Biodiversity offsets won't save British wildlife

Last month, the government launched the largest change to land use regulations in decades. The policy, biodiversity net gain (BNG), seeks to harness private investment to protect and restore England's natural world. Ostensibly a win-win for the environment and developers alike, it pledges to mesh the gears of economic growth with ecological preservation. But who will really benefit, and what will it mean for English flora and fauna?

The air we breathe, the water we drink and the food we eat all rely on biodiversity. The variety of plant and animal life in our ecosystems sustains livelihoods, safeguards food security, and underpins the very essence of human existence. Biodiversity provides us with medicine (did you know a fungus on the fur of sloths can fight cancer?) and improves our mental health: more than four in five of us report being happy in nature. Yet, as the first nation to industrialise, Britain is classified as one of the world's most nature-depleted countries. Nearly one in six species are at risk of being lost.

In an attempt to rectify this, the government's new BNG policy introduces a planning requirement: Any development with more than 10 homes must increase net biodiversity by at least 10 per cent. This means that the abundance and diversity of life in one area will need to improve by a tenth - or be balanced out by improvements in other areas, using "biodiversity offsets" that last for 30 years. 

The idea that you can destroy osprey nests and make up for it by supporting another species elsewhere will sound like total nonsense to most people. It is an approach that takes its logic from the factory, where the production of cars or phones can be scaled up or down in response to market forces. This is not how the natural world works. Life depends on an intricate web of organisms, much of which we do not fully comprehend. In wilful ignorance, the government has decided that our natural world can be sufficiently represented in a simple spreadsheet and scaled up and down as needed.

There's no widely agreed way of measuring biodiversity. Regardless, this government has designed a statutory tool to quantify the unquantifiable and reduce the natural world to "biodiversity units" to facilitate this new environmental calculus.

Many countries require developers to pay compensation for environmental destruction - over 100 have a policy, or are exploring it. Despite their widespread adoption, a recent review of over 400 assessments found no evidence that offsite mitigation actually works. This is primarily because offsetting still allows for activities with clear and immediate damage to nature to be carried out. Evidence from other schemes also suggests that onsite biodiversity declines are commonly higher than assumed, while improvements offsite are overestimated, and only accrue decades later - if at all. Sometimes sites that aren't actually in danger receive "protection", creating offsets which have no value in the real world. Concerns also remain about the permanence of offsets.

The diversity and volume of wildlife and plant life in each area is complex, which means it can't simply be reproduced somewhere else - unlike a tonne of CO2. According to the World Bank's 2016 offsetting guide, schemes like BNG "are not real biodiversity offsets'' because the actions they support "do not necessarily involve the same ecosystems or species that were harmed under the original project".

Why then, if the evidence is so uncompelling, is this regulation going ahead? An important part of the answer is this: this government has made a legal commitment to halt the decline in species abundance by 2030, but its broader political agenda requires it to do so without disrupting the prevailing economic model or damaging the interests of its major political donors, which include property developers. This means they must protect biodiversity in a way that allows for the dominant property development model to advance unabated. BNG purports to do exactly that. In fact, Defra modelling anticipates that developers will avoid 90 per cent of the immediate policy costs because the price of land will likely decrease to compensate for the cost of offsetting.

Using land values to fund improvements in nature is, in isolation, economically sound. Where this policy goes wrong, however, is in allowing for the definite destruction of nature today to pay for uncertain, promised future improvements in the natural world, likely in places that are harder to access and potentially of less ecological significance. 

In doing so this government is playing a risky game that's been lost before. In the Georges Bank, off the east coast of Canada, "rational fisheries management" was used to manage ocean ecosystems. But decades of unsustainable catches, informed by limited scientific understanding and industry capture of the New England Fisheries Management Council decimated local fish stocks. By the time of the cod fishing moratorium in 1992, just one per cent of the original population remained. It is now feared that the food web has been so fundamentally altered by excessive fishing that the cod population may never recover. 

Delivery questions also persist. Planning authorities, who are required to enforce BNG, report "...that their current resource, capacity and expertise is not adequate to deal with their existing planning workload, let alone any increase required to address additional work on BNG." This could see the policy fail on its own terms, with inadequate oversight of damage to nature meaning developers can get away with not purchasing biodiversity offsets. Experts have highlighted potential unexpected effects: "...we've created a system where there's a perverse incentive not to know if you're wrong because then you get exposed to the liability that you paid to get rid of in the first place."

We must recognise nature as the foundation of our collective wellbeing - not use neat accounting tricks to justify the destruction of wildlife and ecosystems. This government should be increasing funding for landscape recovery and agroecological farming, while introducing a land use framework to restore our natural world so that we are able to develop and thrive for generations to come. 

Christian Jaccarini is senior researcher at New Economics Foundation