The developer Tuike Finland Oy cleared forest at two sites, Muhos and Otanmäki. After letters from the Finnish authorities on 6 October, work stopped, because the company had skipped the assessment. The sites are part of a $14.5 billion build-out Google announced in September, so this was not the best look for the start of a multi-year collaboration.

“We had wolves coming into the village because all the wild animals moved out of the forest,” Anni Ranta, 53, told the Guardian. Another resident called the method “American style.” [Editor’s note: That reminds me of being told I was “too American” in a meeting at Nokia once. I think they meant I wasn’t listening enough. In Muhos it meant clearing the forest first and asking afterwards.]

That is an externality in its plainest form: a cost that lands on people who never signed up for it. The villager did not train the model, does not price the tokens, and cannot send Google the bill if her lambs turn into wolf-lunch.

Otanmäki and Muhos are probably a preview. The IEA expects data centres to draw about 945 terawatt-hours by 2030, near 3 per cent of the world’s electricity, with AI the fastest-rising slice. Land, water and power all get drawn down, and little of that reaches the price of chatbot.

Finland has shown the cost can be made to appear. A regulator stopped work at two sites, which means the cost of compute can be counted before the trees come down rather than after. Finland has now launched a criminal investigation, so don’t expect this to go away anytime soon.

Public opinion is probably the bigger lever. We need to make it obvious and urgent to put nature into these megawatt calculations before the diggers arrive, so the economics of the next forest start to reflect reality.

In these newsletters, AI is usually the instrument that reveals a hidden cost. In Otanmäki it is the hidden cost, felled and stacked and visible from the air, and so far these villages are paying the bill.

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

A tree on a city street appears as a local council expense. Someone waters it, prunes it, sweeps the leaves and wrangles complaints about its roots lifting footpaths. The benefits arise elsewhere. An insect from East Asia ran an experiment nobody would have been allowed to design, and the benefit turned up in the death registry.

The emerald ash borer was found near Detroit in 2002. By 2012 it had killed about 100 million ash trees across the US. Geoffrey Donovan and colleagues at the US Forest Service followed it county by county, from 1990 to 2007, across 15 states. Writing in the American Journal of Preventive Medicine in 2013, they found that the borer “was associated with an additional 6113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular-related deaths.”

That’s 21,193 deaths, give or take, in the counties where the trees came down.

Hidden: the tree that only shows up as a cost

Nobody plants a street tree to cut the local cardiac admissions. People plant them for shade, for looks and for property prices, and councils pay for them out of rates. The health effect, if there is one, sits outside the budgets that touch the tree.

The beetle created a natural experiment, that is not normally possible. Most research on green space compares leafy suburbs with bare ones, and leafy suburbs tend to be richer, healthier and better at going to the doctor. Donovan’s team had something closer to a natural experiment: the borer arrived in some counties and not others, at different times, for reasons that had nothing to do with the health of the people living there. The effect grew the longer the infestation ran.

Externality: the council’s tree, the hospital’s bill

When a council loses trees or fails to plant them, the cost lands in a different world. In Australia, heart attacks and strokes are paid for by state hospitals, Medicare, the PBS and private health funds. Life insurers carry the deaths. None of them owns a single street tree.

The pattern repeats in other studies:

• Women’s Health Initiative. Donovan’s team went back in 2015 with individual-level data from this large study of post-menopausal American women (Health & Place). Women living in a county infested with the borer had a higher risk of cardiovascular disease (hazard ratio 1.25, 95% CI 1.20 to 1.31). The outcome covered heart attacks, strokes and coronary death.

• Portland. A 10% increase in tree canopy within 50 metres of a home was linked to 1.42 fewer small-for-gestational-age births per 1,000 (Health & Place, 2011).

• Toronto. Omid Kardan and colleagues found that ten more trees on a city block went with better self-rated health. The improvement was comparable to a $10,000 rise in income, or to “being 7 years younger” (Scientific Reports, 2015).

