Overview: Earth overshoot day calculation

Earth Overshoot Day is the day of the year on which humanity’s demand on nature exceeds the Earth’s annual biological capacity to regenerate. In 2026, Earth Overshoot Day falls on July 30th, meaning that between January 1st and July 30th, humanity’s demand for biological regeneration is equivalent to the planet’s entire annual regeneration. Last year’s Earth Overshoot Day was officially marked on July 24th, 2025. This shift reflects both revisions to underlying data and actual year-to-year trends.

Updated input data, particularly regarding carbon absorption by oceans, suggests ecological overshoot may be slightly smaller than previously estimated. On its own, this revision would have delayed Earth Overshoot Day by approximately eight days. Simultaneously, global overshoot has slightly increased compared to last year, moving the date about two days earlier. The combined effect results in a net shift of six days later than the 2025 official date. Despite this apparent improvement, global ecological overshoot is now higher than at any point in human history; the underlying upward trend is partly obscured by revisions to public datasets.

The need for nowcasting

The National Footprint and Biocapacity Accounts (NFBA) are built on official UN datasets, which typically have a time lag of three to four years. Because Earth Overshoot Day is an estimate of the current year’s consumption, nowcasting is required to provide an estimate of humanity’s current Ecological Footprint compared to the planet’s biocapacity. Nowcasting differs from forecasting as it uses actual proxy data associated with the nowcasted years—such as yield fluctuations, car usage, electricity intensity, and changes in housing stock—rather than relying solely on models that extrapolate past trends.

Methodological overview: accounting for biocapacity

The Ecological Footprint tracks how much mutually exclusive, biologically productive area is necessary to renew people’s demand for nature’s products and services. Demands include food, fibre, and timber; space for roads and structures; energy production; and waste absorption, including carbon dioxide from fossil fuels or cement production. Both biocapacity and Ecological Footprint are compared based on two principles: commensurability, where areas are scaled proportional to biological productivity, and additionality, allowing competing demands on productive surfaces to be added up. The measurement unit used is the “global hectare”, representing a biologically productive hectare with world-average productivity.

Starting point: National Footprint and Biocapacity Accounts

Nowcasting extends the 2026 edition of the National Footprint and Biocapacity Accounts, which include full results from 1961–2023 and estimates for 2024–2026. The 2026 edition incorporates several significant updates. Built-up area calculations were upgraded for over 220 countries using the Global Human Settlements Layer. The carbon footprint of traded goods was improved using IMF and World Bank statistics to extend UN Comtrade data. Fish trade footprints were aligned with the UN FAO Fishstat database and domestic catch data from the Sea Around Us project. Forest product footprints were enhanced with additional FAOSTAT commodities, and the carbon footprint was updated using the Global Carbon Budget 2025, which increased the estimated global ocean carbon sink.

Nowcasting: extending the trends of the National Footprint and Biocapacity Accounts

To determine the date for 2026, researchers first used the 2025 edition reaching to 2022. Revisions in historical data moved the baseline for 2024 to seven days earlier. Secondly, world results for 2023–2025 were estimated. Actual changes in footprint and biocapacity from 2024 to 2025 moved Earth Overshoot Day by 22 hours (approximately one day) earlier. The final 2026 date is 6 days later than the 2025 official mark due to these combined historical revisions and current trends.

Nowcast results for the world: 2024-2026

The carbon footprint nowcast is based on carbon dioxide emissions data from Carbon Monitor and the Global Carbon Project. Fossil emissions increased by 1.1% from 2024 to 2025. For the 2025–2026 period, estimates indicate a 0.8% increase in carbon emissions based on early 2026 data. This assumes consistency for the entire year, despite potential disruptions such as the closure of the Strait of Hormoz, which may affect global emissions through reduced oil consumption or shifts to more carbon-intensive fuels. Carbon absorption is assumed to increase by 0.5% annually.

For 2026, the total Ecological Footprint is estimated to increase by 0.5% compared to 2025, while total biocapacity is expected to decrease by 0.4%. These effects combined increase the ratio of footprint to biocapacity by 0.9% compared to the prior year. Consequently, Earth Overshoot Day 2026 arrives approximately 1 day and 21 hours earlier than it would have under 2025 conditions, settling on the final date of July 30th.