I LIVE close to Holloway Prison in north London, a former women’s jail. It closed in 2016 and is currently a demolition site being readied for flats. Over the fence, I can see huge piles of rubble – and a single magnificent plane tree in the middle of what will become a park. I am glad the developers didn’t raze it to the ground along with all the others.
The work started in 2019, but if it had happened more recently, all the trees would probably have stayed in place, because the site would be subject to a new law in England called . This forces developers to create 10 per cent more wildlife habitat than they destroy in the process of developing a site. The law came into force last month and is “one of the world’s most ambitious ecological compensation policies”, according to at the University of Oxford.
The law is explicitly designed to stop development projects from doing yet more damage to nature, and is much needed. Infrastructure projects are one of the biggest threats to global biodiversity, and biodiversity loss is one of the biggest threats to having a liveable planet.
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Every development in England should now boost the country’s heavily denuded natural capital. That gain must be maintained for 30 years after the development is completed. This all sounds very positive, but the law has its flaws, not least that it relies on one of conservation’s most contentious issues: biodiversity offsetting.
The concept of offsetting is already familiar for carbon, where activities that emit greenhouse gases can be compensated for elsewhere, such as by planting trees. That is sound in principle, but has multiple problems in practice. Biodiversity offsetting is even more problematic.
Like carbon offsetting, the idea is that activities that destroy biodiversity in one place can be offset by preserving or enhancing it elsewhere. To be clear, that is the last resort in what conservation biologists call the mitigation hierarchy. First, you should avoid destroying biodiversity. Next, reduce unavoidable impacts. Third, make good on site by enhancing what remains or restoring what has been lost. Only then is offsetting required, to make up the gap. But there will be gaps, so it will be needed.
That opens the door to fudge. Measuring biodiversity is notoriously difficult. The new law sets out a way to do it, called the . This explains how to assess the size, type and quality of the habitat and convert it into “standardised biodiversity units”. However many units there were before the development starts, there must be 10 per cent more afterwards.
You may already have spotted the loopholes. Say a site contains a rare habitat worth 100 units. As long as there are 110 units afterwards, the developer has discharged its obligation, even if it is 110 units of a totally different habitat. The offsetting element only enlarges the loophole. Can 100 units in one location really be replaced by 110 somewhere else? This is a problem of “fungibility” – whether one type of habitat is directly interchangeable for another.
There are other problems too. The Australian state of Victoria has a biodiversity offsetting programme that allows companies to compensate for destruction by buying credits from nature-positive landowners elsewhere. Again, good in principle, but there is scant evidence the system has made biodiversity gains that wouldn’t have happened anyway, according to by zu Ermgassen.
These problems are writ large in the burgeoning international market for biodiversity offsets. This is envisaged to work like the carbon market, with destructive industries voluntarily buying biodiversity offsets, or credits, to atone for their sins against nature.
According to Brian O’Donnell, director of , governments increasingly see offsetting as a nifty way to bridge the estimated $700 billion annual funding gap between what is available for biodiversity conservation and what is needed to meet the goals of the 2022 Kunming-Montreal Global Biodiversity Framework.
This is “magical thinking”, says O’Donnell’s colleague, Mark Opel. It will take at least a decade for the market to mature, which is too long, and it will provide only a fraction of what is needed. It also invites greenwashing. “We feel this approach is deeply flawed,” says O’Donnell.
The only credible way to bridge the gap is for governments to step in and force companies to act, through carrots or sticks. In that respect, England’s new law is a step in the right direction. But, ultimately, biodiversity offsetting is doomed to failure because of non-fungibility. “Biodiversity is infinitely complex,” says Opel. “It’s not fungible.”
Graham’s week
What I’m reading
What Just Happened?! Dispatches from turbulent times by The Guardian’s brilliant and hilarious columnist Marina Hyde.
What I’m watching
I just got Sky Sports on my TV. So, sports.
What I’m working on
I am back on the biomed beat.
Graham Lawton is a staff writer at 91av and author of Mustn’t Grumble: The surprising science of everyday ailments. You can follow him @grahamlawton
