How the Date of Earth Overshoot Day 2020 Was Calculated

Earth Overshoot Day marks the date when humanity’s demand for ecological resources and services in a given year exceeds what Earth can regenerate in that year. To determine the date of Earth Overshoot Day, Global Footprint Network calculates the number of days that Earth’s biocapacity can provide for humanity’s Ecological Footprint, as explained on this page. The methodology relies on the latest edition of the National Footprint and Biocapacity Accounts, which unavoidably presents a “time gap” with the present time due to United Nations’ reporting procedures.

To address this “gap” and determine Earth Overshoot Day for the current year, Global Footprint Network establishes trendlines from the National Footprint and Biocapacity Accounts data and extends those trendlines to the present year. Where possible, more recent data from reputable sources (Global Carbon Project, etc.) are incorporated to strengthen the assessment for the “gap” years.

In order to take into account the impacts from the coronavirus pandemic this year, Global Footprint Network combined the most reliable data and formed the most reasonable assumptions to assess humanity’s current resource situation. Changes in carbon emissions, forest harvest, food demand, and other factors that could impact global biocapacity or the Ecological Footprint from January 1st to Earth Overshoot Day 2020 were evaluated. The research team concluded to a 9.3% reduction in the global Ecological Footprint compared to the same period last year.

The downloadable research report documents that the main drivers were the carbon Footprint (reduced 14.5% from 2019) and the forest product Footprint (reduced 8.4% from 2019). The result of all data extrapolations and analyzed factors concluded that Earth Overshoot Day 2020 landed on August 22.

logs in a forest
forest products Footprint

Assessment of the COVID-19 impact on the forest products Footprint draws on many data sources, including projections by the Canadian forest industry and data from Brazil’s National Institute for Space Research, who tracks rates of deforestation in the Amazon, and from the Sinchi Institute.

carbon Footprint

Carbon emissions data from the International Energy Agency forms the basis of the ‘COVID-19 carbon-adjustment’ to Earth Overshoot Day. The pre-Earth Overshoot Day period was divided into three segments for accurate assessments.

food Footprint

The pandemic has significantly disrupted the global food system, increasing both food waste and malnutrition among lowest income populations. As a result, Global Footprint Network conservatively assumes there was no change to the food Footprint.