This week, when leaders of the most powerful and wealthy nations in the world gather here in Pittsburgh for the G-20 summit, they can strike a powerful blow for social justice and humanitarianism. By taking concrete steps to fight global poverty, especially through cancellation of the debt burdening poor countries, they can ease human suffering and bring hope to some of the most desperate places on Earth.

The global financial crisis, which has devastated families in Western Pennsylvania and nationwide, is having an even more dire impact in the developing world. Throughout sub-Saharan Africa and the rest of the global South, children who should be in school are instead hospitalized with diseases that could have been prevented with simple vaccinations. But the money many of these countries should be spending on basic education and health care is instead being funneled to multilateral banks in the form of steep debt payments.

The affected countries didn't land in this predicament just by their own irresponsibility. If anything, they are paying the price for recklessness on Wall Street. They have often been victimized by bankers who aggressively made loans to brutal and corrupt governments, knowing full well that those loans would not benefit the people. In many cases, soaring interest rates and compound interest make it impossible for these countries to eradicate debt even after scrupulously making their payments time and again.

The G-20 nations do appear to be coming through with increased assistance in the form of new International Monetary Fund loans. But for the very poorest countries, more loans -- on top of the old ones they can't manage -- may be pouring fuel on the fire.

If they are serious about helping the poorest countries through this worldwide depression, they must implement a bold program for additional grants and expanded debt cancellation. And they must move quickly to establish strict guidelines for responsible lending and borrowing, cracking down on predatory practices that exploit rather than empower debtor nations.

As a first step, they must condemn and regulate so-called "vulture funds," which buy up poor countries' debt for pennies on the dollar on the secondary market and then swoop in to sue for millions in damages. These funds usually operate stealthily, with little transparency, basing their operations in tax havens like the British Virgin Islands

The Democratic Republic of Congo, ravaged by civil war, disease and famine, is one of the world's most violent and troubled nations. Now it's also facing mounting fines resulting from debt-related litigation brought by a New York firm calling itself a specialist in "alternative investment opportunities and special situations within the emerging markets." Having lost 8 million people due to the lack of health care, the DRC should not be forced to contend with speculators trying to profit from the nation's misery.

The G-20 must also put an end to harmful borrowing conditions that can hurt more than the loans help. In order to get its IMF loan, for example, El Salvador was forced to raise taxes and cut gas and transportation subsidies. This at a time when developed countries are increasing similar public investments to stimulate their own economies. Under the current rules, borrowing from the IMF is too often one step forward and two steps back.

Yes, this is an ambitious agenda. But we've seen our leaders mobilize to rescue large corporations at considerable taxpayer cost. This sacrifice was necessary, they told us, because such institutions were "too big to fail." But as Kevin Gallagher, an international relations scholar, recently explained in the London Guardian, the developing world is also "too big to fail."

In today's interconnected world, we cannot wash our hands of global poverty and unjust debt, setting it aside as "their problem," which doesn't affect our prosperity or stability. You reap what you sow, the Bible tells us. And under the existing debt regime, the consequences ricochet back to the developed world in the form of expensive bank bailouts, a degraded environment, increased drug trafficking and military conflict.

But ultimately, we should move to invest in the developing world because it's the right thing to do, because our faith compels us to. The Jewish tradition asks its faithful to repair the world. Christianity compels its followers to love their neighbor as they do themselves. The Islamic tradition recognizes zakah, alms-giving by wealthy members of the community primarily to help the poor, as an essential duty. The world's superpowers must answer this call when their leaders meet in Pittsburgh this week.