This weekend, the 193 member countries of the United Nations will adopt an ambitious plan to end extreme poverty and hunger, improve the health of the world’s poorest, protect the planet, and address climate change.

The usefulness of this plan – known as the Sustainable Development Goals (or SDGs) — is undeniable, as it is built directly upon the success of the Millennium Development Goals (MDGs), which were adopted by the UN 15 years ago and are set to expire at the end of this year.

The MDG era brought arguably the greatest improvements in lives and livelihoods for the largest number of people in human history. The MDGs galvanized an unprecedented mobilization of governments, donors, the private sector, nongovernmental organizations, and community groups to accomplish such feats as vaccinating half a billion children against infectious diseases; detecting and treating 11 million cases of TB; and providing antiretroviral therapy to 6 million people infected with HIV.

Child mortality has fallen by half since 1990—from one in five children dying before their fifth birthday to one in 10. Deaths from tuberculosis have fallen by nearly 50 percent over the same period, an achievement attributable in no small part due to a 40 percent drop in HIV infections.

The goal of cutting extreme poverty in half worldwide was achieved in 2010, five years ahead of schedule. This reflects not just economic growth in China and India, impressive though that has been. Ethiopia, for example, has met every single one of the MDGs, and such nations as Ghana, Bangladesh, and Tanzania have seen dramatic progress on multiple indicators.

According to a study by the Brookings Institution, at least 7.5 million children’s lives have been saved thanks to the MDGs, the majority of these in sub-Saharan Africa.

While the progress that the world made through the MDGs is undeniable, several questions remain about how the SDGs, which are even broader and more ambitious, can be actualized. One of the most important questions is how will these ambitious goals be financed, especially in a time of economic stagnation in rich countries from Europe to Japan, and slowdowns in previously ascendant emerging market “BRIC” economies of Brazil, Russia, India, and China.

The success of the SDGs will hinge on whether the world can solve the challenge of how to finance them. Despite great strides in lowering poverty levels and improving health and education, we currently do not have the financing commitments in place to ensure we make good on ending extreme poverty by 2030.

The Financing for Development conference in Addis Ababa in July laid out a vision for how this can be accomplished, which we strongly support at the Gates Foundation. It outlines the three pillars of available finance: domestic resources from developing countries, traditional ODA especially focused on the needs of the poorest and private finance with the appropriate safeguards.

The primary responsibility actually lies with the developing countries themselves, and even in the poorest countries, domestic and private resources will greatly exceed aid. But well-spent and well-targeted aid will remain indispensable, especially in areas like education and health.

The trend of declining concessional finance and aid for the poorest countries should be reversed. As middle income countries graduate from aid based on per capita GDP, it’s important to ensure that the transition from aid to sustainable growth doesn’t lead to financial gaps that leave behind the poorest and most vulnerable populations—namely women and children.

Private investment will be another critical part of financing the SDGs. The innovative financing mechanisms created to support the global vaccination efforts of Gavi, the Vaccine Alliance, are a great example of how we can tap the capacity and expertise of the private sector. By pooling demand and funding for vaccines, Gavi raised the interest of manufacturers, which in turn spurred them to offer vaccines at significantly lower prices to the poorest countries.

This innovative partnership pools global-aid financing, and uses those resources to bring about significant price discounts from pharmaceutical manufacturers. From there it obtains secure co-financing from the recipient nations themselves—ensuring that these countries become more self-sufficient over time.

Optimizing the contributions and impact from each of these funding sources will be critical in our efforts to eliminate extreme poverty by 2030. By tapping and maximizing all of these possible sources of finance, we could truly be the generation that makes extreme poverty history.

Mark Suzman is President of Global Policy, Advocacy, and Country Programs at the Bill & Melinda Gates Foundation.