"Human beings are at the center of concerns for sustainable development. They are entitled to a healthy and productive life in harmony with nature." -Principle 1 of the Rio Declaration on Environment and Development, 1992

Agenda 21, the U.N. Sustainable Development Plan from Rio de Janeiro 1992 is a United Nations advisory document, adopted with the Rio Declaration on Environment and Development in 1992 at the Earth Summit in Rio de Janeiro, by 178 signatory nations including the United States. This plan provides guidelines for sustainable development, that can be executed at local, national, and global levels.

Notwithstanding its laudable goals, Agenda 21 has surprisingly attracted opposition, mostly in the U.S., where the Republican National Committee adopted a resolution in 2012, "rejecting the U.N. Agenda 21 as erosive of American sovereignty." Other critics believe that Agenda 21 is a plan of international agencies and governments wanting to control land, resources, education and information around the world. The reader of this document should draw his own conclusions on the validity of these claims.