Host Emily Kwong wants to keep an eye on her carbon footprint. Most of it consists of greenhouse gas emissions from driving her car or buying meat at the grocery store. But it's not so obvious how to measure those emissions, or how factories, cargo ships, or even whole countries measure theirs.Enter: NPR science reporter Rebecca Hersher. Together, Rebecca and Emily break down how greenhouse gas emissions are tallied ... and why those measurements are so important in figuring out who's responsible for cleaning up. What should we measure next? Email the show at shortwave@npr.org.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy