The sixth mass extinction to affect life on Earth.

All the creatures we share the Earth with are important in some way, however unprepossessing or insignificant they may appear. They and we are all part of the web of life.

From the dawn of time, extinction has usually progressed at what scientists call a natural or background rate. Today the tempo is far faster.

Many scientists believe this is the sixth great wave - the sixth mass extinction to affect life on Earth.

We were not here for any of the previous mass extinctions, but this time our sheer preponderance is driving the slide to oblivion.

We have more than doubled our numbers in half a century, and that is the most obvious reason why there is less room for any other species.

We are taking their living room to grow our food, their food to feed ourselves. We are exploiting them, trading in them, squeezing them to the margins of existence - and beyond.

Often the choice is hard: conserve a species or feed a community, tourists' dollars or turtles' nests.

In 2003 the World Conservation Union's Red List said more than 12,000 species (out of 40,000 assessed) faced some extinction risk, including:

• one bird in eight
• 13% of the world's flowering plants
• a quarter of all mammals.

That gives you a ballpark figure. Science has described 1.75 million species, some experts estimate that there may be 13 or 14 million in the world in total - but until they are catalogued, nobody knows.

Our pillage of the natural world has been likened to burning down the medieval libraries of Europe, before we had even bothered to catalogue their contents.

Many species keep us alive, purifying water, fixing nitrogen, recycling nutrients and waste, and pollinating crops.

Plants and bacteria carry out photosynthesis, which produces the oxygen we breathe. Trees absorb carbon dioxide, the main greenhouse gas given off by human activities.

Pandas and microbes

Some years ago, when the global annual gross product was about $18 trillion, US researchers calculated the value of the goods and services provided by the Earth to the world economy: $33 trillion.

Tropical cone snails contain toxins which show promise for treating some forms of cancer and heart irregularities. One toxin may be a thousand times more potent than morphine for pain relief.

But millions of cone snails are now killed annually for their shells, and their habitats are under pressure.

That is the argument for utility. But the creatures we can see, and those we can use directly, are just the start of the story.

Lord May, president of the Royal Society (the UK's national academy of sciences), has said: "Most conservation effort goes into birds and mammals - creatures like the panda, a dim, dead-end animal that was probably on the way out anyway.

"Yet arguably it's the little things that run the world, things like soil microbes. They're the least-known species of all."

Complex network

And we continue to tug at the loose threads of the web of life, thinking we can split it into its separate parts.

Brazil nuts are a lucrative harvest in the Amazon. But an experiment to produce them in plantations failed, because the trees bear a good crop in the forest, but are barren in isolation.

We are not removing individual species from the Amazon: we are destroying the entire forest.

US researchers estimate that by 2020 less than 5% of it will remain in pristine condition.

Within 15 years, about a fifth of central Africa's forests will have gone, by one estimate. And the forests of Indonesia are in headlong retreat.

Some species are bucking the trend towards extinction. In 1953 there were about 2.5bn people: today there are 6bn.

Ensuring other species keep their living space is not sentimental. It is the only way we shall survive.

Extinction, whatever Steven Spielberg says, really is for ever.

The web is unravelling...

Planet Under Pressure -- BBC News

World fells trees at ‘alarming’ rate, experts say

Scientists say global deforestation will feed global warming

ABO EBAM, Nigeria - In the gloomy shade deep in Africa's rain forest, the noontime silence was pierced by the whine of a far-off chain saw. It was the sound of destruction, echoed from wood to wood, continent to continent, in the tropical belt that circles the globe.

From Brazil to central Africa to once-lush islands in Asia's archipelagos, human encroachment is shrinking the world's rain forests.

The alarm was sounded decades ago by environmentalists — and was little heeded. The picture, meanwhile, has changed: Africa is now a leader in destructiveness. The numbers have changed: U.N. specialists estimate 60 acres of tropical forest are felled worldwide every minute, up from 50 a generation back. And the fears have changed.

Experts still warn of extinction of animal and plant life, of the loss of forest peoples' livelihoods, of soil erosion and other damage. But scientists today worry urgently about something else: the fateful feedback link of trees and climate.

Global warming is expected to dry up and kill off vast tracts of rain forest, and dying forests will feed global warming.

"If we lose forests, we lose the fight against climate change," declared more than 300 scientists, conservation groups, religious leaders and others in an appeal for action at December's climate conference in Bali, Indonesia.

The burning or rotting of trees that comes with deforestation — at the hands of ranchers, farmers, timbermen — sends more heat-trapping carbon dioxide into the atmosphere than all the world's planes, trains, trucks and automobiles. Forest destruction accounts for about 20 percent of manmade emissions, second only to burning of fossil fuels for electricity and heat. Conversely, healthy forests absorb carbon dioxide and store carbon.

"The stakes are so dire that if we don't start turning this around in the next 10 years, the extinction crisis and the climate crisis will begin to spiral out of control," said Roman Paul Czebiniak, a forest expert with Greenpeace International. "It's a very big deal."

The December U.N. session in Bali may have been a turning point, endorsing negotiations in which nations may fashion the first global financial plan for compensating developing countries for preserving their forests.

The latest data from the Food and Agriculture Organization (FAO) helped spur delegates to action.

"Deforestation continues at an alarming rate of about 13 million hectares (32 million acres) a year," the U.N. body said in its latest "State of the World's Forests" report.

Because northern forests remain essentially stable, that means 50,000 square miles of tropical forest are being cleared every 12 months _ equivalent to one Mississippi or more than half a Britain. The lumber and fuelwood removed in the tropics alone would fill more than 1,000 Empire State Buildings, FAO figures show.

Although South America loses slightly more acreage than Africa, the rate of loss is higher here _ almost 1 percent of African forests gone each year. In 2000-2005, the continent lost 10 million acres a year, including big chunks of forest in Sudan, Zambia and Tanzania, up from 9 million a decade earlier, the FAO reports.

Across the tropics the causes can be starkly different.

The Amazon and other South American forests are usually burned for cattle grazing or industrial-scale soybean farming. In Indonesia and elsewhere in southeast Asia, island forests are being cut or burned to make way for giant plantations of palm, whose oil is used in food processing, cosmetics and other products.

In Africa, by contrast, it's individuals hacking out plots for small-scale farming.

Here in Nigeria's southeastern Cross Rivers State, home to one of the largest remaining tropical forests in Africa, people from surrounding villages of huts and cement-block homes go to the forest each day to work their pineapple and cocoa farms. They see no other way of earning money to feed their families.

"The developed countries want us to keep the forests, since the air we breathe is for all of us, rich countries and poor countries," said Ogar Assam Effa, 54, a tree plantation director and member of the state conservation board.

"But we breathe the air, and our bellies are empty. Can air give you protein? Can air give you carbohydrates?" he asked. "It would be easy to convince people to stop clearing the forest if there was an alternative."

The state, which long ago banned industrial logging, is trying to offer alternatives.

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