational and supply chain efficiency. For example, agricultural carbon removal solutions such as restorative farming approaches hold the potential for increasing crop resilience, reducing water and fertilizer needs, and even enhancing yields.

Columbia Field Trials

Above: biochar field trials. Source: International Biochar Initiative.

Lastly, corporations that move early to set net-negative emission reduction goals stand to generate large brand leadership benefits. Consumers are hungry for innovative climate solutions, and are likely to reward corporations for their leadership in enabling consumers to vote with their wallets for carbon-removing products and services. With strong corporate leadership and academic partnerships, we could start seeing carbon-negative products across numerous industries, including: foods, cements, fertilizers, and even gasoline.

Moving forward. It is clear that companies still have a long way to go just to get to carbon neutrality. But it is important for corporate managers to think about how the long-term pathway to sustainability might involve net-negative emission reduction targets, and how early movers can start generating value through carbon removal today. Right now, little changes in reporting standards and protocols could go a long way to achieving this potential. For one, the CDP could update its Leadership Index and the GRI could update its reporting guidelines to encourage companies to employ net-negative emission strategies. In addition, the LEED green building rating system could encourage the use of more carbon-removing materials. But most importantly, early corporate leaders will have to stand up and commit to a “beyond-neutrality” goal, and show that it is possible to make steady progress towards that goal with a combination of the mitigation technologies of today and the carbon removal solutions that hold promise for our future.



Carbon-as-a-service Businesses?

The Cleantech Group’s annual San Francisco Forum wrapped up earlier this week. The event’s theme was “Cleantech-as-a-service,” and featured parallel tracks named “Cloud” and “Connect.” Overall, this focus on technology-enabled business model innovation shows how mature the cleantech field has become, as the event felt very much like a “standard” tech conference in the Bay Area.

Above: Sheeraz Haji kicking off the Cleantech Forum SF 2015 event.

The growing emphasis on the “tech” portion of “cleantech,” however, has not caught on for all clean technologies. For example, carbon sequestration businesses were conspicuously absent from this year’s Forum. Economic fundamentals can help explain this lack of carbon sequestration businesses on display. Most of the discussion at the Cleantech Forum focused on the left-hand side of the McKinsey GHG abatement curve (below), which makes perfect sense: no amount of clever business model or financial product innovation will help uneconomic businesses (like many carbon sequestration businesses today) flourish.

mck ghg abatement

Above: McKinsey GHG Abatement Cost Curve

The big exception to the above, however, is solar PV — which many would call the poster child of the cleantech-as-a-service revolution. What has set solar apart from other high dollar-per-ton GHG abatement schemes is non-carbon-focused regulations (be it some combination of net-metering, renewable portfolio standards, PACE financing, etc. designed to specifically support renewables).

What is so striking is how little acknowledgement such policies now get in the cleantech conversation. Business model innovation is highly complementary to environmental policies, yet so few of the leaders on stage at the Forum advocated for additional/ongoing policy support. I worry that the focus on business model / financial innovation will only take the cleantech field so far (or will delay its development considerably), preventing us from achieving the rates of decarbonization necessary to prevent climate change.

When former EPA Administrator Lisa Jackson came to speak at Berkeley on March 12th, she remarked that her job at Apple today is still to make good policy, it is just to do it from inside of business instead of inside government. I am eager to see if this philosophy will gain broader acceptance, and I look forward to the discussion at future Cleantech Forums to track how this dialogue unfolds.

How weight loss can put carbon removal in perspective

Six years ago, then U.S. Secretary of State Hillary Clinton compared climate change to weight loss:

“You know, oftentimes when you face such an overwhelming challenge as global climate change is, it can be somewhat daunting,”


“If we keep in mind the big goal, but we break it down into baby steps – those doable, achievable objectives – we can do so much together.”

