The four-year, $24 million study — the largest-ever to show how people are changing their environment — found that humans had depleted 60 percent of the world's grasslands, forests, farmlands, rivers and lakes.
Unless nations adopt more eco-friendly policies, increased human demands for food, clean water and fuels could speed the disappearance of forests, fish and fresh water reserves and lead to more frequent disease outbreaks over the next 50 years, it said.
"This report is essentially an audit of nature's economy and the audit shows that we have driven most of the accounts into the red, if you drive the economy into the red ultimately there are significant consequences for our capacity to achieve our dreams in terms of poverty reduction and prosperity," Jonathan Lash, a member of the Millennium Ecosystem Assessment board, said in London.
Walter Reid, director of the Millennium Ecosystem Assessment, said over the past 50 years humans had changed ecosystems more rapidly and extensively than any comparable period in human history.
"These changes have resulted in a substantial and largely irreversible loss to the biological diversity of the planet," Reid said.
U.N. Secretary-General Kofi Annan stressed that the Millennium Ecosystem Assessment "tells us how we can change course," and urged nations to consider its recommendations.
Earlier in the day at an event in Japan, A.H. Zakri, director of the United Nations University Institute of Advanced Studies, said eliminating trade barriers and subsidies, protecting forests and coastal areas, promoting "green" technologies and lowering greenhouse gas emissions thought to contribute to global warming could help to slow environmental degradation.
The study was compiled by 1,360 scientists from 95 nations who pored over 16,000 satellite photos from the U.S. National Aeronautics and Space Administration, and analyzed reams of statistics and scientific journals.