What We Owe the Next Thing

Volume VII — Planetary and Cosmic

Nine movements, one inheritance.

THE PLATE

Four people talking together by a tall window, the low sun behind them. — Plate VII.11The Handing Over.An inheritance is not a gift. It is a working stock, handed over mid-job, by somebody who has to let go of the handle before the other person has taken the weight.

THE LETTER

This is the seventy-seventh chapter and the last one. You have earned a plain sentence, so here it is: the question of what we owe the next generation is answerable, and it is answerable in pounds, and almost nobody computes it.

Not because it is hard. The parts are all published. Every developed country publishes its public debt, its pension liabilities, its infrastructure stock, its national balance sheet, and — for about fifteen years now — some version of a natural capital account. What almost nobody does is add them up, because each one lives in a different department, is measured on a different basis, and is quoted by a different person trying to win a different argument.

So we are going to add them up. One country, the United Kingdom, because its statistical office publishes all five in a form a person can check. One number at the end, per head, in constant prices. And then the honest part, which is that the number's sign is set by a single parameter that no government publishes and that the two halves of the sustainability literature have been disagreeing about since 1974.

You will not find that discouraging. By the time you reach the end of this chapter you will be able to state the parameter, compute the number both ways, and say exactly what a person would have to believe for each answer to be true. That is a great deal more than can currently be said in most finance ministries, and it is the sort of thing a room can act on.

One more sentence, and then we begin. This edition has spent seventy-six chapters establishing that a stock with a regeneration rate behaves differently from a stock without one. This chapter is what that sentence costs when you write it into a balance sheet and sign it.

— The Editors

DISCOVERY

What is already working

Start where it is already being done well, because it is being done well in more places than the argument usually admits.

Norway has executed Hartwick's rule for thirty years. John Hartwick's 1977 result says that a country depleting an exhaustible resource can hold consumption constant forever if it invests the entire resource rent in reproducible capital. It is a clean theorem, and for two decades after it was proved nobody did it. Then Norway did. The Government Pension Fund Global held NOK 15,765 billion at the end of 2023. Against a population of 5.55 million that is NOK 2,840,541 per person, or about £211,981 per person. For comparison, the entire public non-financial asset stock of the United Kingdom — every school, road, hospital and sewer the state owns — comes to about £19,231 per person. Norway's fund alone is roughly 11.0 times the UK's public physical endowment, per head.

What makes it work is not the fund. It is the rule beside the fund: since 2001 the state may spend only the expected real return, a figure set at 4 percent and cut to 3 percent in 2017 when the expectation changed. A fund without a spending rule is a stock of money that a parliament will eventually find a reason for. A fund with one is an institution.

Wales gave the next generation a lawyer. The Well-being of Future Generations (Wales) Act 2015 created a statutory Future Generations Commissioner with powers to review the decisions of public bodies against seven long-term well-being goals, and it placed a legal duty on those bodies to act consistently with sustainable development. It is the only office of its kind in the world attached to a real legislature. The commissioner cannot veto. What the office does is much more useful: it forces the long-run consequence to be written down at the moment of decision, by somebody whose job is to write it down.

New Zealand put the four capitals in the fiscal cycle. The Treasury's Living Standards Framework organises the country's endowment as natural, human, social and financial-and-physical capital, and the Public Finance (Wellbeing) Amendment Act 2020 requires the government to state its wellbeing objectives alongside its fiscal objectives at each Budget. The significance is procedural and therefore durable: the four capitals are now part of a document that must be produced whether or not anybody is enthusiastic.

The World Bank built the comparative base. The Changing Wealth of Nations now publishes comprehensive wealth accounts — produced, natural, human and net foreign assets — for well over a hundred countries on a consistent basis. It exists, it is free, and it has been running long enough to have a time series. The instrument this chapter builds is assembled from exactly this kind of material, which means it can be assembled for any of those countries by anyone who cares to.

Alaska pays the dividend. The Alaska Permanent Fund has distributed a share of resource earnings to every resident annually since 1982. The design lesson is not the amount. It is that a visible annual payment creates a constituency for the principal. An endowment with no beneficiaries who can feel it is an endowment that will be raided. Alaska's dividend makes the fund politically load-bearing, which is why it is still there.

