A GLOBAÏA explainer · after Jason Hickel (2020)

The Sustainable Development Index

For thirty years we have ranked nations by a single question: how developed are they? But the countries we crown the most developed are, person for person, the ones pushing hardest against the planet's limits. This is the story of a number built to see both at once — human flourishing, and our fair share of a finite Earth. And by that harder test — a good life delivered within the planet's means — not one nation has arrived yet.

Norway, on the old index

#157Norway, once the planet is counted

Begin

BThe measure we trusted

In 1990 the Pakistani economist Mahbub ul Haq gave the world a new way to keep score. Until then, a country's progress was read almost entirely from its money — its output, its growth. Ul Haq wanted something more human. His Human Development Index folded three things every life depends on into a single number between 0 and 1.

It quickly became the most widely used measure of progress on Earth — the yardstick behind the UN's development goals. Its three ingredients are simple:

A long life — life expectancy at birth.
Knowledge — years of schooling, expected and achieved.
A decent income — income per person, on a logarithmic scale.

The three are combined with a geometric mean, so a country can't paper over a terrible score in one with a brilliant score in another. Move the dials below and watch a country's development score respond.

The Human Development Index is a report card for whole countries. Instead of grades in math and reading, it scores three things: how long people live, how much they learn, and how much they earn.

The Human Development Index was a deliberate rebellion against GDP. The Pakistani economist Mahbub ul Haq built it in 1990 to shift development 'from national income accounting to people-centred policies', drawing on Amartya Sen's idea of human capabilities. Two of its three ingredients — how long people live, how much they learn — are outcomes people actually experience; only the third, income, is a means rather than an end. That distinction is the seed of everything the SDI later changes.

The Human Development Index is published every year in the United Nations' Human Development Reports and set the direction of the Millennium Development Goals — so it did not merely describe progress, it steered it. That is the crux: a single headline number becomes the target nations chase. It is exactly why Hickel revises this one trusted metric rather than proposing a complex dashboard — an accessible index can win the political attention a dashboard never will.

HDI is the geometric mean of three sub-indices: life expectancy (normalised 20–85 years), education (the average of mean and expected years of schooling, capped at 15 and 18), and income (natural-log GNI per capita, $100–$75,000, 2011 PPP). Income enters logarithmically precisely because its marginal contribution to development falls off quickly. Hickel flags one weakness he keeps anyway: schooling is an input, not an outcome, so pairing it with life expectancy mixes two different kinds of measure.

CThe hidden flaw

There is a quiet problem buried in that third ingredient. To reach a top income score on the old index, a country needs roughly $75,000 per person — and almost no nation earns that without burning through enormous quantities of energy and material. Income, it turns out, is welded to ecological harm.

Hickel measured the link directly. Across all nations, a country's income explains about 88% of its carbon emissions and 74% of its material footprint. The result is uncomfortable: the very countries that top the Human Development Index are the worst ecological overshooters on the planet.

"HDI promotes a model of development that is empirically incompatible with ecological stability, and impossible to universalise." — Jason Hickel, 2020

Each dot below is a country: human development across the bottom, ecological impact up the side. As development climbs, impact doesn't rise gently — it explodes.

Here's the catch: the richest, 'most developed' countries are also the ones using up way more than their share of the planet. Doing well on the old scorecard usually meant wrecking nature.

The hidden wire is the fossil-fuel economy: income measures economic production and exchange, which in a fossil-energy system is welded to emissions and material use. So the countries that top the Human Development Index contribute the most, per person, to climate change and ecological breakdown — the top of the HDI is the bottom of ecology. Reaching the income needed for 'very high' development effectively locks in very high impact; the coupling is structural, not incidental.

This is an indictment of the development paradigm itself: pursued as the HDI defines it, development 'requires that the world develops to the point of ecological collapse'. You cannot hand every nation the same income-led ladder, because the ladder is ecologically self-terminating — and the global South, which climbed it least, is hit first by the resulting climate damage, already reversing human-development gains in some regions.

Across all nations the coupling is exponential: R² ≈ 0.85 for CO₂ and 0.76 for material footprint against the full HDI, and it is strongest for the income sub-index alone — R² ≈ 0.88 (CO₂) and 0.74 (materials). Concretely, nations scoring the maximum on income ($60,000+) average 40 t of materials and 22 t of CO₂ per person, many times a sustainable level. The current dataset shows the same signal as a raw correlation of r ≈ 0.87 between income per person and material footprint — and r ≈ −0.66 between income and the SDI itself: richer countries score worse.

