Carbon removal is mitigation, stop treating it as a last resort
If you restrict removal use for "unavoidable" emissions, you end up using it for nothing. We need to treat CDR as any other mitigation solution, and let markets allocate its use.
Top-down estimates of CDR needs put us in the multi-gigatonne range by global net zero. Yet, bottom-up, sectoral assessments very often ignore CDR as a mitigation option, assuming substitution, CCS, and demand reduction are the only tools available.
This disconnect both suppresses CDR deployment and makes reaching net zero harder. No real demand for removals will emerge until companies and policymakers start seeing carbon removal as part of the mitigation portfolio, something to use wherever it is the lowest-cost option, not a last resort for “unavoidable” emissions.
The mitigation portfolio
CO₂-generating activities can be mitigated by either:
1) Substituting an activity with a non-CO₂ emitting alternative.
2) Capture of the CO₂ emitted (CCS), or
3) Removing an equal amount of CO₂ from the atmosphere (CDR).
Demand reduction can help bring down the volume of CO₂ from an activity that needs to be mitigated, but for the remaining part, one of the above is needed.
Substitution is the cheapest alternative for the vast majority of emission-generating activities. EVs instead of ICE cars, renewable energy instead of coal, and so on. (This + demand reduction is what is usually meant when talking about emission reductions.) For a subset of activities, CCS will be the cheapest mitigation alternative, and for an even smaller subset, CDR.
These mitigation solutions are equally valid for stopping warming, and should be treated equally in policy and regulation.
CDR is, however, often seen as something that should be avoided and only used when there is no other option. A resource that must be carefully allocated with restrictions on where it may be used. For example, the EU parliament called for the EU commission to create a list of residual emissions for which carbon removal should be allowed. The Science Based Target initiative (SBTi) also indicates it will only allow predefined hard-to-abate emissions to be neutralized with CDR. At the same time, sectoral roadmaps like those for aviation and shipping treat CDR as an afterthought, not as a mitigation solution on the same level as electrofuels, for example.
Rationing or restricting CDR use would mean singling it out, treating it very differently from emission substitution solutions or any other resource in the economy. Doing so would need a strong justification. In my reading, the argument that CDR use needs to be restricted mainly rests on the following underlying assumptions (premises):
That high-integrity CDR is uniquely scarce, or that it is depletable in the relevant horizon.
That some activities must use CDR to reach net zero, so supply (if limited) should be reserved for them.
That markets would fail to allocate CDR appropriately if it was uniquely scarce.
Here, I argue that all of these premises are false, but it would be enough if only one of them falls to be able to reject the conclusion that CDR use must be restricted.
CDR is not uniquely scarce
CDR is limited in how much can be deployed at any given time by money, permitting, supply chains, infrastructure, available workers, and by ecological and social limits, etc. But so are emission substitution solutions and CCS; CDR is not a uniquely constrained solution. The theoretical CDR capacity is much higher than the volume of emissions for which it is likely to be the cheapest option for. For example, one could imagine dedicated fossil-free power plants running direct air capture plants 24/7 in remote areas with large CO₂ storage capacity. Such an effort would mainly be limited by money.
CDR is rate-limited, not stock-limited (depletable)
Using CDR does not deplete a limited stock. Just as for substitution solutions, CDR demand today builds future capacity. This means that using CDR today makes it easier to use more of it tomorrow, not harder. For example, making biochar from biomass waste that would otherwise have decomposed or been burnt saves no CDR capacity for future needs. It uses a resource that otherwise would have gone to waste. The only stock being lowered by (some) CDR solutions is underground CO₂ storage capacity, but the total storage capacity on earth exceeds tens of thousands of gigatonnes, more than ever will be needed (Kearns et al, 2017). Even a very conservative estimate, only including storage in sedimentary basins and adding multiple social and political exclusion criteria, finds 1400 Gt of available storage, close to as much CO₂ as has ever been emitted (Gidden et al, 2025). That study excludes in-situ mineralization, the underground storage method with the largest technical capacity.
CDR is not a must for any CO₂-emitting activity
Another premise of the restrict-CDR-use-argument is that CDR is a must to reach net zero CO₂ for some activities, so capacity should be saved for this (if CDR is limited). But almost no CO₂-generating activities are physically impossible to replace or capture the CO₂ from. (This is not the case for other greenhouse gases such as methane, but they don’t need to go all the way to zero to stop warming.)
Heat and power generation can be done without fossil fuels, synthetic or biobased inputs can replace fossil chemicals, and CCS can be used for those where fossil remain. For activities like aviation that require liquid fuels, biofuels, and synthetic e-fuels are options. CDR is not a physical must for net zero CO₂, stopping temperature rise; it is a tool to reach it faster and more easily. (However, CDR is of course a physical must for lowering temperatures, addressing legacy emissions already in the atmosphere.) The exception are the remaining emissions activities using CCS, which only reach 90-95% capture, but this need is 5-10% of total CCS volume, putting total CDR needs for CCS residuals at well below 1 Gt.
Markets are an effective way to allocate resources
Even if the rate of CDR deployment was lower than the demand for it, markets could allocate its use. Market mechanisms is the most effective tool we know of at distributing resources, depletable or not. This is how nearly all resources are allocated in developed economies. Equity concerns are addressed through taxes and subsidies, rather than rationing. There is no reason to treat CDR differently.
Of course, using markets to reach net zero requires policies like a carbon tax or a cap-and-trade program, such as the EU ETS. Without policy, emission reductions stem from either voluntary action (centered in low-emission, high-profit pools of companies) or from technology adoption that is cheaper than the fossil alternative (such as renewable energy in many regions). Both mechanisms are far too limited to bring emissions anywhere close to net zero. Once policy makes emission cuts mandatory, markets will naturally direct CDR to the sectors where reducing emissions is most expensive.
However, using CDR to reach net zero requires strict quality criteria and other guardrails. One criterion is that only permanent removals should neutralize fossil CO₂ emissions. Land-use emissions can be offset with land-based removals, while short-lived greenhouse gases can be managed with short-lived removals. Strict sustainability criteria, including land-use rules, are essential to prevent social and ecological harm. Removals must also be additional and provide real climate benefits. Additionally, climate policy must impose strict regulations on pollutants like particulate matter and nitrogen oxides, as the impacts of fossil fuel production go beyond carbon emissions.
Conclusion
This logical breakdown shows that there is no strong justification to treat CDR differently from other mitigation solutions. We should not restrict its use, but set strict guardrails and let markets decide where it is used; that also means there is no need to create lists of residual emissions to regulate where CDR could be used. Only then can CDR fulfill its purpose of making net zero cheaper and more achievable. This is also what builds the capacity to in the long run use CDR to adress legacy emissions and bring down global temperatures.