News Picks : Rerouting flights could reduce effect of contrails
BBC: Contrails left by jet planes can extend for 150 km and last for 24 hours. Because they both reflect sunlight away from Earth and trap IR energy, their net effect on climate isn't clear, but they appear to have a larger warming effect than cooling one. A previous study had suggested that the warming could be mitigated by having planes fly at lower altitudes, but that adjustment would increase their fuel use and carbon dioxide production. Now Emma Irvine of the University of Reading in the UK and her colleagues have found an alternative: rerouting flights to avoid regions of cold, moist air where contrails form most readily. To reduce the overall warming potential for shorter flights, the distance added can be up to 10 times the length of the contrail that would be produced. For longer flights, the distance can be increased up to three times the contrail length, but because those flights have more flexibility in their routes, such large distance changes wouldn't be necessary.