Most people I talk to support “sustainability” and “social justice” goals. Ecology teaches us that we need to frame these human aspirations in relation to the biological capacity of the earth: the energy, and resources that support our burgeoning populations and economies.

As human society sets out to achieve ecological sustainability and social justice on earth, we face two serious challenges: One, humanity already over-consumes the biological capacity of the planet; and secondly, humanity suffers from a vast gap between rich and poor.

Free-market fundamentalists claim we’ll close this gap, and restore the planet, by growing our economies, perhaps with “green” jobs, but this business-as-usual approach fails to account for ecological reality.

Do the Math

According to data compiled by the UN, the Global Footprint Network, and Dr. William Rees at the University of British Columbia, total human consumption already exceeds the earth’s capacity by 30 percent. This is known as biological “overshoot.” The UN estimates that most natural services to human societies – forests, fish, fresh water, and clean air – are now declining annually. As human population and consumption grow, our collective overshoot increases.

Meanwhile, the wealthy 15 percent use about 85 percent of the resources – the total energy and materials, the “stuff,” that Earth provides. The “wealthy” includes anyone who has a home, job, transport, access to education, hot showers, convenient fuel, and food every day: people in the so-called “developed” world. If you have those things, you live among the wealthy 15 percent, who use most of the world’s resources.

There is more to social change than the biophysical numbers, but any serious ecologist or justice advocate needs to know how resource overshoot limits our choices to achieve sustainability and social equality. Let’s do the math.

Nature’s rules

Start with these facts:

1. Total human consumption =

     130% of Earth’s capacity

2. The rich 15% use 85% of the stuff;

     while the poor 85% use 15% of the stuff

If we define the sustainable, equitable consumption per person as “1 unit” of stuff, the facts above mean that an average 100 people use 130 “units.” To be sustainable, the total consumption of 100 people needs to be 100 “units” of stuff. And to achieve social justice, each person would use 1 unit. But of course, that’s not how our world works.

Total human consumption of a 100 average people equals 130, not 100, and since the rich 15 use 85% of everything, they use 110 units (130 X 85%). The poor 85, meanwhile, use the other 20 units of stuff.

Therefore:

The average rich person uses:

    110/15   =    7.333  units of stuff

The average poor person uses:

     20/85    =    0.235  units of stuff

How are we doing? Not too well. The average person in the developed nations consume 30-times more than the average working poor, dispossessed, and starving multitudes. And meanwhile, we already use more energy and materials than Earth can annually supply.

So if we want a world of ecological sustainability and social justice, then we must face some difficult facts. To start with, humanity must consume less stuff.

We must reduce the total human consumption for 100 average people from 130 to 100, and then, we must share those 100 units of stuff that the earth can provide.

If we were able to achieve that, then everyone would simply use 1 “unit,” the ecologically sound, socially equitable amount of energy and materials. As we know, in our current situation, we consume more than the earth’s capacity and the rich take almost everything.

Another way to understand this is to imagine humanity as a family of seven people, that earns $100,000 per year but spends $130,000, and one member of the family alone spends $110,000. This family is going broke because one person, 15% of the family, is pigging out.

Dysfunctional? Yes.

Sustainable? No.

Reality bites

By these figures, we see that to achieve sustainability and social justice, the rich would have to consume about 1/7 of what they currently consume. If that happened, the world’s poor could increase their consumption by about 4-times.

That’s the straightforward, biological and physical reality we now face.

Under our current economic system, achieving sustainability and social justice might appear impossible. However, using less and sharing represent nothing more than common decency, the sort of behaviour we supposedly teach our children.

We hear from our alleged leaders, of course, that this is politically and logistically impractical. So, instead, we labour under the delusion that we’ll make the world “equitable” by growing all the economies until the poor, developing countries achieve greater wealth. We’ll make our economies “sustainable” by creating “green” products, hybrid cars, and renewable energy.

If the earth was an infinite storehouse and could provide infinite sinks for our garbage, that would be a reasonable plan. But the earth is not infinite. It remains unequivocally finite.