DThe planet has a budget

Earth is not infinite. Scientists have mapped nine planetary boundaries — safe limits for the pressures we put on the climate, the land, the oceans, the web of life. Cross them, and the systems that kept the last ten thousand years stable begin to wobble.

To turn those planet-wide limits into something a single country can be measured against, Hickel uses two well-understood pressures and divides each by the number of people alive, giving everyone an equal, sustainable ration — a fair share:

1.74 t CO₂ per person, per year

Your consumption-based share of the carbon budget that keeps warming near 1.5–2 °C.

6.8 t Materials per person, per year

Your share of the raw stuff — minerals, metals, biomass, fuels — the planet can supply sustainably.

Both are counted consumption-based: the carbon and materials hidden inside everything a country imports are added in, and what it exports is taken out — so a nation cannot hide its impact by making its goods abroad. Pick a country and see how far past its fair share it lives.

Imagine everyone on Earth gets the same-size slice of a planet-pie: about 1.74 tonnes of carbon and 6.8 tonnes of materials a year. Many rich countries eat ten slices and leave crumbs for everyone else.

This turns planetary science into a personal allowance. Researchers have mapped nine planetary boundaries — four already crossed — and Hickel converts two of them into an equal per-person ration: about 1.74 tonnes of CO₂ and 6.8 tonnes of materials a year. Sharing the budget equally is already generous toward the rich, because a stricter fair-shares rule would give wealthy nations an even smaller allowance so as to leave room for poorer ones.

The budget is counted where goods are consumed, not made — so a rich country cannot look clean by offshoring its factories; the carbon and materials embodied in imports are added back in. That removes the 'we cleaned up our economy' illusion and reassigns responsibility honestly. The global stakes are stark: humanity already extracts around 91 billion tonnes of material a year, overshooting the sustainable level by roughly 80%.

The CO₂ share (1.74 t/cap) is derived from the IPCC (2018) remaining century carbon budget for a 67% chance of holding 1.5–2 °C, divided equally by 2015 population; the material share (6.8 t/cap) is Bringezu et al.'s 50 Gt/yr boundary ÷ 7.358 billion people. Both are consumption-based — CO₂ from the Eora multi-region input–output database, materials from materialflows.net — and both shift each year with population, so they are dynamic thresholds, not fixed constants.

EEnough is enough

Before fixing the ecology problem, the index fixes the income problem. Does a country really become more developed as income climbs from $40,000 to $80,000 a head? Past a point, more money buys longer lives and better schooling barely at all — but it buys a great deal more pollution.

So the Sustainable Development Index sets a sufficiency threshold: income counts fully up to about $20,000 a person, the level at which a society can comfortably deliver health and education for all. A country is never punished for earning more — the extra simply stops boosting its score. Toggle between the two ceilings and watch how the reward for raw income changes.

After a certain point, more money doesn't make people much healthier or better-educated — it just makes more pollution. So the new index says: enough income is enough. Earn more if you like, but it won't raise your score.

Past a point, more income barely moves human development — but it moves pollution a great deal. The paper's comparisons are striking: Costa Rica matches United States life expectancy on a quarter of the income; Georgia rivals Austria's schooling on under a fifth. The crucial thing to get right: this is a saturation, not a penalty — a country is never punished for earning more; the extra simply stops raising its score. Rich countries fall on the SDI because of the ecological divisor, never because income is capped.

Sufficiency redefines the goal from 'grow forever' to 'reach enough, then invest in outcomes'. It even sets a target: nations sitting at the ecological boundaries in 2015 averaged about $8,600 a person, and impressive human development shows up with as little as $10,000–$14,000. Low-income countries can and should grow toward that — but not toward the income levels of today's rich nations, where extra GDP begins to do social and ecological harm.

The one formula change: the HDI's $75,000 income ceiling becomes $20,000, so the income index = [ln(GNI) − ln(100)] / [ln(20,000) − ln(100)], clamped at 1. Because of the log form the curve crosses 0.8 at roughly $7,000, 0.9 at about $12,000 and 0.95 at about $15,000 — all reachable without ecological excess. Hickel is candid that these calibration points are argued from the data, not statistically optimised; there is no formal sensitivity analysis of the $20,000 choice.