Five cases, one pattern, and it is the same pattern as the first chapter of this edition: in every one, somebody found the transfer that was already happening and gave it an account. Norway found the petroleum rent. Wales found the decision memo. New Zealand found the Budget. The World Bank found the national accounts. Alaska found the cheque. None of them invented a new obligation. They measured one that already existed, and the measurement is what made it governable.

That is the discovery move, and it is available to you at any scale. Somewhere in your organisation, your household or your country there is a stock being drawn down and a stock being built up, and no single page carries both.

THE ARITHMETIC

What works, what does not, and where the line sits

Now we build the page.

First, the five categories, each as its own source publishes it.

The United Kingdom, per head of a mid-2022 population of 67.6 million:

  line                                            per head      published as
  ---------------------------------------------------------------------------
  public sector net debt (ex Bank of England)      £39,941      £2,700 bn
  net public service pension liability             £20,340      £1,375 bn
  accrued State Pension entitlement                £59,172      £4,000 bn
  household net wealth                            £224,852     £15,200 bn
  public sector non-financial assets               £19,231      £1,300 bn
  natural capital asset value                      £26,627      £1,800 bn
  sovereign wealth fund                                 £0            none

Every one of those figures is real and every one of them is quoted in public by somebody making a case. None of them can be added to another in that form, and the reason is the first thing worth learning here.

Second, consolidate. A domestic claim is not a transfer.

A gilt is a liability of the British state and an asset of whoever holds it. About 28 percent of them are held outside the country. So of the £39,941 per head of public debt, £11,183 is a genuine claim on the next generation's output by people outside it and £28,757 is one Briton's claim on another. The internal part does not leave the country and does not reduce the national endowment by a penny. It decides who inside the next generation owns the endowment, which is a real and serious question, and a completely different one.

The same consolidation destroys the accrued State Pension line as a liability. A pay-as-you-go promise is booked at £59,172 per head, and it is genuinely owed — but it is owed by the next generation to the one before it, and the matching claim on future labour income is not booked anywhere. Enter one side of a two-sided entry and you have not measured an obligation; you have measured a convention.

Third, notice how soft the largest liability is.

The net public service pension liability in the Whole of Government Accounts stood at £2,631 billion in one year and £1,375 billion in the next. That is a movement of £1,256 billion — about £18,580 a head — in twelve months. Not one pension promise was changed. The entire movement is the discount rate. Chapter IV.09 showed what a rate does to a distant sum and III.05 showed what a rate is made of; here is the same mathematics arriving as the largest single line item in a national account and moving by more than a year of GDP because a parameter was revised.

Fourth, the aggregate. What actually crossed the boundary.

Strip the internal claims and one question survives: is the country's endowment per person larger or smaller than the one this generation received? The ONS national balance sheet answers it directly.

  UK net worth, 2022                     £11,800 bn   ->  £174,556 per head
  UK net worth, 1995                      £2,800 bn   ->   £48,276 per head
  the 1995 figure in 2022 prices (×1.87)               ->   £90,276 per head
  ---------------------------------------------------------------------------
  ΔM, the transfer                                     ->   £84,280 per head
  real growth per head, compound                              2.47% per year

The aggregate intergenerational transfer is strongly positive. Per person, in constant prices, this generation is handing forward a little under twice what it received. That result survives moving the 1995 stock by a fifth in either direction; the delta runs from £66,225 to £102,336 across that range and never changes sign.

If you came expecting the arithmetic to indict, notice that it has not. Hold that, because the next two moves are where the chapter earns its keep.

Fifth — the honest negative, and it is the one the whole literature lives inside.

Two deductions are contested, and each of them is a real intellectual position held by serious people.

The land switch. Land is about 60 percent of UK net worth. A house that doubles in price has not become a better house; the buyer pays the difference. So is a land revaluation an addition to the endowment, or a transfer between generations wearing the clothes of one? Hold land out and the same ledger reads:

  non-land net worth per head, 2022                       £69,822
  non-land net worth per head, 1995 (2022 prices)         £51,457
  ---------------------------------------------------------------------------
  ΔM excluding land                                       £18,365 per head

78.2 percent of the headline transfer is land.

