• cynar@lemmy.world
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            1 hour ago

            They are, but clouds disproportionately reflect IR. Basically the energy comes in as a mix of high, medium and low energy light. The earth re-radiates as low energy IR. Clouds trap this keeping the warmth (and energy) in.

            Clouds and CO2 act in a similar way.

          • chuckleslord@lemmy.world
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            1 day ago

            Yes, but the phenomenon occurs at specific altitudes, so you just fly slightly higher or lower.

        • ZoteTheMighty@lemmy.zip
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          1 day ago

          Gonna call BS on that short. Clouds cool the atmosphere because they reflect incoming visible light. Clouds also absorb infrared light, causing a greenhouse effect, but they also do that when they’re not condensed into clouds. Their infrared absorption depends primarily on their composition, which doesn’t change. Contrails are basically equivalent to cloud seeding, which is a method of cooling the atmosphere by increasing cloud cover.

          • ylph@lemmy.world
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            1 day ago

            Current scientific consensus is that contrails are a net contributor to warming (they trap more heat from escaping the atmosphere than they prevent from entering overall) - but it’s a complex phenomena that’s difficult to model, so studies vary a lot in estimating the magnitude of this effect - from being a fraction of airplane CO2 emissions, to being several time that.

          • chuckleslord@lemmy.world
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            1 day ago

            This isn’t someone guessing, man. He’s citing research on the topic.

            Essentially, these clouds are 50% opacity to visible light, but nearly 100% in infrared. So they block some incoming light, but reflect almost all infrared from the surface. It’s a net warming effect at these altitudes.

    • Siethron@lemmy.world
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      1 day ago

      Depends on your definition of “chemical”. Technically all trails are chem trails, including hiking trails.

    • Red_October@piefed.world
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      2 days ago

      until they decide enforcement means no contrails at all and suddenly they’ve found a new and exciting way to economically ruin the country.

        • pulsewidth@lemmy.world
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          2 days ago

          Contrails are mostly water vapour that’s condensed due to the hot exhaust of airplane engines.

          They are certainly not completely avoidable, they are likely inescapable without sacrificing significant fuel efficiencies (eg: all methods stealth fighters use to suppress or mask their exhaust heat signature)… which would negate any benefits to global warming.

          P. s. I’m not going to watch a YouTube video that could be a few paragraphs of textual explanation, because it’ll no doubt be eight times longer than it needs to be for the benefit of more ad money or promotion in the almighty algorithm.

          • scarabic@lemmy.world
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            19 hours ago

            It’s a 2:35 short , btw. Quite dense and to the point. And one of the points is that you’re wrong about it not offsetting the extra fuel to avoid contrail zones.

          • tomi000@lemmy.world
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            1 day ago

            Pretty sad that your comment gets so much attention while dismissing a huge breakthrough in research.

            • 4am@lemmy.zip
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              1 day ago

              Maybe we shouldn’t have to SMASH THAT LIKE BUTTON to have a discussion on the internet, or sit through an ad read for Brilliant or whatever

              • scarabic@lemmy.world
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                19 hours ago

                Do we seriously have to listen to people air their gripes about internet video anytime a link is shared? Jesus Christ.

              • tomi000@lemmy.world
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                1 day ago

                And maybe people dismiss comments that dont get liked and assume the answer that gets liked is “more correct”. Yes I wish it would work without the likes systemy but in reality 90% of the internet is AI slop and misinformation.

            • pulsewidth@lemmy.world
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              1 day ago

              Its not a huge breakthrough in research, mate - its a feasibility study. Its claims are promising, but until its tested in the real world it’s just interesting, not a breakthrough.

              Upvotes don’t mean much, they don’t change the ranking of comments like on worse social media like Facebook or Reddit. Don’t worry about them. I’ve seen very useful and valuable comments downvoted to heck and vice-versa.

              • tomi000@lemmy.world
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                1 day ago

                Its been tested by now, Ive looked into it a little. Seems like 90% of the time contrails form inside clouds and there is no benefit in avoiding them there. So simply avoiding contrails altogether is not recommended, but avoiding the ones forming in a clear sky would be pretty easy and extremely efficient warming-wise.

                Upvotes matter in the sense that comments with negative upvotes get dismissed more easily without thinking about them. Less people would watch a video from a comment with -5 votes than one with +100.

          • VibeSurgeon@piefed.social
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            1 day ago

            I’m not going to watch a YouTube video that could be a few paragraphs of textual explanation, because it’ll no doubt be eight times longer than it needs to be for the benefit of more ad money or promotion in the almighty algorithm.

