Nature-based carbon removal is a promising pathway for tackling climate change, but, in recent years, peer-reviewed research and investigative journalism have found that many projects have generated far more carbon credits than the climate benefit they actually delivered.
The root cause is structural weaknesses in legacy measurement, reporting, and verification (MRV) frameworks that have allowed carbon removal to be systematically overcredited at two key points: when the baseline is set, and when the carbon removal is quantified.
The baseline problem
A carbon credit is only valid if the carbon removal it represents is additional—meaning it would not have happened without the project. To establish this, every project needs a baseline: an estimate of what would have happened to the forest in the absence of any intervention.
Under legacy registries, suppliers are required to develop their own baselines—selecting the control plots used for comparisons, with no requirement to publicly disclose those selections. This creates a structural conflict of interest, where suppliers are asked to make a choice that directly determines how many credits their project generates. The result is baselines that often overstate the carbon removal, and credits that overstate the climate benefit.
Isometric’s approach is different. We take baseline setting out of suppliers’ hands entirely—independently selecting control plots, generating forest carbon proxy maps, and calculating the baseline.
This not only removes a fundamental conflict of interest, it also eliminates the burden and cost for suppliers. The result is a consistent, rigorous approach across all projects, which gives buyers confidence that every credit issued represents a tonne of carbon dioxide removed from the atmosphere.
The quantification problem
Once a baseline is set, the next challenge is quantifying how much carbon is captured and stored by a forest. Remote sensing tools, like satellite imagery and LiDAR, have made it much easier to do this at scale—and Isometric’s protocols are designed to embrace them—but these technologies aren't a complete replacement for real-world measurement.
Remote sensing tools create models. They infer the amount of carbon stored in a forest from signals like canopy reflectance and tree height, but these signals have limitations. For example, in young forests, canopy reflectance tends to overestimate biomass, while the reverse is true for dense, mature forests. Relying on tree height, meanwhile, provides a two-dimensional view of a three-dimensional reality. Without calibration against real-world measurements, these errors go undetected.
Field measurements—plots where trees are physically measured—are the only reliable way to ensure remote sensing estimates are accurate. Isometric requires them for every project, either as the primary way for quantifying carbon removal or as a mandatory check on any remote sensing approach, repeated at least every five years.
This extends to other ecosystems, like mangroves, where much of the removed carbon is stored in soils and sediments, with significant variation across a single project site. Using default averages or generic models is too inaccurate for this kind of variability. Isometric’s Mangrove Restoration Protocol requires projects to measure the soil carbon directly, rather than rely on modelled estimates, ensuring the accuracy of every credit issued.
Why this matters
Overcrediting isn’t an abstract quantification problem. It means that buyers of nature-based credits are getting less than they paid for and that projects aren’t delivering the climate benefits they promise.
Independent baseline setting, mandatory field measurements, and direct sampling in high-variability ecosystems solve the baseline and quantification problems behind overcrediting. Isometric puts these measures at the heart of its Biosphere protocols because every credit issued should represent actual benefit to the atmosphere.