The natural position. Between 1995 and 2022 the United Kingdom emitted, on a straight-line path between its published endpoints of 700 and 417 MtCO₂e, about 15.64 GtCO₂e. Priced at the Green Book's central carbon value of £269 per tonne, that is a natural deficit of £62,228 per head — and it is a lower bound, because the change in Britain's non-atmospheric natural capital over the same period has no consistent published series and is recorded here as UNMEASURED rather than as zero.

Now put the two together, and the chapter's instrument appears.

Sixth. The whole dispute is one parameter, so make it a parameter.

Write the intergenerational balance sheet as

        IGBS(θ)  =  ΔN  +  θ · ΔM          θ ∈ [0, 1]

where θ is the degree to which manufactured and financial capital can substitute for the natural capital that was consumed. θ = 1 is weak sustainability — Solow in 1974 and Hartwick in 1977: capital is capital, and a fund of bonds can stand in for a fishery. θ = 0 is strong sustainability — Daly in 1990: some natural capital is critical, complementary rather than substitutable, and no quantity of money crosses the boundary. Ernst Neumayer's survey of the dispute is four editions long and has not resolved it, because it is not the kind of thing a survey resolves.

Then the number that decides everything:

        θ*  =  −ΔN / ΔM

the substitutability at which the position crosses zero.

  with land        θ* = 62,228 / 84,280  =  0.74
  excluding land   θ* = 62,228 / 18,365  =  3.39

Read those two lines slowly, because they are the chapter.

With land, Britain's intergenerational position is positive if and only if you believe manufactured capital substitutes for the atmospheric sink at better than about seventy-four pence in the pound. That is a defensible belief. It is roughly what a treasury acts as though it believes.

Excluding land, θ\ is 3.39 — outside the admissible range entirely. No degree of substitutability clears it. The position is negative at every value of θ a person could hold, and that conclusion survives the whole sensitivity sweep on the one input this chapter could not source: θ excluding land runs from 5.584 to 2.131 as the 1995 land share moves from 35 to 55 percent, and never approaches 1.

The four cells, on the same country, from the same published accounts:

                          weak (θ=1)        strong (θ=0)
  ------------------------------------------------------------------
  with land              +£22,052            −£62,228
  excluding land         −£43,863            −£62,228

One country. One year. Four answers, and two signs. Nothing in that table is a modelling error. Every cell is arithmetically correct given a premise that somebody serious holds.

And the carbon value moves it too:

  carbon value       θ* with land      θ* excluding land
  --------------------------------------------------------
  £50 /tCO₂e             0.1372              0.6298
  £120 /tCO₂e            0.3294              1.5115
  £269 /tCO₂e            0.7383              3.3884
  £378 /tCO₂e            1.0375              4.7613

θ* reaches 1 at a carbon value of £364 per tonne with land, and at £79 per tonne without it. The UK government's own published carbon value for 2050 is £378 per tonne. At its own number, even perfect substitutability does not clear the ledger.

This is what an honest instrument looks like. It does not tell you the answer. It tells you precisely what you would have to believe for each answer to be true, and it puts the belief where a board can see it and argue about it, instead of leaving it buried in a footnote about deflators.

Seventh. The cut you did not see coming.

Go back to the positive number, because it is the true one in the sense that matters most immediately: £84,280 per head is actually being handed over. The houses exist. The pension funds exist. The £15,200 billion of household wealth exists and is going somewhere.

The Institute for Fiscal Studies asked where, and when. For those born in the 1980s, inheritances are on course to be worth about 16 percent of lifetime income, against about 9 percent for those born in the 1960s — a rise of 1.78 times. And the median age at which that inheritance arrives is about 61.

Take a forty-year-old and the Green Book's own 3.5 percent rate. Twenty-one years of waiting is a discount factor of 0.4856:

  handed over                                £84,280 per head
  received at 61                             £40,924 per head
  ------------------------------------------------------------
  destroyed by the wait                      £43,356 per head   (51.4%)

And it does not arrive at everyone. On the deliberately conservative assumption that half the cohort receives anything material, those who do receive about £168,561 each, and the rest receive the debt without the estate.

So the failure is not the size of the inheritance. It is the delivery date. We are handing the next generation roughly twice what we got, at an age past which it can no longer change what they were able to attempt, to about half of them. What we owe the next thing is not a quantity. It is a schedule.

DREAM

What becomes ordinary

Describe it in the present tense, because a dream in the future tense is a wish.

