The field of carbon dioxide removal (CDR) is ethically and technically complex. It encompasses a wide range of approaches – from tree planting to ocean alkalinity enhancement to electrochemical capture – each with their own delivery timelines, costs, and ecological impacts. They raise common concerns: Are they a distraction from cutting emissions? How much carbon can be removed, and is it permanent? Are these techniques dangerous? Who controls and benefits from these projects? How will project developers be held accountable if things go wrong? Will projects be implemented in a just way? And, most relevant to this discussion, does using CDR to address the climate crisis actually work?
Beneath these technical and ethical debates lies a critical foundational challenge: monitoring, reporting, and verification (MRV) (Figure 1). In the context of CDR, MRV is the process of tracking, documenting, and assessing the climate benefits of an activity (Table 1). They mainly seek to determine additionality (carbon removals above and beyond what would have happened if the project did not exist) and permanence (how long the carbon stays out of the atmosphere). Without robust MRV, the trust and credibility of the CDR field to deliver its promises will remain fragile.
However, current MRV approaches remain a patchwork of different frameworks and are often voluntary and underdeveloped – especially for marine carbon removal (mCDR), where scientific and regulatory uncertainty is high. mCDR techniques use the ocean as a medium to both capture and store carbon. These processes are inherently difficult to monitor due to the ocean’s vast scale and complex interactions, as well as the absence of a cohesive governance framework that could provide clear standards and oversight. As a result, mCDR MRV frameworks are lagging behind their terrestrial counterparts, which is a challenge I explored in my previous blog. This blog explores challenges for existing CDR MRV, the way MRV for CDR is evolving, and remaining gaps in successful implementation of MRV protocols.
Figure 1. Summary of the MRV process. Source: World Resources Institute
| Consideration | Definition |
| Additionality | The requirement that a CDR activity must demonstrate that carbon removal benefits would not have occurred without the project, based on an inferred no-intervention baseline. |
| Permanence | The durability of sequestered carbon, ensuring that emissions are not later released back into the atmosphere (often defined as more than 100 or 1,000 years). |
| Quantification | Measuring and verifying the net carbon removal of a project on a life cycle basis, using best available science and accounting for uncertainties. |
| Leakage | Increases in GHG emissions outside the project area caused by the project’s activities, such as market shifts. |
| Transparency | Publicly accessible reporting of data, methods, and verification processes to enable accountability and build trust. |
| Environmental and Social Impacts | Monitoring and addressing a project’s broader effects on ecosystems, biodiversity, and communities, following safeguards to minimize harm. |
Table 1. Considerations for high-quality MRV. Source: Adapted from the World Resources Institute
Challenges with MRV
Currently, MRV quality for carbon dioxide removal (CDR) is highly uneven: most MRV remains voluntary and project-specific across markets and technologies, resulting in a large web of certifying bodies and protocols. In some cases, different CDR methodologies share the same certifier; in others, separate bodies oversee standards for the same technique, each with their own approaches. (Figure 2). This host of methodologies result in differences in transparency, permanence assurance, and risk accounting between credit verifiers. MRV can also be very expensive, especially in early-stage or novel CDR methods: for some techniques, such as ocean alkalinity enhancement and enhanced rock weathering, MRV costs can exceed 50% of total project costs. This uncertainty and cost burden are reflected in market dynamics: durable-removal transactions disclosed on one public tracker show large swings in weighted average sale prices, and transaction volumes in the voluntary market have contracted sharply in recent years as many corporate buyers have withdrawn over concerns about greenwashing. These inconsistencies in MRV make it difficult for buyers and standards bodies to compare credits across methods and to build confidence in the market. This, in turn, is a challenge for CDR as a credible tool for climate mitigation.
Figure 2. MRV methodologies and organizations. Source: CDR.fyi
The fragmented, unstandardized nature of the MRV methodology has led to significant controversy. On the terrestrial side, studies have suggested that over 90% of rainforest carbon offsets certified by Verra, the world’s leading carbon standard, are “worthless” and one analysis suggests that most offsets invested in by major corporations such as Delta and ExxonMobile are “likely junk”.
Permanence is another concern. California’s forestry offset program saw almost all of its carbon buffer pool set aside for fire risk go up in flames in 2022, amid reports that wildfires globally now burn twice as much tree cover as they did two decades ago and are likely to worsen.
