Today's global environmental problems -- from climate change to pollution -- don't stop at national borders.  National borders are irrelevant to the earth.  If we're going to protect the earth from human-caused environmental degradation, we need to erase the borders in our minds and address the problems as one world.

Solving today's most pressing environmental problems will take international teamwork, and U.S. leadership.  Consider:

• Global Warming:  The Intergovernmental Panel on Climate Change predicts that the earth will warm 2.5 to 10.8 degrees Fahrenheit in this century, causing rising sea levels, extreme weather, water shortages, and irreversible damage to many of the earth's life-sustaining systems.

• Biodiversity Loss:  Given current extinction rates, more than half of all species of mammals, birds, butterflies and plants may have disappeared by the middle of the next century.  With them will disappear potential disease cures and valuable ecosystems.

• Water:  One in ten people today face severe water shortages; by 2020, shortages may affect as many as one in three. 

• Oceans:  Threatened by warming, pollution and overfishing, our international waters make up 75% of the Earth's surface and provide us with food, transportation, and our weather patterns. 

These challenges are not insurmountable, but they will require global teamwork and cooperation, and the leadership of the United States.