Why is aviation’s true climate impact being kept under the radar?

(Transport and Environment, 19 Nov 2019) Twelve years ago, the IPCC Fourth Assessment estimated aviation’s total climate impact at two to four times that of its past CO2 emissions alone.

This is because aircraft at altitude generate significant additional climate warming – from NOx, the formation of line contrails and cirrus clouds, water vapour, soot, aerosols, black carbon and other factors. When discussing aviation’s inclusion in the EU emissions trading system a year later, the European Parliament called for airlines to surrender additional allowances to cover the non-CO2 impacts. Pressured by airlines and aircraft manufacturers, this proposal was dropped.

The finalised directive called for all impacts of aviation to be addressed “to the extent possible” and included a recital proposing legislation for 2008 to deal with NOx emissions separately. A NOx study by CE Delft, commissioned by the European Commission’s transport directorate, DG Move, and drawing on eminent experts, recommended a cruise NOx charge possibly dependant on flight length. Nothing came of it. 

A decade later, civil society and the European Parliament insisted. The 2017 reform to the EU ETS includes language that requires that “before 1 January 2020, the Commission shall present an updated analysis of the non-CO2 effects of aviation, accompanied, where appropriate, by a proposal on how best to address those effects”. The 2017 regulation also calls on the Commission to speed up work on the 2008 NOx proposal, promote research into contrail formation and evolution into cirrus clouds, into the direct effects of sulphate aerosols and soot, and on effective mitigation including operational and technical measures.

In November 2018, DG Move (although the ETS is a DG Clima responsibility) informed a hearing of the European Parliament’s environment committee that work still hadn’t started nor had the 2008 NOx proposal been advanced. This was clearly disappointing, as firstly a NOx measure is needed (there is a tradeoff; reducing CO2 generally increases engine NOx). Secondly, it again reflected a consistent line that industry, ICAO, member states and the Commission have taken for years: that scientific uncertainties warrant further research but no action. And still, very little money has been made available under the EU’s Horizon 2020 programme – €2.5m, or 0.003%, this year, of its €80 billion overall budget. 

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Transport and Environment, 19 Nov 2019: Why is aviation’s true climate impact being kept under the radar?