            The linked one is a short video with a duration of 02:37. There’s no padding in this one. Naturally, you can’t actually get all of the nuances of the full-duration video, which also can’t cover the full nuances of the study itself that it’s based on (https://iopscience.iop.org/article/10.1088/2634-4505/ad310c).

            Pop science videos making studies accessible to the general public are good, actually. I recommend that you stop being dismissive of them. Had you actually put in the time, you wouldn’t have posted things that are in direct contradiction with the latest science on the subject, spreading misinformation in the process.

            • pulsewidth@lemmy.world
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              1 day ago

              I’ve got no interest in watching even 2.5 minute YouTube videos when I can read the text of the same content in 45 seconds. Instructional videos can be great and valuable, but that’s not what we’re talking about here. There are a wealth of crap pop science videos on YouTube that misrepresent studies.

              The study is interesting, but it’s a feasibility study data utilizing a theoretical models - there are a lot of assumptions here. If they or other researchers go on to perform trials using their proposed flight adjustments to the autopilot software and validate it works, great! Until then, it’s very far from settled science. Here is another recent study that proposes the main problem is incompletely-burned fuel which causes soot particles that sustain the contrails in the atmosphere for much longer than contrails from low-soot contrails, which quickly diaperse. This is an emerging field of study with few published studies and varying ideas on how to resolve issues.

              Maybe if people want to share emerging scientific information that’s important to them on a written forum they should put in the time to look to more valuable text sources, instead of dropping YouTube links with overconfident assertions that will put off people from watching them, eg, “contrails are completely avoidable”.

              • scarabic@lemmy.world
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                19 hours ago

                You have remarkable audacity for continuing to argue the point while also boasting about how you’ll ignore any information that isn’t spoon fed to you in your format of choice. Sooner or later, you’re going to miss something that way and make an ass of yourself, if that didn’t already just happen in front of our eyes.

                • pulsewidth@lemmy.world
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                  18 hours ago

                  God forbid I actually read sources, and prefer reading to taking heads on a video platform that is designed to waste people’s time in endless content crawls.

                  You call me audacious yet here you are stepping into a discussion to try your best to belittle and chastise an internet stranger with a different opinion.

                  • scarabic@lemmy.world
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                    18 hours ago

                    I went to college for English Lit so please don’t lecture me on the virtues of reading. God forbid you stoop to get all the information you can. You are acting like an ass and I’m letting you know. I didn’t get up this morning to chastise you.

                    If there’s any doubt in your mind what you did:

                    1: “this video says you’re wrong” 2: “well I don’t watch videos dahling.” (flips hair, draws on cigarette)

                    See we’re not strangers anymore. You’re that fucking guy who did that fucking thing.

          • Classy Hatter@sopuli.xyz
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            2 days ago

            That YouTube Short seems to be a valid one. It’s by someone who (according to his own words) has a PhD in atmospheric physics. Basically, he says that contrails causes global warming by preventing heat from escaping from Earth, and that contrails are mostly only formed when a plane flies through a cold humid patch. By simply re-routing planes around these cold patches, the contrails could be reduced.

            • phutatorius@lemmy.zip
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              1 day ago

              By simply re-routing planes around these cold patches, the contrails could be reduced.

              And routes now are generally chosen to be the most fuel-efficient, subject to regulatory constraints such as avoiding overflight of areas of high population density. So any alternate path will be longer and burn more fuel.

              • Classy Hatter@sopuli.xyz
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                1 day ago

                According to this one study [1] that focused on Japanese airspace, 2.2% of the flights causes 80% of all contrail energy forcing (EF).

                A small-scale strategy of selectively diverting 1.7% of the fleet could reduce the contrail EF by up to 59.3% [52.4, 65.6%], with only a 0.014% [0.010, 0.017%] increase in total fuel consumption and CO2 emissions. A low-risk strategy of diverting flights only if there is no fuel penalty, thereby avoiding additional long-lived CO2 emissions, would reduce contrail EF by 20.0% [17.4, 23.0%].

                The re-routing can simply be achieved by changing the flight elevation by 2000 feet one or the other direction.

                [1] Teoh, Roger et al. “Mitigating the Climate Forcing of Aircraft Contrails by Small-Scale Diversions and Technology Adoption.” Environmental science & technology vol. 54,5 (2020): 2941-2950. doi:10.1021/acs.est.9b05608

                • 4grams@awful.systems
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                  1 day ago

                  My legit question is then, is the impact on the average temperature by reducing the visible trails greater or less than the impact of adding the emissions from the extra fuel spent.