The intergenerational balance sheet is published annually, per head, in constant prices, alongside the budget. It is one page. It carries the five categories, the consolidation that removes internal claims, the natural position, and θ*. Nobody finds this remarkable. It is simply one of the things a treasury produces, in the way that a cash-flow statement is one of the things a company produces, and for the same reason: somebody once pointed out that profit and cash were different, and after a while everybody agreed.

Because θ* is published, the argument has moved. It is no longer possible to be vaguely in favour of future generations. A minister who wants to say the country is handing forward more than it received must say what θ they are using, and a minister who wants to say the opposite must do the same. The disagreement is still total and it is now productive, because both sides are pointing at the same number and disagreeing about one parameter rather than at two different numbers and disagreeing about everything.

Firms publish the same page. A mining company's intergenerational position is the Hartwick test done honestly: rent extracted, rent reinvested, θ implied. It goes in the annual report beside the reserves statement, and analysts model it, and a company whose θ exceeds 1 explains itself the way a company with a going-concern qualification explains itself.

The delivery date has moved. Some of the transfer arrives at twenty-five rather than sixty-one, because a country that can see the schedule on a page can see that the schedule is a choice — and the mechanisms for moving it are ordinary instruments, not new ones: an endowment at majority, a lifetime receipts basis, a first-home matching account, a universal share in a public fund the way Alaska does it. None of these requires anybody to be generous. They require a page that shows what is already being transferred and when.

And the natural position is measured properly, not because a philosophy won but because the UNMEASURED line was embarrassing enough, for long enough, that somebody funded the survey.

DESIGN

The structure that gets there

Four moves, in order. Each is small and each unlocks the next.

One: build the account before anybody asks for it.

The five categories are already published. Consolidation is arithmetic. The natural position needs one physical series and one declared price. A competent analyst can build a first version of a national or corporate intergenerational balance sheet in a fortnight, and the first version is the thing that creates the demand for the second.

The rule from Chapter I.01 applies exactly: you are not forecasting, you are measuring something that is already happening.

Two: publish θ, not the answer.

This is the governance move and it is the one that makes the rest durable. A single number invites a fight about the number. A number plus its decisive parameter invites a fight about the parameter, and a fight about a parameter is a fight that can converge, because a parameter can be bounded by evidence even when it cannot be settled by it.

State the four cells. State the carbon value. State what is UNMEASURED. An account that hides its own switches is an advertisement.

Three: attach it to a signature.

Measurement without an instrument decays into a report nobody reads by the third year. Attach the account to something that has a counterparty: a covenant, a fiscal rule, a coupon, a statutory duty, an office with standing. Norway attached it to a spending rule; Wales attached it to a commissioner; the next movement attaches it to a bond. The structure matters less than the fact that somebody has signed something that refers to the number.

Four: govern the schedule, not only the stock.

Having built the page, ask the second question that the page makes askable: when does the transfer arrive, and to whom? This is where the largest and cheapest gains are, because moving a receipt forward costs nothing in aggregate — the sum transferred is unchanged — and changes what a generation can attempt at the age when attempting is possible. A country that has computed £84,280 per head and £40,924 at the point of receipt has, in the difference, the strongest argument for early endowment that has ever been available, and it did not have to persuade anyone of anything philosophical to get it.

DESTINY

How it holds when nobody is pushing

Three things keep it alive, and one thing kills it.

It is annual and it is in the budget pack. Anything produced once is a report. Anything produced every year on a fixed date is an institution, and the second edition of any account is always easier than the first because the arguments about method have already happened.

Somebody outside the producer verifies it. The account names its own assumptions, so it can be checked, and a number that can be checked and is checked acquires a kind of weight that no amount of advocacy provides. This is the whole of Volume VI's argument about the commons, applied to a spreadsheet: monitoring by people accountable to the users is the design principle that distinguishes the arrangements that last from the ones that do not.

It has a beneficiary who can feel it. Alaska's lesson. An account with no constituency gets defunded in the third bad year. An account attached to a payment, a covenant or a commissioner has somebody whose interest is served by its continuation.

Now the honest part. Here is where this fails.

