Defining "ecological footprint"

Earth-worthy accounting

The world’s population is currently using 1.75 Earths’ worth of resources. You’ve probably seen this statistic before, or one like it. You are almost guaranteed to have heard the phrase “reduce your footprint” before.

Both concepts come from the Global Footprint Network, which collects and processes data on the ecological footprint – among other things. Since its founding in 2003, the Network has been tracking data on the resources the Earth has, and the resources humanity uses. The difference between the latter and the former has persistently – although not uniformly – grown.

Can we expect this pattern to continue? The Footprint Network doesn’t know.

“We’re just accountants; we don’t speculate about the future,” says Dr Mathis Wackernagel, founder and president of the Global Footprint Network.

Accusations of speculation and uncertainty are rife in environmental discourse – even when predictions are made with some of the most comprehensive scientific processes in the world, such as by the IPCC. The Footprint Network has opted to avoid it entirely.

“Let’s do just bookkeeping,” summarises Wackernagel. “Just rear mirror.”

Despite the rear-mirror thinking, or perhaps because of it, the term “ecological footprint” has taken off since its inception. You can’t open a magazine, newspaper or ‘corporate responsibility’ page of a website without seeing a statement about a carbon, environmental, or ecological footprint.

But the Footprint Network has a clear definition for ecological footprint that rarely makes it into these places. Is it ever used correctly?

“The question is more the opposite: do you ever find applications where the term is used the right way?” says Wackernagel.

The real definition of “ecological footprint”

Wackernagel first developed the idea of biocapacity and ecological footprint with his PhD supervisor, Professor William Rees, at the University of British Columbia, Canada, in the early 1990s.

It starts with biocapacity, or biological capacity: the ability of an ecosystem to regenerate what’s demanded of it by people. The Footprint Network calculates biocapacity from United Nations datasets, which track food growth, production of fibres and timber, carbon dioxide and waste absorption, and physical space from built infrastructure. About 15,000 data points are collected per country, per year.

Biocapacity is expressed in area: the number of hectares with globally average productivity, or “global hectares”. A highly productive piece of land might be 10 actual hectares, but 20 global hectares, while 10 hectares of desert might represent more like 2 global hectares.

Ecological footprint is the other side: the number of global hectares a person, company, or country needs to sustain it.

Wackernagel says there are three things that make biocapacity a powerful communication tool.

“One is, you get out of this silly beauty competition of environmental problems. Which problem is the most beautiful one? Is it climate change? Is it species loss? Is it pollution? Is it loss of agricultural lands? Food? Is it loss of freshwater? The litany goes on. Actually, it’s everything combined.”

Increasing your resource security is exactly the same practice as reducing your footprint. If you use less, you need less. What matters is the framing.

The second, is that it provides people with very explicable numbers and facts, that can be described in different ways. One of the Footprint Network’s preferred methods is Earth Overshoot Day: the date each year when the world exceeds 12 months’ worth of resources.

“Even primary school students understand ‘from January 1 to July 29, we people have used as much as Earth can renew in the entire year’,” says Wackernagel.

“The third thing is probably the most important one. A doctor once told me a thing which was very insightful. He said, ‘people are much more worried about empty fridges than overflowing garbage cans’. So how does it link to us? That’s why we talk much more about resource security.”

Increasing your resource security is exactly the same practice as reducing your footprint. If you use less, you need less. What matters is the framing.

This is part of the logic behind the shift to Earth Overshoot Day – and the emphasis on country ecological footprints, rather than individual footprints. You can still calculate your personal ecological footprint on the Footprint Network’s site, because it’s such a popular educational tool, but Wackernagel says he wishes they didn’t have it.

“It can lead easily to kind of this suffering and sacrifice feeling in the beginning – ‘oh my god, they want me to give up my chocolate’,” he says.

The power of a single number

A couple of months ago, I wrote a news article for Cosmos on koalas receiving an “endangered” listing in New South Wales, Queensland and the Australian Capital Territory.

It’s still not really clear how many koalas there are on the east coast, but we do know their numbers are in decline. Grant Hamilton, an associate professor in ecology at Queensland University of Technology, told the Australian Science Media Centre that remaining koala population numbers needed to be established, and his research in drones and AI could help.

When I asked Hamilton how much this would cost, he wouldn’t give me an estimate – even a ballpark.

“Conservation is a complex science, and when you focus on one number, you’re just going to miss it,” he explained to me.

A thousand-, million-, or billion-dollar price tag on finding koala numbers, he believes, would distract people from the work required to actually monitor and conserve their populations.

“This is the tension between journalism and science sometimes. Where’s the exclamation mark? It’s all the stuff around the exclamation mark which is really pretty important,” he said.

Hamilton’s koala price tag falls into the same category as Wackernagel’s chocolate. Certainly, there are costs involved – but by focussing on them, we risk sensationalising them.

“This is the tension between journalism and science sometimes. Where’s the exclamation mark? It’s all the stuff around the exclamation mark which is really pretty important”

Associate Professor Grant Hamilton, QUT.

But the ecological footprint, and Earth Overshoot Day, show that this force can be used for good as well.

“Numbers are really powerful,” says Associate Professor Jen Martin, a researcher in science communication at the University of Melbourne. “Because if we talk in really general terms, often people find it very hard to relate to what we’re saying.”

“What you risk if you leave out the numbers altogether, is that people can refuse to engage emotionally with what you’re telling them because they have no sense of: is that good? Bad? Otherwise? Big? Small?

“So I think yes to numbers, but numbers that have been really carefully tailored to the audience and have relevance and meaning to that audience and understandable.”

The audience is key here. Accuracy is the most important detail if you’re talking to policymakers. Relatable comparisons are more important if your audience is categorised “general”.

“I know some people hate the swimming pool/Sydney Harbour/MCGs [comparisons],” says Martin. “But I actually think they’re quite useful if they’re meaningful to their audience.”

And everyone, or almost everyone, understands the concept of 1.75 Earths – even if it doesn’t actually exist.

How we talk about this

In 1972, the United Nations held a conference on the environment in Stockholm. Its tagline was “only one Earth”.

“That’s pretty clear,” says Wackernagel. Twenty years later, at the 1992 Rio di Janeiro conference, he says the meaning was getting diluted.

“[The conference had] this definition of sustainability that said, ‘how can we meet the needs of present generations without compromising the ability of future generations to meet their own needs?’ I hope you haven’t fallen asleep yet.”

And, of course, it hasn’t really worked. “Since 1992, we have doubled fossil fuel consumption,” says Wackernagel.

But environmental organisations – the Footprint Network among them – are thinking harder and longer about how to get their message across. What’s explicable? What hits home? What includes the problems you want to talk about?

“The more people who think about this, the more positive improvements we’re likely to see and the less money and effort we’ll see wasted on people sending information out into the world in a completely untargeted way,” says Martin.

It seems that environmentalists are getting smarter about the way they communicate.

In another 20 years, our bookkeepers will tell us whether or not it’s worked.

Please login to favourite this article.