Robyn Williams: The Science Show. Hello, I'm Robyn Williams. Today for Christmas we look back. Two voices, both from North America, from two men whose families came from outside America; David Suzuki and President Obama. The President has barely a month to go before stepping down. This is what he said about science when he first took office:

Barack Obama: Over the past few weeks, Vice-President-elect Biden and I have announced some of the leaders who will advise us as we seek to meet America's 21st century challenges. From strengthening our security, to rebuilding our economy, to preserving our planet for our children and our grandchildren. Whether it's the science to slow global warming, the technology to protect our troops and confront bioterror and weapons of mass destruction, the research to find life-saving cures, or the innovations to remake our industries and create 21st century jobs—today, more than ever before, science holds the key to our survival as a planet and our security and prosperity as a nation. It's time we once again put science at the top of our agenda and worked to restore America's place as the world leader in science and technology.

Right now, in labs, classrooms, and companies across America our leading minds are hard at work chasing the next big idea, on the cusp of breakthroughs that could revolutionise our lives. But history tells us that they can't do it alone. From landing on the Moon, to sequencing the human genome, to inventing the internet, America has been the first to cross that new frontier because we had leaders who paved the way: leaders like President Kennedy, who inspired us to push the boundaries of the known world and achieve the impossible; leaders who not only invested in our scientists, but who respected the integrity of the scientific process.

Because the truth is that promoting science isn't just about providing resources, it's about protecting free and open inquiry. It's about ensuring that facts and evidence are never twisted or obscured by politics or ideology. It's about listening to what our scientists have to say, even when it's inconvenient, especially when it's inconvenient. Because the highest purpose of science is the search for knowledge, truth, and a greater understanding of the world around us.

I am confident that if we recommit ourselves to discovery, if we support science education to create the next generation of scientists and engineers right here in America, if we have the vision to believe and invest in the things unseen, then we can lead the world into a new future of peace and prosperity.

Robyn Williams: President Obama, eight years ago. How things change.

And so to someone who seems hardly ever to change; David Suzuki. This is how he was introduced in Adelaide in March at the wonderful Botanic Gardens.

Speaker: [Aboriginal language] On behalf of the Kaurna people I welcome you all to Kaurna country and I do this as the ambassador of the Adelaide Plains people. My brothers, my sisters, let's walk together in harmony. When I was a young lad my uncle said to me, 'Whenever you need a helping hand, son, you'll find one at the end of your arm.'

Robyn Williams: Come on up old man.

[Applause, cheers]

Robyn Williams: Hey, I haven't said who he is yet! First of all, thanks to the University of South Australia for putting on this brilliant Planet Talks. Three questions. Well, the first question is have you heard of Venki Ramakrishnan? Well, think about him. He is the new president of the Royal Society of London, one of the most powerful and important scientific leaders in the world. And he went to Unley Primary School. Two of the happiest years of his life, he says. The first Indian to be in such an amazing position.

The second question which I hope David Suzuki will answer is what did Maggie Trudeau do with Mick Jagger 40 years ago? Smiling, you see. He wants a DNA analysis, yes. There speaks a geneticist. And what David Suzuki did 40 years ago last October was start Quirks and Quarks which is the sister program to The Science Show. My name is Robyn Williams, I've done it since way back then but he went walkabout doing other things, like founding the David Suzuki Foundation where I talked to him last year, and the Foundation is full of incredibly bright charismatic people, young people doing wonderful work around the world, which is perhaps what David is going to talk about as well. Meet David Suzuki.

David Suzuki: Thank you Robyn, thank you for that, it's so great to see you, and still up and running and kicking arse, good for you. It's always such a joy to return to Australia, but especially to Adelaide. I first want to say it's a privilege to stand on the traditional land of the Kaurna people who lived and cared for it over thousands of years. And I'm so overjoyed that Uncle Lewis O'Brien is here to welcome us this day.

Uncle Lewis conferred on me one of the greatest honours I've received which was a name, a Kaurna name, and I have carried it with a tremendous sense of honour but also responsibility to live up to that name, so thank you Lewis O'Brien.

I was also delighted to visit yesterday the Suzuki Forest. Do you know about that, Robyn? It's…I don't know, somewhere up in the hills, I don't know where in the heck we went, but it was degraded land that Mike Rann when he was Premier set aside to be restored and designated as a forest in the future. I was thrilled to see that it's flourishing, and to learn that it is right next to Schwarzenegger Forest, so I'm sure the terminator is going to be looking out after my little trees too.

