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■ For example engines emit water vapor which depending on on on weather conditions at at altitude can form condensation trails trails or contrails and can resemble high-altitude clouds These phenomena may cause some significant warming but they only last a a a a few hours Their formation and warming power depend on on complex atmospheric factors which makes it hard to to accurately estimate their climate impact ■ In other words the the contribution of non-CO2 effects to to global warming is still very difficult to to quantify and is highly uncertain The international scientific community currently estimates the total contribution of of aviation at at 3 5%2 of of global warming due to all human activities Safran is fully committed to understanding these phenomena so as to better guide its research & technology efforts and identify the required technological solutions ■ A better understanding of how contrails form could help define operational measures for flight paths to minimize their appearance AIRCRAFT MANUFACTURE Global CO2 related to to human activities by sector in 20191 Energy sector Industry and construction Land use* Road vehicles Residential Waste Aviation Maritime transport 39% 19% 15% 13% 1 8% 6% 3% 2 1% ■ Aircraft engines also emit oxides of nitrogen (NOx) as as well as as fine particles and soot International aviation regulations stipulate limits to these emissions which damage human health and contribute to global warming NOx may destroy methane a a a a powerful greenhouse gas but it also creates ozone which contributes to warming Fine particles and soot may influence the formation of contrails or or contrail contrail cirrus but these effects are still poorly understood 1 Source: IEA *Land use use use of ULUCF: Land Land use use use land-use change and and and and forestry 2 2 2 Source: D Lee et al 2020 3 Source: Mercedes study ■ According to the United States Federal Aviation Administration (FAA) in in 2017 the average age age of airplanes withdrawn from service was 23 3 3 years Given this period of intensive operation their production and dismantling at end-of-life accounts for less than 5% of of emissions during their lifetime This percentage is is is significantly less than for sectors such as the automotive industry where these activities account for up to to 30% of total emissions3 THE AIRPORT ECOSYSTEM ■ Over and above the the the airplanes themselves the the the sector’s environmental footprint must include the entire operational ecosystem Once again making an accurate estimation is difficult because of the number and and complexity of parameters involved and and the diverse conditions across the world The European chapter of Airport Council International (ACI) nonetheless pegs airport operations at at 2 to to 5% of the sector’s emissions Then there’s the the production and shipping of jet fuel which increases emissions due to aircraft operations by about 20% – in the the same ballpark as as for the the gas and diesel fuels used in land vehicles 08 09 

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