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I’ve spent the last 3.5 years researching how to resolve contradictions between Sust Dev Goal 9 (expand infrastructure networks) & SDG14/15 (protect ecosystems & wildlife). Here’s the summary of my PhD analysing this epic problem 
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🧵" title="collectie" aria-label="Emoji: collectie"> /1
Built infra is currently proliferating around the world at fastest rate in history. If we built all the infra that’s projected using business-as-usual practices, the planet’s stuffed - the emissions from just building it all use up basically our whole carbon budget /2
There are also vast impacts on nature. The obvious stuff is the land use change from destroying natural systems & replacing them with concrete. But our work led by @aurora_torresm also shows biodv loss embedded in concrete/cement supply chains /3
There’s so much upstream damage you never see - in this preprint, we systematically identify all the species globally threatened by society’s hunger for construction minerals– the hidden biodv impacts of our enormous reliance on concrete infrastructure /4 https://www.biorxiv.org/content/10.1101/2022.03.23.485272v1.abstract">https://www.biorxiv.org/content/1...
Returning to direct impacts of infra, here we review big-pic overlaps between biodiversity around the world & projected infrastructure expansion, & discuss the policy transformations req’d to stop all this new infra harming nature /5 https://www.sciencedirect.com/science/article/pii/S2590332219301332">https://www.sciencedirect.com/science/a...
My take is we need to think about reducing the impacts of new infra from 2 perspectives: supply-side (we need practices that reduce the harm of supplying new infra) & demand-side (we need to build less wasteful infra) /6
So, on supply-side, I spent most of my PhD focusing on a growing practice for reducing impacts of infra on nature: biodiversity offsetting. In 2019 we reviewed the evidence for whether they actually work. Results were mixed /7 https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12664">https://conbio.onlinelibrary.wiley.com/doi/full/...
Basically, offsets can work (ecologically) if invest enough in doing them well & don’t harm sensitive or slow-growing nature in the first place. They’re best suited to simple ecosystems like degraded wetlands, & have a dodgy record for complex stuff like woodlands /8
But the quality of evidence is v low. So, we contributed our bit to the evidence by evaluating 2 biodv compensation policies around the world: Biodiversity Net Gain in England, & the Native Vegetation Framework in Victoria. /9
I’m pretty excited about our evaluation of Victoria’s historical offset policy, but can’t say anything publicly yet. Watch this space. /10
For England’s BNG, we built a database of all BNG assessments from a set of early-adopter councils, to see what actual habitat changes we can expect on the ground. Our evaluation shows BNG facilitates a considerable loss in the area of greenspace… /11 https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/conl.12820">https://conbio.onlinelibrary.wiley.com/doi/full/...
… compensated for mostly by promises of smaller, but higher quality, habitat patches within the built environment delivered in the future. Will these actually get delivered? The governance looks very shakey, which I’ve written about here /12 https://theconversation.com/biodiversity-why-new-rules-to-ensure-nature-benefits-from-building-projects-could-fail-179701">https://theconversation.com/biodivers...
Alongside BNG, we have protected species legislation, so protected species don’t get harmed by new developments. Do these work? Well in a paper led by @BronwenHunter we show that the evidence base behind species mitigation measures is very weak /13 https://besjournals.onlinelibrary.wiley.com/doi/full/10.1002/2688-8319.12089">https://besjournals.onlinelibrary.wiley.com/doi/full/...
OK, back to offsets. >99% of all the world’s offsets are linked to government ecological mitigation legislation, and most mature offsetting systems rely on regulatory markets to deliver offsets (i.e. developers can buy biodiversity credits from private or state providers) /14
Now offsets act to reduce the harm of new infra through 2 different mechanisms. 1) they make up for the damage caused; 2) they internalize the cost of damaging biodiversity into the development planning process, incentivizing not harming as much biodv in 1st place /15
So offset markets where credits are expensive & genuinely restrict development can be a sign that offsets are working WELL (i.e. stopping development that affects rare biodv features which are so rare that there are no credits available), not BADLY as often assumed. /16
Problem is, we see common patterns across some offset schemes: when credits get expensive or credit supply falls, governments often intervene to relax trading rules to stimulate further offset supply - undermining one of their key ecological benefits! /17 https://www.sciencedirect.com/science/article/pii/S0006320720309198">https://www.sciencedirect.com/science/a...
All of this means that offsets cannot be relied upon alone to reconcile infra expansion & nature objectives. We need to reduce unnecessary infra, & increase spending on conservation that’s not tied to development (i.e. is not a ‘defensive expenditure’ like offsets) /18
Which is why I get so concerned when I see that UK statutory biodv spending has dropped by ~30-40% in real terms since 2008, even as GDP/year has increased by £250bn since then! /19 https://www.nature.com/articles/d41586-021-01819-w">https://www.nature.com/articles/...
More on that story here. We show (using @UNDPbiofin data) the Environmental Kuznets curve is rubbish in the context of UK investment in nature /20
https://www.exeter.ac.uk/research/leep/publications/biodiversity-funding/">https://www.exeter.ac.uk/research/...
https://www.exeter.ac.uk/research/leep/publications/biodiversity-funding/">https://www.exeter.ac.uk/research/...
So, supply-side initiatives for stopping the ecological harms of new infra are not enough. We need to reduce the development of unnecessary infra. But isn’t all new infra necessary, you ask? Absolutely NOT. Beyond 50t concrete/capita, there’s no wellbeing-infra relationship /21
So can we create economies that rely less on infra expansion? Well here we look at this question in a lot of detail, using the case study of housing infrastructure in England /22 https://osf.io/5kxce ">https://osf.io/5kxce&quo...
We look at housing in England & show if the govt follows its business as usual housing strategy by 2050 housing ALONE consumes the whole carbon budget for 1.5C. But, we still have a huge amount of unmet housing need in England /23
But it may well be theoretically possible to meet England’s unmet housing need using the existing housing stock, as the distribution of housing space across income groups is incredibly unequal – a fairer housing system could house us all /24
But the policy transformations to deliver this would have to be breathtakingly ambitious, & big part of the story is definancialising housing so it’s treated more as a consumption good & less like a financial asset. All discussed in here /25 https://osf.io/5kxce ">https://osf.io/5kxce&quo...
So, in sum: we CAN prob reconcile SDGs 9 & 14/15, but it requires: way better biodiversity offsetting, & building less unnecessary new infra, which means redesigning our economies to tackle our structural economic reliance on infra growth & construction sector. /26
All these ideas have come from/been heavily inspired by the amazing >100 collaborators I’ve worked with. I’m esp influenced by work of @martine_maron @aurora_torresm @megcevans @ProfTimJackson @juliapgjones @JKSteinberger @CorletWalker @EJMilnerGulland @jryancollins /27
And the biggest shout out goes to my extraordinarily kind & clever mentor @wildbusiness. A sensational academic, group leader & person.
Also in my view @DICE_Kent is one of the great Conservation Science institutes – I’ve learned so much. /end
Also in my view @DICE_Kent is one of the great Conservation Science institutes – I’ve learned so much. /end
