Singer also argued that the United States is obligated to dramatically reduce its use of fossil fuels. That’s partly because of global warming and because more countries need scarce fossil fuels as they develop.

“The U.S. has an obligation to take pretty drastic measures when it comes to global warming.”

He was critical of President Bush for failing to join in international efforts to reduce global warming and for boasting that the United States would not reduce its use of gasoline because “it’s an American way of life.”

He said the refusal to do more “shows a lack of global ethics.”

Singer, author of dozens of books, including “One World: The Ethics of Globalization,” gave the annual Business Ethics Lecture at Minnesota State University Wednesday night.

Singer, 59, was born in Australia. He holds part-time positions as an ethics professor at Princeton University and at the University of Melbourne. He was named by Time Magazine as among the 100 most influential people.

Singer holds a utilitarian ethical philosophy, based on the concept of maximizing happiness and pleasure and minimizing suffering.