HUMAN BEINGS are a truly remarkable species. We are able to conceive of notions such as democracy, equality before the law, justice, science and morality - concepts with no counterpart in nature.
But we have our shortcomings too. We demarcate borders that often make no ecological sense: dissecting watersheds, fragmenting forests, disrupting routes of animal migration. These human boundaries mean nothing to the flow of water, the oceans, or the atmosphere, yet we try to manage natural resources within such confines.
When human numbers were small, our technology simple and our consumption mainly for survival, nature was generally able to absorb our impact. Even so, it is believed that the Palaeolithic people that migrated across the Bering Strait and down towards South America extinguished slow-moving mammals in their path with little more than stone spears and axes.
As is well documented by authors such as Jared Diamond in Collapse and Ronald Wright in A Short History of Progress, cultures have arisen, flourished and disappeared as human demands outstripped the carrying capacity of surrounding areas. In pre-history and even medieval times, humans were essentially tribal animals, confined to their tribal territory, perhaps meeting a couple of hundred people in a lifetime. They did not have to worry about what tribes were doing on the other side of the ocean or giant lakes, or over mountains and deserts. But in the past century humanity has undergone an explosive transformation.
Consider that in 1900 there were only 1.5 billion humans in the world. In a mere 100 years, the human population has quadrupled. Almost all the modern technology we take for granted has been developed and expanded since the late 1800s. Our consumptive appetite has grown rapidly since World War II and economic globalisation now dominates the political and corporate agenda.
All these factors - population, technology, consumption and the global economy - have amplified humanity's ecological footprint: the natural resources required to meet our needs and demands. Consequently, we are altering the biological, chemical and physical make-up of the planet on a geological scale; in the four billion years since life on Earth began, no other single species has so changed the biosphere.
The phrase 'sustainable development' was coined in 1987, in the famous Brundtland Commission report, Our Common Future. The report called for protection of 12 per cent of the land area of all countries, a target which has no scientific basis, but which very few countries have managed to achieve. We are just one of the planet's 15 to 30 million species, yet we seem to take it for granted that we can take over 88 per cent of the land.
And we seem determined to do it, destroying habitat and ecosystems around the world while driving tens of thousands of species towards extinction every year. We make tiny patches of oceans marine protected areas while slaughtering fish and accidentally killing turtles, birds and marine mammals with long line fishing, drift nets and bottom trawlers.
Marine biologist Boris Worm and his co-workers at Dalhousie University in Nova Scotia, Canada, predict that if we continue to overfish, pollute and destroy ocean habitat as we do today, every fish species now exploited will have a population so small as to render it commercially extinct by 2048.
We have spread our toxic debris in the soil, air and water so that all of us now carry dozens of toxic compounds in our bodies. A few months ago in Canada three members of parliament volunteered to be tested for a battery of more than 80 toxic substances.
All three were shocked to find that they all carried dozens of these toxins in their bodies. Our use of the air as a dumping ground for carbon dioxide and other greenhouse gases has altered the chemistry of the atmosphere, which in turn is acidifying the oceans as CO2 dissolves as carbonic acid.
We have no means of dealing with these global environmental issues with the level of urgency required. We must now ask what the collective impact of all 6.7 billion human beings on Earth will be. We have never had to do this before. We are tribal animals and it is difficult for us to comprehend the task.
We need the perspective of many of the world's small island states; nations that are in imminent danger of being submerged by sea level rise. The metaphor of the canary in the coalmine is very apt. I was in Kyoto in 1997 when island states pleaded for action to protect their land, but to no avail.
North America along with Europe, Japan, Australia and other industrialised countries created the problem of climate change, and our industrial and economic growth now serves as a model for the developing world to follow.
And if rich nations such as the United States, Canada and Australia can't cap their emissions, why should countries such as India, China or any other developing nations, pay the slightest attention to demands that they reduce theirs?
These days, not only small island states, but many of the rich industrialised nations are also in grave danger from climate change. So, why are we still failing to act?
There are, I believe, a number of factors that blind us to the reality of the problem, and two of them stand out for me. In 1900, the world population stood at 1.5 billion people. There were only 16 cities with more than a million people. London was the largest with 6.5 million people. Tokyo was the seventh largest with 1.5 million.
Most people lived in rural village communities and, as farmers, understood the importance of weather and climate. Farmers know about the movement of water and its necessity in the soil. They know how to build topsoil and fight off predators. Farmers are much closer to the natural world than those who buy food in a supermarket.
Fast forward a century. By the year 2000, world population had quadrupled to six billion and there were more than 400 cities with over a million people. The 10 largest cities in 2000 all had more than 11 million people. Tokyo was the largest city in the world with 26 million. Can you imagine a population increase from 1.5 million to 26 million people in 100 years?
By the year 2000, we had been transformed from a farming species into an urban-dwelling one, especially in the industrialised nations where some 85 per cent of us live in large cities. We are city animals now and in a city we live in a human-created environment where it becomes easy to think that we are special and different, that we are separate from nature.
A few years ago I presented a television series called The Nature Connection, in which I asked 10-year-old children where they thought electricity came from when they turned on the lights, where water came from when they turned on the tap, and what happened when they flushed the toilet or put garbage on the kerb. They didn't know!
When I asked where their food came from they said from the supermarket. Many of them didn't know that vegetables grow in the soil, and were shocked to find out that hamburgers and hot dogs are made from the muscles of animals.
If we are so ignorant of the fact that it is the biosphere - the zone of air, water and land where all life exists ¬ that provides these services, that gives us electricity and water and food, and that absorbs our waste, it becomes easy to assume and accept that the economy is the real bottom line. If we have a healthy economy, we have good garbage collection and sewage treatment services.
