BBC News Online: Sci/Tech

World celebrates Earth event

More than 500 million people in 85 countries all over the world are celebrating Earth Day on Saturday.

The event has been marked annually since 1970 to promote awareness of environmental issues.

It aims to bring together everyone to "promote a healthy environment and a peaceful, just, sustainable world".

The Millennium Dome in London will be staging a recycled music concert, and there will be mass plantings in Chile, together with a mock nuclear power station evacuation in South Africa and a car-free day in Sydney, Australia.

The Worldwatch Institute, which is based in Washington, has issued an Earth Day report card detailing some of the concerns raised by the event.

'Profound changes'

Ed Ayres, editorial Director of the Worldwatch Institute, says: "We probably have no more than half a century in which to make fundamental changes in the way we do business as a species on this planet.

"The changes are going to be as profound as those which took place in the industrial revolution, if not more so."

One in four vertebrate species is extinct or is on the verge of extinction, one in six people alive today is chronically hungry and the rapid use of fossils fuels has led to 160 billion tonnes of carbon dioxide being released into the atmosphere in only 30 years - compared to 110 billion tonnes in the previous 180 years.

However, the institute also offers some hope.

The rise of citizen groups, the growing use of micropower and small-scale renewable energy schemes could begin to reverse some of these damaging trends.