Revealed: the data was always there

None of this needed new science. The ingredients sat in three unconnected places: a federal map of where the beetle had spread, county death records, and land-cover imagery. The insight came from holding them up against each other.

Australia already has most of the pieces.

• Melbourne’s targets. In 2012 the City of Melbourne set a goal in its Urban Forest Strategy to lift public-realm canopy from 22% to 40% by 2040. It also capped any one species at 5% of the tree population. That cap is a lesson learned from leaning too hard on elms and planes, much as American cities leaned on ash.

• National benchmarking. RMIT’s benchmarking for Hort Innovation and Greener Spaces Better Places tracks green cover across 131 urban council areas. By 2020, 69% of them still had less green cover than in 2013. Its Victorian snapshot put average urban canopy at 18.83%, down from 20.89% in 2013.

• Heat. The January 2009 heatwave in Victoria caused an estimated 374 excess deaths, a 62% rise on the expected toll (Victorian Department of Human Services).

Shade is the most obvious mechanism tying canopy to health. It is one of several candidates: cleaner air, lower stress and more walking are the others. Nobody has pinned down which does the work.

The caveats

A natural experiment is stronger than a snapshot. It is weaker than a trial. Donovan’s 2013 study works at county level, so it can’t say who died or why, and critics have pointed to wide error bands and a weak result in the control model for accidental deaths. The authors themselves wrote that “little is known about the mechanisms linking trees and cardiovascular disease.” Kardan’s Toronto study and the Portland birth study are associations. Treat the numbers as a signal worth acting on, and test them before anyone bets a health budget on them.

Opportunity: a canopy dividend

If tree loss raises heart and lung disease, then tree cover has a value for health budgets. Several of the levers of systems change could help turn this into an opportunity:

• Research. Link Australia’s canopy data (satellite and LiDAR, council tree inventories) to hospital admissions and deaths by small area, and test whether the American finding holds here. Victoria, with its heat record, canopy targets and linked health data, is the natural place to start.

• A metric. A canopy dividend would estimate the health cost avoided per hectare of canopy, by suburb. Councils would get a number to set against the pruning bill. Health funds would get a number they can recognise.

• Capital. A health fund, a state health department or a life insurer could co-fund planting in low-canopy, high-heat suburbs, with payments tied to measured canopy growth. A green bond or outcome contract could carry the upfront cost until the evidence matures.

• Regulation. Planning rules that count tree loss on private land as a health cost, where much of the recent decline has happened.

Councils plant the trees and health budgets bank the savings. Once there’s a number connecting the two, the second has a reason to help pay the first.

As always, feedback and suggestions welcome.

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

Last week I wrote in Looking Forward that Australia’s populist surge maps onto government neglect, health resilience alone explaining 63 per cent of variation in the One Nation vote. That is a pattern - these two studies confirm the dynamic.

The last school changes the vote

In the Journal of Economic Geography, Marli Fernandes and José Tavares tracked French towns that lost their only school against near-identical towns that kept theirs, every presidential election from 1995 to 2022. Lose the last school and the far-right vote rises 0.53 points, the mainstream left 0.97. Whole towns moving, not polling noise.

What matters is that it is the last school. Keep a second school, or another within two kilometres, and the effect vanishes. Local access to services moves votes. The far-right gain shows up only where abstention was high and the mainstream was already weak.

The empty building draws gunfire

Chicago asked a similar question in a different context. In 2013 it shut 49 elementary schools; a decade on, 26 still stand empty. In Social Science & Medicine, Thomas Statchen and colleagues matched the blocks around them against blocks around schools left open: shootings ran about 10 per cent higher, concentrated where the building was left to rot rather than reused. An empty school is a dead space a neighbourhood has to live around.

Both are observational, one country and one city. But the damage tracks vacancy, not closure alone, and vacancy is a choice.

