Study: ‘Radical collaboration’ required to clarify climate impact of contrails

The Rocky Mountain Institute’s (RMI) Contrail Impact Task Force has released a report urging the aviation industry to improve its understanding and management of contrails due to their significant non-CO2 climate impacts. This report emphasizes the need for “radical collaboration” among aviation stakeholders to mitigate the sector’s overall climate footprint.

Recommendations

1. Contrail Prediction Models: Airlines are encouraged to use advanced contrail prediction models to identify and avoid regions where warming contrails form. Investment in better weather models, retrofitted humidity sensors, and enhanced satellite imaging is crucial.
2. Collaboration on Trials: Sector stakeholders should collaborate on trials to validate and assess the feasibility of contrail avoidance strategies. This will help refine prediction models and gather practical knowledge for integrating contrail management into airline operations.
3. Air Traffic Management: Prioritize research, simulations, and trials in air traffic management to prepare for potential future challenges like capacity constraints and congestion. Adaptation of systems and processes over time is necessary.

Climate Impact of Contrails

• Contrails have a significant climate impact, estimated to be between half and three times the impact of aviation’s CO2 emissions.
• Persistent contrails can form artificial cirrus clouds that trap heat, contributing to global warming.
• Reducing uncertainty about the warming effect of contrails is essential as the main mitigation strategy—using additional jet fuel to avoid cold and humid areas—results in more CO2 emissions.

Challenges in Quantification

• Precise quantification of contrail impacts is difficult due to factors like changes in humidity, temperature, wind, time of day, seasonal and regional variations, cloud interactions, and technological limitations.

Industry Commitment

• The aviation industry, responsible for about 2% of global CO2 emissions, aims to reach net zero by 2050. However, eliminating carbon emissions alone may not suffice to halt the climate impacts of air travel.
• The full warming impact of aviation includes both CO2 and non-CO2 effects, with contrail-induced warming being a significant driver.

Regulatory Developments

• The European Union’s Monitoring, Reporting, and Verification (MRV) programme requires airlines to report non-carbon emissions, including contrails, nitrogen oxides, and sulfur for all flights departing from the EU starting January.
• Analysis by Transport & Environment (T&E) suggests that only five of the 100 most contrail-intensive routes in the European Economic Area (EEA) would be covered under a proposed scheme limiting scope to flights within the region, the UK, and Switzerland for its first two years.
• Legal experts at Opportunity Green have raised concerns that this framework might conflict with the Emissions Trading System (ETS) Directive adopted by EU lawmakers in 2022.

The RMI report highlights the need for continued investment in research, better predictive technology, and collaborative efforts to manage contrail impacts effectively. Addressing both CO2 and non-CO2 effects is crucial for mitigating the overall climate impact of aviation.

Based on an article from BusinessGreen.