The United States and Canada have one of the world's longest borders.  Because the countries are also highly industrialized and very interested in environmental issues, a large amount of collaboration on saving the environment is to be expected.

Two of the largest issues for North America are pollution and the preservation of ecosystems that stretch across the border into both countries.

To improve communication on environmental issues, the ministers of the environment of Canada and the United States meet regularly.

Environmental collaboration between Canada and the US has been going on for years.  The Great Lakes Water Quality Agreements (GLWQA) have helped these countries to deal with excessive fishing, eutrophication, and toxic contaminants in the water for the last five decades.

The International Joint Commission was established in 1909 to regulate both countries for the GLWQA.  The Commission has investigated issues of concern to the region and has helped to prevent conflicts over environmental issues.

The North American Free Trade Agreement (NAFTA) is an example of a recent treaty that takes environmental issues into the account.  NAFTA included a provision to create a group for Environmental Cooperation, which has helped to coordinate environmental policy since then.

The two countries signed the Air Quality Agreement in 1991 to deal with the increasing problem of acid rain.  Both nations agreed to lower levels of sulfur dioxide and nitrogen oxides, chemicals that often travel through the air over national borders.