By the time you finish this article, world population will have grown by 3,000 and a species will have disappeared. Paul Cullen examines the subject of next week's Earth summit
She is ancient - and she feels it. She is going thin on top, has put on an extra belt around the middle and her nerves are jangling. She has never been more filled with life, yet, slowly but surely, she is dying. Welcome to Planet Earth.
Scientists believe our planet came into being about 4,500 million years ago, and for much of the time since nothing much happened. Continents were formed, species evolved and ice ages came and went. It was all rather sedate. Then humans arrived.
Since then, the Earth has embarked on a rollercoaster ride - at ever-increasing speeds. Man's ability to harvest food, make tools, exploit mineral resources and wage war has ensured his domination of the planet. But his very success has sown the seeds for self-destruction, according to the pessimists.
The quickening pace of what we term "human progress" is evident from the ever-shortening time it takes to reach each successive population milestone. It took all of recorded history until 1804 for the world's population to reach one billion, and another 123 years to reach two billion in 1927. The third billion was added in 33 years, the fourth in 14 years and the fifth in 13 years, with the six-billion mark being passed only 12 years after this in 1999.
Just where this journey is leading us will exercise the minds of the thousands of politicians, diplomats and environmental activists attending next week's World Summit on Sustainable Development in South Africa.
Are we on the road to disaster or will human inventiveness save the day? Do we even know where we're headed? And are we moving so fast - just like the aircraft on September 11th - that there's little we can do anyway?
Well, is the glass half-empty or half-full? The world is wealthier than ever, yet poverty is at record levels. We recycle more yet we still create more rubbish than ever before. Wind- and solar-power generation have grown in popularity, but more energy than ever is being created through coal- and gas-fired and nuclear generation. We have conquered diseases only to see new epidemics spawn and spread.
Today, the world has a population of about 6.1 billion - by the time you finish reading this article it will have grown by about 3,000. About half this number live on less than $2 a day; 1.2 billion live on less than $1 a day.
In the past 30 years, the temperature of the world has risen by about one degree centigrade. It mightn't seem much but the consequences are dramatic.
Sea levels are rising and some predict they will rise by almost a metre during this century. Glaciers are melting and ice masses are retreating. Africa's highest mountain, Kilimanjaro, has lost one-third of its ice field in the past decade; within 15 years, the field should have disappeared completely. The Arctic ice sheet has thinned by 42 per cent in the past 35 years.
Meanwhile, animal and plant species are disappearing at a rate the Earth hasn't seen for 65 million years. One species will have disappeared in the time you spend reading this article.
Some 40 per cent of agricultural soils are degraded. Half the planet's forests have disappeared and half its wetlands have been drained or filled in. Two billion people live in countries that are experiencing water shortages. More than one billion people are farming fragile lands that cannot sustain them.
Today, a giant pollution cloud hovers over much of Asia, the result of massive burning of fossil fuels. HIV/AIDS sweeps through Africa, killing the equivalent of 15 plane-loads of people every day.
In 1970, the UN started celebrating Earth Day each year on April 22nd. Since then, the world's population has doubled, mostly in the countries at temperate zones around the Earth's middle. So has the consumption of fish, and the amount of oil extracted from the Earth's crust. The number of cars in the world has swelled from 246 million to almost 800 million. Air traffic increased by a factor of six.
Our mass gobbling of finite resources has achieved some results. We live a few years longer. Massive wealth has been generated, although not shared. We have the Internet, mobile phones and video-recorders.
But these are gains for humans, not for the Earth. And humans can't live without the Earth. Even a conservative organisation such as the World Bank is prophesying a nightmarish scenario if we carry on living as we are. This week it wondered aloud whether consumption would become the modern equivalent of the Cold War arms race, with people in the developing world demanding the same levels of consumption enjoyed by the West. It estimates that half the world's population will face "severe water shortages" by 2025.
Yet over-consumption - rather than over-population - lies at the heart of the Earth's problems. The West, with one-quarter of world population, consumes 80 per cent of energy.
The US alone, with 6 per cent of population, eats up 30 per cent of resources. No one wants to be poor but we can't all be rich - or at least not at present rates of consumption.
Optimism is often a rare commodity in environmental matters, but it isn't all bad news. When the world pulls together and acts quickly, it can achieve results. The banning of CFCs in the 1980s seems to have stemmed the damage that was being done to the ozone layer.
Here at home, the banning of smoky coal and the levy imposed on plastic bags have been spectacular successes.
This is the challenge facing the Johannesburg summit. The omens aren't good, particularly since the US walked away from the Kyoto Protocol on CO2 a few years ago.
Perhaps the best argument against excessive gloominess is previous experience. Time and again, man has muddled through by coming up with ingenious solutions to seemingly insurmountable problems. From Malthus on, generations of doomsayers have been confounded by man's ability to increase productivity, combat disease and tap into new sources of energy.
It may be, therefore, that rumours of the Earth's imminent demise have been greatly exaggerated. For the sake of all of us, we must hope so.