Why Earth Overshoot Day And The Ecological Footprint Are Pseudoscientific Nonsense

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Humans consume more resources than our planet can sustainably produce, according to the Global Footprint Network (GFN), which has been organizing days to mark “Earth Overshoot Day” since 1986. "Humanity is using nature 1.75 times faster than our planet's ecosystems can regenerate," says the group. "This is akin to using 1.75 Earths." Rich nations "overshoot" their resources before poorer ones, according to GFN. The US, Australia, Denmark and Canada overshoot before the end of March, while Cuba, Nicaragua, Iraq, and Ecuador don't overshoot until December.

"Earth Overshoot Day" is based on something called the "Ecological Footprint," which is used by the World Wildlife Fund, the United Nations Environment Program, the United Nations Development Program's Human Development Report, and the International Union for Conservation of Nature.

But is the Ecological Footprint good science? It's not.

Six years ago I helped debunk Earth Overshoot Day and the Ecological Footprint calculation it's based upon in a paper for the peer-reviewed scientific journal, PLOS Biology called "Does the Shoe Fit? Real vs. Imagined Footprints."

We broke down the six measures that comprise the Ecological Footprint and found that five of the six, including food and forestry, were either in balance or surplus. The only thing out-of-balance were humankind's carbon emissions.

But solving that problem doesn't require that rich nations become poor — or that poor nations remain poor — but simply that we move toward energy sources that don't produce carbon emissions, a process known as "decarbonization."

And the only two cases of nations significantly decarbonizing their energy supplies, France and Sweden, did so not by becoming poor but rather by becoming far richer thanks to the use of nuclear energy. Today, France spends little more than half as much as Germany to produce electricity that produces one-tenth of the carbon emissions, thanks to nuclear.

How did the creators of the Ecological Footprint hide what they had done? By implying that the way to solve climate change is by expanding forest cover to absorb industrial carbon emissions.

All of the supposed "overshoot" of resources is from carbon emissions that the Footprint converts into forest area needed to offset the emissions.  The Footprint thus leads readers to ignore all the other ways of absorbing or never emitting CO2.

It gets worse. Different forests absorb carbon dioxide at different rates over time. But the Ecological Footprint arbitrarily chooses a single number to represent the rate of carbon uptake for all forests around the world for all time. The Ecological Footprint method is best known as "garbage in, garbage out."

The implication of the Ecological Footprint is thus either that everyone in wealthy developed nations like the US, Europe, and Australia should try to live like Cubans and Nicaraguans, or that we should convert all of the world's old-growth forests to fast-growing tree farms.

When we published our paper in 2013, it was widely covered in the media, including by Scientific American, New Science, and Le Monde, but that hasn't stopped the European Commission and other governmental bodies from recognizing "Earth Overshoot Day" on social media.

The Ecological Footprint and Earth Overshoot Day were created at the same time that Western European nations and the United Nations embraced a neo-Malthusian approach to environmental problems. 

Ironically, the UN promoted the use of wood fuels over nuclear. In a 1987 report called “Our Common Future,” the UN denounced nuclear energy and insisted that poor nations should use wood fuel more sustainably. “The wood-poor nations must organize their agricultural sectors to produce large amounts of wood and other plant fuels.”

The lead author of “Our Common Future” was Gro Brundtland, former Prime Minister of Norway, a nation which just a decade earlier had become fabulously wealthy thanks to its abundant oil and gas reserves.

Figures like Brundtland promoted the idea that poor nations didn’t need to consume much energy, which turned out to be howlingly wrong. Energy consumption is as tightly coupled to per capita GDP today as it was when today’s rich nations were themselves poor.

There is no rich nation that depends primarily on wood for energy, just as there is no poor nation that depends primarily on fossil fuels or nuclear.

The Ecological Footprint has as much scientific merit as astrology, phrenology, and flat-earth theories. It's time to treat the Ecological Footprint as the pseudoscientific theory it is.