Condensation trails have been suspected of causing " regional-scale surface temperature " changes for some time . Researcher David J. Travis , an atmospheric scientist at the University of Wisconsin-Whitewater , wrote in the science journal '' Nature '' that the effect of the change in aircraft contrail formation during the three days after the September 11 attacks was observed in surface temperature change , measured across over 4,000 reporting stations in the continental United States . His research documented an " anomalous increase in the average diurnal temperature change " . The diurnal temperature range ( DTR ) is the difference in the day 's highs and lows at any weather reporting station . Travis observed a 1.8 °C ( 3.24 °F ) departure from the two adjacent three-day periods to September 11 – 14 . This increase was the largest recorded in 30 years , more than " 2 standard deviations away from the mean DTR "
September 11 attacks
September 11 attacks
Contrail