Clinton’s analogy comparing fighting climate change to weight loss can be extended to help put carbon removal in context. In this analogy:

  • Conservation and mitigation: analogous to going on a diet. The no-brainer strategy for starting to lose weight is to eat fewer calories, just like the no-brainer strategy for preventing climate change is to reduce carbon emissions from activities such as burning fossil fuels, deforestation, and intensive industrial agriculture.
  • Removing carbon from the atmosphere: analogous to exercising. Sometimes diet alone isn’t enough to lose weight, exercise is needed too. In the same way, simply stopping carbon emissions might not be enough to prevent climate change — we might also need to remove excess carbon from the atmosphere and/or oceans. And even if we could prevent climate change without carbon removal, pursuing carbon removal strategies slowly and in moderation is likely to be beneficial regardless, much in the same way that moderate exercise is healthy regardless of whether it is necessary for weight loss.
  • Adapting to changes in the climate: analogous to buying new clothes. Buying new clothes does nothing to help you lose weight — but it does make like more comfortable while you are overweight. No doctor has ever said, “it’s OK to be obese — you can adapt to this condition by planning what new clothes you should buy as you grow larger…” just like scientists largely agree that climate adaptation is no substitute for preventing climate change in the first place.
  • Albedo modification geoengineering techniques: analogous getting lap-band surgery. Lap-band surgery can have devastating side effects and so is only recommended in extreme circumstances. What’s more, the procedure only works in conjunction with diet and exercise. In the same way, albedo modification geoengineering techniques are viewed as highly risky and uncertain, and require dramatic emission reductions and carbon removal for them to be phased out.

“Carbon-removing” gas stations: the future of transportation?

Over the past several decades, gas stations have remained largely immune to the disruption that has radically altered other industries. But as climate change continues to increase, the imperative for innovation at the pump will start to increase significantly.

gas stations

Above: A time traveler from the 1970s would recognize today’s gas stations. The same could not be said about telephones…

Today, moving people and goods around the planet accounts for nearly 15% of global carbon emissions:

-images-Assessment Reports-AR5 - WG3-Chapter 01-03_figure_1.3 (1)

Above: IPCC Working Group 3 Chapter 1 Assessment Report 5 Figure 1.3

Scientists, however, are increasingly convinced that we will need to not just eliminate those emissions, but also remove and sequester large volumes of excess carbon from our atmosphere and/or oceans to prevent climate change. In effect, the carbon-emitting gas station of today is incompatible with the carbon-removing transportation sector that is required to prevent climate change. As a result, a central challenge for gas stations will be innovation: how can the gas station of the future remove excess carbon from the atmosphere instead of emit underground reserves of carbon into the atmosphere?

Fortunately, a handful of approaches have already started to emerge that offer the prospect of carbon-removing gas stations in the not-too-distant future:

Approach #1: Fill gas pumps with carbon-negative biofuels. Sustainably-grown biomass can be transformed through thermochemical processes into liquid fuels with a low carbon footprint. If some of the emissions associated with the biomass conversion are captured and sequestered underground, the net emissions from these fuels can be negative — meaning that each gallon of fuel actually sequesters more carbon from the atmosphere than it emits. While biofuels already supply a significant portion of fuel consumed in the UStoday’s biofuels are nowhere close to having even a net-zero emissions profile. To achieve net-negative emission profiles, then, biofuel projects will require capture and sequestration of emissions, such as the technology demonstrated at the Midwest Geologic Sequestration Consortium project.

Above: the ADM ethanol production facility in Decatur, Illinois capturing carbon emissions and sequestering them underground.

Approach #2. Use direct air capture systems to make fuels from excess carbon in the atmosphere. Audi has recently engaged the Swiss startup Climeworks to produce a carbon-neutral gasoline alternative using the Climeworks direct air capture technology. Coupling systems like those Audi is developing with sequestration projects could eventually result in fuels with carbon-negative emission profiles.

Above: Audi makes “e-diesel” using a Climeworks direct air capture system at this plant in Germany.

Of course, the gas station of the future might not actually sell gasoline: we could ditch the internal combustion engine altogether for other types of “engines” that are powered with carbon-negative sources of energy. For example, we could transform our vehicles to run on electricity supplied by a carbon-negative power grid (which could be achieved through utilizing biomass energy with carbon capture and storage, nuclear energy with direct air capture systems, and/or pyrolysis systems that produce electricity and biochar). Another alternative would be to develop carbon-negative sources of hydrogen for fuel-cell-based transportation systems.

