Biodiversity credits shouldn’t copy the carbon market playbook

Here is the argument I want to make plainly, before anything else: the biodiversity credit market should stop trying to copy carbon’s trick of reducing everything to one tradable unit, and should instead measure its own success by how continuously and independently a claim can be verified. Chasing a single elegant number, the way carbon markets did with metric tons of carbon dioxide equivalent (tCO2e), is not what this field should be racing toward.

It may, in fact, be the wrong goal altogether.

The clearest evidence for this sits in plain view, in numbers that most people read as an embarrassment rather than as information. Every few months, a new market research report tells us exactly how large the global biodiversity credit market is. The trouble is, no two reports agree. One puts the 2025 market at roughly $90 million. Another, published around the same time, puts it at $7.1 billion. A third lands somewhere near $5.7 billion. These are not small rounding-off differences. They are the same year, the same broad market, and estimates that differ by a factor of nearly 80.

Most commentary treats this gap as a sign that the data are still catching up with a young market, but I read it differently. The disagreement is not a data problem waiting for better satellites to fix. It is telling us something true about biodiversity that the carbon market never had to reckon with.

Carbon succeeded, commercially speaking, because it found one clean unit. The tCO2e behaves the same whether it was avoided in Assam or Amazonas. That fungibility is precisely what let carbon markets scale into the billions, and it is why so many people now assume biodiversity simply needs its own version of the same trick: one tidy number that a hectare of restored mangrove and a hectare of protected grassland can both be reduced to.

But a hectare of mangrove forest is not interchangeable with a hectare of grassland: pretending otherwise is closer to a category error than a measurement gap, and I suspect it is the real reason estimates of this market vary by a factor of 80, depending on who is counting. Different analysts are not simply using different data. They are quietly making different assumptions about what should even count as a biodiversity credit in the first place, because there is no shared definition anchoring the count the way tCO2e anchors carbon.

This has a name in the policy world now. Researchers evaluating biodiversity credit suppliers against integrity criteria set by bodies such as the International Advisory Panel on Biodiversity Credits have found that achieving both “commensurability” — the ability to compare things by a common standard, like one credit against another — and genuine ecological meaning in a single metric is a real and possibly unresolved tension, not a matter of trying harder. Some in the field are now openly discussing a more plural approach of considering several honest metrics together, rather than one number pretending to hold everything a landscape means. This lends real weight to the argument I opened with.

There is a second, harder reason to resist chasing carbon’s model, and it comes directly from carbon’s own recent history. In January 2023, a nine-month investigation by The Guardian, Die Zeit, and the nonprofit Source Material found that more than 90% of the rainforest offset credits certified by Verra, the world’s largest carbon credit certifier — credits used by companies including Disney, Shell and Gucci — were likely worthless, and the promised climate benefits may not have actually been delivered.

A separate, and to my mind even more revealing, episode followed. In October 2024, U.S. authorities filed criminal charges, including for wire fraud and securities fraud, against Ken Newcombe, a former chief executive of the carbon project developer C-Quest Capital, over the alleged over-issuance of more than 5 million carbon credits. Newcombe denies the charges, and the matter remains before the courts, so that much should be said plainly.

What is not in dispute is this: Newcombe sat on Verra’s board from 2007 until December 2023, and Verra had adopted a crediting methodology that he himself helped write. The regulator and the regulated were, for a period, quite literally at the same table.

I raise this not to single out one certifier for blame, but because it points at something structural, and it is exactly the trap the biodiversity market risks walking into. A market built around chasing one simple, tradable number creates a strong incentive to keep that number moving, and whoever controls how the number gets calculated ends up holding real power over whether it can be trusted. Carbon learned this the expensive way, after the credits had already been sold, retired, and used to back real corporate climate claims.

Biodiversity credit markets are still young enough to learn this lesson in advance rather than after the fact. That is the actual opportunity sitting inside all this market size confusion: rather than a data gap to be closed as quickly as possible, it’s a genuine invitation to design differently from the outset. Success should be measured less by how quickly the field converges on one elegant unit, and more by how many separate eyes are able to check a number before real money changes hands on the strength of it.

So, the next time a report lands claiming to finally know the true size of the biodiversity credit market, it may be worth reading the 80-times gap between reports not as noise to be filtered out, but as the most honest data point in the entire market right now.

Jubanayan Saikia is co-founder and CTO of Nature Ledger, a small, early-stage team building real-time biodiversity and environmental verification infrastructure, alongside co-founder and CEO Sayanika Deka. He holds a bachelor’s degree in computer applications from Madurai Kamaraj University and a master’s degree in social work from Periyar University.

Banner image: Doll orchids are threatened due to extensive collection for the ornamental plant trade. Image courtesy of Bhathiya Gopallawa.