FBuilding the SDI

Now the two halves come together. Take human development — long life, knowledge, sufficient income — and divide it by how far a country overshoots its ecological fair share.

SDI = Human development ÷ Ecological impact

Division is the whole point. It enforces strong sustainability: a brilliant social record cannot buy off a wrecked environment, and a light ecological footprint cannot excuse poverty. Stay within your limits and the divisor is near 1 — your development shines through. Overshoot badly and it grows, dragging the score down. The penalty rises gently at first and then steeply, so small overshoots are forgiven and gross ones are not. Build the formula piece by piece below.

The trick is one little symbol: ÷. Take how well a country treats its people and divide it by how badly it treats the planet. You have to be good at both, or your score sinks.

The whole design lives in one operation: development divided by ecological impact. That makes the SDI a 'strong sustainability' measure — the two sides cannot trade off. A brilliant social record cannot buy off a wrecked environment, and a light footprint cannot excuse poverty. It forgives small overshoots but punishes gross ones, because the boundaries themselves are uncertain — run four times your fair share and your development score is literally halved.

Because it is a division, there are two ways to score badly — fail your people, or overrun the planet — and only one way to score well: do both. That removes the free passes other indices allow, and it maps the two ecological terms straight onto the Sustainable Development Goals for responsible consumption and climate. It is built deliberately as one headline number so it can compete with the HDI for political attention.

SDI = Development Index ÷ Ecological Impact Index, where development is the geometric mean of the life, education and sufficiency-capped income indices. EII = 1 + (e^AO − e^1)/(e^4 − e^1), switching to the linear EII = AO − 2 once AO > 4 (the branches meet at AO = 4, where EII = 2 and development is halved). Average Overshoot AO = √[max(MF/6.8,1) · max(CO₂/1.74,1)] — a geometric mean of the two floored ratios, so undershooting one boundary can never offset overshooting the other. Since EII ≥ 1, the SDI can never exceed the development index.

GThe great reversal

Run every country through the new formula and the league table turns upside down. The nations that dominated the old index — Norway, Switzerland, the United States — tumble toward the bottom, dragged down by their enormous footprints. Rising in their place are middle-income countries that deliver long, educated lives on a fraction of the impact: Costa Rica, Cuba, Sri Lanka.

Drag your eye across the lines. On the left, rank by human development alone. On the right, rank by the Sustainable Development Index. Hover a country to follow its journey.

Flip the scorecard and the leaderboard flips too. Norway falls from 1st to near-last; Costa Rica and Sri Lanka leap to the top — because they give people good lives without trashing the planet.

The league table turns upside down. Under the HDI more than 20 countries score above 0.9; under the SDI, none do. Norway falls from 1st to 157th and the United States to 159th — dragged down by their footprints — while Cuba, Costa Rica and Sri Lanka rise to the top by delivering long, educated lives at low impact. The bottom of the SDI is not simply 'poor countries': it holds both the very poor and the very high-impact rich, for opposite reasons.

The reversal redefines who counts as a development success, relocating the examples worth studying away from the richest capitals toward efficient middle-income nations. It states each group's task plainly: the highest-development countries must sharply cut their impact, while the lowest-impact countries must sharply raise their social outcomes. No nation today is a finished model.

In the 2015 analysis the SDI top three are Cuba 0.859, Costa Rica 0.830 and Sri Lanka 0.825, while Norway drops from HDI #1 to SDI #157, the USA to #159 and Qatar to #152. The asymmetry is quantified: SDI leaders overshoot their boundaries by only ~1.09× (materials) and ~1.47× (CO₂), against HDI leaders' 5.09× and 7.91×. The live chart defaults to 2019; in the latest data (2022) Costa Rica leads at 0.833 and Qatar sits last at 0.052.

HThe world remade

Painted across a map, the new geography of progress is unfamiliar. The wealthy North, usually a solid block of "high development", thins out. Pockets of Latin America, the Caribbean and parts of South Asia glow. Switch the map between the Sustainable Development Index, the old Human Development Index, and the underlying ingredients — and scrub through three decades to watch the picture move.