There are also concerns about conflicts of interest between players in the carbon market – including project developers, standard-setting bodies, and auditors – that may incentivize over-crediting. Project developers design and implement offset projects and pay auditors to verify their emissions reductions. These auditors are often accredited by standards bodies like Verra or Gold Standard, which earn fees based on the number of credits issued. Because both the auditors and the standards rely financially on the developers, there is incentive to approve more credits. If MRV cannot be trusted, it undermines the premise of CDR as a climate solution.
Addressing Concerns with MRV
In response to the above concerns, multiple high-level frameworks and public initiatives have emerged to standardize MRV. At the international level, Article 6.4 of the Paris Agreement has established a carbon trading mechanism that allows countries and private actors to generate and exchange credits from emission reductions and removals, underpinned by MRV requirements to ensure environmental integrity and avoid double counting. In October 2024, the Article 6.4 Supervisory Body approved two standards – one sets rules for how methodologies are built – covering baselines, additionality, and leakage – while the other focuses on removals, with safeguards for permanence and monitoring. Another example is the European Union’s 2024 Carbon Removal Certification Framework (CRCF), which sets an EU-wide voluntary standard for MRV and aims to increase transparency and trust in removal credits.
On the national level, Japan has advanced standardized MRV through its Joint Crediting Mechanism (JCM), a bilateral system that facilitates technology transfer from Japan to its partners and allocates shares of the reduction towards both countries’ NDCs. Although the majority of projects currently funded by the JCM are focused on emissions reductions, the portfolio is expanding to include REDD+ and other carbon capture projects. The JCM employs methodology-specific MRV protocols approved by joint committees between Japan and its partners, conducted by third party entities and guided by the ISO standard (the ISO sets global standards for consistency and credibility; for carbon markets, key ones include ISO 14064 for GHG accounting and ISO 14065 for validation and verification). As of August 2025, the 31 countries, mainly in Asia, have signed on to the JCM and it includes over 250 projects.
The US currently lacks a similar national-level CDR MRV oversight mechanism, but investments have grown; the 2021 Bipartisan Infrastructure Law (BIL) and the 2022 Inflation Reduction Act (IRA) provided historic levels of funding towards CDR development and scaling through programs such as the 45Q tax credit, the CDR Purchase Pilot Prize, and the Regional Direct Air Capture Hubs program. Some of the BIL funding was allocated towards advancing MRV best practices. However, these initiatives now face growing risk of rollback; the Trump administration has repeatedly targeted the IRA, including freezing or terminating programs related to climate work. The 2025 “One Big Beautiful Bill” (OBBB) Act rescinded or paused unobligated IRA funds, cutting down on staff numbers and disrupting CDR-related research under the USDA and NOAA. While the 45Q tax credit was preserved, its eligibility category has been expanded to include projects that use captured carbon for oil production. This may signal the administration’s willingness to support fossil fuel-aligned carbon capture technologies, while deprioritizing those that focus on climate benefits.
Some non-governmental organizations are also preparing MRV standards or guidelines, including within the mCDR field. A notable advance is Planetary Technologies’ open-source OAE MRV protocol, first released in February 2023 and now in its third version. The protocol offers a standardized methodology to calculate carbon removal, estimate lifetime storage, and assess ecological impacts. In June 2025, Planetary achieved a milestone with the first-ever verified OAE credits – 625.6 tCO₂ – issued under a joint protocol with Isometric and 350Solutions.
Despite such advances, gaps remain. The newly approved Article 6.4 guidelines were criticized for being rushed through and excluding certain types of nature-based projects. Many groups fear the EU’s CRCF “lacks integrity” and is “filled with climate-threatening loopholes”, citing low standards and risks of double counting. And, while the new US policies supporting CDR all include MRV provisions, they are mainly focused on scaling up the industry and do not account for quantification uncertainty or leakage risk. The problem is even more acute in the mCDR space, which receives relatively little attention or funding; most of the IRA and BIL investments had gone to direct air capture (DAC), a land-based novel CDR method.
Conclusion
MRV must be central to any CDR or carbon trading policy if removals are to be credible. Current frameworks show progress, from Article 6.4 introducing stricter MRV baselines to Japan applying standardized protocols across projects with all its partners. Yet conflicts of interest in offset markets persist when developers pay auditors and standards bodies rely on issuance fees. This means independent, third-party verification must be formalized and financially insulated from project developers. In the mCDR field, independent verification and standardized MRV protocols are especially critical given the unique funding constraints, open-system dynamics, and evolving regulatory landscape. Ultimately, MRV needs to be a central pillar of any CDR technique for it to become a viable climate solution.
Great Job Patree Witoonchart & the Team @ Climate Law Blog Source link for sharing this story.
