PRINCETON, N.J. — In 2000, the world’s leaders met in New York and issued a ringing Millennium Declaration, promising to halve the proportion of people suffering from extreme poverty and hunger by 2015.

They also pledged to halve the proportion of people without safe drinking water and sanitation; move toward universal and full primary schooling for children everywhere — girls as well as boys; reduce child mortality by two-thirds and maternal mortality by three-quarters; and combat HIV/AIDS, malaria and other major diseases. These pledges, reformulated as specific, measurable targets, became the Millennium Development Goals (MDGs).

Last month, 10 years on from that meeting, world leaders returned to New York for a United Nations summit that adopted a document called Keeping the Promise, which reaffirmed the commitment to meeting the goals by 2015. The U.N. press release called the document a “global action plan” to achieve the MDGs, but it is more an expression of aspirations than a plan. What chance do we really have of keeping the promises made in 2000?

As the Yale philosopher Thomas Pogge has pointed out, the task has been made easier by moving the goal posts. Even before 2000, the World Food Summit, held in Rome in 1996, pledged to halve the number of undernourished people by 2015. By contrast, the corresponding MDG was to halve the proportion of the world’s people who are suffering from hunger (as well as of those living in extreme poverty). Because the world’s population is rising, halving the proportion of people suffering from hunger (and extreme poverty) means that the number will not be halved.

But worse was to come. When the Millennium Declaration was rewritten as a set of specific goals, the baseline for calculating the proportion to be halved was set not at 2000, but at 1990. That meant that progress already made could contribute to the achievement of the goal. And the goal became halving “the proportion of people in the developing world,” which makes a big difference, because the developing world’s population is growing faster than the population of the world as a whole.

The net effect of all these changes, Pogge calculates, is that, whereas world leaders pledged in 1996 that by 2015 they would reduce the number of undernourished people to no more than 828 million, now they are pledging only to reduce the number in extreme poverty to 1.324 billion. Since extreme poverty is responsible for about one-third of all human deaths, this difference effectively means that — if the final promise is actually honored — each year about six million more people will die from poverty-related causes than would have died had the original promise made in Rome been kept.

In any case, according to a recent World Bank/International Monetary Fund report, we are not on track to meet even the scaled-back global target of halving the proportion of hungry people in developing countries. Rising food prices — possibly related to climate change — have reversed past progress and last year briefly pushed the number suffering from hunger above the one-billion mark. That this should happen while developed nations waste hundreds of millions of tons of grain and soybeans by feeding them to animals, and obesity reaches epidemic proportions, undermines our claims to believe in the equal value of all human life.

The target of halving the proportion of people in extreme poverty is within reach, but mainly because of economic progress in China and India. In Africa, after economic stagnation in the 1990s, a decade of encouraging economic growth is reducing the proportion of the population living in extreme poverty, but not quickly enough to halve it by 2015.

There is better news on achieving gender parity in education, a key to reaching other goals, including lower infant mortality, which often comes about because educated women have fewer children. We also have a good chance of meeting the target of reducing by half the proportion of people in developing countries without safe drinking water — but to achieve the same with sanitation is proving more difficult.

On health goals, however, we are not even close. Maternal mortality is falling, but not fast enough. More people with HIV/AIDS are getting inexpensive anti-retroviral drugs and their life-expectancy has increased, but universal access is still far off, and the disease is still spreading, if more slowly than before. Progress has been made in reducing malaria and measles, and the rate of child mortality has fallen partly as a result, but the goal of a two-thirds reduction will not be met.

For a long time, rich countries have promised to reduce poverty, but have failed to match their words with adequate action. Of course, some important progress has been made. Millions of lives have been saved, but millions more could be saved.

To make sustainable progress in reducing extreme poverty will require improvements in both the quantity and quality of aid. Just a handful of countries — Denmark, Luxembourg, the Netherlands, Norway and Sweden — have met or exceeded the U.N.’s modest target of 0.7 percent of GDP for foreign development assistance. But without trade reform and action on climate change, more and better aid will not suffice.

For now, it looks very much as if, come 2015, the world’s leaders will have failed to keep their (watered-down) promises. That means that they will be responsible for permitting the needless deaths, every year, of millions of people.

Peter Singer is a professor of bioethics at Princeton University. His most recent book, “The Life You Can Save,” addresses the obligations of the rich to the poor (www.thelifeyoucansave.com). © 2010 Project Syndicate