The colours also read as accountability. Measured against an equal share of the atmosphere, the wealthy North is responsible for the overwhelming majority of emissions beyond a safe limit — the United States alone for roughly 40 percent — and for most of the world's excess resource use. The countries that glow greenest here are rarely the ones that overran the budget.

Colour in the world by the new score and the map looks strange: some rich countries fade, while places like Costa Rica light up. 'Most developed' is no longer where you'd expect.

Painted on a map, progress becomes unrecognisable: the wealthy North fades from 'top' to 'bottom' while parts of Latin America, the Caribbean and South Asia glow. Because impacts are counted where goods are consumed, rich importers cannot pin the blame on the countries that manufacture for them. Setting the two maps side by side, across three decades, is a vivid prompt on how the values we choose to measure redraw the world.

The map reads as accountability. It assigns responsibility in hard multiples of a fair share: the United States alone is responsible for around 40% of emissions beyond the safe boundary, and the global North for the great majority of both excess emissions and excess resource use. That relocates development 'leadership' toward nations rarely centred in the conversation — and puts the largest obligation squarely on the wealthiest.

A choropleth of 162 nations, 1990–2022, toggling SDI, HDI, life expectancy, CO₂, material footprint and income. On a fair-shares basis Hickel (2020) attributes 92% of emissions in excess of the planetary boundary to the global North (USA 40%, EU-28 29%); Hickel et al. (2022) attribute 74% of excess resource use. By region in the current data, Latin America and the Caribbean lead on SDI (mean ≈ 0.73) while North America sits lowest (≈ 0.17), despite topping the HDI.

IThe efficiency race

Watch the nations move. Each bubble is a country — sized by its population, coloured by its region. Human development runs along the bottom; ecological impact up the side. The green corner, bottom-right, is the goal: high development, light footprint. Press play and the world drifts from 1990 to 2022.

Notice what doesn't happen. No bubble settles into the green corner. As countries develop, almost all of them drift upward into overshoot — the empirical heart of the decoupling debate.

And the evidence there is sobering. Researchers find no sign that the world's economies are pulling resource use away from growth fast enough to matter — and of the handful of wealthy countries that did manage to cut carbon while still growing, the pace was so slow they would need on the order of two hundred years to bring emissions into line with a safe climate, spending many times their fair share of the carbon budget along the way.

Press play and watch every country move over 30 years. The dream spot is 'great lives, light footprint' — but almost nobody lands there. Getting richer keeps dragging countries the wrong way.

Press play and development and impact rise together, decade after decade — almost no country reaches the green corner of high development and light footprint. The dream is 'absolute decoupling': growing prosperity while emissions and materials actually fall. Cutting income loose from carbon is possible with clean energy, but cutting it loose from material use is harder still — there is no historical example of a nation shrinking its material footprint while growing its economy at normal rates.

History has bundled rising human development with rising impact, and breaking that bundle is the defining challenge. The decarbonisation rates the Paris goals require sit outside what standard models call achievable — which is why parts of the literature, and the IPCC (2018), point to reducing aggregate economic activity in rich nations. The reassurance that matters: scaling down throughput need not lower human development, if income is shared more fairly, public services are strengthened, the working week shortens and wages rise.

Development (capped income · life · education) versus average overshoot, 1990–2022, bubbles sized by population. The load-bearing evidence is Ward et al. (2016): permanent decoupling of GDP from material and energy use is impossible for essential, non-substitutable resources. Hickel & Kallis (2020) find no absolute resource decoupling at global scale; Vogel & Hickel (2023) estimate the 11 high-income countries that did absolutely decouple CO₂ from GDP (2013–2019) would need ~223 years on average to cut emissions 95% — roughly 27× their Paris-compliant carbon budgets.

JAnatomy of a country

Pick any nation and take it apart. Where does it stand on each index? Where does it live within its ecological budget — and where does it overshoot? How has its story moved since 1990?

Type in your country — or any country — and see its whole story: how long people live, how much they learn and earn, and how heavily it leans on the planet.

A single SDI number hides two different failure modes; take it apart and you see which one a country has. France scores poorly despite excellent health and schooling — its heavy footprint is the drag. Niger scores poorly for the opposite reason — a tiny footprint but very weak development. The United States and Qatar have decent social scores annihilated by extreme impact. Same low score, opposite diagnoses — and opposite cures.