These days I always begin my talks by saying that I'm not here to speak on behalf of any group or organisation, I don't speak for any political party or corporation, I'm here speaking as a grandfather and as an elder. And I believe this is the most important part of my life. You see, I don't have to play games anymore to get a job, a promotion or a raise, I can speak the truth from my heart. If that offends people, that's their problem, not mine.

Elders have that credibility, I believe, because we are no longer driven by the need for more money or power or celebrity or sex. Well, there are a few elders, they need help, they've got problems. But most elders are like me, those are long past in our lives, so we can speak with a great deal of credibility. And elders have something no other group in society has; we've lived an entire life. We've learned a lot. We've made mistakes, we've suffered failures, we've had a few successes. Those are hard-won life lessons. And I believe it's our job, it's our responsibility now to trawl through that life of experience for those nuggets that are lessons that are worth passing on to the generations to come. So I urge my fellow elders everywhere: Get the hell off the golf course or the couch and get on with the most important part of your life.

Now, before I begin, I must admit that ever since I arrived in Australia last Sunday I've been peppered by the press with questions about nuclear waste. I've only been in Australia for five days, the heavens sakes, I'm supposed to tell you what to do with nuclear waste? My family has only been in Canada for 120 years and Canada as a country has only existed for 150 years. I have lived all my life and my culture has never had to worry about something like sustainability. The only group with any credibility on sustainability over thousands of years are the indigenous people everywhere. So to South Australians, to all Australians, I say if you want to deal seriously with the issue of nuclear waste, let the Kaurna and the other Indigenous groups make the decisions, they are the only ones that provide the viewpoint and the perspective to do it.

You see, we stand at a unique moment in all of the history of life on this planet. That's 4 billion years of life. 99.9999% of all species that have ever existed in the 4 billion years are extinct. Extinction is the norm. But for the first time in those 4 billion years, one species that created the conditions for its own demise (that's us) recognises the possibility of extinction and has the tools to avoid a catastrophic end.

You know what we face. Human activity—burning fossil fuels, machines, agricultural practices, especially raising cattle, warfare—are altering the chemistry of the atmosphere that in turn is trapping heat on the planet. I first realised that we have to take climate change seriously when I came to your country. In 1988 I was a guest in Melbourne of the Commission for the Future, and at that time scientists showed me the evidence that they were gathering in climatology. And I went back to Canada saying this is no longer a slow-motion catastrophe, we've got to get going on it right away. Your leading scientists and the reality of life—drought, massive fires, reef degradation—show that you have a serious problem and that there are also solutions here for clean energy in abundance.

Australia should be leading the world. And I must say I've been so proud of South Australia, that Mike Rann set in motion a path towards a future of clean energy, you're at 40% renewable energy now, on the way to 50% and possibly 60%. South Australians should be boasting to the world about what you are doing here. I certainly intend to when I go home.

The failure of the federal governments of Canada and Australia to act in the face of the evidence and the enormous alternative opportunities to climate change is why many scientists and experts now declare the futility of simply eliminating the use of fossil fuels, and call for megaprojects like geo-engineering and the massive implementation of nuclear energy. It's crazy but we are at a desperate position.

Australia with vast deserts and sunlight Canadians would kill for, and you can't develop alternative solutions? Disgraceful! Japan, the most earthquake prone country on the planet brings nuclear plants to…what? To boil water. And this in a country that has boiling water in over 6,000 hot springs. We boast as a species that we are intelligent.

In Canada, First Nations, environmentalists, climatologists have now been labelled 'the forces of no' and 'eco-terrorists'. Of course climate is just one of the issues, there's a whole suite of ecological issues that are confronting us now. Oceans cover 70% of the planet's surface, and they are a mess. Overfishing, islands of plastic, dead zones from agricultural run-off, sea level rise by warming and expansion of water, and acidification from the dissolving of carbon dioxide in the ocean as carbonic acid.

80% of the forests on the land are gone. Hydrologic cycles are changing. We dread the disappearance of the monsoon reliability. Species are going extinct at a rate unparalleled since the last great extinction episode 65 million years ago. Toxic pollutants now have been poured into air, water and soil. I'm sorry, however well you live, every one of us here carries dozens of toxic chemicals because of what we've done to the rest of the planet.