It seems the economy is what fills our stores with goods and gives us a dependable source of electricity. And so the economy becomes the highest priority for urban dwellers.
Economics and ecology are words built on the same root - 'eco'- from the Greek word 'oikos', meaning home. Ecology is the study of home; economics is the management of home. Ecologists attempt to determine the conditions and principles that govern life's ability to flourish and survive.
It makes sense, therefore, that we should encourage ecologists to find out exactly what those conditions and principles are, so that we can manage our homes and social systems accordingly. But we have elevated the economy above everything else, and this is the crisis we face.
The economic system that has been foisted on people around the world is so fundamentally flawed that it is inevitably destructive. We must put the 'eco' back into economics and determine the conditions and principles required for true sustainability.
So why is economics out of sync? First of all, nature performs all kinds of services. Nature pollinates flowering plants, it decays materials and returns them to the Earth, it creates soil and it drives the nitrogen, carbon and water cycles.
All of these are economically valuable services performed by nature, but economists call them 'externalities', by which they mean services that are outside the conventional economic equation; economists externalise the real world that keeps us alive.
I confronted this attitude when fighting to prevent logging in a valley where the native community said they didn't want the trees cut. I encountered a logging company executive who asked whether "tree huggers" like myself would be willing to pay for the trees in the valley - because if not, those trees would not have any value until someone cut them down.
Yet as long as those trees are alive, they remove carbon dioxide from the air and release oxygen - not a bad service for animals like us who depend on oxygen for survival. To an economist, that service is an externality. Those same trees cling to the soil so when it rains the soil doesn't erode into and destroy salmon spawning beds.
That is an externality. Those trees pump hundreds of litres of water out of the soil and into the air to affect weather and climate. That is an externality. Those trees provide habitat for countless bacteria, fungi, insects, mammals and birds. That is an externality. So in our crazy system, that forest, while standing and performing countless invaluable services, has no economic value.
In reality, there are no externalities, there is no environment 'out there', with Homo sapiens 'over here' trying to manage our relationship with the biosphere. We are the environment. We take a breath of air and some of that air stays in us. The environment crisis is a crisis of humans and we are treating ourselves as a repository for all the pollution we send out through our chimneys and exhaust pipes.
Yet conventional economists continue to insist that natural services are externalities, and that the economy can grow forever. In fact, not only do they believe it can grow forever - and it cannot - they believe it must grow forever. Since World War II they have equated economic growth with progress.
Nobody wants to stop progress but, if economic growth is what we define as progress, who will ask what an economy is for? With all this growth, are we happier? How much is enough? We do not ask those questions. We have fallen into the trap of believing that economic growth forever is possible and necessary.
Now let me explain why this attitude is absolutely suicidal. Anything growing steadily over time is called exponential growth. Anything with exponential growth has a predictable doubling time. So if a population is growing at one per cent a year it will double in 70 years; two per cent a year and it will double in 35 years; three per cent and it will double in 23 years; four per cent in 17.5 years.
Now let me give you the example of a test tube full of food for bacteria; this represents our world. I put one bacterial cell into that test tube - representing humans - and it divides every minute, which means the population is growing exponentially. So at time zero you have one cell; at one minute you have two cells; at two minutes you have four; and at four minutes you have 16. At this rate, after 60 minutes, the test tube is full of bacteria and there is no food left.
When is the test tube only half full? The answer, of course, is at 59 minutes; but a minute later it is filled. So at 58 minutes it is 25 per cent full; 57 minutes, 12.5 per cent full; and at 55 minutes only three per cent full. So if, at 55 minutes, one bacterium said to its companions that they had a population problem, the other bacteria would likely be incredulous, pointing to the 97 per cent of test tube that would still be empty.
Suppose that at 59 minutes the bacteria realise they do have a problem and they only have one minute left. They give massive amounts of money to scientists, and in less than a minute those bacterial scientists invent three test tubes full of food - this is like finding three new planets for our use. It would seem that they (and we) would be saved.
But what would actually happen is this: at 60 minutes the first tube would be full; at 61 minutes the second would be full; and at 62 minutes all four would be full. By quadrupling the amount of food and space, we can only buy two extra minutes!
But how do we add more air, water, soil or biodiversity to the Earth? We cannot. The biosphere is fixed and finite and every biologist I have talked to agrees that we are past our 59th minute. So all those leaders claiming that we have to keep the economy growing are advocating acceleration down a suicidal path.
When I say this to politicians and business people, they get angry. They remonstrate that our stores are filled, cities are growing and booming and we're living longer and healthier lives. So how can we be past the 59th minute? I say it without apology.
We are promulgating an illusion that everything is all right by using up the rightful legacy of our children and grandchildren. That is not sustainable, it is suicidal. This is the challenge for our time. We have created a system that is completely out of balance with the real world that keeps us alive. We have to set a new bottom line, one dictated by the reality that we are biological creatures, completely dependent for our survival and well-being on clean air, clean soil, clean water, clean energy and biodiversity.
We are social animals who need strong families and supportive communities, full employment, justice, equity and security and freedom from racism, terror, war and genocide. And we remain spiritual beings who need sacred places in the natural world that gave us life. Let's focus on the real bottom line so we can move to a truly sustainable future.
David Suzuki is emeritus professor of the Sustainable Development Research Institute at the University of British Columbia, Canada. This essay is an edited extract of his lecture, The Challenge of the 21st Century: Setting the Real Bottom Line, the 2008 Commonwealth Lecture in London, England.
