As a study on global development released by the Gates Foundation reveals that millions more could die if major economies cut their investments, Mr Gates said that he wants to prove the money is “worth spending”.
He said: “We are being questioned more than ever, and the budget framework is tighter than ever.
“You have to prove the benefit… of if the money is worth spending. And my answer is yes. But we haven’t been forced to make the argument that way quite as strongly as we have now.”
He added that the “world is improving” – but that the gradual steps do not often make the headlines.
He told told The Daily Telegraph: “Often you miss the story of improvement… It’s always very gradual…. because it’s one life at a time.”
He vowed to work alongside congressman in the US, who ultimately pass the budget, and convince those in power that development is cheaper than waging war.
Mr Gates and his wife Melinda have pumped billions into their philanthropic organisation The Bill & Melinda Gates Foundation since launching it in 2000.
Employing more than 1,500 people, the charity aims to tackle some of the world’s biggest problems, such as poverty, hunger and poor health, to help save lives.
The software billionaire has previously said he wants to “eradicate” diseases such as malaria and polio within 15 years.