The Taskforce on Nature-related Financial Disclosures (TNFD) must “urgently” consider metrics beyond MSA, an executive at environmental consultancy Ramboll has said, while suggesting that Britain’s net gain mechanism offers a more robust approach.

The recommendation of the mean species abundance (MSA) metric among others by TNFD has set “quite a low bar … which is a bit disappointing” for measuring biodiversity, Samantha Deacon, principal of biodiversity and ecosystems at Ramboll said.

“MSA is quite a fragile metric. You can add one species, and your mean has increased, or you can lose one and it goes the other way,” she told Carbon Pulse.

Numbers of animals such as birds could fluctuate naturally, due to elements such food and weather, affecting the MSA despite the habitat condition remaining stable, she argued.

“It could be challenging for companies – if they only use MSA, it could be a risk. The TNFD does need to work on expanding its indicators and metrics … quite urgently.”

TNFD launched 14 ‘core global metrics’ that all companies should report on as part of its final recommendations release this week. It is preparing further ‘core sector metrics’ alongside ‘additional metrics’.

The taskforce recommended using MSA for helping to measure acute physical risk under its guidance on assessing nature-related issues under the LEAP approach.

MSA is applicable across ecosystems and “incorporates many different pressures on biodiversity”, the taskforce said. As a ‘realm’ the metric MSA makes estimations rather than primary data collection, TNFD said. MSA includes some plants as well as animals.

BRITISH ONE BETTER

The biodiversity net gain (BNG) approach in the UK, which measures habitat condition, is a “more robust and better metric” than MSA, Deacon claimed.

The UK-specific BNG metric will be used by developers in the country to prove a 10% net gain to biodiversity under legislation coming into force in November. BNG takes into account key factors on habitat condition, distinctiveness, location, and size.

“What we like about the BNG metric is that it’s habitat-based – you’re looking at characterising condition and scale of a habitat. The theory is if you restore and compensate at habitat level, then your species health will benefit,” Deacon said.

In response to Deacon’s statements, Tony Goldner, executive director of TNFD said: “As outlined in the documents released on Monday, the taskforce is continuing to evaluate a wide range of aggregate assessment metrics and indices and will update its advice on metrics as and when appropriate based on ongoing market use and feedback.”

“We signpost to a range of different indices and metrics available in the market today for the consideration of market participants to use as part of their assessment of nature-related issues and have not endorsed any one of them over any other. The taskforce hopes to see ongoing innovation in the metrics space,” Goldner said.

The TNFD approach relies partly on biomes, area classifications defined by the species that live in that location, with areas such as ‘tropical and sub-tropical forests’ covered under a guide launched this week.

However, “biomes from an ecology point of view are quite limiting”, Deacon said. “You’ve got centuries worth of classification systems and ecologists are used to using those. They’re at national levels. I think the authors of the TNFD just found that too complicated.”

“We’ve got to look for ways to translate what we’ve been using for decades as ecologists into the TNFD biome system. Where’s the ecology in TNFD? I think there’s definitely work to be done there.”

Deacon welcomed the launch of TNFD’s final recommendations in general for creating a unified framework that can be applied globally. “I very much think it’s going to be taken up and accepted and used, which is really important,” she said.

Aside from MSA, TNFD also recommended metrics including:

• Accounting for Nature’s Environmental Condition Accounts
• Forest Landscape Integrity Index
• Forest Structural Condition Index
• Potentially Disappeared Fraction of species
• Ecosystem Intactness Index
• Marine Cumulative Human Impacts
• Proportion of Land Degraded

By Tom Cox – t.cox@carbon-pulse.com