The millennium ecosystem assessment: what is it all about?

Hundreds of scientists from over 70 nations are now engaged in an intensive effort to assess what we know about the status of the world's ecosystems. Here, we describe the fundamental nature of this assessment, what it hopes to accomplish and how it will go about its work. The results of the Millennium Ecosystem Assessment will serve as a baseline for future assessments, as well as a blueprint for action for sustaining the ecosystem services upon which we all depend for our well being.