Count what you are actually cutting

Here is the budget question the spreadsheet doesn’t ask: what does keeping this place cost, against what losing it costs? Donella Meadows put what a system measures near the top of her leverage points, far above the line item that triggers a closure. Measure only the saving and you keep shutting things that bill you back in votes and gunfire.

That gap is the opportunity. The studies price the withdrawal; the move is to fund the building’s next life before it goes dark. Australia’s map of neglect gives some good places to start. How can we start to include these disparate, downstream costs on the town’s short-term balance sheet?

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

Re-introducing wolves into the environment has been a hotly debated issue. The main costs measured by a cost to ranchers’ livestock (wolves have got to wolf). However, if you add in the value to society of avoided vehicle collisions with deer, the benefits generally outweigh the cost 63 times.

The most valuable thing a wolf does in Wisconsin is not kill deer; it frightens them. A returning pack does not have to thin a herd to change a county, because deer that live in fear of wolves move differently, keeping away from the ditches, verges and open crossings where they are most exposed, and it turns out that roughly seventy-three percent of what follows comes from frightened deer rather than fewer deer. Jennifer Raynor, Corbett Grainger and Dominic Parker found the effect in an unlikely dataset: car-crash records. Writing in the Proceedings of the National Academy of Sciences (PNAS) in 2021, they showed that once wolves recolonise a county, collisions with deer fall by about 24%.

The politics of the wolf runs on one side of the ledger

The wolf is fought over in courtrooms and ballot measures across the American West, and the argument runs almost entirely on what a wolf takes from a rancher. That number is real, verified and compensated, so it dominates every hearing. The benefit side has never had a number to set beside it - it was sitting off the farm entirely, in the insurance data.

The fear does the work

The famous version of this story is Yellowstone, where wolves returned in 1995, the elk stopped over-browsing the willow along the rivers, and the beaver and songbirds came back behind them: a cascade that became a viral parable about one predator rewiring a whole valley. Wisconsin is the same mechanism with a price tag attached. Ecologists call it a “landscape of fear”: a prey animal avoids the places a predator hunts, i.e. roads. That behaviour produced around 38 fewer collisions in the average wolf county every year. The deer a wolf eats matter less than the deer a wolf scares.

The benefit hides in the insurance ledger

Across the United States each year, deer collision cause 29,000 injuries, 200 deaths and close to $10bn costs of car wrecks of collisions, hospital stays and higher premiums. In the 29 Wisconsin counties wolves had returned to, the avoided collisions were worth $10.9 million in total, around $375k per county. Set against the verified cost of wolves killing livestock, the benefit runs 63-to-1.

Several of the six levers of systems change:

• Research. Build the thing the paper only sampled: a collisions-per-county panel, run nationally, that turns predator range into a line an actuary can actually read.

• Capital. An insurer or a state highway budget that saves $375,000 a county has a reason to help pay for predator recovery that no conservation appeal has ever been able to give.

• Public opinion and regulation. A rancher and collisions are, for once, looking at one number they can both sign, and that is the thing that moves a delisting hearing.

Restoring the wolf paid a dividend that was hidden, revealed in fewer wrecks on the county roads at nightfall.

As always, feedback and suggestions welcome

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

Following a newspaper closure, municipal borrowing costs increase by 5–11 basis points, costing the municipality an additional $650,000 per issue. This effect is causal and not driven by underlying economic conditions. The loss of government monitoring resulting from a closure is associated with higher government wages and deficits and increased likelihoods of costly advance refundings and negotiated sales. Overall, our results indicate that local newspapers hold their governments accountable, keeping municipal borrowing costs low and ultimately saving local taxpayers money

It seems that the clear-eyed bean counters in the bond market can put a value, and price, on local journalism, which, tragically, local citizens and businesses don’t seem to be able to. The mechanism is scrutiny. A local paper sits through council meetings, reads budgets and asks who got the contract. Once it closes, nobody does. The study finds that after a closure, government wage ratios rise by about 1.3 percentage points, roughly $1.4m a year in the median county, and deficits widen. Taxpayers foot the bill.