We are species out of control. We are expanding our ecological footprint. The amount of air, water and land we require to live as we do is simply expanding. Climate change is just the most obviously pressing issue we confront now. But I have to say it has taken a hell of a long time before it's come to the level that it's at now.

The first international conference on climate was held in Toronto in 1988, and at that time the scientists were convinced the evidence was in, and were so alarmed by what they were seeing that they issued a call for a 20% reduction in greenhouse gas emissions in 15 years. That was the call, but we didn't take it seriously. And the record of political and corporate denial and monkeywrenching is why many scientists and experts despair and declare now openly that it's too late to turn things around.

When Sir Martin Rees, one of the eminent astronomers in Britain, was asked, 'What are the chances that there will be any human beings left by the year 2100?' His answer sent a chill up my spine: 50/50. James Lovelock, the inventor of the concept of Gaia, has written a book that declares 90% of humanity will be gone by the end of the century. And you all know Australia's eco-philosopher Clive Hamilton has written a book, Requiem for a Species. And guess what species it's a requiem for? It's for us. And now an American ecologist, Guy McPherson, is declaring human beings will be gone within decades in this century.

My response to all of that is why are you saying that it's too late? There's no point. Surely we're going to struggle and fight right to the end. Yes, it's urgent, and that's the message I get. But to say no, it's too late, that's ridiculous, that's simply too soul-destroying to hear that. But I think that the urgency is what we have to listen to. We have very little time to act. So I would suggest in your country and mine, do not offer your vote to a single candidate at any level of government unless they declare that climate change is an issue that they will devote a great deal of their lives to.

And it mustn't be a political football. It's not just the Green party that will say this, we must demand it of every candidate for political office. The signs are depressing, it's true, but I cling to hope, and that hope is based on more than just a Pollyanna-ish idea; ‘Oh, don't worry, good things will happen.’ My hope is based on the faith, one that love…and please, don't think I have suddenly become a dippy hippy…I believe that love is the driving force of our species, and it is love of our children and grandchildren that must override all of the economic, political and social pressures.

But more than that, we don't know enough to say it's too late. And let me give you an example of why I say that. The most prized species of salmon in the world is called the sockeye salmon. It's the salmon with the bright red flesh and lots of fat in it, it tastes great, especially when it's raw. Sockeye salmon are…the biggest run in the world is in British Columbia in the Fraser River. And ever since pre-contact levels of sockeye salmon, the runs were between 100- and 120 million fish each year, but after contact, when we damned rivers and had landslides that blocked the Fraser, we got a catastrophic decline. But the Fraser River in British Columbia has the largest sockeye run in the world, and we like to get 30–35 million animals coming back.

In 2009 we barely got a million sockeye returning to the Fraser. And I remember looking at Tara my wife and saying, that's it, there just isn't the biomass to get them to their spawning grounds, they're toast, they're gone. One year later in 2010 we got the biggest run of sockeye salmon in 100 years. I use that story not to show how stupid I am. Nobody knows what the hell happened. But nature shocked us with surprise. And I believe nature has got a lot more surprises up her sleeve. We just have to pull back and give her room and she will be far more generous than we deserve. That's my hope.

I was in the United States, I studied there for eight years, getting an education in the 1950s that we couldn't get in Canada at that time. And I was starting the last year in college in Massachusetts in 1957, and on October 4 the Soviet Union shocked the world by announcing they had launched Sputnik. And that was really a frightening time. The Soviet Union was a very powerful force at that time and every hour and a half we could hear the 'beep beep' of Sputnik thumbing its nose at us. The Americans immediately tried to launch their own satellites and every one blew up on the launch pad.

Meanwhile the Russians launched the first animal in space, a dog, Laika. The first man, Yuri Gagarin. The first team of cosmonauts, the first space walk, the first woman, Valentina Tereshkova. Americans didn't flinch. They didn't say, oh my God, they're so far ahead we can't afford to catch up, they said we've got to catch these guys. And it was a glorious time. Here I was, a Canadian living in the States, all you had to do was say 'I like science' and they threw money at us. It was glorious.

