The financial sector often talks of decarbonizing investment portfolios as a way to fight climate change. But portfolios can be "cleaned" without having any real impact on the problem, says investment expert Nili Gilbert. Bringing science to finance, she unpacks how investors can actually help decarbonize the world -- a costly endeavor, estimated at three to five trillion dollars per year between now and 2050 -- and ensure the climate transition is just, global and interconnected. "Changing the markets can be a way to change the world," she says.