Humans threaten future of the earth

It is a stark warning for the future of the planet - human activity is threatening natural life on a disastrous scale.

More than half of the natural processes needed for life on earth are close to collapse, a huge new study of the planet's health has found. New disease strains, global warming and even algae could tip the earth into disaster.

"At the heart of this assessment is a stark warning," said the 45-member board of the Millennium Ecosystem Assessment, a ?13 million study involving more than 1,300 researchers from 95 countries. "Human activity is putting such strain on the natural functions of earth that the ability of the planet's ecosystems to sustain future generations can no longer be taken for granted."

Ten to 30 per cent of mammal, bird and amphibian species are threatened with extinction according to the assessment, the biggest review of the planet's life-support systems.

"This has resulted in a substantial and largely irreversible loss in the diversity of life on earth. More land was changed to cropland since 1945, for instance, than in the 18th and 19th centuries combined. The harmful consequences of this degradation could grow significantly worse in the next 50 years," it said.

In 100 years, global warming, widely blamed on cars, factories and power plants, might take over as the main source of damage.

"The assessment shows the future is really in our own hands. We can reverse the degradation of many ecosystem services over the next 50 years," said Dr Walt Reid, the report's lead author.

UN secretary-general Kofi Annan said: "Biodiversity, the very basis for life on earth, is declining at an alarming rate."