What the report calculates
The report has two parallel accounting views. The ecological estimate is expressed in global hectares (gha): hectares normalized for average biological productivity. The climate estimate is expressed in tonnes of carbon-dioxide equivalent per year (tCO₂e).
They overlap, but they are not interchangeable. Ecological Footprint accounts represent fossil carbon as the hypothetical productive area needed to absorb emissions after ocean uptake. CO₂e includes other greenhouse gases and uses global-warming potentials. Converting every tonne of CO₂e into gha would mix two incompatible accounting frames, so EcoSi does not do it.
The public baseline
Our factor set begins with the latest year in the 2026 National Ecological Footprint and Biocapacity Accounts that has a full component breakdown: 2023. The published global totals are approximately 2.5646 gha of Ecological Footprint per person and 1.50065 gha of biocapacity per person.
The personal category allocation used by this beta—Food, Home, Mobility, Goods and Services—is an EcoSi scenario allocation. The official Consumption Land Use Matrix (CLUM) required for a country-compatible personal footprint is licensed separately and is not present in the public workbook. We therefore do not describe this result as official, certified or CLUM-compatible.
How answers change the baseline
Each question changes one non-overlapping slice of a category. A meat-frequency answer changes only the relevant food slice; it does not also increase a generic shopping slice. This avoids the most obvious double counting.
personal category = fixed shared share
Σ (household baseline slice × activity multiplier)Choices are expressed as multipliers around an average. The average and every “I’m not sure” choice use 1.0. Lower-impact choices use a multiplier below 1.0; higher-impact choices use a multiplier above 1.0. The complete factor values are embedded in the calculator source and versioned as ecosi-beta-2026.1.
Services include a floor for infrastructure, government, healthcare, education and other shared systems. It cannot be reduced to zero through individual answers. This is a feature of consumption accounting, not a judgment about the user.
Earths and personal Overshoot Day
“Earths” compares the personal gha estimate with the world’s biocapacity per person, not with the biocapacity of the user’s country.
Earths = personal gha ÷ 1.500648682
Overshoot day number = ceil(days in year ÷ Earths)If the result is at or below one Earth, the report says the scenario stays within one Earth’s annual budget and does not invent an Overshoot Day.
The separate climate scenario
The tCO₂e figure uses category proxies calibrated around a world-consumption scenario. It is intended for prioritization, not inventory reporting. Flight, fuel, food and energy factors draw on primary methodologies such as ICAO, IPCC and FAOSTAT; global defaults remain proxies where the user does not provide country-specific bills or distances.
For a corporate inventory, regulatory filing or offset purchase, use a jurisdiction-specific calculator with documented system boundaries, the current grid factor, fuel well-to-tank treatment and a declared IPCC global-warming-potential basis.
Why the report shows a range
Input uncertainty is unavoidable: most people estimate travel, food frequency and purchases. EcoSi creates a low and high scenario around the central estimate. This is a scenario range, not a statistical confidence interval. A full error distribution for the underlying National Accounts is not currently published.
Your report lists answers that used defaults. Returning to those questions is usually the fastest way to narrow the range.
What the footprint does not measure
- It is not a direct measure of biodiversity loss, freshwater depletion, toxicity or mineral scarcity.
- Carbon-uptake land is a theoretical accounting demand, not an offset and not proof that spare forest land exists.
- Public national data can miss groundwater depletion, soil degradation and changes in long-term ecosystem productivity.
- A short questionnaire cannot represent every product origin, supply chain or rebound effect.
- Results can change when a new data edition or factor set is released.
Primary sources
- National Ecological Footprint and Biocapacity Accounts, 2026 Edition
- Ecological Footprint Standards 2009
- Global Footprint Network Calculator FAQ
- IPCC 2006 Guidelines with 2019 Refinement
- ICAO Carbon Emissions Calculator methodology
- FAOSTAT emissions intensities
Last reviewed 12 July 2026. Corrections can be sent to hello@ecosi.global.
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Every result includes the factor version, defaults and scenario range described above.
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