"We are now living with a series of concurrent and long-term crises," U.N. chief says

A staggering 45 million children younger than 5 are now estimated to suffer from acute malnutrition, the U.N. food agency chief says.

"We are now living with a series of concurrent and long-term crises that will continue to fuel global humanitarian needs," Cindy McCain says.

The aim is not just financing, but also finding innovative solutions to help the world's neediest, she says.

More than 345 million people are facing high levels of food insecurity this year .