And in 1961 President Kennedy announced that Americans would get humans to the Moon and back within a decade. When he announced his plan he didn't have a clue how the hell he was going to do it. He just knew that they had to get to the Moon and beat the Russians. And look what happened. Not only are they the only country to land people on the Moon and get them back, but all of the unexpected benefits that have come out of making that commitment. Even today, 60 years later, when Nobel prizes are announced, believe me, Americans cop a huge number of those science Nobel prizes. Why? Because in 1958 Americans said we've got to beat the Russians in the space program. Every year NASA publishes a magazine called Spinoff. Hundreds of unanticipated spin-offs have come out of the space program, from laptop computers to GPS to cell phones to space blankets and ear thermometers, hundreds of these things have come simply by seizing the moment and the challenge and saying we've got to beat it. And I believe that's the moment we're at here. Climate change represents the ultimate crisis for our species that becomes a huge opportunity if we seize the moment and commit ourselves to beating it.

I returned to Canada in 1962 and had I studied for eight years in the States. I was a hotshot geneticist, I was going to make my name as a big scientist, and I got completely side-tracked by a woman. Not Tara, she is too young for that, but this has happened all through my life, usually with disastrous consequences, but in this case I've been ever grateful to her, and the great regret I have is that I never met her. But in 1962 a woman named Rachel Carson published a book called Silent Spring and it changed my life. We have to remember, in 1962 there wasn't a Department of the Environment in any government on Earth. The word 'environment' didn't mean in 1962 what it has come to mean today.

The discovery that DDT kills insects by Paul Müller won a Nobel Prize for him in 1947. We thought DDT pesticides were fantastic until Rachel Carson's book came out. And for me as a scientist what stunned me was the realisation that science can be very powerful, but we don't know enough to anticipate all of the unknown things in nature that we can't expect to be affected. When DDT began to be used on a wide scale, it was only when eagles in the United States began to disappear that scientists tracked it down and discovered a phenomenon called biomagnification. Up the food chain you concentrate DDT hundreds of thousands of times until you get to the shell glands of birds or the breasts of women. How could we have managed DDT properly when we only discovered biomagnification after eagles began to disappear? And that has happened over and over again.

When CFCs began to be used on a wide scale, we had no idea that high up in the atmosphere ultraviolet light would break chlorine free radicals off CFC that would scavenge ozone. When nuclear bombs were dropped over Japan we didn't know there was a phenomenon called radioactive fallout. And now we have such conceit we want to genetically engineer plants and animals for our use. We want to indeed engineer the planet with geo-engineering to deal with the issue of climate change. I believe it's a form of madness to have the hubris to think that we are capable of doing that.

For me, again as a scientist, the most profound message I got from Silent Spring was that in nature everything is connected to everything else. And I realised scientists look at things in bits and pieces, all on the assumption if we look at enough bits and pieces we will fit them back together to get a picture of the whole system. But we spray chemicals on farmers' fields to kill insects and end up discovering that fish and birds and human beings are affected. Everything is connected, and we can't determine all of those interconnections through science.

I just want to tell you a story that one of the programs that the David Suzuki Foundation undertook that I am so proud about was to try to illustrate this issue of inter-connectivity. One of the rarest ecosystems on the planet is called temperate rainforest, and in North America we have the largest temperate rainforest extending from Alaska down to the northern part of California, and it's that thin band pinched between the Pacific Ocean and the coastal mountain range, and it has the highest biomass, the weight of living things, of any ecosystem on Earth. And the reason for that is we've got big trees. But the dilemma for scientists was how can we have such big trees when the soil is nitrogen deficient? It rains a lot, that's why it's a rainforest. That rain washes nutrients, but especially nitrogen, out of the soil. So it was a real paradox for us. You've got these big trees and you've got not enough nitrogen in the soil to raise them. And it turned out the solution was the salmon.

You see, the salmon are born in thousands of rivers and creeks all up and down through the temperate rainforest, and they are born in fresh water. They go out to sea, there are five species of salmon that live, depending on the species, 2 to 5 years at sea, then they come back to spawn in the original rivers and waters where they were born.

Now, it turns out that almost all of the nitrogen you find on land is the normal isotope of nitrogen called nitrogen-14. But in the oceans there is a very large proportion…well, small, but still a very significant proportion of the nitrogen in the oceans is nitrogen-15. It's a slightly heavier atom isotope that we can detect the difference between N-15 and N-14. So the salmon go to sea for 2 to 5 years, they load up in nitrogen-15, and then they return to their spawning rivers and creeks by the tens of millions up and down the coast. So they are loaded with nitrogen now, and everyone celebrates. If you've ever gone to a spawning experience on the coast, you know the birds and the seals and the whales, everybody is making noise because now this mass of creatures is coming back. And they get to the river, and the major predators of the salmon are eagles, bears and wolves. So they will eat the salmon as they are coming up to spawn, and then of course they poop and pee nitrogen-15-loaded urine and faeces throughout the forest. So they are literally fertilising the forest.

