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As websites go, World Clock - created by media group Poodwaddle - is a compelling piece of work.
Click on it and a colour chart displays our planet's vital signs: human birth rates, death rates, disease levels and a host of other measurements.
The top line is the most dramatic, however. It shows that Earth is now inhabited by more than 6,700,000,000 people and that number continues to rise at a staggering rate.
Watch the site and its whirling digits. After a minute the population figure rises by 145, an increase of more than two people per second.
Click elsewhere and other startling statistics flash before the eye. In those same 60 seconds, 52,000 tonnes of carbon dioxide are pumped into the atmosphere; around 25 hectares of rainforest are lost; while encroaching deserts conquer a further 10 hectares of the Earth's surface.
Our ecological woes are piling up before our eyes - and there is no doubt among many politicians, campaigners, environmentalists and scientists as to their cause: humanity's swelling numbers.
Use of oil, land and water is rising dramatically because numbers of people are rising dramatically. And according to statisticians, this trend will continue for another 40 years until - around 2050 - the world's population will finally reach a plateau of nine billion people, an increase of more than a third on its current level.
Our world is going to be jam-packed.
A population the size of Germany's is being added to the planet each year, with the equivalent of one new city added every day.
Australia's population now stands at 21.5 million and by 2050 is expected to reach around 33 million, an increase of more than 50 per cent, and one - in percentage terms - that will far outstrip the world's average population rise.
Today there is one birth every one minute and 51 seconds in Australia compared with one death every three minutes and 48 seconds, says the Australian Bureau of Statistics.
There is also a net gain to the population of one international migrant every two minutes and 58 seconds, which adds up to an overall increase of one person every one minute and 37 seconds.
Hence that swell in numbers, which will continue on for several more decades until they reach that whopping figure of 33 million in 2050 (though less conservative estimates put forward figures as high as 42.5 million).
Natural resources hoovered
The question is: can Australia take this population jump without major social upheaval?
Indeed, can the planet support nine billion humans?
After all, we are not some species of beetle for which a scrap of foliage is a square meal. We are Homo sapiens, beasts that requires huge amounts of energy a day and which have already transformed much of the planet to ensure we are supplied with sustenance.
We have turned most of Europe's great forests into farmland, slaughtered millions of American bison in a few decades, and are hoovering up all the planet's great fishing grounds.
Today, humans appropriate 40 per cent of the planet's plant matter and that figure is destined to rise substantially - with grim consequences for the rest of the plant and animal kingdoms.
Tasmanian tigers, Bali tigers, passenger pigeons and dodos have already paid the ultimate price; red wolves, Florida panthers and Asiatic lions are set to follow suit.
Famous biologist Edward O. Wilson from Harvard University in Cambridge, Massachusetts, estimates that at current rates of human disruption, half of all species now living on Earth will be extinct in 100 years as human populations continue to swell.
According to a poll by the American Museum of Natural History, this view is backed by biologists, who say they now believe the world is in the middle of a mass extinction event triggered by swelling human numbers.
Nobel prize-winning chemist, Paul Crutzen has even called the current geological era the "anthropocene", reflecting our influence over the planet.
Homo sapiens has a lot to answer for, in short.
It could be worse
Not everyone despairs. It could have been an awful lot worse, says Peter McDonald, director of the Australian Demographic and Social Research Institute in Canberra.
He points out that in the '60s, statisticians were confidently forecasting there would be around 16 billion people on our planet by 2050.
"Now we anticipate there will only be nine billion after which numbers will start to slide back slowly. In other words, over the past 40 years, we have reduced the expected world population by seven billion - mainly by implementing family planning programs in the Third World. I consider that a success."
However, even if the experts had unfettered ability to implement family planning programs, humans will still reproduce.
The planet's population is destined to reach just fewer than 9.2 billion by 2050, assuming fertility starts to move towards 1.85 children per woman, according to the UN's World Population Prospects.
The crucial question is: what kind of planet will human beings then be living on? And closer, to home: what kind of nation will Australia be with 33 million inhabitants?
