Bear
Well-Known Member
http://www.dw.com/en/climate-friendly-air-travel-say-what/a-39549089
Air travel is bad for the climate - but it doesn't have to be. Climate-friendly flight routes and renewable jet fuel could make flying in planes way more environmentally friendly - this would just need to be implemented.
ncreasing global air traffic is commonly regarded as a climate catastrophe, with the aviation industry alone comprising 5 percent of greenhouse gases produced annually.
With the German Aerospace Center (DLR) expecting jet fuel demand to increase 50 percent by 2030, environmental prospects for the industry are dire.
But what if flying could be carbon-neutral; indeed, climate-friendly? It's a little-known fact that this is possible.
Flying high increases warming
To reach the goals of the Paris climate agreement to limit global warming to well below 2 degrees Celsius, every person on Earth would be limited to producing an average of only 2 tons of CO2 annually over the next 30 years.
However, a roundtrip between Berlin and New York in a relatively efficient Airbus 380 generates greenhouse gases equaling some three tons of CO2 in the environment. That's because, in addition to the direct CO2 emissions (one ton CO2 equivalent), the flight results in increased formation of ozone in the clouds (two tons).
A particular problem for air traffic is emissions is the high altitude. In addition to CO2, production of nitrogen oxide through jet engine exhaust produces ozone, a major cause of global warming.
Contrails, or condensation trails, are also produced, which create clouds made of ice crystals that can also trap greenhouse gases, warming the climate.
Overall, the climate impact of jet fuel combustion is about three times as high when planes are in the stratosphere than when they are on the ground.
Climate-friendly flying?
With climate-optimized flight routes, however, the negative effects of flying can also be reduced and can "even go in the opposite direction," according to Stefanie Meilinger of the International Center for Sustainable Development at Bonn-Rhein-Sieg University in Germany.
The greatest potential lies in preventing the creation of clouds. "Condensation trails and fog clouds are formed out of ice crystals in certain weather conditions," Meilinger explained. Climate-optimized flight routes would work by avoiding such weather, hence limiting cloud generation.
Beyond this, such clouds can have either a warming or cooling effect on the climate.
That would depend on the substratum and ratio of different reflections, she explained.
"If the solar radiation is reflected by clouds formed by plane flight back into outer space, this has a cooling effect," she said. "But if the Earth's radiation of heat into space is hampered by clouds, the climate is further heated."
This all depends on the route the plane flies. "With our current routes, we have an overall warming effect," Meilinger told DW.
To protect the climate, optimize flight routes
Under the direction of DLR and in cooperation with the German Meteorological Service (DWD) and the German Air Traffic Control (Deutsche Flugsicherung), Meilinger has analyzed Lufthansa flights to assess the possibility of designing air traffic routes that limit climate damage. Ideally, they should even contribute to climate protection.
Meilinger's research team developed software for climate-optimized flight routes which, once combined with weather forecast data, meant planes could avoid regions with warming clouds. Moreover, regions for cooling cloud formation on the flight route could also be targeted.
The scientists simulated climate-optimized flight routes for 40,000 Lufthansa flights, which in models succeeded in reducing the overall climate warming effects. "Even net-cooling air traffic" was realized on some European routes, stated the report.
"On the one hand, there is the possibility to close particularly climate-damaging air routes for air transport," explained Urban Weißhaar, a flight route expert at Lufthansa Systems. "The other possibility is the inclusion of cloud formation in emissions trading."
This, however, would result in some effects on passengers and airlines.
Cloud formation with climate impact could be priced, like CO2 emissions. Airlines with climate-friendly routes could gain an advantage by paying less money for pollution certificates - making any additional costs by a small detour very worthwhile. For climate protection, at least.
Air travel is bad for the climate - but it doesn't have to be. Climate-friendly flight routes and renewable jet fuel could make flying in planes way more environmentally friendly - this would just need to be implemented.
ncreasing global air traffic is commonly regarded as a climate catastrophe, with the aviation industry alone comprising 5 percent of greenhouse gases produced annually.
With the German Aerospace Center (DLR) expecting jet fuel demand to increase 50 percent by 2030, environmental prospects for the industry are dire.
But what if flying could be carbon-neutral; indeed, climate-friendly? It's a little-known fact that this is possible.
Flying high increases warming
To reach the goals of the Paris climate agreement to limit global warming to well below 2 degrees Celsius, every person on Earth would be limited to producing an average of only 2 tons of CO2 annually over the next 30 years.
However, a roundtrip between Berlin and New York in a relatively efficient Airbus 380 generates greenhouse gases equaling some three tons of CO2 in the environment. That's because, in addition to the direct CO2 emissions (one ton CO2 equivalent), the flight results in increased formation of ozone in the clouds (two tons).
A particular problem for air traffic is emissions is the high altitude. In addition to CO2, production of nitrogen oxide through jet engine exhaust produces ozone, a major cause of global warming.
Contrails, or condensation trails, are also produced, which create clouds made of ice crystals that can also trap greenhouse gases, warming the climate.
Overall, the climate impact of jet fuel combustion is about three times as high when planes are in the stratosphere than when they are on the ground.
Climate-friendly flying?
With climate-optimized flight routes, however, the negative effects of flying can also be reduced and can "even go in the opposite direction," according to Stefanie Meilinger of the International Center for Sustainable Development at Bonn-Rhein-Sieg University in Germany.
The greatest potential lies in preventing the creation of clouds. "Condensation trails and fog clouds are formed out of ice crystals in certain weather conditions," Meilinger explained. Climate-optimized flight routes would work by avoiding such weather, hence limiting cloud generation.
Beyond this, such clouds can have either a warming or cooling effect on the climate.
That would depend on the substratum and ratio of different reflections, she explained.
"If the solar radiation is reflected by clouds formed by plane flight back into outer space, this has a cooling effect," she said. "But if the Earth's radiation of heat into space is hampered by clouds, the climate is further heated."
This all depends on the route the plane flies. "With our current routes, we have an overall warming effect," Meilinger told DW.
To protect the climate, optimize flight routes
Under the direction of DLR and in cooperation with the German Meteorological Service (DWD) and the German Air Traffic Control (Deutsche Flugsicherung), Meilinger has analyzed Lufthansa flights to assess the possibility of designing air traffic routes that limit climate damage. Ideally, they should even contribute to climate protection.
Meilinger's research team developed software for climate-optimized flight routes which, once combined with weather forecast data, meant planes could avoid regions with warming clouds. Moreover, regions for cooling cloud formation on the flight route could also be targeted.
The scientists simulated climate-optimized flight routes for 40,000 Lufthansa flights, which in models succeeded in reducing the overall climate warming effects. "Even net-cooling air traffic" was realized on some European routes, stated the report.
"On the one hand, there is the possibility to close particularly climate-damaging air routes for air transport," explained Urban Weißhaar, a flight route expert at Lufthansa Systems. "The other possibility is the inclusion of cloud formation in emissions trading."
This, however, would result in some effects on passengers and airlines.
Cloud formation with climate impact could be priced, like CO2 emissions. Airlines with climate-friendly routes could gain an advantage by paying less money for pollution certificates - making any additional costs by a small detour very worthwhile. For climate protection, at least.