Now, the bears are normally solitary animals, but during the salmon season they will fish in the same pool with literally dozens of others. But when they grab a salmon they take off into the forest up to 150 metres on either side of the river because they want to eat it by themselves. I mean, I understand that. They want to eat the best parts which, as you all know, are the brains, the belly and the eggs, and then they will dump the carcasses, lots more, they go back for another one. On average, a bear will take about 600 salmon in a season. So they are spreading the carcasses again through the forest. The carcasses left are eaten by ravens and salamanders and slugs. But the major exploiters of the carcasses are flies. So flies lay their eggs. Within a few days that carcass is a seething mass of maggots loading up with nitrogen-15 from the salmon, dropped to the forest floor over winter, and in the spring flies hatch by the trillions at the very time the birds from South America are coming through on their way to their nesting grounds in the Arctic. So, you see, those birds have been genetically programmed to come through at the very time those salmon, through the flies, are feeding them on their way to the Arctic.

If the salmon are not taken out of the river and sink to the bottom, within a week or so they are covered with a thick mat of fungus and bacteria, and the fungus and bacteria are eaten by copepods and insects and other invertebrates, so when the baby salmon emerge from the gravel four months later, the rivers are filled with nitrogen-15 containing invertebrates, so that the salmon can feast on their way down to the ocean. So in dying, the salmon prepare a feast for their offspring.

And then what we funded was scientists to go in and actually take the cores of trees in salmon bearing areas and non salmon bearing areas, and we showed that when you pull out the core and look at the fat rings, they are loaded with nitrogen-15. And the skinny rings when they've hardly grown, you find very little nitrogen-15. So the salmon are literally feeding the forest with their carcasses. So it's a magnificent story of the interconnection of the north and southern hemisphere and the oceans and land and the air.

Modern humans come along: oh, those indigenous people, they don't know anything, we're going to manage these resources. And so we say, well, we've got all these salmon there, that's the Minister of Fisheries and Oceans, for the commercial fishery. Oh, but then there are all those indigenous people, that's the Ministry of Indian Affairs. Oh, what about the sports fishermen? Well, that the Department of Tourism.

So we divide the salmon into three areas. The trees, that's the Minister of Forests. And the rivers, well, that's the Minister of Energy and the Minister of Agriculture and the Minister of Urban Affairs. And then we have all the rocks and the mountains, that's the Minister of Mining. And oh yeah, what about the eagles, the wolves and bears? That's the Ministry of the Environment. Now let's manage everything.

I mean, it's absolutely absurd because the way we look at the world has shattered it into pieces that have no connection to each other, and we ensure we will never manage those incredible systems. So that was Rachel Carson's great contribution, to me at least, was that everything is interconnected.

Impelled by Rachel Carson's book, I joined millions of people around the world in what we now see was a modern environmental movement. And the action, activity, was enormous. In only 10 years we got the United Nations forming UNEP, the United Nations Environment Program, calling its first international conference on the environment in Stockholm. And we began to get committees on the environment at every level of governments, from domestic, municipal, to the provincial, to the national level. And we've got laws to protect air, we've got laws to protect water, endangered species, and millions of hectares of land were set aside as parks and reserves.

In British Columbia, Tara and I were part of that huge movement, and we celebrated successes that we'd been involved in as well in our areas. There was a proposal to build a dam at Site C on the Peace River and we stopped it. Another proposal that Tara was very active in raising money to stop a dam to be built at Altamira on the Xingu River in Brazil, and we stopped that. We stopped the American proposal to bring oil supertankers off the north slopes of Alaska through British Columbian waters to be refined in Seattle. We stopped drilling proposals in the Arctic and in Hecate Strait.

And those are great victories. But now 30 to 35 years later, guess what? We are fighting the same battles all over again. What we thought were victories were not victories. And as environmentalists we failed fundamentally to use those battles as a means of informing people and educating people to see our relationship with the world in a different way. We have to shift the paradigm.