                  My gut tells me no, those number seem small, but small numbers often lie, and impacts to the chemical makeup of the atmosphere is an ongoing change whereas a trail of condensation is a short lived phenomenon.

                  This is not an argument either way, it seems like a legitimate question to me. It’s also not the question that “chemtrails” conspiracy theorists would ask.

                  • Classy Hatter@sopuli.xyz
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                    1 day ago

                    Here’s a short answer: For a hundred-year time span, “diverting up to 1.7% of the flights could reduce the total EF by 35.6%. The reduction in total EF is contributed almost entirely by the reduction in contrail EF, while the change in the CO2 EF as a result of a diversion appears to be negligible.”

                    Long answer:

                    In that study, they created an algorithm that would divert flights vertically if they are going to create a large contrail, and if diversion is possible (the new airspace isn’t already in use). The algorithm chooses a flight path that has the best total energy forcing (EF). They then applied that algorithm for 6 one-week periods of recorded data. Those weeks were spread around the year.

                    From “Supporting Information” of that research report (the main text isn’t freely available):

                    To compare the climate forcing of contrails and CO2 emissions, the absolute global warming potential (AGWP), the time integral of the [radiative forcing] of CO2 over time, is used as a first-order approximation to quantify the CO2 EF and total EF (contrails plus CO2)

                    Although approximately 25% of the emitted CO2 remains in the atmosphere after a millennium, we applied the 100-year [time horizon] to be in line with the Kyoto Protocol, and assumed that the AGWP is normally distributed in the Monte Carlo simulation

                    For the six weeks of data, diverting up to 1.7% of the flights could reduce the total EF by 35.6% […]. The reduction in total EF is contributed almost entirely by the reduction in contrail EF, while the change in the CO2 EF as a result of a diversion appears to be negligible.

                    If an AGWP of a longer [time horizon] of 1000 years […] is used to quantify the EF of CO2, this sensitivity analysis suggest that the overall reduction in the total EF will be significantly smaller at 12.2% […]. In contrast, the total EF could be reduced by up to 50.1% […] if a shorter [time horizon] of 20-years […] is used.

                    While the potential changes in the global mean surface temperature, quantified using the Absolute Global Temperature Potential (AGTP) are also important, we have refrained from quantifying it because the current level of scientific understanding remains low.

                    Even when considering a thousand-year time span, diverting the flights still has a positive effect. And we can always play with the idea that mankind figures out a way to remove CO2 from the atmosphere, which would make those numbers for shorter time spans more meaningful.

              • scarabic@lemmy.world
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                18 hours ago

                As said in the video everyone refused to watch, it doesn’t require all new routes but occasional 1-2% course deviations or altitude changes for a minority of flights. It’s also claimed that contrails have far, far more warming effect than any additional carbon that might be emitted by this. But hey, he posted it in a video so FUCK HIM, RITE?

            • Chozo@fedia.io
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              2 days ago

              Wouldn’t rerouting be more fuel-intensive in most scenarios, though? I feel like burning more fuel to make fewer clouds isn’t the right play.

              • VibeSurgeon@piefed.social
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                1 day ago

                It would require a slight increase in fuel consumption, traded off with a large decrease in heating caused by the water vapour.

                Seriously, you should watch the video, it covers all of this stuff.

              • Classy Hatter@sopuli.xyz
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                2 days ago

                According to him, the contrails have very potent effect on global warming. Apparently, contrails from just one year’s flights has almost the same effect as all the CO2 emitted by all flights ever. Re-routing extends the flight by only so much, so the added CO2 emission has negligible effect.

            • evidences@lemmy.world
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              2 days ago

              I’m not saying this is wrong because I don’t know shit but when ships crossing the Atlantic were forced to switch to low sulfur fuel a few years ago the North Atlantic rose in temp a few degrees. Turned out the sulfur in the exhaust was causes clouds to form in the atmosphere and was shading the ocean and masking global warming in that region. Pretty much the opposite effect of what you’re saying this dude is claiming.

              • Classy Hatter@sopuli.xyz
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                1 day ago

                Speaking with my limited knowledge, there apparently are cooling contrails and warming contrails, but the warming ones are more common. I don’t know why or when the contrails are cooling or warming.

        • tomi000@lemmy.world
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          1 day ago

          This is a very important piece of info that people who care about reducing flight emissions should know.