So what is Earth Overshoot Day & why should we care…
Each year Earth Overshoot Day marks the date when humanity’s demand for ecological resources and services exceeds what Earth can regenerate in that year.
Earth Overshoot Day is hosted and calculated by Global Footprint Network, an international research organisation, that provides key decision-makers with a menu of tools to help the human economy operate within Earth’s ecological limits.
In order to calculate the date of Earth Overshoot Day for each year, Global Footprint Network calculates the number of days of that year that Earth’s biocapacity suffices to provide for humanity’s Ecological Footprint.
The remainder of the year corresponds to global overshoot. Earth Overshoot Day is computed by dividing the planet’s biocapacity (the amount of ecological resources Earth is able to generate that year), by humanity’s Ecological Footprint (humanity’s demand for that year), and multiplying by 365, the number of days in a year:
Earth Overshoot Day = (Planet’s Biocapacity / Humanity’s Ecological Footprint) x 365
For this year (2019), Earth Overshoot Day is the same date – 29 July as last year. As you can see from the chart below, Earth Overshoot Day has been gone from 29 December (in 1970) & getting earlier and earlier, until we are at 29 July for 2019.
Ultimately, the precise Earth Overshoot Day date for each year is less significant than the sheer magnitude of the ecological overshoot, as well as the overall trend of the date progression year on year. Over the past decades, the date has been creeping up the calendar every year, and may appear to have slowed over the past decade.
So what can each of us do to make a real and lasting change to Earth Overshoot Day:
Firstly, you can calculate our own personal Earth Overshoot Day using the Ecological Footprint Tool
Secondly, go to our companion post to find out Three ways to reduce your Earth Overshoot Day.