Critical natural assets, UK & Ireland: the map worth building | Part II

“Well, the river runs deep and the water is cold as ice The river runs deep and the water is cold as ice I go down there every chance I get It's where my baby she met her death And the river runs deep and the water's cold as ice”

‘River runs deep’ by JJ Cale, from his seminal 1971 debut album, Naturally

In my first effort on this topic I argued that the map was never the bottleneck. The reason nature stays unpriced is that most of what it does for us behaves like a public good, and it is obviously difficult to charge people for something you cannot fence off. But I want to come back to the map itself now, because there is a second thing worth saying about it, and I think that this one is more hopeful.

The critical natural assets paper from Rebecca Chaplin-Kramer and colleagues is a great read. Mapping 90% of nature's contributions to people across the whole planet, and showing that 30% of land carries the local ones, is a real piece of work, and the global scale is the point rather than a limitation. It was built to answer a global question, and it answers it well.

But the authors say something that tends to get lost behind the numbers. They rate the approach above the maps themselves, and they call for it to be re-run at the scale where decisions are actually made, with better data and local knowledge. I believe that deserves more attention than the 30% does, because for once we are in a position to act on it. The British data has quietly become remarkable.

Consider what the global study had to work with. Land cover at 300m, from 2015, and population at 1km, from LandScan. Those are the right tools for a planetary optimisation, but realistically they are coarse for anything smaller. Now look at what we readily have to hand. UKCEH maps British land cover at 10m and updates it every year, and the Environment Agency's LiDAR now covers about 99% of England at 1m. Natural England has, for the first time, modelled the extent, depth and condition of English peat, and census data comes at small-area level. The distance between the global inputs and the domestic ones is not incremental, rather it is the difference between a continental weather chart and a local forecast.

And the tool box is pretty open too! The models behind the paper, InVEST, prioritizr and Co$ting Nature, are freely available, and the code and outputs are published on the Open Science Framework. So the question is not whether we could rebuild this for Britain and Ireland at 10m, as we plainly can. The question is why we would keep working from a planetary average when we don't have to.

A domestic version would do things the global one cannot. It would sharpen the numbers to the point where they guide a decision, telling a water company which sub-catchment to invest in rather than which country. It would add the service the global model deliberately left out, the regulation of water quantity and low flows, which the Climate Change Committee has just made one of its three headline hazards, with a projected 5 billion litre daily shortfall in England by 2050. And, run across a range of targets rather than a single one, as the authors themselves ran it, it would trace the accumulation curve, the relationship between how much land you secure and how much benefit you keep. That curve, with restoration costs attached, gives an allocator or an aset owner the one figure none of the headlines contain, and the one my first piece said was missing: the marginal cost of a unit of resilience. I for one would love to know that number!

I should be honest that this takes a slug at a number I used last time. The 47.9% of UK land that reads as critical to the local services, the figure behind my claim that nature is not a 2% concern in these islands, comes from that same global model, and it would move (possibly really move) under a proper domestic run of the data. Ireland's is higher again, partly because extensive pasture is classed there as semi-natural. None of this is a criticism of the paper, but it is the reason to take its authors at their word and build the national version.

I don't have to argue that in the abstract, because since I put out my first thought piece, one of the paper's own authors, Rachel Neugarten , did something extremely generous. She wrote to agree that the map is not the barrier, and to point out how much further the method already reaches. The authors can map not only the people downstream who benefit but the habitat upstream that supplies the service, and attach a unit of value to each patch of it, kilograms of sediment retained, numbers of coastal people protected. Then for me came the honest heart of the whole problem: they are scientists, not financiers, and cannot yet see how to turn that into something investable - Rachel kindly asked for ideas.

So here is the start of one (and yes, it is only the start of one!). A physical quantity is not yet a cashflow - what I mean by that is that kilograms of sediment retained by a given hectare is exactly the numerator that has been missing, but it needs a denominator: someone who avoids a cost when that hectare does its work, and a contract under which they pay for it. The science supplies the attribution, this parcel delivers this service to these beneficiaries, which is the harder and more valuable half. Finance has to supply the payer and the price side of things, and the price is rarely the service in the abstract. It is the avoided cost to the beneficiary: the dredging the reservoir no longer needs, the treatment a water company can defer, the defences a coast can now do without. Pair retained sediment with avoided dredging and we will start to have a number a treasurer or a CFO recognises.

