Poster's note : concerning lack of certainty, relevant to a range of geoengineering interventions. Note Partennen's previous work in this regard.
Simulated 2050 aviation radiative forcing from contrailsand aerosols Chih-Chieh Chen and Andrew Gettelman NCAR [email protected] Atmos. Chem. Phys. Discuss 13 June 2016 Abstract The radiative forcing from aviation-inducedcloudiness is investigated by using the Community Atmosphere Model Version 5 (CAM5) in the present (2006) andthe future (through 2050). Global flight distance is projectedto increase by a factor of 4 between 2006 and 2050. However,simulated contrail cirrus radiative forcing in 2050 can reach87 mWm−2, an increase by a factor of 7 from 2006, and thusdoes not scale linearly with fuel emission mass. This is dueto non-uniform regional increase in air traffic and differentsensitivities for contrail radiative forcing in different regions.CAM5 simulations indicate that negative radiative forcing induced by the indirect effect of aviation sulfate aerosolson liquid clouds in 2050 can be as large as −160 mWm−2,an increase by a factor of 4 from 2006. As a result, the net2050 radiative forcing of contrail cirrus and aviation aerosolsmay have a cooling effect on the planet. Aviation sulfateaerosols emitted at cruise altitude can be transported down tothe lower troposphere, increasing the aerosol concentration,thus increasing the cloud drop number concentration and persistence of low-level clouds. Aviation black carbon aerosolsproduce a negligible net forcing globally in 2006 and 2050in this model study. Uncertainties in the methodology and the modeling aresignificant and discussed in detail. Nevertheless, the projected percentage increase in contrail radiative forcing isimportant for future aviation impacts. In addition, the roleof aviation aerosols in the cloud nucleation processes cangreatly influence on the simulated radiative forcing fromaircraft-induced cloudiness and even change its sign. Futureresearch to confirm these results is necessary. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
770894ba463a357de29e02fa566eb05c.pdf
Description: Adobe PDF document
