By Alex Kirby BBC News Online environment correspondent

An interactive atlas of the world's natural wealth paints a graphic picture of humanity's inexorable spread.

It shows that since 1850 humans have affected almost half the planet's land.

Give nature half a chance, and it will take care of itself

Dr Mark Collins

It cites one estimate that current extinction rates mean we are losing one major drug every two years. But the atlas, produced by the United Nations, says nature is resilient enough to survive our impact.

Entitled the World Atlas Of Biodiversity: Earth's Living Resources For The 21st Century, it is the work of the United Nations Environment Programme World Conservation Monitoring Centre (Unep-WCMC), based in Cambridge, UK.

It has been collated from the centre's research, the work of independent scientists, and governmental and other reports.

Planetary bulldozers

The centre says the data will be made available to users by a unique interactive mapping service accessible from the Unep-WCMC website.

This will let them create their own maps comparing subjects from wilderness density to human population.

Sperm whales: Human influence is pervasive (Image: Unep)

The amount of data currently downloaded from the site every month, the centre says, would fill seven 12-metre (40-foot) articulated trucks.

The atlas details extinctions past and present:

• up to 95% of Earth's species may have disappeared during the later Permian extinction episode, about 250 million years ago
• starting 45,000 years ago, a high proportion of larger land animals became extinct, just at the time when humans arrived
• 80% of the maize varieties used in Mexico in 1930 have been lost
• it is estimated that fewer than 1% of the world's 250,000 tropical plants have been screened for medicinal potential
• scientists believe that current extinction rates mean we are failing to discover one major drug every other year.

Yet 80% of people in developing countries depend on medicines based largely on plants and animals, while 56% of the top 150 prescribed drugs in the US derive from the wild.

The atlas says humans have altered and had a direct impact on almost 47% of the global land area in the last 150 years.

Fair shares

One scenario suggests that biodiversity will be threatened on almost 72% of the land area by 2032.

We know the potential of under 1% of tropical plants (Image: M Schneider/Unep/Topham)

Up to 48% of south-east Asia, the Congo basin and parts of the Amazon will be converted to farming, plantations and urban areas, it says, compared with 22% today.

Unep's executive director, Dr Klaus Toepfer, said humanity was now diverting about 40% of the Earth's productivity to its own uses, much of it in an unsustainable way.

He said: "We must address the issue of genetic resource-sharing by giving developing countries an economic incentive to protect wildlife, paying them properly for the plants and animals whose genes get used in new drugs or crops."

Bouncing back

The atlas also shows how roads and settlements are spreading into former wildernesses like the Amazon, the Arctic and the deserts.

Brian Groombridge, co-author of the atlas, said: "There is little true wilderness left to support the expansion of the human population on this planet."

But the director of Unep-WCMC, Dr Mark Collins, said: "We know enough about the distribution of species and ecosystems to ensure that the world's biodiversity is managed effectively.

"Give nature half a chance, and it will take care of itself."