The bad news is that international experts have just pushed the estimated likely impact of aviation on climate change upwards. Although the United Nations Intergovernmental Panel on Climate Change (IPCC) had until now kept to a guarded 3%, the figures it published last month raise the estimated impact to 4.9%. Coincidentally or not, the president of the International Air Transport Association (IATA), Giovanni Bisignani, has also just announced that airlines are committed to halting further increases in CO2 emissions by 2020. He also notes in passing that emissions by aircraft declined in 2008 and that biofuels have the potential to reduce aviation’s carbon footprint by another 80%.

The impact of aviation on climate change is the subject of an incessant war of communication between the aviation sector and environmentalists. A Brussels-New York flight generates a climate impact comparable to heating a house for a year, say some. The fuel consumption of an Airbus A380 is lower than a small family car per 100 km per passenger, replies the opposite camp. It is not easy to make sense of the different announcements, estimates and projections, but what is certain is that the aviation industry is today facing a major challenge.

The EU has responded politically by including the sector in the European emissions trading scheme (ETS). Starting in 2012, airlines that fail to respect a certain emissions level will be obliged to buy quotas. Unanimity is lacking, however, on the real benefits of the system for the environment. Uncertainties also remain on the impact of aviation’s emissions of nitrogen oxide (NOx), which the EU may also decide to regulate.

Industry plans to take up the environmental challenge by investing in research into alternative fuels, lighter structures, aerodynamics and engines. Today’s aircraft are 70% more fuel efficient than those of 40 years ago (20% compared with the aircraft of a decade ago). Making optimal use of flights - using shorter itineraries, rethinking landing procedures, limiting waiting time before take-off and so on - can also save millions of tonnes of CO2.

Where does the drive to cut emissions stand today? Europolitics takes a look.