The decline of journalism

I grew up passionate about journalism; my first two jobs (if you don’t count gardening and being a barman) were in journalism. My first role was as a local feature writer and part-time advertising salesman for the Rutland and East Staffordshire Tatler. The magazine has now sadly passed, and perhaps my abject failure at cold-calling local businesses could have been a warning. My second job, an internship actually, was shadowing the political editor of The Economist; sitting in on their weekly editorial meeting was a career highlight. In that room of big brains, it was easy to feel the industry was both necessary and secure.

Unfortunately, journalism, especially local journalism, is in freefall. In the US, print newspaper circulation has dropped by 70% from 2005-2025, with more than 40% of all local newspapers closing. Incredibly, the industry has lost 75% of its workforce since 2005. Today, over 50 million people live in a news desert in the US, up from 37 million twenty years ago, and as a result, 1,525 counties rely on only a single source of news.

Where the money went

The causes are varied, but it’s clear that social media has sucked money out of advertising budgets; now, 73% of all advertising is digital, and more than half of that is controlled by Google and Meta. Further, we’ve seen hedge funds, such as Alden Global Capital, buy up and gut local newspapers.

Less scrutiny, more waste

The result is less independent transparency and oversight of local officials in power, and as such there’s more double-dealing, corruption, and waste, which then affects the financial viability of the town.

What the watchdog is worth

In the litany of bad news, this data should be a godsend. It seems like a perfect opportunity for a foundation to fund local reporting - part of the payback to the board should be a measurable discount on public borrowing. Bond desks could treat news deserts as a forward indicator of fiscal drift; the data is public and the lag is three years, so patient investors have time to use it. Once a city understands the interest bill attached to losing its paper has got a real number attached, subsidizing local reporting looks less like charity and more like smart treasury management.

Now put the two numbers next to each other. The extra $650,000 on a single bond issue is more than it costs to run many a small local newsroom for a year: the Gotham Gazette covers New York City politics on a $350,000 budget, and grassroots sites get by on a fraction of that, some on as little as $100,000. The town is not weighing a public good against a tight budget; it is paying more, in interest alone on a single deal, to be worse governed. The cheapest fiscal reform available to some of these counties would actually be a functioning local paper.

Alternatively, or in addition, there are also new models of charity, along the lines of tithing, where local people make pledges to support local journalism. Whatever works is worth a try.

Accountability is usually argued for in the language of democracy, which is real but hard to price. The bond market has priced it anyway. The finance wonks have worked out what the watchdog was worth; the rest of us are catching up.

The HERO summary

• HIDDEN: A town’s paper closes and nobody sits through the council meetings.

• EXTERNALITY: Weaker oversight raises borrowing costs, wages and deficits; taxpayers pay.

• REVEALED: Borrowing costs rise 5-11 bps, about $650k per issue, after a closure; causal, not correlation.

• OPPORTUNITY: Fund local reporting as measurable ROI; trade news deserts as a fiscal-drift indicator; towns treat newsrooms as treasury management.

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

Here’s how Ambient Noise tracks on our H-E-R-O frame:

Hidden

Chronic noise is a modern phenomenon - not much of it in the countryside. The cleanest evidence of harm is already fifty years old - from Public School 98 in Manhattan. An elevated train ran about 220 feet from one side of the building, disrupting the noisy-side classrooms every four or five minutes. In 1975 the environmental psychologist Arline Bronzaft compared children’s reading scores according to which side of the building their classroom faced. On average the noisy-side classes lagged three to four months behind the quiet-side; the worst eleven months behind. Same school, same teachers, same curriculum, same children, the only variable being the wall. Then the HERO part of the story: the transit authority laid resilient rubber pads under the track to keep the noise down, and the reading gap disappeared. Simple rubber pads helped kids gain a year of reading.

