Amid all of the political turmoil and global crises, one source of hope stands out: our ability to power modern life with zero emissions. Scientists warn that to limit global warming, emissions need to be cut significantly in the coming years to reach net-zero by mid-century. Bill McKibben, founder of climate justice organization 350.org and Third Act, joins WITHpod to discuss his new book "Here Comes the Sun: A Last Chance for the Climate and a Fresh Chance for Civilization," reasons he's optimistic and more.