And Nature doesn’t really care about our social theories, economic presumptions, or our whining about wanting more. Humanity is now like a clever but obsessive adolescent, who must be warned: "Sorry, this will sound really annoying, but there are real limits to your freedom to consume."

Suppose we soften the blow for the rich world, the spoiled child of humanity. We could live within the earth’s capacity if the rich simply cut their consumption in half and the poor could then double their current consumption. Here is how that would work, by the numbers:

The average rich person would use 3.67 units of stuff, instead of 7.33. And then, the average poor person could use 0.53 units of stuff (slightly more than double), instead of 0.235. This equation alone would feed the 1-billion starving, and end world hunger.

Our equation for 100 average people would then look like this:

Rich consumption:  

    15   X   3.67   =   55 units of stuff

Poor consumption:  

    85   X   0.53  =   45 units of stuff  

Total  =  100 units of stuff for 100 average people.

In this scenario we would be sustainable and the world’s poor could grow their economies to the point of doubling their use of energy and resources.

If we achieved this simple change in human consumption patterns, we could exist within the carrying capacity of the Earth.

Is this difficult to imagine? Is it fair? The ratio between the average rich and poor would then be about 7-to-1, far more equitable than the current 30-to-1 ratio. To achieve this, the rich only have to give up half their consumption. That could be achieved primarily by eliminating wastefulness, planned obsolescence, plastic packaging, exotic holidays in jet airplanes, and the most wasteful of all human inventions: cars.

Growth fundamentalists will grumble at this because they imagine a world in which they can look forward to being richer, consuming more, not less. However, biophysical reality sets the limits. We do not get to rewrite the laws of biology and physics for our own convenience.

Two problems remain

Even if humanity could make this simple change – the rich cut consumption by half, the poor double their consumption, and we achieve sustainability – we still face two problems.

First of all, we currently add 75 million new people to the planet every year. What stuff are they going to use?

To live decent lives, these new humans would need the infrastructure services roughly equal to a nation such as France, Germany, or Egypt. And then again, every year.

Human population growth proves to be both an ecological and social justice issue. The planet is finite. I’m mystified that some people find this so difficult to accept. Since we have already reached biological overshoot, human population growth pushes us farther out over the cliff.

For example, we now face declining oil and fish yields, but few people realize that oil and fish yields per capita peaked in the 1970s, thirty years ago. Each day, as we add more people and degrade our ecosystem, the average human – regardless of stock market paper wealth – becomes biophysically poorer.

Like the over-spending family, having a new baby every year, and spending more, while degrading their assets, every year we have less to go around and more mouths to feed.

To achieve sustainability and social justice, we must stabilize human population. We are breaking the back of the natural world with our insistence on endless growth of both population and consumption.

Fortunately, we could stabilize human population with three simple and socially beneficial policies worldwide: Women’s rights, contraception, and education.

The second challenge we face is that we share this planet with millions of other species. These non-human earthlings possess a right to life and habitat as much as we do. Furthermore, humanity relies on the benefits of biological diversity and symbiosis within the ecosystem.

We cannot design human culture to devour every last niche of the planet, every river and forest, the last corner of the ocean and stretch of grassland. We need to preserve every acre of wilderness that still exists on the earth.

Living within Earth’s budget

Growth is not evil, it just isn’t permanent.

In nature, all growth stops. New organisms may replace the old, diversity can increase, but there exist no cases in nature of endless growth. As Dr. Albert Bartlett at the University of Colorado points out, “After maturity, continued growth is either obesity or cancer.” In a finite world, we cannot grow ourselves out of overshoot.

Years ago, Canadian master ecological logger, Merv Wilkinson, came to our small, island community in British Columbia to show us how he had managed to earn a living for over 50 years, selectively logging the forest he grew up in, and still retain a healthy forest with more standing timber than the day he started logging. As we walked through the woods, he explained the nuances of soils, natural seeding, tree growth rates, cutting rates, and selection criteria for harvest. Then, he stopped, thought for a moment, and said: “It’s simple really: Just cut below the annual growth rate.”

That is now the lesson for humanity on a global scale. We simply have to learn to live within the capacity of our single island in space, planet Earth. To achieve this, the wealthy must find peace with a lower-consumption lifestyle.