The value of carbon is relative, biodiversity is absolute

There is evidence that reforestation reflects a biodiversity gain of more than 200% in a degraded area

Originally published in Portuguese at Valor Econômico – 7/22/2024 5:01

Carbon dominates the climate agenda, but biodiversity is the heart of the matter.

The ton of carbon is a good unit of measurement, but the carbon itself is meaningless. Biodiversity is the reason and purpose of the entire climate agenda. We want species richness because the greater the biodiversity, the greater the redundancy of the ecosystem, and the greater the redundancy, the more resilient these systems become to change. Without biodiversity, the biosphere would be more susceptible.
Individually, species are not very resilient, because adaptation to a new environment happens precisely through speciation, that is, the emergence of a new species. If species could quickly adapt to climate change, the risk of extinction, which creates global urgency, would be lower. But they can’t. Carbon is used as an indicator of biodiversity, even though it is an inefficient and ineffective one, as shown in the literature on silent forests (flora without fauna). Why then haven’t we invested in biodiversity credits instead of carbon in the last 30 years? I identify three main reasons:

The first is the difficulty in identifying and measuring biodiversity. This is, in fact, a problem that impacts all of biology. Our knowledge about the species is very limited. Since Aristotle, we have only identified 1.5 million of them and we have no idea how many there are. In other words, we do not know whether this number represents 0.1%, 1% or 10% of the total. We are not able to sample all forms of life, and even with an army of taxonomists, we would not be able to identify all species.

But it’s a problem with a solution: DNA sequencing. Since all living beings are composed of it, it is logical to use this technology to identify them. Since 2001, the cost of sequencing a genome has fallen from $100 million to less than $1,000. DNA sequencing technology has advanced 10 times faster than silicon chip technology, described by Moore’s Law, which says that – every year – capacity doubles and price halves.

Specific genes located within mitochondria function as a barcode of life and allow us to identify the species present in a sample of water, soil or sediment from the DNA that is left in the environment with fragments or residues of these organisms (environmental DNA or -DNA). When we find the DNA of a species that has not yet been described, and these are the majority, we create an operational taxonomic unit, which allows us to calculate biodiversity using even species that we do not know.

In fact, we used this technology to identify biodiversity on a large scale in the Três Irmãos reservoir on the Tietê River, in São Paulo, in partnership with Tijoá, which has more than 800 km2. In just one sample of one liter of water, we detected DNA from more than 80% of the organisms present. In 10 samples, species richness reached saturation, showing that we characterized all the organisms present there.

DNA is the big data of biology and if we accept using operational taxonomic units to identify an organism without naming it, we will bring unprecedented precision and robustness to ecology.

The second is the difficulty in pricing biodiversity. If it is difficult to measure the value of a life, imagine all species. However, carbon credits have shown that we can price conservation efforts and results and this also applies to biodiversity. If we can measure the gain in biological diversity of an area that has been preserved or recovered, using DNA, then the biodiversity credit can be priced at the opportunity cost of this gain.

We already know that the recovery of degraded areas brings greater gains in biodiversity per monetary unit, in a similar way to conserving an intact forest, which we are calling REEDD+ (reduction in emissions ‘and extinctions’ from deforestation and forest degradation).

The cost of reforestation, which is around R$35,000 per hectare, is a well-established parameter in the market and there is evidence that it reflects a biodiversity gain of more than 200% in a degraded area. These are parameters that serve as the basis for credit pricing. Additionally, the base price may include premiums for special aspects of biological diversity, whether technical (preservation of key species for ecosystem services such as pollination), emotional (protection of charismatic fauna), moral and spiritual.

The third is the difficulty of comparing biological samples. Even with DNA as an absolute metric for richness and abundance, how can we compare the importance of different species? Or, as I once heard a researcher say at a conference, how many butterflies are worth an elephant? The answer may lie in a new theory by researcher Lee Cronin, from Scotland. He suggests using the Assembly Index, which measures the complexity of objects – whether molecules, organisms or ecosystems – based on the number of steps required for their construction and the total number of copies observed in nature. Although it does not exactly answer the original question, the assembly index adds a measurable, replicable and absolute layer of information to biological samples, allowing you to differentiate and rank them based on complexity.

With these three fundamental issues resolved, the challenges that remain are those of adoption, more linked to incentives than to theory or technology. The first is accessibility to opportunities. The carbon market is dominated by certifiers who capture a large part of the value allocated to conservation initiatives, creating a barrier for small landowners, who represent more than 80% of the total in Brazil (data from the Rural Environmental Registry, CAR). Because DNA can be converted into bytes and protected by cryptography, creating verifiable credits on the blockchain would be a more effective and cost-effective alternative to certification.

The second challenge is commercial, dependent on companies becoming evangelists – those who will actively promote and adopt new practices – and lead the acquisition of biodiversity credits based on objective, rather than consensual, metrics to usher in a new era of effective biodiversity conservation. To be seen.

Mauro Rebelo is a marine biologist, PhD in Biophysics, professor at the Federal University of Rio de Janeiro (UFRJ) and founder of Bio Bureau.