Flying makes greenhouse gasses. Whether water vapor or just standard schmutz is the worst of them I don't know, but both of them contribute to the dirty and impermeable bubble we're creating around the planet. And sometimes they work together. As with all clouds, first you've got your little particle of dust, then you've got the humidity glomming onto it (here's a snapshot post on how clouds are formed). But what's so bad about clouds?
Have you ever noticed that cloudy nights are often warmer? It isn't simply that heat makes clouds form – it's also that clouds trap heat from escaping at night. “A Penn State study compared regions of the United States where contrails tended to form more strongly with areas where they didn’t. The more contrail-heavy the area, the less the variation between daytime highs and nighttime lows tended to be.” (Global News)
There's some debate about the cloud effect, but none at all about the stinky emission effect. “Aviation is on track to have a 1.5 billion-ton carbon footprint by 2025. The entire 27-nation, 457-million-person European Union emits some 3.1 billion tons of CO2 yearly at this point.” (Christian Science Monitor)
What can I do?
1. Fly less. Okay, that one was obvious, but maybe the hardest for those of us with money in our pockets and an itch to see the world, or far flung family, or a business to run. But maybe we can be a bit more grounded, and sit with our current locations a bit more. Do one or two things to improve where you are instead of flying away from it all (I'm talking to myself, especially). If you're going on a family trip, consider driving. Yes, it takes longer, and is essentially torture, but at least future family will have a planet. And birds. And air. If it's for work, a constant pressure on companies by employees to allow more long distance communication, via Zoom or Skype or any of the bazillion apps that work beautifully, will help us all in the long run.
2. Ask about your plane. If it doesn't have wings that lift up like the hand on the arm of a traffic cop telling you to stop, don't buy. There are many emission reducing designs that airlines have access to, but might not use if they would rather wear out they're ancient investments, and cut corners on new tech. Don't let them get away with it. Boycott bad design.
3. Fly during the day, never at night. Scientists don't seem to be in unanimous agreement about this one. Dr Minnis of NASA, Dr Dahl (Green Medinfo), and many others say red eyes create a frozen shell where nighttime contrails form, impeding heat from escaping as it normally would.
“Planes flying between 6 p.m. and 6 a.m. were responsible for 60 to 80 percent of contrails' warming effect on temperatures. That's because contrails at night trap outgoing heat radiation.” (Christian Science Monitor)
And, just to give us all the warm fuzzies, here's an excerpt from a Slate article:
“In even the most optimistic scenarios, by 2050, aviation could amount for as much as 15 percent of global emissions. (It’s now just 2 percent.) In the U.S., under a “deep decarbonization pathway,” aviation could account for as much as 50 percent of all transportation emissions by 2050. (It’s now about 10 percent.)” (Slate.com)
Articles to read:
“Hot Trails: To Fight Global Warming, Kiss the Red-Eye Good-Bye” by Christina Reed
“Just Plane Wrong: Global aviation is the fastest-growing cause of climate change. And the EPA might let it off the hook.” by Eric Holthaus
http://www.slate.com/articles/business/moneybox/2015/06/air_travel_and_climate_regulation_why_the_epa_might_let_big_aviation_off.html
“Clouds Caused By Aircraft Exhaust May Warm The U.S. Climate” by Gretchen Cook-Anderson, Chris Rink, and Julia Cole
“Cloudy with a chance of contrails: NASA clears up skies with new fuel” by Josh Kenworthy
http://www.csmonitor.com/Environment/2017/0317/Cloudy-with-a-chance-of-contrails-NASA-clears-up-skies-with-new-fuel
“Empty skies after 9/11 set the stage for an unlikely climate change experiment” by Patrick Cain
http://globalnews.ca/news/2934513/empty-skies-after-911-set-the-stage-for-an-unlikely-climate-change-experiment/
“Can aircraft trails affect climate? Grounding planes after the 11 September attacks may not have caused unusual temperature effects.” by Anna Barnett
http://www.nature.com/news/2008/081231/full/news.2008.1335.html
“Artificial Weather Revealed by Post 9-11 Flight Groundings” by Sayer Ji
“A blanket around the Earth” by NASA