There's a comprehensive list of challenges impacting the wider world- but fixing them poses a costly challenge.

World hunger, health, war, education, poverty and climate change are among the problems that need addressing, but fixing them remains elusive.

Author and Copenhagen Consensus Center president Bjorn Lomborg says he's working with economists to identify cost-efficient solutions to these problems.

"That's not the only thing you need to think about, but it's an important part. How much will it cost, and how much good will it do? I'm simply saying- why don't we try to do the stuff that does the most good for the least money?"

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