Berkshire Hathaway (BRK.A) CEO Warren Buffett asserted his giving pledge has helped the world.

Speaking at the 2016 Concordia Summit, Buffett said it is sometimes difficult talking about giving away to charities, but he believes billionaires are working harder to make the world a better place. Still, Buffett urged the richest of the world to give away much of their wealth in a smart, efficient way.

He also said the pledge has encouraged many billionaires to give their fortunes away faster than they would have if they hadn't joined the pledge. "I'm sure there's going to be more money given sooner," he said.

According to Buffett, discussions among wealthy families have sometimes been difficult, even awkward, because family members have disagreed about the best ways to donate to charities and which goals are most important. "It would be a touchy subject sometimes with our children, with the public," he admitted, adding that billionaires from varying backgrounds—from the founders of Airbnb to dynastic families—have joined his giving pledge.

His discussions between billionaires have focused on finding effective ways to achieve philanthropic goals, according to Buffett, stressing the "enormous utility" that billionaires' wealth can have to produce vaccines, alleviate hunger and achieve other humanitarian goals.

"There are important vaccines that can save lives," he said, "but the world delivers very uneven results."

Part of the problem, according to Buffett, has been getting billionaires to focus on how they wanted to make the world a better place. "We intentionally avoided the idea of getting people together to sell people on their own philanthropy. What we wanted it to be was a learning experience for everyone involved."

Buffett also acknowledged that wealth inequality has grown, and he said having too much money "doesn't do good for your family."

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