State of the Earth study launched

The report will examine the impact of human activities on the Earth

By the BBC's Andrew Craig

The United Nations has launched a $21m (£15m) assessment of the Earth's ecosystems.

All of us have to share the Earth's fragile ecosystems and precious resources

UN Secretary-General Kofi Annan

It will examine the processes that support life on Earth, including grasslands, forests, rivers and lakes, farmlands and oceans.

The study was launched on Tuesday in the Italian city of Turin.

It forms the centrepiece of this year's United Nations (UN) World Environment Day.

Fragile Earth

The Millennium Ecosystem Assessment is an attempt to find out how human activity is threatening the world's natural processes.

Coordinated by the UN's Environment Programme, 1,500 scientists around the world will examine the fitness of various ecosystems, both as reserves of natural diversity, and as providers of the goods and services that people need.

How healthy are the Earth's rivers?

UN Secretary-General Kofi Annan said the assessment would "map the health of our planet, and so fill important gaps in the knowledge that we need to preserve it".

"All of us have to share the Earth's fragile ecosystems and precious resources, and each of us has to play a role in preserving them," said Mr Annan.

"If we are to go on living together on this Earth, we must all be responsible for it."

Public-private partnership

The assessment will involve government scientists, charities and campaign groups, as well as private companies.

One of its hardest tasks will be to integrate information on small, local ecosystems with bigger pictures on the scale of regions, countries and continents.

The four-year process will be complicated. For example, a field newly cleared from what was a forest may be in excellent shape as a food production system, but may have lost its ability to preserve biodiversity and guard against erosion.

But the study aims to create a map that shows, not just the dangers that the global environment faces, but also a route out of them.