Climate change is real, case closed. But there's still a lot we don't understand about it, and the more we know the better chance we have to slow it down. One still-unknown factor: How might clouds play a part? There's a small hope that they could buy us some time to fix things ... or they could make global warming worse. Climate scientist Kate Marvel takes us through the science of clouds and what it might take for the earth to break its own fever.

Rivers are one of nature's most powerful forces -- they bulldoze mountains and carve up the earth, and their courses are constantly moving. Understanding how they form and how they'll change is important for those that call their banks and deltas home. In this visual-packed talk, geoscientist Liz Hajek shows us how rocks deposited by ancient rivers can be used as a time machine to study the earth's history, so we can figure out how to more sustainably live on it today.

It's a fateful moment in history. We've seen divisive elections, divided societies and the growth of extremism -- all fueled by anxiety and uncertainty. "Is there something we can do, each of us, to be able to face the future without fear?" asks Rabbi Lord Jonathan Sacks. In this electrifying talk, the spiritual leader gives us three specific ways we can move from the politics of "me" to the politics of "all of us, together."

"We have seen advances in every aspect of our lives -- except our humanity," says Luma Mufleh, a Jordanian immigrant and Muslim of Syrian descent who founded the first accredited school for refugees in the United States. Mufleh shares stories of hope and resilience, explaining how she's helping young people from war-torn countries navigate the difficult process of building new homes. Get inspired to make a personal difference in the lives of refugees with this powerful talk.