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.
Source: transebvnews