Earth's ecosystems face 'large-scale collapse'

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Earth's ecosystems face 'large-scale collapse'Lewis Smith

October 25, 2006, The Times

 

EARTH'S natural resources are being used 25 per cent faster than the planet can renew them, analysis by conservation group WWF indicates.

Measurements of crop yields, carbon dioxide emissions, fishing and the use of forests suggest that mankind's ecological footprint is too big to be sustained.

Since 1961, it has more than tripled in size and, for the past 20 years, mankind has been living beyond its ecological means, a WWF report says.

It is the equivalent, in banking terms, of living off capital rather than interest.

Using UN projections of the growth of the human population and economies, the report predicts that by the middle of the century "large-scale ecosystem collapse" is likely.

The world's average footprint is calculated to be 2.2ha per capita, but only 1.8ha of each person's consumption can be regenerated by the planet each year.

Carbon dioxide emissions are the biggest single factor within the footprint, accounting for up to 48 per cent of man's impact on the globe, according to the WWF Living Planet Report.

The speed at which resources are used is destroying biodiversity at an unprecedented rate. By tracking 1313 species of vertebrates from around the world, the report indicated a 30 per cent slump in wildlife since 1970.

Tropical species, including mammals, reptiles and birds, were the worst hit of the 695 land-based animals monitored. They declined by an average of 55 per cent, while the populations of temperate creatures have, overall, remained stable since 1970.

Marine species declined by an average of 25 per cent in the Pacific, Atlantic, Indian and Southern oceans. The index monitored 274 species and there was particular concern about the loss of cod, tuna and turtles.

Late last century, the land habitats that vanished fastest were tropical grassland, flooded grasslands and savannas, and tropical dry forests.

Mangroves were highlighted as the most endangered habitat, with more than a third being lost to developments between 1990 and 2000, twice the rate at which tropical forests were being destroyed.

Jonathan Loh, of the Zoological Society of London, one of the report's authors, said: "The Living Planet Index is a stark indication of the rapid and ongoing loss of biodiversity worldwide. Populations of species in terrestrial, marine and freshwater ecosystems have declined by more than 30per cent since 1970, a rate that is unprecedented in human history."

The ecological footprint is designed to measure the extent of human demand on the land and seas, and the report concludes that, for the past two decades, people have been turning resources into waste faster than the planet can turn waste back into plants and creatures. "Humanity is no longer living off nature's interest but drawing down its capital," the authors say.

They say a 50 per cent reduction in carbon dioxide emissions and fish catches would make it possible to close the gap between resource use and replacement by 2080.

Among the animals to have suffered most is the saiga antelope, whose numbers have dropped by 90 per cent in the past decade because of hunting in Mongolia. Wildebeest have declined by 20 per cent in the past 30 years because of encroachments on their migration routes by farmers.

Polar bears have suffered population falls of up to 30 per cent, mainly because of the loss of sea ice, which is attributed to global warming.