By Jeffrey D. Sachs
Special to CNN
Editor's note: Jeffrey D. Sachs is director of the Earth Institute and a professor at Columbia University. He also serves as special advisor to U.N. Secretary General Ban Ki-moon on the U.N. Millennium Development Goals. From 2002 to 2006, he was director of the U.N. Millennium Project. He is president and co-founder of Millennium Promise, a nonprofit organization aimed at ending extreme global poverty and achieving the Millennium Development Goals. He has twice been named among the 100 most influential leaders in the world by Time magazine and is the author of the bestsellers "Common Wealth" and "The End of Poverty."