Years ago I visited a small village in the Andes Mountains in Brazil, and I learned that children in the village are taught that that mountain is an apu. In their language, apu means God. And as long as that apu casts its shadow on their village, it will determine the destiny of everyone in that village. Now, imagine how those kids when they grow up will treat that mountain, compared to a Canadian kid growing up in the Rockies who is taught all their lives those mountains are full of gold and silver. You see, the way we see the world and our place in it shapes and determines the way we will act towards it. We humans are predators. We have to eat plants and animals in order to live. We alter ecosystems in order to serve our needs, thinking of the burning program that you have with your Indigenous people in Australia. We modify habitats so that we can survive in them. But the way that we do it and the sense of values that we hold determine how we are going to actually behave.

When a forest is a sacred grove, then lumber and pulp will be taken with great reverence. When the river is the circulatory system of the land, we will extract energy, fresh water and fish very carefully. When soil is seen as a complex community of life, we will no longer treat it just as dirt. When another species is our biological kin, sharing with us thousands of genes identical with each other, then it seems to me we treat our kin with greater gratitude and love. When a house is our home, that's very different from a piece of real estate or a starter house or a tear-down. When the planet is our mother, then who would treat our biological mother the way we treat the Earth? The way we see the world shapes and constrains the way that we act towards it.

Three years ago I received a call…you know that the big battle in Canada right now is over the future of the tar sands in Alberta. Three years ago I got a call from the CEO of one of the largest companies in the Alberta tar sands. I was shocked. But he said would it be possible for me to come and talk to you. I said absolutely, I would be thrilled. I said I'm not into fighting, I'm no longer fighting because we can't afford losers. We've all got to be winners.

So he came down to my office the next morning and he came to the door and I thanked him profusely, I told him what an honour it was to have him come to me, and I said, but please do me one favour, before you walk in the door, please leave your identity as a CEO of an oil company outside the door. I want to meet you as a human being to human being, because I don't want to talk about the tar sands or its future, I don't want to talk about the economy until you and I as human beings agree on what the most fundamental needs are for human beings on the planet.

I'll tell you, he was not very happy about leaving his identity. But to his credit, he walked through the door. So I took him to my office, I sat him down, I said, I know how difficult this is for you. But let me tell you where I'm starting from. I said, our world…you and I live in a world that is defined, that is shaped and constrained by laws of nature. Those are laws that we can't do anything about, we have to live within them.

I can see right away I was in danger of losing him. I said, you know, in physics they tell us you can't build a rocket that will travel faster than the speed of light. And nobody denies that or gets mad about it, that's a limit on what we can do. The laws of gravity tell us you can't build an antigravity machine here on Earth, we accept that. And the first and second laws of thermodynamics tell us you can't build a perpetual motion machine. And, except for a few hucksters, most of us agree that that is true and we live with that.

In chemistry it's the same. The atomic properties of the elements, diffusion constants and reaction rates all inform us of the kind of reactions that we can perform in a test tube and the types of molecules that we can or cannot synthesise, and we live with that, those are dictated by what nature, what chemistry tells us. And in biology it's the same. Every species has a maximum number that can live indefinitely that are defined by the carrying capacity of ecosystems or habitats. And you exceed that number, the ability of an ecosystem or habitat to support more, and that population will crash.

Humans, because of our brains, we are not confined to a specific habitat or ecosystem, we can live from the Arctic to the deserts to temperate and tropical rainforest to wetlands to mountains…I mean, we are a very adaptive organism. But our home is still the biosphere, the zone of air, water and land where all life exists, that's our home, and it's finite, it can grow. So guess what? It has a carrying capacity for our species. Of course the number of our species that can be supported is based on two things, that is our numbers but also our consumption per capita. When you add that together, Australia, Canada, the US, Europe are very overpopulated because of our high consumption. But most scientists I talk to agree, we've exceeded the carrying capacity of the biosphere for our species. Man, do people get mad at me when I say that! How dare you say that! Look at the beautiful city of Adelaide, look how we're living, we're healthier, we're happier. Yeah, we're creating the illusion of great success by using up what should be the rightful legacy of our children and grandchildren. Ask any elder.

And biology dictates that you and I are animals. I gave a talk in Austin Texas many years ago, and it was a big audience with lots of children in the front and I said, now kids, if you remember one thing from my lecture, remember we are animals. Man, did their parents get pissed off at me! 'Don't call my daughter an animal, we're human beings.' And my response was, listen madam, if you don't think we're animals…are you a plant? We are animals, and as animals, biology dictates our fundamental needs.

