Stop Relying on the Kindness of Strangers for Carbon Dioxide Removal: The Case for a Carbon Takeback Obligation

Scrubbing the Skies | April 15, 2026
Originally posted on LinkedIn

By Wil Burns
Co-Director, Institute for Responsible Carbon Removal (IRCR), American University

1.    Introduction

As the Intergovernmental Panel for Climate Change concluded in its Sixth Assessment Report, “[t]he deployment of [carbon dioxide removal] to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved.” Moreover, while the Parties to the Paris Agreement envisioned that reaching net zero emissions by mid-century could effectuate the treaty’s temperature targets, recent research concludes that this is no longer the case. The recent first international conference on the topic of temperature “overshoot” concluded that while holding temperatures to 1.5°C above pre-industrial levels remains the long-term limit under the Paris Agreement, exceeding that limit is inevitable at this point. Indeed, globally averaged temperatures may consistently exceed 1.5°C above pre-industrial levels by 2030.

Returning temperatures to below this critical temperature threshold after “overshoot” will require the world to reach “net negative emissions.” This necessitates a robust commitment to both aggressive decarbonization and deployment of carbon dioxide removal approaches, perhaps at a very large scale. Of course, the larger the overshoot, the greater our commitment to uncertain and potentially risky carbon dioxide removal will have to be, emphasizing the need to accelerate global reductions of greenhouse gas emissions.

The lowest scenarios for CDR deployment in a recent report projected a need for four gigatons of annual removals by 2050. However, the central range in that study, and another, was 7-9 gigatons annually by 2050. Moreover, some studies project the need for as much as twenty gigatons of yearly removals in the latter half of this century.

Yet, achievement of these levels of carbon removal seems chimerical at the current time. One recent study concluded that there is more than a 50% gap between CDR pledges by Parties to the Paris Agreement in their Nationally Determined Contributions and what would be necessary to hold temperatures below 2°C, with a much greater gap for achieving 1.5°C. Given recent emissions trends, these projected needs are probably substantial underestimates. Moreover, many of the pledges made the Parties to Paris are not currently backed by legislation or other legally binding mechanisms.

Virtually all of the current demand for durable (long-term) carbon removal flows from the voluntary carbon markets (VCMs). However, this market is extremely small, pegged at approximately 44 million tons of contracted removals to date. Moreover, Microsoft, which has purchased approximately 80% of the contracted cumulative volume of carbon removals to date, has recently communicated to a number of suppliers that it is pausing carbon removal purchases. Even before this announcement was made, recent analysis indicates that buyers by 2030 may only be retiring 30-50 million tons of carbon removal from the voluntary market annually, representing less than 5% of the carbon removal needed in 2030 to meet IPCC scenarios consistent with holding temperatures to 1.5C.

To scale the CDR sector to a level that is fit for purpose in 2050 and beyond will require durable policy support that ensures robust and certain demand. A critical component of such support includes quantity-driven market-based instruments that fall under the broader rubric of “market pull policies,” anchored in compliance markets.  My Institute believes that an approach denominated as a “carbon takeback obligation” (CTBO) could be an effective compliance-based mechanism, ensuring that carbon dioxide removal plays the role that it must in climate policymaking.

2. The Nuts and Bolts of a CTBO

In its most distilled form, the overarching message of CTBO is “if you take it out of the ground you also have to put it back into the ground.” As such, a CTBO establishes a “mandatory link between carbon sequestration and fossil fuel extraction.” The CTBO targets the upstream segment of the fossil carbon supply chain, meaning the extractors of fossil carbon. Because it is implemented at the source of the supply chain, the policy focuses on the producer's responsibility rather than downstream entities. As such, the CTBO operates as a form of extended producer responsibility (EPR) for fossil fuel emissions. The EPR is premised on the “polluter pays principle,” a “cornerstone of many pollution-related regulations” at the domestic and international levels.

The simplest method to operationalize a CTBO is to impose the obligation at the point of extraction for four major sources of carbon dioxide emissions: oil, gas, coal and cement. A government-established storage certificate system would oblige extractors and importers of fossil fuels to either recapture and store a portion of their emissions through the development of carbon removal projects, or pay others to do so. Certificates could be implemented as an asset class or unit, facilitating transferability to other regulated entities to optimize efficiency.

Most CTBO proposals contemplate a phased-in mandate, typically imposing a requirement of a 1% takeback of carbon emissions in the base year, and escalating over time to a 100% mandate by the middle of the century. For example, California’s proposed Carbon Dioxide Removal Market Development Act would require companies subject to the California cap-and-trade system to purchase negative emissions credits.

This phased-in approach is salutary for a couple of reasons. With CDR infrastructure at a nascent stage of deployment, it would not be practically possible to sequester the entirety of 40 billion tons of emissions from unabated fossil fuels overnight. Additionally, a phased approach would send signals to the marketplace that could help to structure investments in a rational and orderly fashion to ensure adequate supply of carbon removal over the course of decades. It would also give governments time to help generate supply of carbon removal and lower long-term costs of removal through approaches such as targeted tax incentives and procurement.

CTBO costs would likely be comparable to achieving climate goals through the imposition of a global carbon price, or potentially even lower if one factors in policy risks attendant to a politically determined carbon price. In addition to simplifying carbon management, a CTBO simplifies carbon accounting by eliminating the tracking of carbon emissions through supply chains, in contrast to conventional life cycle assessments

Of course, it would be foolhardy to believe that a CTBO would be politically viable in the United States at this point in history given the strong political headwinds against climate policy. And even in places such as Europe, the fossil fuel industry would invariably seek to scupper such proposals. However, the time to start seeking to build the case for a CTBO in government fora and in the public sphere is now.

As Schenuit recently observed, “increasing recognition of likely temperature overshoot pathways – and their potentially irreversible impacts – can be expected to create a renewed CDR momentum in the 2030s.” It will be important when such inflection points arrive to have socialized a clear vision of compliance mechanisms for carbon removal that can work, and are perceived as fair. We believe that a CTBO, premised on imposing responsibility for cleanup on those who generate carbon pollution is such an approach.