Given that the warming impacts of contrails are short-lived (roughly a day), I think it is a good idea to do research now on the weather forecasting needed to avoid producing contrails. But I don't really see a reason to actually start avoiding them now, with the associated costs in terms of fuel, CO2 emissions, and time. We can start avoiding them in a few decades when it might have become urgent to have cooling.
Eliminating contrails from flying could be cheap
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Re: Eliminating contrails from flying could be cheap
#42It'd be worth it just to shut the chemtrail nuts up.
You don’t understand conspiracy loon logic. By the very act of hiding the chemtrails you are demonstrating that you are doing something nefarious.
Plus, the invisibility of a thing does not stop the conspiracy loons from building conspiracies around it. 5G RF is invisible, yet still being used by the government to control our brains. For chemtrails, the conspiracy is just going to turn into: "They're spraying invisible chemicals all over us to turn us into communists." There's no end to it.
Re: Eliminating contrails from flying could be cheap
#43If the incoming radiation can pass through, why can't it pass through on the way out?
The radiation on the way in has a different frequency than on the way out. For example, there is UV included in sunlight. But black body heat at Earth's temperature radiates in infrared. Clouds are very opaque to infrared, and more (though not completely) transparent to UV.
This is the actual answer. The clouds aren't differentially reflecting sunlight into and out of the atmosphere, they are reflecting the black body radiation emitted by the earth.
Re: Eliminating contrails from flying could be cheap
#44The article mentions that some flights produce a net cooling effect. I wonder if it could be cost effective to divert flights toward contrail formation when it's predicted that they'll produce cooling (I also wonder what the actual circumstances are when they produce cooling--low surface temperatures, maybe?).
Re: Eliminating contrails from flying could be cheap
#45Earlier quoted context omitted.
Wikipedia[1] states it very clearly: > It is considered that the largest contribution of aviation to climate change comes from contrails. In general, aircraft contrails trap outgoing longwave radiation emitted by the Earth and atmosphere more than they reflect incoming solar radiation, resulting in a net increase in radiative forcing. In 1992, this warming effect was estimated between 3.5 mW/m2 and 17 mW/m2. In 2009,…
> Contrail cirrus may be air traffic's largest radiative forcing component, larger than all CO2 accumulated from aviation, and could triple from a 2006 baseline to 160–180 mW/m2 by 2050 without intervention. Okay, but how does this compare to the forcing of the overall anthropogenic CO2 accumulation?
According to Wikipedia:
> For carbon dioxide, the 50% increase (C/C0 = 1.5) realized as of year 2020 since 1750 corresponds to a cumulative radiative forcing change (delta F) of +2.17 W/m2
Re: Eliminating contrails from flying could be cheap
#46If the incoming radiation can pass through, why can't it pass through on the way out?
Every wavelength of the electromagnetic spectrum that is not actively being generated, is decaying. At minimum the expanding universe saps frequency.
More directly,radiation (light,photons) is absorbed and re-emmited by matter but the re-emitted energy is always at a lower frequency.
This absorbed & re-emitted longer wavelength radiation is what can become trapped.
Re: Eliminating contrails from flying could be cheap
#47This is something the military, e.g. fighter jets worry about. The altitudes (in a given airspace) that form contrails are briefed as part of "tactical weather". You try to avoid them if able, because no matter how stealthy you are, you are lit up for all to see if you fly at those altitudes.
Fun fact: the B-2 bomber has a LIDAR-based contrail detection sensor, called the Pilot Alert System.
https://tridsys.com/our-divisions/optical-precision-sensors/
Re: Eliminating contrails from flying could be cheap
#48This is something the military, e.g. fighter jets worry about. The altitudes (in a given airspace) that form contrails are briefed as part of "tactical weather". You try to avoid them if able, because no matter how stealthy you are, you are lit up for all to see if you fly at those altitudes.
Avoiding con-trail creation has been a factor for military aviation since at least WWII; bomber pilots then were briefed on what altitudes to fly at to avoid them as well, but not because they were especially stealthy.
Re: Eliminating contrails from flying could be cheap
#49Did I miss the part of the article stating what percentage of all effects this would have? Like if it moves the needle 0.000001% is it worth the effort? Not to play whatabouttism, but the top 8 countries after China (US through Germany) together emit about the same amount of CO2 as China alone. Not saying we shouldn't improve where we can, as the sum of many small efforts helps the whole.
Re: Eliminating contrails from flying could be cheap
#50It'd be worth it just to shut the chemtrail nuts up.
They will find next conspiracy theory to cling on, if any thing keeping them in currently relatively harmless spot is an advantage