Overshoot Day is calculated using UN data to work out each country’s ecological footprint and the ‘biocapacity’ of the planet. Biocapacity is Earth’s ability to produce renewable resources and absorb waste, while the ecological footprint measures demand on nature including consumption of resources and emissions.

Global warming caused by vast amounts of CO2 from the burning of fossil fuels is driving the deficit, according to the Global Footprint Network. The organisation says that achieving a 43 per cent cut in global emissions by the end of the decade would require Overshoot Day to be pushed back by 19 days every year between now and 2030.

An interesting read.