But exactly what the carbon-removing gas station of the future looks like is far from certain. For example, the sustainable supply of biomass could be much smaller than is needed to supply carbon-negative biofuel demand. Direct air capture systems likely would add a significant premium to gas prices (even compared to biofuel alternatives), making their widespread adoption politically/economically challenging. And the electrification of heavy-duty transportation (aviation, shipping, etc.) is notoriously difficult to accomplish, making it challenging to generate net-negative emissions across the entire transportation sector if only electrification were pursued.

So in all likelihood, the gas station of the future will look like a combination of all of the above options. But if our society is going to mitigate climate change, one thing is for certain: tomorrow’s gas stations will need to be significantly different from today’s.

A busy week in Carbon Removal: February 8-15, 2015

The second week of February, 2015, proved to be a busy week in all things carbon dioxide removal (“CDR”).

First and foremost, the National Academy of Sciences came out with an extensive report on CDR that garnered significant media attention (including my own). The full report is worth the read, but if you only read two lines, I’d recommend the following in terms of importance for the CDR field:

“Even if CDR technologies never scale up to the point where they could remove a substantial fraction of current carbon emissions at an economically acceptable price, and even if it took many decades to develop even a modest capability, CDR technologies still have an important role to play.”


“If carbon removal technologies are to be viable, it is critical now to embark on a research program to lower the technical barriers to efficacy and affordability while remaining open to new ideas, approaches and synergies.”

Second, a great article was published in Nature Climate Change on the potential for bioenergy with carbon capture and storage (“bio-CCS”) to generate net-negative electricity for the Western US. A summary of the report is available from UC Berkeley, and the research has garnered considerable outside media coverage. The biomass fuel supply curve developed by the report’s authors is particularly interesting, and suggests that 100MM+ ton CDR from bio-CCS is possible in the western US largely from waste and residue feedstocks (which hold the potential to be more sustainable than dedicated feedstocks, assuming wastes aren’t valued for other competing uses…).

Supply curve of available solid biomass post-2030.

Above: Biomass supply curve in Western US from Nature Climate Change “Biomass enables the transition to a carbon-negative power system across western North America

Third, the AAAS Annual Meeting hosted a session titled, “Going Negative: Removing Carbon Dioxide From the Atmosphere” that looked into a wide range of CDR-related issues. The highlights from the session included:

  • Pete Smith from the University of Aberdeen kicked off the session with the conclusion that there is no magic bullet for CDR – pros and cons exist for all approaches – and that more RD&D is needed to develop viable CDR approaches. In addition, Pete noted that sustainability will be critical for developing CDR solutions, and that a negative emission technology strategy will have to develop hand in hand with food-, water-, and biodiversity-security strategies.
  • Jen Wilcox from Stanford summarized some of the key findings from the NAS report on CDR. One of the more interesting results she highlighted was from a paper she authored that estimated the amount of CDR potential in the existing fly ash, cement kiln dust, and iron/steel slag industries today — which could present low-hanging fruit for turning today’s industrial wastes into valuable inputs for tomorrow’s CDR process (even though the study finds that such industrial sources represent about 0.1% of total US emissions). More importantly, Jen highlighted that CDR and CCS technologies share a number of open research questions, and could benefit from an overlapping research agenda.
  • Peter Byck from ASU presented his video Soil Carbon Cowboys and discussed the exciting scientific research his team is planning to conduct to assess the potential of adaptive management practices of livestock rearing. And Lisamarie Windham-Myers from the USGS shared her work with soil carbon sequestration, highlighting groups like the Marin Carbon Project
  • The final two presentations of the session, from Ken Caldeira of Carnegie Institution for Science  and Jae Edmonds of Joint Global Change Research Institute, provided an interesting point of conclusion for the session. In particular, Jae’s work showed that integrated assessment models of energy systems enthusiastically build bio-CCS projects as a means to decarbonize the energy sector. Bio-CCS (as well as its cousin direct air capture and sequestration, or “DACS”) are highly industrial systems, which contrast greatly to the ranching and “carbon farming” techniques highlighted by Peter and Lisa Marie in the previous two sessions. The industrial CDR approaches lag far behind the biological approaches in terms of early enthusiasm outside of the academic community, and it will be critical for these industrial approaches to find an enthusiastic supporter base in industry (or elsewhere) for them to gain traction and meet the promise identified in the integrated assessment models.

