Airlines could reduce their contribution to climate change
by 10% with as little as a 1% increase in operating costs, according to a study
published by peer-reviewed journal Environmental Research Letters.
They could accomplish this improvement by optimizing flight
routing to account not only for fuel savings, but also for more nuanced
atmospheric conditions, said the study's authors, who hail from scientific
institutes in the U.K., Belgium, the Netherlands, Germany and Norway.
Aviation accounts for roughly 5% of climate change, the
authors said. Airlines, meanwhile, plot routes to minimize fuel consumption, a
cost-saving measure that also reduces greenhouse emissions.
However, because planes fly high in the atmosphere, their
non-greenhouse related emissions have a greater significance on climate change
than do such emissions from other human activities. Non-greenhouse emissions
include the contrails that aircraft create as well as nitrogen oxides, which
produce ozone and methane. Those emissions, though, have differing impacts
depending upon where they take place.
For example, explained the authors, while nitrogen oxides
typically warm the environment, in some regions such emissions can cause
cooling. Similarly, contrails are typically a warming agent, but they can sometimes
have a cooling affect, based upon region and time of day.
"Hence the climate impact of these [non-carbon dioxide]
emissions depends strongly on the altitude, geographic location and time of the
emission," the study says.
In conducting the study, the authors analyzed transatlantic
air traffic on five winter days and three summer days with the goal of finding
the highest possible ratio of savings in emissions versus the increase in
operational costs -- most of it for fuel burn.
They found that by taking on 1% more cost in the form of
less fuel-efficient routes, airlines could reduce their climate change impact
by 10%.
"This cost-efficient reduction in the climate impact is
mostly achieved by avoiding the formation of warming contrails and by producing
the cooling contrails," the authors wrote.
They noted that airlines, driven by profit-minded
shareholders, would likely be hesitant to take on the extra 1% in cost without
incentives.
They also said that more robust research must be done before
climate-optimal routing is mature enough to be implemented.