The industry has made some significant process, Brandt points out, but there are still no commercial scale advanced biofuel plants in the US. (Advanced biofuels, or "drop in" fuels, can be used in existing engines, but are cleaner burning than traditional jet fuels - oh and they can be made from things like municipal waste, hence the lovely photo of a dump in Mumbai.)
Now, she argues, airlines have an incentive to purchase biofuels to avoid paying a tax every time they fly to and from Europe. "In the short-term, airlines may see passing on the cost of the ETS to the customer as the easy solution but this would be a very unpopular long term solution."
Photo by KPA/Zuma/Rex Features