FAA Administrator Marion Blakey said that “aircraft greenhouse gas emissions might become a serious barrier to aviation growth long-term” in a speech last week to an emissions colloquium at ICAO in Quebec. Also at the colloquium, Massachusetts Institute of Technology professor Ian Waitz presented preliminary research that says in one estimation, U.S. commercial aviation emissions may be correlated to a few hundred premature deaths a year and have climate costs of $16 billion a year. But, Waitz said, “There is a very positive side to the story.” He stressed that while aviation accounts for approximately 3 percent of the nation’s fuel burn, the rate of premature deaths as a result of the emissions is only “a small fraction of one percent” of the yearly total attributed to poor air quality. Waitz added that there has been a 95-percent reduction in the number of people affected by aviation noise in the last 30 years despite a massive increase in air travel.