Disaggregation turns the index into a diagnostic that hands each government its specific homework: build social provision, or cut throughput. It also explains Hickel's deliberate exclusions — basic needs like electricity and nutrition are near-universal among good performers and treated as covered, while employment and democracy were left out because the data show no reliable link to ecological impact. The index measures the potential to deliver good lives efficiently, so it is not inequality-adjusted: an unequal low-impact country appears as a model of potential it could realise by sharing what it already has.

Each profile shows SDI and HDI ranks, the six component series (1990–2022) and the two overshoot ratios. The worked contrasts from the 2015 table: France (SDI #95) carries life expectancy 82.4 and an education index of 0.840 but 21.2 t materials / 7.5 t CO₂; Niger (#136) has 3.3 t / 0.55 t but life expectancy 59.7; the USA (#159) pairs a 0.90 education index with 32.4 t materials and 18.4 t CO₂. By design the composite is always shown beside its parts, so the reasons for a score stay visible.

KNo one is there yet

Here is the most honest finding of all: no country scores above 0.9. Not one nation today delivers genuinely high human development while staying near its ecological limits. By this measure, every country is still developing — just in two different directions.

For poorer nations, the path is the encouraging one. Costa Rica, Cuba, Sri Lanka and Bangladesh have shown it is possible to reach long, educated lives by investing in universal public health and schooling — without an ecologically ruinous economy.

"Poor nations are the 'easy' part … It is rich nations that are the hard part." — Jason Hickel, 2020

Wealthy countries face the harder, more hopeful task: keeping their hard-won health and education while bringing their footprints back down to a fair share — for the richest nations, a reduction of roughly 40 to 50 percent. The evidence suggests efficiency alone won't get them there fast enough — which is why Hickel points toward post-growth economics: distributing income more fairly, investing in public goods, shortening the working week, and measuring success by how much good life we get from each tonne of impact, not by endless growth. The Sustainable Development Index is simply a compass for that journey — "a metric that stands ready to measure progress toward the ecological transition that needs to happen, but which is not yet underway."

Nobody's won this game yet — every country still has homework. Poorer countries need better health and schools; richer ones need to tread far more lightly. The good news: we already have examples of both.

The word 'development' changes meaning: rich nations must develop down their impact, poor nations must develop up their outcomes, and by this measure every country is still developing. Worth teaching honestly — holding up an exemplar is complicated: Costa Rica's low impact is deliberate policy (renewable energy), but Sri Lanka's is partly just a less intensive economy, so 'be more like Sri Lanka' comes with no clear playbook. The index is a compass, not yet a map of the route.

The agenda is asymmetric but shared: build social foundations where they are missing, cut throughput where it is excessive — with sufficiency and fair shares, not GDP, as the organising goals. Hickel is explicit that the rich-nation path needs more than efficiency: a shift to economic models that scale down material and energy use while maintaining social outcomes. The index also disrupts development hierarchies that place Western nations automatically at the top, demoting them in line with their ecological cost.

No nation exceeds SDI 0.9 (max: Cuba 0.859 in 2015; Costa Rica 0.833 in 2022) — because the impact index is ≥ 1, the SDI can never beat the development index, and every high-development country carries overshoot well above 1. O'Neill et al. (2018) independently find no country meeting basic needs within a sustainable footprint; Hickel (2019) estimates rich nations must cut throughput ~40–50%. With absolute decoupling unproven at the required pace (Hickel & Kallis 2020; Vogel & Hickel 2023), the literature points to post-growth provisioning — sufficiency, public services, fairer distribution, shorter working time.

LThe deeper question — justice

The index answers how efficiently a country turns ecological damage into good lives. But it raises a harder question it cannot answer alone: is that damage fair? The overshoot we saw painted across the map is not shared evenly — a small number of wealthy nations ran through most of the world's safe budget, while the countries that used the least are, again and again, the ones already hit hardest by the consequences.

Measured against an equal share of the atmosphere, the wealthy North is responsible for the overwhelming majority of emissions beyond a safe limit, and for most of the world's excess resource use. That imbalance has a history and a price tag. In 2026 the World Inequality Lab — the research team behind the World Inequality Database, including the economists Thomas Piketty and Lucas Chancel — put numbers to it in a study called the Global Justice Report. Adding together the damages of slavery, colonialism and climate breakdown from 1800 to today, they arrive at a figure equal to roughly two and a half years of the entire world's economic output — a debt owed, in the main, from rich countries to poor ones.

