Six considerations for trusting high-integrity carbon dioxide removal credits – and one caveat

Food safety and carbon crediting share similarities, though the former is well established.

Removing carbon can be an invisible service: so there’s little wonder that trust is an outstanding concern for the public. Typically, carbon dioxide (CO2) is a colourless, odourless gas. No one can see, for example, when a wetland or a direct-air-capture plant sucks up CO2 and stores it – any more than one can see the amounts being released in vehicle exhaust tanks or a coal-burning power plant.

In both instances, we rely on science-informed equations, often known as methodologies, to count. This is well established: since 2008, New Zealand officials have used data to calculate the CO2 removed by newly planted forests and award credits, for example.

But these calculations can rely on complex choices, particularly when projects must estimate their impact by projecting a “world without us” scenario. Recent investigations led by The Guardian and academics concluded that forest-protection and cook-stove programmes, for example, were getting far more credits than justified – as a consequence, the reputation of voluntary carbon credits has plummeted in recent years.

In that backdrop, new carbon dioxide removals technologies such as biochar and bioenergy with carbon capture are emerging. These projects are also reliant on carbon credits for finance, often from the voluntary market. We’ve consulted our experts, and have six reasons why we’re feeling positive the refined system could work:

1)      We know verification works elsewhere. The carbon credit issuing system relies on a broad system of rules, best practice, checks and monitoring – all supported by independent verifiers. In its overall structure, it resembles the systems that govern against another invisible issue: foodborne illnesses. Few of us know much about food safety legislation, or get to see the monitoring reports from the restaurants and eateries we visit. Some of us experience the unpleasantness of a rare systemic breakdown. Yet overall, we trust the system enough to purchase the food made under its rules, and eat it. Still, carbon crediting remains a young, developing system trying to get oversight right – compared to the maturity and strength of government food safety mechanisms.

2)      The carbon credit industry has had a reckoning. The high-profile investigations into over-crediting in media and academia sent shock waves through the verification market. The standards bodies, whose job it was to identify and avoid exactly these types of issues, investigated the problems and attempted to set things right, including through cancelling erroneous carbon credits. Shortly before the controversies, a new body called the Integrity Council for the Voluntary Carbon Market was established. Although it has also attracted criticism, the body is attempting to set a new course for the market, by independently and critically assessing methodologies for flaws.

In New Zealand, data and science-informed calculations have long estimated forestry removals.

3)      Leading methodologies are more detailed than you might guess. Let’s take Puro.Earth’s 160-page rulebook for calculating credits when kilns with little oxygen transform wood into biochar, locking carbon away. One rule requires the project to assess the storage time, temperature and moisture content of the feedstock – in order to calculate and subtract the amount of the potent greenhouse gas methane generated by any stockpiles. Elsewhere, projects must quantify their indirect effects: for example, whether deforestation might occur because of an increased demand for wood to produce biochar – a step encouraging the use of materials that right now go to waste. These are examples of good practice being applied.

4)      Carbon removal is often expensive, which makes it unlikely to happen unless someone pays. In general, the most problematic carbon credits often pay for people not to do something: not to chop down virgin forest for new farmland or provide fuel for traditional stoves, for example. There can be myriad reasons not to do something, so it is harder to prove that your credits are the reason for the change – not for example, local land-use regulations or growing preferences for modern cooking tech. In contrast, carbon dioxide removal involves payment for something: and typically, quite an expensive something, often costing more than $100 per tonne. We believe that large price tag should offer some reassurance that this won’t happen without carbon finance.

5)      We’re getting a Government endorsement scheme. The New Zealand Government is developing its own review system for voluntary carbon credits. Schemes that show they meet the official criteria and integrity principles in an assessment conducted by an independent expert (or a group like the Integrity Council for the Voluntary Carbon Market) will get the new quality signal. The policy aims to give people additional confidence the fundamentals are sound, in order to unlock private investment in climate action. Like others, we’ve shared our thoughts on the need for detailed, rigorous and ongoing assessments.

6)      We’re watching – but help is needed. We’re a group of more than 30 academics and early-career researchers at universities and institutions across New Zealand, aiming to road-test carbon removal technologies and maintain international best practice for measurement, reporting and verification. We’re keeping an eye on national and international developments and providing expert feedback. Our knowledge will allow us to collectively act as a watchdog, during our five-year project and in the years that follow. Even so, we’re aiming to boost awareness of carbon removal, best practice and issues of concern so that others can carry this mantle.