4 innovations Bill Gates says the next president has to prioritize

The billionaire philanthropist points to President John F. Kennedy's 1961 call to put a man on the moon as a shining example of a world leader bringing public and private sectors together for the betterment of society.

"In the face of fear, President Kennedy successfully summoned our country to harness American ingenuity and advance human progress," Gates writes.

Because of Kennedy's exhortation, we now have complex weather mapping tools and satellites that give us turn-by-turn directions.

Gates believes it's imperative that the next president of the United States - and other world leaders - tackle equally important challenges. Here are the four he sees as the highest priorities.