Bill and Melinda Gates are interviewed in New York, Wednesday, Jan. 21, 2015. As the world decides on the most crucial goals for the next 15 years in defeating poverty, disease and hunger, the $42 billion Gates Foundation announces its own ambitious agenda. (AP Photo/Seth Wenig)

The $42 billion Gates Foundation says the lives of poor people around the world will improve more over the next 15 years "than at any time in history."

Bill and Melinda Gates in an interview laid out the vision for the world's largest charitable foundation as they prepared to travel to the World Economic Forum and its annual networking meeting of heads of state and business leaders.

The international community, led by the United Nations, is deciding this year on the most crucial development goals for the next 15 years in defeating poverty, disease and hunger.

The Gates Foundation's own ambitious 15-year agenda, spelled out in its latest annual letter, foresees the elimination of polio and three other diseases and says Africa will be able to feed itself.

But climate change, an increasingly alarming global issue, is only briefly addressed, though the U.N. secretary-general has warned that this is the last generation that can do anything to avoid its worst effects. The foundation's letter calls "right now" for the development of cheaper, zero-carbon-emissions energy sources.

The Gates Foundation's annual letter was published online early Thursday. It looks ahead to a world where polio and Guinea worm, along with at least two others, will be eliminated.

Melinda Gates listens while her husband Bill Gates talks during an interview in New York, Wednesday, Jan. 21, 2015. As the world decides on the most crucial goals for the next 15 years in defeating poverty, disease and hunger, the $42 billion Gates Foundation announces its own ambitious agenda. (AP Photo/Seth Wenig)

It will be a "much better eradication track record in these 15 years than in all of human history," Bill Gates said in the interview Wednesday.

Polio could be the first to go. Africa hasn't had a case in the past six months, and with most of the cases recorded in Pakistan last year, the government there is stepping up, "knowing they're last, the spotlight's on them," Gates said.

It takes three years of no documented cases to certify that a disease has been eradicated, so the earliest that polio will be declared over is 2018.

"It'll be 2018 or within one or two years of that," Gates said.

The foundation has been assertive in the fight to end malaria as well, but that won't be achieved in the next 15 years, he said.

Bill Gates listens while his wife Melinda Gates talks during an interview in New York, Wednesday, Jan. 21, 2015. As the world decides on the most crucial goals for the next 15 years in defeating poverty, disease and hunger, the $42 billion Gates Foundation announces its own ambitious agenda. (AP Photo/Seth Wenig)

Melinda Gates spoke out strongly about another goal, cutting in half the number of deaths for children under 5. It was achieved between 1990 and now, and doing it again would bring the death rate to one child in 40 over the next decade and a half.

"Sometimes these things don't make the headlines, but they should," she said.

The couple said they plan to meet with World Health Organization chief Margaret Chan in at the World Economic Forum in Davos. The foundation last year announced it would spend $50 million on the emergency response to Ebola in West Africa, where both WHO and Chan have been criticized for their handling of the worst outbreak of the disease in history. More than 8,000 people have died.

"I think the biggest lesson coming out of the Ebola outbreak is we need to invest in primary health care centers, those little health posts that the people come in and they're referred up in the system," Melinda Gates said. "Had those been functioning and working better in West Africa, the disease would have been contained much more quickly."

Explore further Bloomberg donating $100M to help fight polio

© 2015 The Associated Press. All rights reserved.