Starting in 2013, up to 100 European airports will take part in a plan to reduce carbon dioxide (CO2) emissions by half a million tonnes a year by using Continuous Descent Approach (CDA) landings. The CDA approach allows planes to descend all the way from cruising altitude to the runway in one smooth glide, saving up to 450 kilograms of CO2 per landing, compared with the traditional stepped descent, the International Air Transport Association said. The plan was officially announced at the Aviation and Environment Summit in Geneva recently, where executives also said they were aiming to use second- generation bio-fuels, including some derived from algae, so as to not drain food and water resources.