Moving Beyond Carbon: Advancing Aviation Contrail Accounting and Reporting

RMI conducted pilots with BCG, Roland Berger, and Estuaire to compare contrail accounting methods. The results show that a bottom-up, flight-specific approach is significantly more accurate than the standard 1.7x multiplier, revealing that 2% of flights cause 80% of contrail impacts. The report advocates for a phased transition toward high-fidelity accounting to enable targeted corporate travel policies and alignment with emerging EU regulations.

• Flight-by-flight, bottom-up accounting is significantly more accurate for measuring CO2, contrails, and other non-CO2 effects than current standard methods. In pilot tests, this approach resulted in an average non-CO2 impact of 1.3x to 1.32x, which is lower than the commonly used baseline multiplier of 1.7x.
• Contrail climate impacts are highly concentrated, with a very small fraction of flight bookings responsible for the vast majority of the warming effect. Specifically, 2% to 2.14% of flight bookings account for 80% of the total contrail impact.
• The use of a single, static multiplier (such as 1.7x) to account for non-CO2 effects is too broad and likely leads companies to misrepresent their true climate impact because it ignores variability in region, season, time of day, and weather.
• Granular data reveals specific flight characteristics associated with higher warming impacts, such as flights during winter, cool spring and fall months, evening and nighttime departures, and medium- to long-haul routes.
• The European Union's Monitoring, Reporting, and Verification (MRV) framework, which requires airlines operating within the European Economic Area to report non-CO2 emissions from January 1, 2025, may soon turn voluntary corporate Scope 3 non-CO2 reporting into a formal requirement.
• RMI proposes a four-phase framework for corporate aviation accounting: Phase 1 focuses on conceptualization and testing; Phase 2 on stakeholder engagement and capacity building; Phase 3 on developing customized low-emissions travel policies; and Phase 4 on scaled application.

APA

RMI (2025). Moving Beyond Carbon: Advancing Aviation Contrail Accounting and Reporting. https://rmi.org/resources/moving-beyond-carbon-advancing-aviation-contrail-accounting-and-reporting/

Chicago

RMI. Moving Beyond Carbon: Advancing Aviation Contrail Accounting and Reporting. 2025. https://rmi.org/resources/moving-beyond-carbon-advancing-aviation-contrail-accounting-and-reporting/.

Wikipedia

{{cite report |author=RMI |title=Moving Beyond Carbon: Advancing Aviation Contrail Accounting and Reporting |date=8 December 2025 |url=https://rmi.org/resources/moving-beyond-carbon-advancing-aviation-contrail-accounting-and-reporting/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2025moving, author = {{RMI}}, title = {{Moving Beyond Carbon: Advancing Aviation Contrail Accounting and Reporting}}, institution = {RMI}, year = {2025}, month = dec, url = {https://rmi.org/resources/moving-beyond-carbon-advancing-aviation-contrail-accounting-and-reporting/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }