Dear Democracy Now! Visitor: We are an independent, ad-free daily news program that serves millions of viewers and listeners each month. In this US election year, Democracy Now! is more important than ever. For 20 years, we’ve put a spotlight on corporate and government abuses of power. We lift up the stories of ordinary people working to make change in extraordinary times. We do all of this with just a fraction of the budget and staff of a commercial news show. We do it without ads, corporate sponsorship or government funding. How is this possible? Only with your support. A generous funder will match your donation dollar for dollar if you donate right now. That means when you give $10, your donation will be worth $20. Pretty exciting, right? So, if you've been waiting to make your contribution to Democracy Now!, today is your day. It takes just a couple of minutes to make sure that Democracy Now! is there for you every day.

Your Donation: $

The Three-Day Grounding of Air Traffic After September 11th Shows That High Altitude Jet Plane Contrails Can Affect Temperatures On Earth

August 12, 2002
Story
WATCH FULL SHOW

Following the Sept. 11th attacks, the Federal Aviation Administration grounded all commercial aircraft in the United States. For three days the skies were nearly as clear and quiet as they’d been since before the Wright Brothers skidded aloft.

These almost empty skies presented scientists with an unprecedented chance to answer a question that has vexed them for years: Do the wispy tracings left behind by jets–known formally as contrails–somehow alter the environment?

A new study in the British journal Nature finds that high-altitude jet contrails have an effect on daily temperatures. The sudden three-day grounding of commercial flights after last September’s terrorist attacks allowed researchers to study the true impacts of contrails from jet trails on climate. The absence of flights eliminated the thin blanket of cirrus clouds that usually forms from the water vapor in the exhaust from jet planes, allowing daytime temperatures to rise and nighttime temperatures to fall.

On a typical travel day, scientists have counted more than 14,000 flights crisscrossing the skies. In the long term, the skies are expected to become even more crowded, making contrails a growing concern for some atmospheric scientists.

Guest:

  • David Travis, climatologist at the University of Wisconsin and lead author of a study, published in Nature magazine, on the effect of the grounding of air traffic.

The original content of this program is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License. Please attribute legal copies of this work to democracynow.org. Some of the work(s) that this program incorporates, however, may be separately licensed. For further information or additional permissions, contact us.