Can sustainable fuel cut the climate cost of flying?

Flight emissions are a major contributor to climate change, but Canadian businessman John Risley says it's not realistic to think people will just stop air travel. He tells Matt Galloway about his company’s work on curbing those emissions with sustainable aviation fuel, made from waste fats and plant sugars. The Aviation Environment Federation's Cait Hewitt says that sustainable fuel solutions are decades away, and baby steps won’t cut it.