Climatologist develops contrail avoidance model
Released: May 1, 2008
Environmental sustainability often takes a back seat to capitalism and big business. Case in point: while scientists have pointed to jet engines as a contributor to climate change, the airline industry is projected to double the number of flights by 2020. So how do those familiar with aviation’s impact on climate, and bring it to the fore of the public agenda? Bring 70 of the nation’s top scientists, aeronautical engineers and policy makers together to discuss among other things, noise pollution, air pollution and condensation trails (contrails).
Among those in attendance at the Aviation Climate Change Research Initiative (ACCRI) was David Travis, professor of climatology at the University of Wisconsin-Whitewater. Travis’s current research on contrails in airspace has major implications for the dialogue about climate change. “I suspect that these jet contrails greatly contribute to global warming,” Travis said. “ They act similar to natural high clouds by trapping heat that would otherwise escape and create a warming effect. I wanted to bring my research into that discussion at ACCRI.” After September 11, when all flights were grounded, Travis studied the temperatures on the ground, and he noticed a considerable impact on the range of temperature between day and night. With the skies clearer than normal, the days were warmer and the nights cooler.
Travis discussed his findings with the other attendees at the gathering, where growing evidence was presented that argued for a reduction in contrails. However, the methods for reducing contrails would conflict with those of other scientists and policy makers who were concerned with other problems caused by aviation. Travis, for example, would advise pilots to fly at lower altitudes to scale back the formation of high clouds that create contrails. However, other scientists argued that flying at low altitudes would create more problems with noise pollution—currently the leading source of lawsuits against the Federal Aviation Agency (FAA). Also, flying at lower altitudes in a denser atmosphere would require more fuel to burn, thereby emitting more air pollutants.
“Every solution creates its own set of problems,” Travis said. “ This is especially obvious to those at the FAA, because they knew how tough it would be to implement these measures in aerospace.”
With problems come compromises. Travis and his colleague, Andrew Carleton of Penn State University are developing a contrail avoidance model for pilots to follow when flying at normal altitudes. “ The Contrail Avoidance Model,” outlines where condensation trails are more likely to form in the high skies. Say, for instance, that a pilot travels from New York to San Francisco, this model would spell out where not to fly. But then the problem of air pollution comes back into the equation since planes would have to fly off course and stay in the air much longer. “ We understand the objections about this contrail avoidance model, however, this model would more than make up additional fuel burnt,” Travis said. “ Somehow we must find a middle ground with this solution.”
Although attendees at ACCRI could not solve all those problems on climate change one can look for Travis to be a major player in condensation trail research. “I am optimistic that something can be done about this,” Travis said. “Already, in certain places like Great Britain, consideration is being given to develop a new policy that would require pilots to adjust altitudes when flying through British airspace.” He has recently submitted a collaborative grant between UW-Whitewater and Penn State University to the National Science Foundation to support the continuation of his research.
- LeQuez Spearman,spearmanlt22@uww.edu