It fails when the producer picks θ quietly, which converts an instrument into propaganda in a single step, and it fails in that direction almost every time because the producer is usually the party being measured. It fails when the natural position is set to zero rather than left UNMEASURED, because a zero is a claim and a blank is not. It fails when the account is used to say the country is doing well — the number is not a score and the moment it is treated as one, the incentive to widen the coverage disappears. And it fails, most quietly, when the schedule question is never asked, because then a correct and rising account sits beside a generation that cannot buy a house and the account looks like an insult rather than an instrument.

Each of those four is avoidable by disclosure, which is why the disclosure is the product.

DELIGHT

What it feels like

There is a particular pleasure in a number that refuses to settle an argument and instead shows you exactly where the argument is. It is the pleasure of a good map of contested ground. You stop feeling stupid for being unable to decide, because the map tells you that the undecidability was real and was located in one place, and that everything else was arithmetic you could do.

And there is a second pleasure, better than the first, which anyone who has built one of these accounts will recognise. You start it expecting to find out whether we are doing well or badly. You finish it having found out what we are actually handing over — the roads and the houses and the funds and the skills and the thinned soil and the warmer air, all in one column, none of it hidden behind a department. The question changes under your hands from an anxious one to a working one, and working questions are better company.

The plane goes down on the bench blade up. The wood is still on the bench. Nobody in the room is making a speech about continuity, because the job is not finished and the light is going.

OPERATIONALIZE THIS

At the level of finance

The instrument: an intergenerational covenant bond — a two-way sustainability-linked note whose KPI is the issuer's published per-head intergenerational balance sheet.

The precedent is real and recent. Enel issued the first sustainability-linked bond in 2019; the ICMA Sustainability-Linked Bond Principles followed in 2020; Chile issued the first sovereign SLB in 2022; and Uruguay's sovereign SLB of the same year was the first with a two-way step, rewarding outperformance with a lower coupon rather than only penalising failure. The structure exists, the documentation exists, and the investor base exists. What has never been done is to point it at a comprehensive intergenerational account instead of at a single emissions path.

The mechanics.

KPI. Per-head comprehensive net worth in constant prices, published annually, with θ*, the four cells, and an explicit UNMEASURED register. The covenant is on the publication and the method, not on the level — an issuer cannot promise an outcome it does not control, and an investor should refuse a covenant that pretends otherwise.
The trigger. Two of them, deliberately different in kind. A money trigger: per-head comprehensive net worth, real, non-declining over a rolling five years. A physical trigger: a named critical natural stock — a catchment, a fishery, a soil carbon stock, a habitat area — non-declining in physical units, not in value. The second trigger is the strong-sustainability constraint written into a contract, and it is the whole reason this instrument is worth building rather than buying an ordinary green bond.
The coupon. Two-way, on Uruguay's model. On a $2,000 m ten-year note at 5.00 percent, a 25 bp step is $5.0 m a year, $50.0 m undiscounted, and $38.6 m in present value at 5 percent. A 15 bp step — Uruguay's size — is $23.2 m.
Verification. Named verifier, named method, named publication date. Budget $400 k a year, which is $3.1 m in present value over the term and leaves the covenant net-positive to the issuer at $35.5 m. Spread across the United Kingdom, an account of this kind costs about £0.0047 per person per year.
Balance-sheet treatment. The step is a contingent interest cost, disclosed under the issuer's ordinary financial-instrument standard. The account itself is not an asset and should not be capitalised. Its value is informational and it belongs in the notes.
Counterparty. For a sovereign, the multilateral banks that structured Chile's and Uruguay's deals. For a firm, your existing relationship bank's sustainable finance desk, which has the ICMA documentation on a shelf. For a city or a university, the internal version first: a covenant between the endowment and the operating budget, documented in a week, which gives you a track record before you meet an external lender.

The honest negative inside the instrument, stated before an analyst finds it. The 25 bp step is 0.0022 percent of the £1,400 billion the Climate Change Committee estimates the UK's net-zero investment requires to 2050. This instrument finances nothing. Sell it as climate finance and the first analyst who divides two numbers will not read the second page. Sell it as what it is — a priced, dated, externally verified commitment to publish a number that does not currently exist anywhere — and it is cheap, honest and unusually hard to abandon quietly.