≈240% Colonial and climate damages since 1800, as a share of one year of world output

~99% Share of people who would end up better off under the report's plan for a fairer economy

Here is the hopeful part, and the reason it belongs on this page. The report set out to test whether the SDI's implied goal — a genuinely good life for everyone, kept within the planet's means — is actually reachable. Their answer is yes, by 2100, but only if three things happen at once:

Clean energy, fast — replacing fossil fuels across the economy within a generation.
Sufficiency — shorter working hours, less waste, and a shift of effort from making more stuff toward health, education and care.
Far less inequality — narrowing the gap between and within countries, so incomes converge toward a shared, comfortable standard rather than a fortunate few pulling ever further away.

Crucially, they find that targeted sufficiency works better than blunt shrinking: reorganising rich economies around enough — free time, public services, gentler consumption — cools the climate more than simply making everyone poorer would, while raising well-being rather than lowering it. It is the same lesson the index teaches, turned into a plan: the goal is not more, and not less for its own sake, but enough, for everyone, within the planet's means.

"The compression of global inequality is not only compatible with deep decarbonisation; it is a necessary condition for shared prosperity on a finite planet." — The Global Justice Report, World Inequality Lab, 2026

You can watch that compression happen. For two centuries the richest tenth of humanity has held around half of all the world's income, while the poorest half has lived on under a tenth. The report's pathway turns it around: after 2025 the two lines cross, and by 2100 the poorest half at last holds close to a fair share.

The report is careful to call itself a starting point for public debate, not a finished blueprint — a transparent set of numbers that citizens, unions and parliaments can argue over and improve. What stands in the way of a good life for all, it concludes, is not technical impossibility but political choice — and the patient work of building a movement behind it.

The SDI shows rich countries used up most of the planet's safe budget — that's not just a fact, it's unfair. But there's good news: researchers have shown a genuinely good life for everyone, without wrecking the Earth, is actually possible. It needs clean energy, 'enough instead of endless', and a much smaller gap between rich and poor.

The SDI diagnoses ecological overshoot but is silent on its distribution. The Global Justice Report supplies that political economy: it quantifies colonial and climate debt (~240% of world GDP) and models a path to high well-being within 2 °C, resting on decarbonisation, sufficiency and inequality compression — with targeted sufficiency outperforming uniform degrowth.

A high-development, low-overshoot world is shown to be feasible by 2100, but only through redistribution as well as decarbonisation. The headline for policy: sufficiency and fair shares — not GDP growth — become the organising goals, and the binding constraint is political will, not physical possibility. The plan is offered as a deliberative basis, explicitly open to contestation.

World Inequality Lab (Chancel, Piketty et al., 2026). An input–output framework, not an IAM, models four dimensions jointly: convergence to €60,000/cap by 2100, bottom-50% wealth share 2→30%, warming held to ~1.8 °C. Sufficiency delivers ~44% of mitigation; targeted sufficiency (1.8 °C) beats uniform degrowth (1.9 °C). Complements — does not restate — Hickel's SDI; cites Hickel & Kallis (2020), Fanning & Hickel (2023).

MWill it last — resilience

There is one more thing the index cannot see. The SDI is a snapshot: it grades how well a country delivers good lives within its limits right now. But a healthy-looking present can be quietly drifting toward a cliff. The Earth's great systems — ice sheets, forests, ocean currents — have tipping points: thresholds beyond which change becomes fast and hard to reverse. A country can look sustainable today and still be on a path that ends in collapse.

So a newer idea asks a harder, forward-looking question. Instead of scoring where we stand, it asks: what are the odds we reach a safe and just future at all? In 2026 a team led by researchers at the Potsdam Institute and Stockholm Resilience Centre — including the Earth scientist Johan Rockström — proposed measuring resilience as exactly that: a probability. Run the many ways the future could plausibly unfold, and count the share that end up both safe (a stable climate) and just (a decent living standard for everyone). That share is the score.

