If we want to reduce carbon in the atmosphere to slow or even reverse climate change, we need to cut way down on emissions. And many scientists say even that will not be enough; we'll actually have to suck some of the carbon dioxide that already exists out of the air.
So what does that mean, planting jillions of trees? Giant vacuums?
Christopher Field at Stanford University is well-versed in atmospheric carbon and the ideas about reducing it.
He visits with some hard truths about carbon capture ideas.