The number that decides it. One figure, on the front page:

                              θ*  =  −ΔN / ΔM

If θ is below your organisation's own working assumption about substitutability, the position is positive on your own stated beliefs and you should publish it. If θ is above 1, no belief anyone holds clears it, and that is not a reason to withhold the account — it is the reason the account exists.

The first ninety days.

Day	Action	Artifact
1–15	Pull the five categories for your entity as published	Five sourced lines
16–30	Consolidate: remove internal claims, both sides	The consolidated ledger
31–45	Build ΔM over one generation, in constant prices	ΔM, with sensitivity
46–60	Price the natural position; register what is UNMEASURED	ΔN, as a lower bound
61–75	Compute θ* and the four cells; circulate to one sceptic	The one page
76–90	Attach it to a signature — covenant, rule, duty or coupon	The signed document

What this edition is a foundation for

The seventy-seven chapters behind this one did one thing, repeatedly, in different materials. They took a conviction that most people already hold — that an economy which eats its own foundation is not a clever economy — and they gave it units.

Units are the whole of it. A conviction with units can be put in a covenant. It can be verified by somebody who does not share it. It can lose an argument on Tuesday and win it on Thursday when the survey comes back. It can be taught, which means it can outlive the people who first held it, which is the only durability that has ever mattered.

So what is now available that was not available before this edition began is not a philosophy. It is three working things: a sourced corpus, in which every figure carries a citation and can be checked by a hostile reader; an instrument catalogue — seventy-seven Operationalize This movements, which read together are a working library of financial structures for regenerative enterprise, from the shared-savings facility in I.01 to the covenant bond on this page; and a question bank of nine hundred and twenty-four appreciative questions in 4D order, which is a facilitation curriculum that any competent person can take into a room on Monday.

What that is a foundation for is the thing this edition deliberately did not attempt: the accounts themselves. Not more argument about whether natural capital should be on a balance sheet, but the actual balance sheets — for countries, for firms, for catchments, for cities — built annually, verified externally, published with their switches showing. This chapter's instrument is one page of one of them. There are a great many pages and most of them have never been drawn.

You are equipped for that. That is not encouragement; it is the arithmetic of what you now hold. You can find the transfer that is already happening. You can consolidate it so that internal claims stop masquerading as obligations. You can price the part that is priceable and register the part that is not, in a way that refuses to turn unknown into nothing. You can name the one parameter that decides the sign and hand the decision to the people whose decision it properly is. And you can attach the whole of it to a document with a counterparty and a date.

The next generation does not need us to be certain. It needs us to be legible — to hand over the tools with the marks still on them, blade up, and the working stock counted, so that the people who take the weight can see immediately what they have and what it cost. That is what we owe the next thing, and it is, as of this page, entirely computable.

The light is still on the bench. The wood is still good.

— The Editors, in closing

APPRECIATIVE QUESTIONS

Twelve, for a room

Discovery — what is already working

What has this organisation handed forward — to a successor team, a next generation of staff, a community — that turned out to be worth more than anybody expected at the time? Who made that happen, and what did it cost them?
Where do we already keep a long-horizon account of something, however informally — a maintenance log, a reserves policy, a succession plan — and what makes that one survive when others lapse?
Which of the five categories on the page can we already produce from published sources this week, without asking anybody for anything?

Dream — what becomes possible

If our intergenerational position were on one page beside the budget every year, what conversation would happen in this room that currently does not happen at all?
Imagine we are known as the organisation that publishes its θ. What does that buy us with the people we most want to work with?
If the transfer we are already making arrived twenty years earlier in the lives of the people who receive it, what would they be able to attempt?

Design — what we build

What is the one physical stock — in units, not in money — that we would be willing to covenant as non-declining, and who would we let verify it?
What θ do we act as though we believe, and what evidence would move us half a point in either direction?
Which single thing on our account should be marked UNMEASURED this year, and what would it take to measure it next year?

Destiny — how it holds

Who, five years from now, would notice first if this account stopped being produced — and what would we have to give them for that to be true?
What is the signature that would make this real, and what does the person who would sign it need to see on the page?
When our successors read this account, what will they be glad we wrote down even though it was inconvenient to us?

WORKS CITED

Solow, R. M. (1974). "Intergenerational Equity and Exhaustible Resources." The Review of Economic Studies, 41 (Symposium on the Economics of Exhaustible Resources), 29–45.

