New Scientist: AIR travel isn't yet guilt-free, but it might be getting a bit greener. A UN agreement announced on 4 October means that airlines will have to curb their greenhouse gas emissions for international flights from 2020. The deal, brokered by the International Civil Aviation Organization (ICAO), seems like a big step forwards for efforts to tackle climate change. The agreement is a historic milestone for air transport, says ICAO council president Roberto Kobeh González. "We have ultimately determined...