progress The most effective way to increase fuel ef ciency is to invest in the most modern and especially environmentally friendly aircraft. For this reason, the Lufthansa Group is currently implementing the larg- est eet modernization program in its history: By 2025, it will take delivery of 251 latest-generation aircraft, which will mostly replace older models (see page 29, While air transport contributes a mere 2.4 percent of CO2 emissions caused by human activity worldwide, this value is expected to increase as demand for mo- bility continues to grow strongly. To limit the ecological effects of ying, the aviation industry has developed the four-pillar strat- egy for climate protection, which bundles different environmentally relevant measures (see illustration above). These range from technological progress and improved infrastructure to operational measures and economic instruments. The four-pillar strategy is also the basis for the Lufthansa Group’s fuel-ef ciency activities. Fleet development). Among these will gure 116 aircraft of the Airbus A320neo family, which will be up to more than 15 percent more fuel-ef cient than comparable prede- cessor models thanks to geared-turbofan technology. The new CSeries aircraft manufactured by Bombardier, of which Swiss is set to receive the rst exemplars from summer 2016, will y with similar fuel-ef ciency. Thus, the Lufthansa Group foresees further improvements in its en- vironmental balance sheet. Innovation in aircraft and engine technologies Alternative fuels progress 1 Improved use of airspace Airport infrastructures adapted to needs Improved 2 More ef cient aircraft sizes Optimal ight routes and speeds Optimized processes on the ground Operational measures N 3 6 E12 15 S 33 30 21 3 A global, sensibly designed, market-based system for reducing emissions to com- plement the other three pillars measures Sustainability Report Balance // Issue 2016 // Lufthansa Group // 45