~1 in 3 Plausible futures that stay safe and just, on current knowledge, in their model

Know more Learning where the Earth's thresholds sit is itself a way to build resilience

Two findings stand out for anyone thinking about the years ahead. The first is that timing beats speed. Because the climate reacts slowly, cutting emissions has to begin well before a threshold is reached; cross it first, and no rate of action — however heroic — can pull the world back to safety. The second is more subtle, and matters for every scorecard on this page: resilience is not a fixed fact about the planet. It depends on how early we act, how much we honestly know, and whether we use that knowledge. A country could raise its apparent odds simply by choosing not to look at the danger — which is exactly why any measure of progress has to be handled in good faith.

The two lenses fit together. The Sustainable Development Index asks, "are we living a good life within the planet's means today?" Resilience asks, "will we still be safe and just tomorrow — and are we acting early enough to get there?" One is a diagnosis of the present; the other, a compass for the future. Both are anchored to the same idea this whole page has been circling: a space that is at once safe for the Earth and just for the people on it.

The SDI is a photo of right now. But the planet has 'points of no return' — once you cross them, there's no going back. So the real question isn't just 'are we OK today?' but 'what are the chances we stay OK?' The answer depends on acting early, knowing the risks, and being honest about them.

Resilience reframed as a probability: the share of plausible futures that remain both safe (stable climate) and just (a living standard for all). It adds what a static index omits — tipping points, timing, uncertainty and agency. Key teaching point: 'timing beats speed', and a metric can be gamed by choosing ignorance.

Two complementary tools: the SDI diagnoses the present; a resilience index estimates the odds of a safe-and-just future and pinpoints the decisive lever — act before thresholds, not after. It reframes investing in Earth-system knowledge (where the thresholds sit) as itself a resilience-building policy, and warns against optimising a metric by suppressing information.

Anderies, Rockström et al. (2026, preprint): an Information-Based Resilience Index = P(system reaches a safe-and-just state | information set), over a stylised two-region World–Earth model. Safe < 350 ppm; a per-capita income floor for justice. Baseline ≈0.31, falling to ~0.18–0.21 with realistic tipping thresholds; a 'critical delay' of ~20–30 ppm means timing dominates decarbonisation rate. Not an empirical country ranking — a method.

NSources & citation

This page is an interactive explainer of the peer-reviewed paper that defined the index:

Jason Hickel (2020). The sustainable development index: Measuring the ecological efficiency of human development in the anthropocene. Ecological Economics, 167, 106331. doi:10.1016/j.ecolecon.2019.05.011

The interactive charts use Hickel's own updated dataset of the SDI and its components for 162 countries, 1990–2022. The Human Development Index values shown for comparison are reconstructed from the same life-expectancy, schooling and income figures using the standard UNDP formula. The world map uses Natural Earth country geometry (public domain). Where we quote the paper's specific country rankings, those reflect its 2015 analysis; the interactive charts default to 2019 and let you scrub across the full record.

Beyond the index itself, this explainer draws on the wider body of research behind it — on fair shares, decoupling and post-growth economics:

O'Neill, Fanning, Lamb & Steinberger (2018). A good life for all within planetary boundaries. Nature Sustainability 1, 88–95.
Hickel (2019). Is it possible to achieve a good life for all within planetary boundaries? Third World Quarterly 40(1), 18–35.
Hickel & Kallis (2020). Is green growth possible? New Political Economy 25(4), 469–486.
Hickel (2020). Quantifying national responsibility for climate breakdown. The Lancet Planetary Health 4(9), e399–e404.
Hickel, O'Neill, Fanning & Zoomkawala (2022). National responsibility for ecological breakdown. The Lancet Planetary Health 6(4), e342–e349.
Vogel & Hickel (2023). Is green growth happening? The Lancet Planetary Health 7(9), e759–e769.

The closing two sections widen the lens beyond the index itself — to the justice of who overshoots and who pays, and to whether a good-and-safe future can be sustained. They draw on:

Chancel, Mohren, Moshrif, Odersky, Piketty & Somanchi et al. (2026). The Global Justice Report: A Plan for Equality & Prosperity Within Planetary Boundaries. World Inequality Lab. gjp.wid.world
Anderies, Bechthold, Donges, Fetzer, Wunderling, Barfuss & Rockström (2026). An information-based World–Earth system resilience index. EGUsphere (preprint under discussion). doi:10.5194/egusphere-2025-6345

GLOBAÏA built this explainer to make the index legible to a broad public. Any errors of simplification are ours, not the author's. The underlying science and all numerical methods are Hickel's. For the full dataset and methodology, see sustainabledevelopmentindex.org.