It is not just the kids. The same nights that cost them reading are, for the adults in the same houses, a cardiovascular insult. According to the World Health Organization, more than a million healthy life-years are lost every year to traffic noise in western Europe. The European Environment Agency says a full one in five Europeans (110 million) suffer from noise pollution, which results in 66,000 premature deaths, 50,000 new cases of cardiovascular diseases and 22,000 new cases of type 2 diabetes. Additionally, noise could cause thousands of cases of depression and dementia. While the word is out about air pollution; noise pollution is still thought of as an annoyance rather than a health burden.

In health, the pathway is fascinating, and missing from the measurements. Noise spikes fragment sleep: it activates the sympathetic nervous system, increases cortisol, leads to endothelial dysfunction and raises blood pressure. Sustained across years, these correlated with hypertension and with downstream heart disease. You don’t even have to wake up.

On Saturday night in Tokyo I had my own cortisol spike. At two in the morning, a few hours into sleep, I woke to blaring klaxons and a tannoy screaming “Earthquake! Earthquake!”. That was genuinely a freak-out moment, six floors up. I felt, physically and metaphorically, at sea. My phone lit up with the same warning: “strong shaking expected soon, seek shelter nearby”. The point is not the drama; it’s the cortisol spike. It took me two hours to get back to sleep. That was the loud, conscious version. The sneakier one is likely happening every day - truck deliveries at 3am or the plane on approach that does the same thing to your body without ever waking you.

Externality

Noise is already measured, but not in the right way. The way it’s been done doesn’t reflect the impact it has on people. In particular with health: it’s measured as an average; the average is not the point; the spikes are. The costs to society hide in the spikes, especially relating to the cardiovascular and cortisol issues. The operator of the road, the rail line or the airport captures the benefit, while the residents underneath pay in heart disease, lost sleep and, for children, lost learning, none of which costs the operators anything. The average stat fails in three ways:

• Theoretical. The map that decide planning permission, night curfews and compensation are usually computed from traffic-flow data and propagation models, rarely checked against a real reading at anyone’s actual window.

• Averages. They are reported as an annual average, the Lden and Lnight metrics, but the harm comes from events; a night with a handful of loud pass-bys can post a respectable yearly average while wrecking the sleep of everyone beneath it.

• Static. Reroute the freight line or open a depot that takes deliveries at 2am, and the map that decides your rights may not be redrawn for a decade.

Averaging is simply the wrong operation for this exposure. The official metric is not just coarse and stale; it is unable, by construction, to see the mechanism through which noise does its damage.

Revealed

What has changed - and this is the key to this entire newsletter - is that measurement has become cheap enough for those exposed to take things into their own hands, and build datasets themselves. New York University’s Sounds of New York City project has run more than fifty calibrated acoustic nodes since 2016, logging over 150 million ten-second recordings at an accuracy adequate for most noise codes, mounted high and far-field so the speech that reaches them is judged unintelligible. And I have been testing sound recording for a project of my own; it is remarkable how far you can get with hacking hardware nowadays. Raspberry Pi 4 does genuinely sophisticated processing, and where you need only the raw sound-pressure reading an ESP32 board will do it for about $20. The privacy objection is pretty easily dealt with - don’t share raw data, just the insights (’seventeen pass-bys above sixty decibels between midnight and six.’)

Even simpler than a dedicated audio device is a phone. There are already sleep apps that measure sleep - you can have your iPhone listen for apnea, so why doesn’t it also listen for environmental sounds? These could be joined together to create swarm intelligence.

I’ve not seen anybody connect the wearable data with sound as a biomarker, but it surely wouldn’t be hard. Pair that node with the sleep data from the wearable already on the resident’s wrist, and you link a measured noise to broken sleep. No airport authority, health department or consultant holds this - none could assemble it without the residents. It is a dataset a town of two thousand people could build this year.

