Humans have caused much of this damage during the past half century. Soaring demand for food, fresh water, timber, fiber, and fuel have led to dramatic environmental changes, from deforestation to chemical pollution, the report says.
The already grim situation may worsen dramatically during the first half of the 21st century, the report's authors warn.
Over 1,300 governmental and private-sector contributors from 95 countries collaborated to create the landmark study. For four years they examined the planet's many habitats and species and the systems that bind them together.
The United Nations Environment Programme compiled the report and released the results yesterday in Beijing, China.
"Only by understanding the environment and how it works, can we make the necessary decisions to protect it," UN Secretary General Kofi Annan said in a press statement accompanying the report's release. "Only by valuing all our precious natural and human resources, can we hope to build a sustainable future."
The report paints a rather bleak picture for biodiversity throughout much of the natural world. Perhaps 10 to 30 percent of Earth's mammal, bird, and amphibian species are facing extinction.
The massive ecological survey was begun in response to Annan's Millennium Development Goals, a UN initiative that aims to dramatically reduce socio-economic problems, such as hunger and extreme poverty, by 2015.
"The Millennium Ecosystem Assessment gives us, in some ways for the first time, an insight into the economic importance of ecosystem services and some new and additional arguments for respecting and conserving the Earth's life-support systems," said Klaus Toepfer, executive director of the Nairobi-based UN Environment Programme.
Current human usage patterns of Earth's environment have increased the global food supply, albeit too slowly to accomplish the UN goal of halving world hunger by 2015.