FiveThirtyEight: When the latest international Climate Conference wrapped up in Lima, Peru, last month, delegates boarded their flights home without much official discussion of how the planes that shuttled them to the meeting had altered the climate.
Aircraft currently contribute about 2.5 percent of global carbon dioxide emissions. That might not seem like much, but if the aviation industry were a country, it would be one of the worlds top 10 emitters of CO2. And its emissions are projected to grow between two...