Opportunity

Once the signal is legible it becomes actionable, and fundable. A measured, event-based, address-level noise index is a sellable to property valuers, lenders and insurers. It can benefit both sides - checking reality rather than assumptions (maybe those planes aren’t that loud after all...). Measured evidence gathered over a year is different than a resident swearing ‘it feels loud’. And acoustic glazing, facade insulation and quiet road surfacing are mature technologies held back mainly by the absence of a before-and-after number to make them fundable.

In my work, I generally see six levers of systems change: capital, research, startups, regulation, public opinion and orchestration, and this pulls on three of them. Research, in particular a new citizen-science created dataset. Public opinion, because the person kept awake now can point to evidence. And regulation, because whoever can prove averages don’t predict harm can help set better rules.

So now is the time to ask you to give me your sound stories; have you seen projects looking to make this link? Let me know what you agree / disagree with, and if you have other HERO Metrics to share.

About this newsletter: HERO Metrics follows the numbers that move systems. Each edition takes a single hidden signal, an external cost or a value that markets aren’t pricing, and looks at four steps: Hidden, the harm or worth sitting in plain sight; Externality, the way its cost lands on someone who never signed up for it; Revealed, the cheap new instrument or process that makes it legible; and Opportunity, what becomes real and fundable once it can be measured. Markets are one of civilisation’s great inventions. HERO Metrics aims to make them work better for everyone.

That disconnect is the point of this newsletter, HERO Metrics, which looks to surface externalities such as this, and start to fix broken systems.

The May 2025 study in JAMA Network Open, led by researchers at the Mayo Clinic and Rochester Epidemiology Project, looked at 419 people with Parkinson’s set against 5,113 matched controls, tracked from 1991 to 2015. One of the authors, Prof Ray Dorsey, a long-time friend and colleague, has done more than most to reframe Parkinson’s as a largely man-made disease rather than an inevitability. He’s published two well-received books (The Parkinson’s Plan in 2025 and Ending Parkinson’s Disease in 2020). His colleague, and lead researcher on the project, Brittany Krzyzanowski PhD, spoke with me a few months ago about her research. It was a fascinating conversation due to its unintuitive finding, and more importantly, it sparked loads of ideas about what could be done about it (hint: think distributed, collective action).

Each edition takes a single hidden signal and follows it from invisible to investable, through the four moves: Hidden, then Externality, then Revealed, then Opportunity. Here is the golf course through all four.

Golf courses and Parkinson’s have a surprising and unsettling relationship

Hidden: Green space, clean air, oh, and higher odds of Parkinson’s

Buying a house by a golf course reads as buying health: green space, clean air, a daily walk on the links, the reward at the end of a working life. The Mayo data complicates that picture. Within a mile of a golf course the adjusted odds of Parkinson’s ran 126% higher, and the risk held between one and three miles out before fading with distance. A signal this counterintuitive stays invisible for a plain reason: nobody shopping for a fairway view is looking for it.

Externality: The greens budget becomes the neighbour’s neurology bill

My experience taking Economics at Cambridge University left me a little frustrated - there were far too many assumptions about perfect markets and homo economicus. However, a highlight was the learning about concept of externalities, which has stayed with me, and in my view, helps explain much of what is wrong with today’s overly financialised world.

An externality is a cost pushed off a company’s books and onto everyone else’s, something that Kate Raworth and Mariana Mazzucato among others have championed. Here the pathway runs through the tap. In water service areas that contained a golf course the odds of Parkinson’s were close to twice those of areas without one.

Krzyzanowski told me golf courses are sometimes treated with pesticide at heavier rates than farmland (that impossible green is a chemical achievement), and that the worst aquifers are a particular geology, “full of holes and crevices, so when it rains the agricultural chemicals fly right through and get straight to the water.” Where the water sits on that vulnerable ground, the odds of Parkinson’s ran 82% higher than in comparable areas. In some places, she said, those chemicals have shown up in groundwater at two hundred times the legal limit. The pesticide keeps the fairway green, travels through the aquifer, and reaches people who never chose the exposure and will never see a bill for it. Someone pays; it is just not the person who sprayed the grass.

