This project methodology enables technology-based mitigation of atmospheric warming caused by aircraft contrail cirrus, which are clouds composed of ice crystal hydrometeors that act as short-lived climate forcers (SLCFs). When aircraft pass through cold and humid regions of the atmosphere (ice supersaturated regions or ISSRs), water vapour in the aircraft emissions triggers nucleation of ice hydrometeors that can persist for many hours, which collectively cause an annual net warming effect across all commercial flights equivalent to approximately 1% of total anthropogenic climate impact (Using GWP100 climate metric this equates to ~650 MTCO2e annually.[1]). The methodology provides a process to mitigate contrail cloud radiative forcing by enabling modification of an existing flight plan to avoid ISSRs, which lead to persistent warming contrails. The net radiative impact mitigated is converted into CO2e, which is then issued as Certified Mitigation Outcome Units (CMOUs) by Gold Standard.
[1] Lee et al. (2021), The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018, Atmospheric Environment, Volume 24, 117834.