And so I said to Mr CEO, I said what do you think is the most important thing every human being on Earth needs? And I could see he was thinking money, a job. I said, look, if you don't have a breath of air for three minutes, you're dead. If you have to breathe polluted air, you're sick. So can you as a human being agree with me that one of the highest priorities of our species is to protect clean air? And then I said, you and I are 70% water by weight, we're just a big blob of water with enough thickener added we don't dribble away on the floor. But, you know, our bodies leak water, right, it comes out of our skin and our eyes and our mouth and our crotch and we lose water all the time. I said, Mr CEO, if you don't have water for 4 to 6 days, you're dead. If you have to drink contaminated water, you're sick. So can you agree with me that clean water, like clean air, has got to be the highest priority of our species?

And then I said, you and I could go maybe 4 to 6 weeks without food but then we would die. If we have to eat contaminated food we get sick, and most of our food is coming from the Earth. So will you agree with me that clean food and clean soil has got to be up there with clean air and clean water? And then I said, all of the energy in your body is provided to us through photosynthesis. That energy is captured by plants, converted into chemical energy and we get it by eating the plants or the animals that eat the plants, we store that energy in our bodies, and when we need it, when we have to move or whatever, we burn those molecules of energy and liberate the energy of the Sun back into our bodies. So photosynthesis should be up there with clean water, clean air and clean soil.

And finally I said, Mr CEO, the miraculous aspect for me of life on this Earth is that those four things that indigenous people call the four sacred elements—earth, air, fire and water—those things are cleansed, replenished, created by life. It's the web of living things that give us the four sacred elements. Before there were plants in the oceans and on land, the air was absolutely toxic for animals like us. Oxygen is a very reactive element. When you liberate oxygen it immediately oxidises things, it rusts iron, and it disappears. It was plants that converted carbon dioxide into oxygen and over millions of years, until the present time, it's all of the green things in the ocean and on land that are keeping our atmosphere at 19% oxygen.

And in Vancouver we get all of our water from three watersheds surrounded by old-growth rainforest, the tree roots, the other plant roots, soil, fungi and bacteria filter that water so that we can drink it. And it's life that creates the very soil that we grow our food on. All of our food, as you well know, was once alive. But in order to grow our food in soil, as anyone who read The Martian or saw the movie The Martian when Matt Damon gets stranded on Mars and he has to stretch his potatoes out to four years instead of one so he can be rescued, there is lots of sand and gravel and dust on Mars, there is absolutely no soil. And so in order to grow his potatoes he had to dig a hole in the sand, poop in it and then get more life. We need soil and that is created by life itself. And people that talk about terraforming the planet…my god! Anyway, don't let me get into that, it's the nuttiest idea I've ever heard.

Anyway, so those are the things that to me define our most fundamental needs that should be the foundation of the way we create an economy and get our jobs and live. I said, Mr CEO, earth, air, fire and water and other living things that are our relatives, can you agree with me, these are the basis on which we live and flourish? Will you shake hands with me and agree that we both believe that that must be protected before anything else? And I'm sorry to say that he couldn't bring himself to shake my hand. He left and I never heard from him again.

Now, it was an unfair situation, I sprung it on him. He didn't know that's what he was in for, and it was unfair because he had come down as a CEO of a company to negotiate with me. If he were to go back to his shareholders and say, 'Well, I had a discussion with Suzuki, I have to agree, anything that we do must not compromise the air, the water, the soil, photosynthesis or biodiversity,' he'd be fired in a flash. And so the system that we've created can't accept that as the foundation on which it operates.

There are other things I told the CEO. There are other things we call boundaries. We draw borders around our property and, boy, people will kill and die to protect those borders. We draw boundaries around our cities and our provinces, our states and our countries. We go to war and murder and kill to protect those boundaries. Those boundaries are absolutely meaningless to nature. I mean, you just had to see it at the COP meetings in Paris. 196 countries dealing with the atmosphere that belongs to no one through the lenses of 196 political boundaries. It's crazy because you can't do it.

