Your postcode predicts your health better than your genome, and little in the health system is built to act on it. Most of what shortens or lengthens a life is settled well outside the clinic, in heat, housing, walkability, air, green space and the simple matter of whether there is anyone nearby to talk to, acting on a whole suburb for decades at a stretch. Michael Marmot spent two landmark reviews demonstrating that the gradient of health tracks the gradient of place and power rather than the distribution of hospitals, and in Australia the gap shows up on the train line: residents of the hardest-pressed suburbs can trail those a few stops away by eight to ten years of life.
The trouble is that the determinants of health have no natural owner, and so no payer. A canopy of street trees, a safe crossing, a wetland to walk beside, a bench where people actually meet: each demonstrably buys years of life, and none of it appears on anyone's balance sheet as an asset worth building. Health budgets pay to treat the heatstroke, the fall and the loneliness downstream, where extreme heat alone now kills more Australians than bushfires and floods combined, while little is funded to head them off upstream by changing the street. The money sits at the wrong end of the pipe.
Worse, on the rare occasions we do improve a place, the value we create tends to leak straight back out of it. New York's High Line is the cautionary tale: a disused freight viaduct turned into a linear park that, by Dark Matter Labs' reckoning, threw off around US$3.4 billion in surrounding land-value uplift, little of which reached the people who had lived beside the tracks. The park was a triumph; the dividend went to the developers, and many of the locals it was meant to serve were priced out of the very neighbourhood it beautified. As Indy Johar, who founded Dark Matter Labs, keeps pointing out, we are strikingly good at creating public value and strikingly bad at deciding who gets to keep it.
So this is not really a parks problem. It is a plumbing problem: who captures the value that health creates, and whether that value can be routed back to the street that created it. The instrument I have been sketching, a local dividend, does three things in one move. Patient capital builds the determinants of health up front; the uplift and the avoided costs that follow are captured rather than left to leak; and a resident co-operative, not a developer, holds what the place becomes worth.
The elegance, such as it is, lies in the fact that one build throws off several returns, each landing on a different balance sheet:
- Residents, at the point of sale. A small deferred charge on the title, settled only when the house eventually changes hands, paid out of the uplift the works created. Nothing to find while you still live there.
- Insurers and reinsurers, year after year. A cooler, greener, better-drained street floods, burns and overheats less, and the people on it live longer and claim later, so the catastrophe book and the mortality book both improve at once. This is the argument of my earlier piece on insurance, brought down from the planet to the pavement.
- The land itself. Captured for the community through the co-operative rather than surrendered to whoever reaches the development application first. A single broad-leaved street tree in Perth was found to add roughly A$17,000 to a median house price (Pandit and colleagues, 2013), and a street has room for a great many trees.
- The council. Collecting through the rates notice it already sends out, and matching from the emergency callouts and road maintenance it no longer has to fund.
None of this is hypothetical. Every piece of it already runs somewhere. DC Water in Washington issued an Environmental Impact Bond in 2016 that paid out against measured green-infrastructure outcomes; the RE.bound programme structured deals in which avoided insurance losses serviced the bond; Community Land Trusts and Britain's community municipal investments already hold assets and their returns in residents' hands; and Victorian councils have levied special-charge schemes and collected environmental-upgrade finance through the rates system for years. What is missing is not a mechanism but the wiring diagram that connects them and points the whole apparatus at health.
Take a street in Melbourne's north that touched 44°C three summers ago, the sort of afternoon when the ambulances start arriving. It could be rebuilt with a canopy, a rain garden cut into the verge, a shaded crossing and a pocket park, without a single resident writing a cheque up front. A decade on, the footpath runs several degrees cooler, the street is more walkable and plainly worth more, the uplift repays the original build, and the gain is held by a co-operative the residents own rather than a developer who moved on years before. One build, several returns, and for once the dividend stays on the street.