It’s a bird; it’s a plane; it’s…a new factor in the growth of global warming?

The nation’s commercial airlines deserve a little credit for consistently carrying out their jobs. Rain or shine, their 35,000 daily flights ferry people of all kinds — the college graduate, the business executive, the vacationer — throughout the country and around the world.

Of late, the major carriers have had a few bumps in the road: plunging revenues, an unpredictable and seemingly never-ending volcano eruption, heightened security and regulation due to terrorism, disastrously long ticket lines, flight delays and even cancellations.

A new study in a recent issue of ACS’ Environmental Science & Technology is piling on to the worries for general aviation by predicting increased emissions from aircrafts over the next few decades.

Despite the non-stop activity in the skies, transport on the ground has gotten a fair share of scrutiny regarding its role in climate change, and few scientists have ventured to address how aircraft might be influencing global warming.

For the first time in a decade, new projections of future aircraft emissions says that carbon dioxide (CO2) and other gases from air traffic will become a significant source of global warming as they double or triple by 2050, according to Bethan Owen, Ph.D., of the Dalton Research Institute.

The prediction of aviation emissions could paint a clearer picture of the collective forces that cause climate change. In 2008, total U.S. CO2 emissions were on the decline but were measured at 5,921 million tons. Overall, total U.S. emissions have risen by about 14 percent from 1990 to 2008.

In ES&T, the researchers point out that aviation has grown strongly over recent decades but currently isn’t one of the main drivers of global warming. International aviation — the source of 60 percent of carbon dioxide emissions from aircraft — isn’t included in the Kyoto Protocol. Global air traffic currently contributes about 2 to 3 percent of CO2 emissions — the main greenhouse gas linked to global warming.

The scientists’ computer model forecast that emissions of carbon dioxide will likely double or triple within the next 50 years and could increase by seven times the current levels by 2100. They say that while there has been progress in increasing fuel efficiency through new technology and better operational management, it hasn’t counteracted the increase in air traffic. 

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