Common mistakes
Easy-to-resolve misunderstandings about the biodiversity unit
This section covers the most common mistakes people make when thinking about the biodiversity unit, frequently conflating it with other layers of measurement abstraction (metrics and units) or with other market functions (validation or pricing).
In this section:
Biodiversity vs carbon
There is considerable conflation between carbon markets and biodiversity markets. Carbon markets certainly have had problems with a lack of credibility, transparency, double counting, and equity (58). But, they always had a universal unit, a ton of carbon. Biodiversity markets can iterate on carbon-market failings, but the unit problem is a separate problem, and conflation between the two issues has delayed the design and adoption of an appropriate unit.
Where possible, we have incorporated lessons learned from carbon market failings in the selection of negotiable unit attributes and Indigenous co-design. However, the majority of unit decisions were constrained by logic, pragmatism, and multidisciplinary theory. The main reason we were able to clearly elucidate these constraints was to remove issues that were irrelevant to the discussion (see Figure 1).
The most powerful tool we had in negotiating this unit, was the willingness to leave intractable, but irrelevant debates out of the discussion.
Unit vs metric
Metrics are the first level of scientific abstraction. A metric is any core measurement, which usually has a scientific protocol for standardization. It typically includes not just the measurement itself, but a set of repeatable instructions or parameters. For example, the "diameter of a tree at breast height" is the core metric in almost all forest carbon estimates. Everything else is calculated from this raw data with standardized instructions in obtaining the metric, and extrapolated with allometric equations for scale.
In biodiversity, "species observation" might be a metric, but identifying a species is very different with different protocols depending on the kingdom (insects, trees, fish, etc.) or ecosystem (identifying dolphins in the ocean is different from sand crabs on the beach). Raw data, like game-camera footage, is converted into a metric like a species observation, through a formal process that controls for taxonomy, natural variation, DNA vs phenotypes, and species evolution. Other metrics of biodiversity have been proposed (such as eDNA testing of water), and local Indigenous people use their own metrics (such as the taste of the bark of an Amazonian tree). Both are highly accurate chemical tests, but practically impossible to correlate to one another.
It’s useful, but not essential, to use metrics and units that can be understood by different cultures across industrialized and non-industrialized paradigms. We do recommend metrics that meet cross-cultural epistemological requirements - prioritizing game cameras over eDNA. What is essential is that metrics are abstracted sufficiently for global markets, while retaining accuracy.
Metrics are constantly evolving with technology and scientific developments. The aim of this paper is not to constrain metrics, but instead to differentiate between metrics which are useful for market purposes (cleanly generate an accurate unit) and those which are useful for scientific purposes (measure ecosystems in other ways).
Much of what has made the unit debates intractable is the attempt to standardize metrics, which are desirably heterogeneous, instead of providing a comparable format for their final abstraction. This paper does not constrain metrics, it merely asks if metrics can be used in an ecosystem unit or not.
Unit vs methodology
Methodologies are the second level of scientific abstraction. A methodology is a protocol to make meaning out of metrics. The methodology chosen by researchers, often validated in open review, is a protocol to measure and quantify the biodiversity of a particular ecosystem, usually using a combination of metrics in a formal abstraction. In the biodiversity crediting market, these methodologies are technical documents that explain how to generate biodiversity credits. Once a methodology is published, the methodology can be used by projects worldwide to calculate their credits. Some methodologies have certification from companies that provide certification of biodiversity credits. Most methodologies are ecosystem-specific and constrained by action (i.e., a methodology for increasing pollinators in farmland).
Not all crediting schemas will use methodologies, some may credit from metrics alone. But in all cases, methodologies are independent of the final comparable abstraction, the unit, and merely clearly describe how the unit was calculated and from what metrics and with what justification.
Much of what has made the unit debates intractable is the attempt to prioritize one methodology over another, which are desirably heterogeneous, instead of providing a comparable format for their final abstraction. This paper does not constrain methodologies, it merely asks them to report their output in a final abstraction, an interoperable unit.
Unit vs price
A unit is not a price. A price depends on the buyer-perceived market value at the time of sale (related to, but not to be conflated with, the Value category in this paper). This includes the perceived market value and reputation of each project developer, certifier, methodology, metric, ecosystem, action, and even charismatic species involved in unit composition.
As already described, units need to be logical and tangible in their composition. However, buyers do not have to be rational in pricing. In fact, the field of behavioral economics tells us they are likely to be quite irrational (59). Indeed, early market pricing for restoration is already nearly triple that of conservation, and inverse to species density, showing anthropomorphic buyer motivations (4, 53).
Our task, in this case, is merely to design units that accurately reflect biodiversity itself. Not to promote pricing or value judgments on biodiversity.
We did bow to current market pricing in our choice of area/time granularity. Preferring the smallest functional ecosystem unit of hectare/month over alternatives such as sqkm/year. But this decision will not affect final market pricing for biodiversity, which will be based on market normalization in the future. Fluctuations in the price of the credit, or the price of land a credit is associated with, do not affect the unit it is measured in.
Unit time vs. monitoring time
The time component of the unit was chosen as one month (30 days) for minimum viable granularity. Larger monitoring periods (duration of crediting periods, methodology requirements, etc.) can be easily subdivided into smaller time intervals for conversion to this unit.
Controls and requirements for monitoring period length fall outside the scope of the unit design and must be accounted for by methodologies, certification bodies, international standards, and verifiers (see Figure 1).
Much of what has made the unit debates intractable is the option to select from a wide variety of seemingly arbitrary scales for standardizing time (month, year, twenty years) and area (hectare, acre, meter-squared). The point of a unit is to make a logical choice that makes intuitive sense to people who will use the unit, stick with it, and obtain stakeholder consensus around that choice. And this is what we have done.
Unit vs verification/validation
Methodologies, metrics, and units may be audited by independent parties in order to validate claims about biodiversity outcomes. Indeed, we recommend third-party validation. However, the validity of reported units and the comparability of reported are completely separate issues. The authors of this paper can all claim to be ten feet tall, and the truth of this claim does not affect the tape measure used to measure our height (see Figure 1).
We do note that making units tangible and simple greatly reduces the opportunity for manipulation of reporting, and this was a strong consideration in unit dimensions.
Unit vs market
This biodiversity unit does not have to be used as a commodity or transact in a marketplace. A unit that meets the requirements for a commodity has advantages in tangibility, market adoption, and accounting for expiration (biodiversity is either alive or dead) (28). However, given the strong presence of charitable stakeholders in this space, one could argue that an effective unit cannot only be commercial (13). It is preferable if this unit is used interchangeably across commercial and noncommercial settings. This unit can be also called a biodiversity ‘credit’, ‘certificate’, ‘asset’, or any other semantic variation as long as they are identical dimensions.
Much of what has made the unit a wicked problem is the endless debate about the commercialization of Nature, a highly emotional argument. In turn, the solution is to use it as a measurement across philosophical divides.
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