The answers to both questions are profoundly worrying, says Clive Hamilton, former head of the Australia Institute and now professor of public ethics at the Centre for Applied Philosophy and Public Ethics.
"Growth of emissions of greenhouse gases is intimately linked with population growth," he says. "Yet no one seems to want to talk about it. You get shouted down if you raise the subject."
There is a simple limit to what Australia can take in terms of population growth, adds Hamilton.
"People like to depict this country as a big empty nation but the only part that can support large numbers of people is that strip of land down the east coast and it is already suffering severe environmental degradation because of the weight of human numbers living there."
Then there is the question of climate change.
A carbon emission limit will one day be placed on Australia, as it will be on all nations, says Hamilton.
"It is inevitable," he states.
But with a vastly inflated population, it will be more difficult for Australia to meet its carbon emission obligations.
"The more people we have, the bigger the sacrifice each person will have to make to their lifestyles," he points out.
A key move, says Hamilton, will be to cut back on Australia's immigration, which reached 180,000 individuals in 2005-2006.
"I am liberal, but there is only so much the country can take," he says.
Soberingly, Australia's problems are modest compared with those now facing countries in Africa and in parts of the Indian subcontinent, where population rises and the impact of climate change will be greatest.
For one thing, there is no chance that those nations will ever meet their desire to have a high-consumption lifestyle like the one enjoyed by the developed world, says American anthropologist Jared Diamond.
"We often promise developing countries that if they will only adopt good policies - for example institute honest government and a free-market economy - they too will be able to enjoy a First World lifestyle," he says.
"This promise is impossible - a cruel hoax: we are having difficulty supporting a First World lifestyle even now for only one billion people."
And in a world where there could be seven or eight billion people in developing nations, there is no chance there will be enough water, energy, metal, medicine or land for them to escape grinding poverty.
Clive Hamilton is even more pessimistic. "I cannot see any way to avoid the fact that there are bound to be continent-wide famines on a very large scale in Africa and Asia over the next few decades," he states.
Such views echo those of other influential doomsayers, including biologist Paul Ehrlich at Stanford University in the San Francisco Bay Area, US.
"We have grown in number to the point where our presence is perceptibly disabling the planet like a disease," he says.
Plague, pestilence and widespread starvation will be the inevitable consequences, he adds.
It's apocalyptic stuff, although past alarms, in particular those sounded by Ehrlich, have not stood the test of time.
"In the 1970s the world will undergo famines...hundreds of millions of people (including Americans) are going to starve to death," he wrote in the '60s.
"I would take even money that England will not exist in the year 2000."
Not surprisingly, many critics have pounced on these prognostications and ridiculed them.
For their part, Ehrlich and others, including leading environmentalist James Lovelock, retort that we have simply been lucky until now.
Technological innovation - such as the rise of big agribusiness in the '70s and '80s - has staved off disaster.
Armageddon has only been postponed.
The end of man?
Some experts now believe little can be done; others think there is still room for hope.
For Les Knight, however, there is only solution: an end to humanity.
The only solution, Knight says, is to eradicate Homo sapiens, not through violent means but merely by deciding not to reproduce.
Without billions of protein-hungry, top-of-the-food-chain carnivores devouring the planet's resources, other creatures would have a chance.
Hence his establishment in the US of the Voluntary Human Extinction Movement.
"We are the humanitarian alternative to human disasters," says Knight. "Each time a child is prevented then the planet gets another chance to breath."
Knight spreads his message via the Internet and claims tens of thousands of followers.
Dubbed 'eco-sexuals' by the US press, these voluntary extinction supporters follow the movement's simple creed: "Live long and die out".
It is amusing but not that serious an option for humanity.
It is not in any species' nature to seek its own extinction.
Nevertheless, Knight's ideas are provocative and do have resonance.
"As numbers drop, the last humans will benefit particularly," he says. "They will experience our world as it should be enjoyed - without billions of people on it."