Fourth and finally, interesting CCS innovations were on display at the ARPA-E conference in DC. Such innovations from ARPA-E programs like IMPACCT will prove critical for enabling both fossil and bioenergy CCS projects in the future. CCS was only a small fraction of the overall ARPA-E conference, and the session dedicated to CCS focused on the nascent market for utilizing CO2 in industrial applications. I am hopeful that the ARPA-E conferences in the future will highlight more innovations with shared CDR applications, including direct air capture, gasification, and thermochemical biomass conversion technologies.

What “net-zero” emission targets means for the carbon removal field

The Carbon Brief recently published a fantastic article explaining the implications of “net zero” climate targets in the context of international climate negotiations. The Carbon Brief article does a great job of highlighting the fact that “negative emission technologies” – or carbon dioxide removal (“CDR”) approaches are critical for enabling the global economy to achieve a “net zero” commitment.

The article goes on to note that, “however, there are clear limits to negative emissions and many options…remain unproven.”  The emphasis is mine, as I think this fact has enormous implications for preventing climate change.  Without proven, scalable, and sustainable CDR solutions, “net-zero” targets will prove highly challenging to meet: “net-zero emission” would become simply “zero emission” targets – certainly doable, but today looking far from certain from occurring.

A “net-zero” (let alone “below-zero”) target, then, risks being an empty goal if such targets are not accompanied by increased efforts to develop CDR technologies. A recent report on CDR from the National Academy of Sciences highlights that:

“If carbon removal technologies are to be viable, it is critical now to embark on a research program to lower the technical barriers to efficacy and affordability while remaining open to new ideas, approaches and synergies.”

The NAS study stops short of identifying details of what research is needed to develop scalable, sustainable, CDR solutions, and there is little talk in established science/technology R&D funding agencies about scaling up levels of CDR R&D. So as talk of “net zero” targets increase, so too must conversation about increased R&D funding for CDR in order to make such “net zero” targets credible.

Media coverage of carbon removal post-NAS report

In past several days, numerous media outlets have weighed in on the National Academy of Sciences (“NAS”) report on “climate interventions” (including yours truly). The Carbon Brief does a great job of aggregating these responses, which reveal both positive and negative signs for future discourse on carbon dioxide removal (“CDR”) — i.e. removing and sequestering excess carbon from the atmosphere and oceans.

The main negative sign is that many media outlets are still conflating CDR as “geoengineering” alongside Albedo Modification (“AM”) – despite the fact that the NAS report specifically fought against this this confusion:

“Carbon Dioxide Removal and Albedo Modification (i.e., modification of the fraction of short-wavelength solar radiation reflected from Earth back into space) have traditionally been lumped together under the term “geoengineering” but are sufficiently different that they deserved to be discussed in separate volumes.”

For example, the review from the Guardian quotes Eli Kintisch from Science Magazine who describes both CDR and AM as “a bad idea whose time has come.”

The Union of Concerned Scientists response does a better job of separating CDR from AM in its coverage. But their coverage, which focuses on the conclusion that “carbon removal and sequestration are more costly than reducing emissions,” risks leaving their readers with the wrong impression that we shouldn’t invest in developing CDR systems today. In fact, the NAS report highlights that it is very important to invest in developing CDR systems in addition to rapidly scaling up climate mitigation and adaptation solutions (given the importance of viable, sustainable, CDR options in the event we do not decarbonize as quickly as necessary to prevent climate change). CDR solutions are in a similar state of development as solar energy solutions were in the 1970s — concluding that such 1970’s solar projects were “expensive” misses the point that large cost reductions were possible and, if achieved, could prove transformative to our energy industry.

The best news I see from this coverage is that there seems to be little opposition from mainstream outlets to CDR (definitely not the case with AM). The only opposition to CDR comes from the Guardian article, which cites Naomi Klein and Rachel Smolker from Biofuels Watch as detractors. The overwhelming majority of leading NGOs, policy, and industry leaders have not called for CDR research and development to be limited, which is highly encouraging for the CDR field .