Scientists show how smarter flight decisions could help fight climate change
The Global Warming per Activity tool, highlighted on Wednesdaay in Nature, measures how long and how strongly each aviation activity affects the atmosphere — whether that activity lasts hours or a century.
The scientists also quantified uncertainty in every component, enabling users to assess risk by calculating the probability that a given tradeoff would help mitigate warming.
'This new decision tool uses the information to provide accurate risk quantification for climate tradeoff decisions,' lead author Michael Prather, a professor of Earth system science at UC Irvine, said in a statement.
For example, airlines could decide to reroute flights to avoid conditions that generate contrails — the line-shaped vapor trails produced by engine exhaust — but in doing so, they might need to consume more fuel.
If the contrails were reduced sufficiently, however, there could be a net positive gain for the climate, according to the study.
In general, civil aviation contributes to global warming via carbon dioxide from fuels, nitrogen oxides that impact ozone and methane levels and the creation of lingering contrails. Although each pollution source plays a role in trapping atmospheric heat, efforts to reduce one offender typically increase another.
Using the new metric, the scientists determined that if aviation choices led to even a 3 to 5 percent decrease in contrails or in nitrogen oxide emissions, these declines could outweigh a 1 percent surge in carbon dioxide emissions over a 100-year period.
Careful strategies that might increase fuel usage, they observed, could therefore bring a potential reduction in the long-term climate impacts of flying. The researchers stressed, however, that they considered only climate change tradeoffs and not economic costs.
Nonetheless, they touted their method for its abilities to empower airlines and regulators to make smarter decisions, with more accurate, activity-based comparisons.
By quantifying the probability of a positive climate outcome, the authors said they aimed to provide a way to evaluate climate tradeoffs with confidence and equip policymakers with clearer insight into the consequences of their actions.
The tool could also be applicable to climate-related decisions made in other industries, such as shipping, agriculture or manufacturing, the researchers noted.
'This is a win for both science and society,' Prather said. 'Our findings show that we don't have to choose between reducing carbon emissions and tackling other warming pollutants. We can find a balance that leads to meaningful progress.'
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