Hartwick, J. M. (1977). "Intergenerational Equity and the Investing of Rents from Exhaustible Resources." American Economic Review, 67(5), 972–974.

Daly, H. E. (1990). "Toward Some Operational Principles of Sustainable Development." Ecological Economics, 2(1), 1–6.

Pearce, D. W. and Atkinson, G. D. (1993). "Capital Theory and the Measurement of Sustainable Development: An Indicator of Weak Sustainability." Ecological Economics, 8(2), 103–108.

Neumayer, E. (2013). Weak versus Strong Sustainability: Exploring the Limits of Two Opposing Paradigms, 4th edn. Edward Elgar.

Hamilton, K. and Clemens, M. (1999). "Genuine Savings Rates in Developing Countries." The World Bank Economic Review, 13(2), 333–356.

Arrow, K. J., Dasgupta, P., Goulder, L. H., Mumford, K. J. and Oleson, K. (2012). "Sustainability and the Measurement of Wealth." Environment and Development Economics, 17(3), 317–353.

World Bank (2021). The Changing Wealth of Nations 2021: Managing Assets for the Future. World Bank, Washington DC.

Dasgupta, P. (2021). The Economics of Biodiversity: The Dasgupta Review. HM Treasury, London.

Auerbach, A. J., Gokhale, J. and Kotlikoff, L. J. (1991). "Generational Accounts: A Meaningful Alternative to Deficit Accounting." Tax Policy and the Economy, 5, 55–110.

Kotlikoff, L. J. (1992). Generational Accounting: Knowing Who Pays, and When, for What We Spend. Free Press.

Barro, R. J. (1974). "Are Government Bonds Net Wealth?" Journal of Political Economy, 82(6), 1095–1117.

Rawls, J. (1971). A Theory of Justice. Harvard University Press. (The just savings principle, §44.)

Parfit, D. (1984). Reasons and Persons. Oxford University Press. (Part IV, on the non-identity problem.)

Stern, N. (2007). The Economics of Climate Change: The Stern Review. Cambridge University Press.

Office for National Statistics. National balance sheet estimates for the UK. Annual series, 1995 onwards.

Office for National Statistics. Total wealth in Great Britain: April 2018 to March 2020 (Wealth and Assets Survey).

Office for National Statistics. UK natural capital accounts. Annual series.

Office for National Statistics (2018). Pensions in the national accounts: a fuller picture of the UK's funded and unfunded pension obligations.

HM Treasury. Whole of Government Accounts, years ended 31 March 2021 and 31 March 2022.

HM Treasury. The Green Book: Central Government Guidance on Appraisal and Evaluation, and the supplementary guidance on valuation of greenhouse gas emissions.

Office for Budget Responsibility. Fiscal Risks and Sustainability. Annual.

Climate Change Committee (2020). The Sixth Carbon Budget: The UK's Path to Net Zero.

Bourquin, P., Joyce, R. and Sturrock, D. (2020). Inheritances and Inequality within Generations. Institute for Fiscal Studies, Report R173.

Norges Bank Investment Management. Government Pension Fund Global: Annual Report 2023.

Welsh Government. Well-being of Future Generations (Wales) Act 2015.

New Zealand Treasury. The Living Standards Framework, and the Public Finance (Wellbeing) Amendment Act 2020.

International Capital Market Association (2020, revised). Sustainability-Linked Bond Principles.

Ostrom, E. (1990). Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge University Press.

Cooperrider, D. L. and Whitney, D. (2005). Appreciative Inquiry: A Positive Revolution in Change. Berrett-Koehler.

Note on figures. Every figure in this chapter is computed in lib/verify/VII_11.py and printed with its inputs, its units and its provenance — INPUT for a published statistic, ASSUMED for a declared modelling choice, ILLUSTRATIVE for a figure swept for sensitivity, and UNMEASURED where no consistent series exists. The 1995 land share is ILLUSTRATIVE and is swept from 35 to 55 percent; θ* excluding land stays above 1 across the whole sweep. The change in Britain's non-atmospheric natural capital between 1995 and 2022 is recorded as UNMEASURED, which is why ΔN is stated throughout as a lower bound and never as a total. Chapters III.05 and IV.09 carry the discount-rate arithmetic this chapter leans on.