Revealed: The data sat for decades, waiting to be read

Records like these have sat around for decades, scattered across turf-management logs, aquifer maps and disease registries that nobody had held up against each other. That’s where Krzyzanowski thrives. “I don’t have to go out into the field and collect water samples and draw blood,” she told me. “I’m just downloading a data set somebody already made, and running models with it. That’s the beauty of being a geographer.”

The craft is turning messy data into insights. Every golf course was treated as a single pin dropped in its car park, useless for working out who lived close, so she drew the boundary of each course by hand; for the nationwide follow-up, tens of thousands of courses, she has opened a public map with instructions that let anyone trace one, credited by name.

The paper is a case-control study, so it shows a strong association and stops short of proving cause, and it could still be confounded by age, wealth, or where people happen to draw their water. Her summary of the field is the reason this newsletter exists: “researchers all over the world are modelling these toxins, and nobody’s taking the data and testing it.”

A signal engine that only produces exciting findings is worse than useless, so the job is to attack each one and keep what survives. This one, probably, survives long enough to be worth acting on before the science is fully settled.

Opportunity: Measure the exposure, and prevention becomes a market

A revealed signal is only worth anything if someone can act on it, and this one opens moves across the system at once:

• Test and filter. Home and municipal water testing, and filtration for households on vulnerable groundwater, are buildable today.

• Disclose. Proximity and water-source disclosure at the point of sale, the way flood risk slowly became a line you could read on a listing before you bought.

• Research. The individual-level exposure studies that would move this from association to cause, and settle it either way.

• Fund. Capital that treats a health-and-environment signal as an opportunity rather than a liability.

Brittany’s work ignited global coverage (including here in Australia) and she’s been invited to Tasmania in 2027 to help build something like this in Australia. She’s also just published new research in Nature that shows the link - again, in a dose-dependent way - between living in proximity to a dry cleaner’s and developing Parkinson’s. Another of her findings shows a correlation between newer groundwater (which is more exposed to chemicals) and Parkinson’s. One of the findings was that water drawn from porous, chemical-absorbing carbonate aquifers carried up to 62% higher Parkinson’s risk than water from glacial aquifers. It’s as if toxic chemicals that fry your brain shouldn’t just be dumped into local water supplies...

This is bigger than one disease. Donella Meadows argued that the highest leverage in a system is often the flow of information: what gets measured, and who is allowed to see it. A signal that improves healthspan and lightens the environmental load at the same time is a number that I’d like to know more about.

What this newsletter is for

HERO Metrics is a newsletter designed to build - in public - something bigger, a better way to run our economy and our society. If we can chip away at these externalities one by one we’ll hopefully close some of the ways in which capitalism is broken. I’m a big fan of markets, competition and of capitalism (which, as Peter Thiel points out, is often the opposite of competition). But the current neoliberal, profits-above-all implementation has gone too far - it’s not just wrong, but it’s bad for the capital owners, as our societal connective tissue, our climate boundaries and institutional capabilities are breaking down. It happened slowly, now it’s happening rapidly.

Researchers and outraged citizens (in particular those affected) have little agency in today’s world compared to Big Corporate and politicians who rarely pass legislation based on what people actually want. What the research team cited above found was not really a story about golf; it was about a health signal sitting in ordinary data that the market, and the property market especially, has no way to see. And that got me thinking, what else is like this?

This case study suggests a pathway to do something about it: consumer advocacy -> data gathering -> impact validation -> theory of change -> measurable, real-world impact. Some of these metrics will survive scrutiny and some will not, which is the point of doing it in the open. Krzyzanowski is already building the next version of her golf-course map from the public, one credited contributor at a time; and I would like to hear from you if you know of other externalities that could move systems.

If you are sitting on a number no one seems to be pricing, a signal you have noticed and cannot stop seeing, send it: the strongest ones show up in a future edition, credited by name. As always, feedback and suggestions welcome.