World-renowned economist Jeffrey D. Sachs ’76, who left Harvard this summer for a post at Columbia University, returned to Cambridge yesterday to charge America with failing to meet its commitments to help fight global health crises.

Sachs, who now serves as the director of the Earth Institute at Columbia, spoke at Harvard as part of the ninth annual Thomas J. White Symposium.

Sponsored by Partners in Health, a non-profit group that improves health care in poor communities in the United States and around the world, and the Institute for Health and Social Justice, the talk took placed in a Science Center auditorium packed with 500 doctors, students and volunteers.

“The United States is the richest, most technologically advanced and the natural leader of the world. If it doesn’t step up, no one will,” Sachs said.

He said the United States has failed to live up to the financial commitments it made to sustainable development, poverty eradication and global health at this summer’s U.N. Earth Summit in Johannesburg.

The U.S. has only given one-seventh of its promised aid, he said.

Along with 190 other developed countries, the U.S. set goals to contribute 0.7 percent of its gross national product (GNP) to aid developing countries. Currently, however, the United States only contributes 0.1 percent of its GNP.

In global health, for example, the U.S. will contribute only $200 million next year to the U.N. Global Fund to fight AIDS, Tuberculosis and Malaria, when it should be contributing $2.5 to $3 billion annually.

These three diseases are preventable and treatable, but kill eight million people each year.

Taking a jab at what he said was the United States hypocrisy, Sachs pointed out that only weeks after President Bush demanded the U.N. put “words into actions” on global security, the U.S. has yet to act on its Johannesburg promises.

Crunching the numbers, Sachs said that each American was effectively only giving 71 cents annually to combat these diseases.

Sachs said he has canvassed shopping malls to find out whether average people would support increasing that contribution.

“There’s no one who wouldn’t give more,” Sachs said.

Even in the face of economic decline and budget deficits, Sachs said he believes the U.S. can do more.

If the U.S. can afford to give trillion-dollar tax cuts and to set aside $100 billion—1 percent of its GNP—for a war with Iraq, he said, then it can contribute more than $200 million.

By investing in public health instead of war, Sachs said, the United States could save 30 million lives.

Sachs has calculated that if the richest nations put together $25 billion annually, they could take care of the health needs of the developing world.

That amounts to every American putting one penny away from every $10 earned.

Sachs then spoke of his own experience visiting a clinic—which had no medicine—where 450 people were dying of treatable diseases in a room with only 160 beds.

“That’s three people dying in one bed,” Sachs said.

Near the end of his speech, Sachs called on students to raise their voices to get the U.S. to contribute more.

He said that Harvard students can join student groups, like the Student Global AIDS Campaign or Global Justice, that work to fight AIDS and global injustices.