And then there are other things—capitalism, communism, the economy, markets, corporations—these are not forces or laws of nature, we invented them, for Gods sake. But if you listen to the news about the economy every morning, my God, you'd swear they were a thing out there. Oh, the market is not looking too healthy today. And you think of this poor market sitting there with an ice pack on its head going, 'I feel really lousy today.' What the hell! We invented the damn thing! And yet we are constantly trying to shoehorn nature to fit our economic or corporate agenda. It can't work that way. We have to do it the other way and shoehorn our inventions into nature's needs.

So this is a challenge, and I'd like to end it by suggesting something the David Suzuki Foundation did for the Earth Summit meetings in 1992, to provide perhaps a different perspective on our place in nature. We call it a declaration of interdependence.

This we know: We are the Earth, through the plants and animals that nourish us. We are the rains and the oceans that flow through our veins. We are the breath of the forests of the land and the plants of the sea. We are human animals, related to all other life as descendants of that first born cell. We share with these kin a common history, written in our genes. We share a common present, filled with uncertainty. And we share a common future, as yet untold. We humans are but one of 30 million species weaving the thin layer of life enveloping the world. The stability of communities of living things depends upon this diversity. Linked in that web, we are interconnected; using, cleansing, sharing, and replenishing the fundamental elements of life. Our home, planet Earth, is finite, all life shares its resources and the energy from the Sun, and therefore has limits to growth. For the first time we have touched those limits. When we compromise the air, the water, the soil, and the variety of life, we steal from the endless future to serve the fleeting present.

This we believe: Humans have become so numerous and our tools so powerful that we have driven fellow creatures to extinction, dammed the great rivers, torn down ancient forests, poisoned the earth, rain, and wind, and ripped holes in the sky. Our science has brought pain as well as joy; our comfort is paid for by the suffering of millions. We are learning from our mistakes, we are mourning our vanished kin, and we now build a new politics of hope. We respect and uphold the absolute need for clean air, water, and soil. We see that economic activities that benefit the few while shrinking the inheritance of many are wrong. And since environmental degradation erodes biological capital forever, full ecological and social cost must enter all equations of development. We are one brief generation in the long march of time; the future is not ours to erase. So where knowledge is limited, we will remember all those who will walk after us, and err on the side of caution.

This we resolve: All this that we know and believe must now become the foundation of the way we live. At this turning point in our relationship with the Earth, we work for an evolution: from dominance to partnership, from fragmentation to connection, from insecurity to interdependence.

Thank you.

Robyn Williams: Sustained applause for David Suzuki, aged 80, still stirring them up at WOMADelaide in March. And there will be another WOMADelaide Festival in March 2017. And The Science Show returns there next week with David Suzuki and friends, including Indira Naidoo, talking about love of country.

Indira Naidoo: My work has led me very much to believe that it is all about love. You really can't get people to care about the environment unless they love it. And it is quite a difficult proposition for people, like most of us in Australia, who live in cities, we are quite disconnected from nature, we are disconnected from our food, which is most people's connection to nature. So for my journey, which has been a slightly unusual one I guess, coming from broadcasting and journalism to now very much a passionate advocate for addressing climate change and the environment, really has come from a place of love.

And it wasn't until I went back to my apartment in Potts Point in inner Sydney and I was standing on my balcony and looking out on all the bare concrete and tarmac around Potts Point, which is the point of greatest population density in Australia, 12,000 people per square kilometre live in my suburb, and I realised that I was actually at the heart of the problem and I was at the heart of the disconnection.

I was at a farmers market that week and a farmer gave me the most amazing tasting cherry tomato, Robyn, to try, and it was the sweetest most delicious tomato I had ever had. And when I went back and said to him, 'Where did this come from, who grew it?' He said, 'I grew it myself. It's an heirloom variety. It doesn't store or transport well, so you have to eat it after it's been picked.' And I said, 'Well, how can I get more of them?' And he said, 'Well, buy some of my tomatoes, save some of the seeds, plant it in a pot and you can have these tomatoes whenever you want.' I am still reaping tomatoes from that seed nine years later. Not only did I grow tomatoes, I grew 43 different herbs and vegetables on that small balcony. And in one year I grew 70 kilos of produce.

Robyn Williams: Indira Naidoo on The Science Show next week. And all the very best for Christmas from me, Robyn Williams, and producer David Fisher. And we end in the traditional way.

John Clarke: We three Kings of Orient are,

One on a tractor, one in a car,

One on a scooter tooting his hooter

Following yonder star.

Oh, star of wonder, star of light,

Star of beauty, she'll be right,

Star of glory, that's the story,

Following yonder star.