Two things then make that number bankable. The value has to be measurable and verifiable over time, so that payment follows delivery rather than promise, which is where the same high-resolution monitoring that builds the map earns its keep again. And because one hectare usually supplies several services at once, it usually needs several beneficiaries paying together for the economics to bind tightly, aggregated to the catchment so the transaction costs are bearable. And the good news? None of that is beyond us. It is ordinary structuring work, waiting on the attribution the paper's authors can now provide - so who will take up the challenge? The science has quietly produced the one input finance always lacked, a defensible unit of value tied to a specific piece of ground. Notice, too, what the same habitat-scale method measures almost as a by-product: not just what a parcel delivers, but whether it is in the condition to keep delivering it.

Which returns me to the line I ended the first piece on: that designation is not the same as function. It deserves more than a parting line, because a higher-resolution, condition-aware map is exactly the instrument that would let us act on it. Could it be that our national nature target counts the wrong thing? 30x30, 30% of land protected by 2030, is measured in hectares designated. Designation is a line on a map, not a description of what the land is doing. The Committee's own figures make the gap plain: about a tenth of UK land is currently protected, and in England only around 7% of it is in good ecological condition. We are already part of the way to a target that, even met in full, would leave the great majority of the protected estate perhaps not actually functioning.

I would contend that he Chaplin-Kramer paper anticipates exactly this. It warns that treating these areas as protected in the fortress sense, fencing them off and restricting the use of them, can destroy the value that made them worth protecting, because so much of what nature does for people is bound up with land that is worked and lived on. A grazed upland or a farmed floodplain can deliver flood attenuation and clean water while staying in use. Peat is the clearest case: most of it is unprotected, much of it sits on working estates, and its value turns almost entirely on condition, whether it is wet or drained, not on whether a boundary has been drawn around it. Lock these places up and you can lose the benefit you were trying to secure; ignore their condition and you might as well never have had it.

So the target worth caring about is not the area designated but the area in good condition, and condition is not delivered by a boundary. It is delivered by spending money on land that stays in use, which is harder to measure and harder to fund. A national map of where the services come from, and in what state the land supplying them is, is precisely the instrument that would let us set a target on function rather than on area, and pay against it. So in many ways, the same data that sharpens the first argument answers the second too.

There are two questions to leave you with, then, for anyone building nature into a strategy this year. If the method matters more than the map, and the data has never been better, why are we still quoting a global average instead of building our own? And if the target worth hitting is condition rather than designation, what will it take to fund it, on land that has to stay in use to be worth anything? The global map told us the assets are real and worth keeping. The national one, if we build it, would tell us where they are and what it costs to keep them working. I closed my first piece by saying the pricing awaits. And now this is the map that ends the wait, and the one worth building.

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References

Part one: "Critical natural assets, UK & Ireland: a map, not a market", LinkedIn, June 2026. https://www.linkedin.com/pulse/critical-natural-assets-uk-ireland-map-market-eoin-murray-nufhe/?trackingId=FzN8ds51Q1W6Y6kwEdqenw%3D%3D

Primary source and data

Chaplin-Kramer, R., Neugarten, R. A., Sharp, R. P. et al. (2023). Mapping the planet's critical natural assets. Nature Ecology & Evolution, 7, 51–61. https://doi.org/10.1038/s41559-022-01934-5

Chaplin-Kramer, R. et al. (2022). Critical natural assets - data and code. Open Science Framework. https://osf.io/r5xz7/

Supplementary Data 1 to Chaplin-Kramer et al. (2023): per-country critical-asset percentages.

Policy and targets

Climate Change Committee (2026). A Well-Adapted UK — the Fourth Independent Assessment of UK Climate Risk (CCRA4-IA). 20 May 2026. https://www.theccc.org.uk/publication/a-well-adapted-uk/

Convention on Biological Diversity (2022). Kunming-Montreal Global Biodiversity Framework, Target 3

Natural Capital Project. InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs). Stanford University. https://naturalcapitalproject.stanford.edu/software/invest

Mulligan, M. et al. (2020). Co$ting Nature (version 3). https://www.policysupport.org/costingnature

prioritizr: systematic conservation prioritisation in R. https://prioritizr.net/

Datasets

UK Centre for Ecology & Hydrology. Land Cover Map (10 m, Great Britain and Northern Ireland; updated annually).

Environment Agency. National LiDAR Programme (1 m composite digital terrain model, ~99% coverage of England).

Natural England (2025). England Peat Map. Natural England Research Report NERR149

Office for National Statistics, National Records of Scotland and NISRA. Census small-area population data (2021/2022).

Provenance note: the UK percentages above come from the global 2 km model applied per country. They are indicative rather than survey-grade, which is the argument the article makes - the case for a higher-resolution domestic re-run rather than a reason to distrust the paper.