photo: marya/Creative Commons
Radiative forcing has been on TreeHugger's radar for a while, and after finding out about this next study it'll be on your's too: According to research by the DLR German Aerospace Center, airplane contrails have a much, much greater impact on global warming than do the carbon emissions caused by planes' engines. I can't emphasize the 'much, much' part of that enough.I'll just quote the Reuters summary and add some emphasis:
Aircraft condensation trails criss-crossing the sky may be warming the the planet on a normal day more than the carbon dioxide by all planes since the Wright Brothers' first flight in 1903.
In any given day the net warming effect of contrails and the cirrus clouds related to them was found to be 31 milliwatts per square meter. Warming caused by aviation over the past century-plus was 28 milliwatts per square meter. But while contrails dissipate quickly, those carbon emissions keep warming for decades and decades, an important consideration for dealing with the issue.
Why do contrails cause so much warming? In dense areas of contrails (parts of Europe and the eastern United States) the contrails themselves trap heat, as do the cirrus clouds related to them--so-called 'contrail cirrus' clouds, "a type of cloud that consists of young line-shaped contrails and the older irregularly shaped contrails that arise from them."
Ways to reduce contrails (besides not flying...), flying at lower altitudes, avoiding areas of the sky with high moisture content, developing new engines that reduce contrail formation. A balance would have to be struck though between these measures if doing so would result in burning more fuel.
Read more: Global radiative forcing from contrail cirrus
More on Aviation:
What the Heck is Radiative Forcing & Why Should My Aviation Carbon Offset Include It?
World's Airlines Pledge to Cut Emissions 50% by 2050