@AdamRidley11
The predominant warming effect in a greenhouse is from stopping convection not from reflecting radiation. This is further proved by replacing your glass panels with polycarbonate (almost transparent to infrared). Because polycarbonate has lower thermal conductivity than glass you will actually get a warmer greenhouse despite virtually no infrared reflection at the panels. Another major factor in blocking convection is that you build up the relative humidity which in turn helps absorb the infrared emitted from the surfaces inside.
@gefginn3699
Great post Sabine. I'm glad you have the patience to gather all this information and package it nicely here. You are a trooper. So many variables would make me feel overwhelmed. 🤩
@JonPMeyer
That was an outstanding explanation! Thank you for not trying to simplify everything to the point at which your explanations become incorrect. I have been trying to understand how to correctly explain the warming effect of certain gases for many years and I have NEVER heard anyone explain the “altitude” issue like you did. Also, I really appreciate the explanation of stratospheric cooling and why that prediction supports the human-caused climate change story. There is quite a bit of good science content on YouTube these days, but your channel is among a very small number of really great ones!
@ElonTrump19
"I think where I got this wrong" - So let's summarize: 1 - Early climate models of CO2 show an inherent possible balancing. 2 - long term data seems to confirm this model. The climate data you've shown seems to indicates that nature, Mt Pinatubo , not man has the greatest effect in regards to CO2. 3 - We are talking about a small effect with limited range. 4 - Our sun provides the bulk of the heat we feel. Does anything I have mentioned suggest we are in a "world ending crisis" which demands that we submit to the will of those who know better? We know the earth has been a lot warmer and we know it has been a lot cooler. Yet we are still here. Sabine, I greatly appreciate your content!
@douglasmackenzie3566
Sabine, Emissions altitude is a mathematical construct quite similar to calculating the the average depth of snow in North America. So is actually an after-the-fact calculation based on previous assumptions. A lot of IR gets from the ground all the way to outer space through the atmospheric window from about 8 to 14 microns wavelengths. This actually covers the peak emissions temperature of the entire surface to cold cloud tops in differing amounts depending on wavelength and cloud cover…You are capable of checking how much yourself. If you apply Planck’s law to say 5 degrees instead of the 1 degree we often look at, you realize there will be a heat imbalance driving the assumed temperature colder again by the “Planck feedback” as the warm surface radiates more to outer space than it “receives”. Yes bands broaden, but not enough. You have to invoke more clear sky, thus lower planetary albedo to get enough sunlight watts to surface….but higher temperature is likely to cause more clouds, thus higher planetary albedo,as the higher resultant water vapor convects upward. So this indicates that “global warming” is limited by Planck’s law. Pierrehumbert Fig. 4.44 plus a Stephan Boltzmann calc of IR are instructive in this calculation. BTW, use of Modtran is much preferable to the emissions altitude approach. Wishing you luck as you continue.
@john_hunter_
Interesting that I haven't seen a proper explanation of the greenhouse effect until now.
@Criterion5
Please note your info graphics exaggerate the thickness of the atmosphere. 60 miles deep on a planet 8000 miles in diameter would result in a drawing about the thickness of a sharpie pen nib.
@bahchiin
Thanks!
@fotoyartefotoyarte1044
so, I´m a "normal" guy (let´s say);I´ve been trying to figure out how much of this climate emergency really makes sense or if it´s all a vicious circle, an emergent phenomenon of bad science caused by pervesive incentives. People calling doubters "anti science" doesn`t work. This kind of explanations on the other hand, ARE what we need. Thank you Sabine
@bobtarmac1828
My go-to science teacher. Thank you!!
@mathswithgarry7104
It would be interesting to see a discussion about the effect of clouds reflecting heat back to space, which is a feedback effect.
@Marley-ii6ls
I would once and for all like to see a proper exhaustive, comprehensive, discussion where scientists from opposite sides of the discussion go head to head until every aspect of this issue is thoroughly hashed out once and for all. From my understanding the climate alarmists will not take on this challenge. I suspect because they would have nothing to gain, since they have political momentum on their side and could possibly lose credibility if the inconsistencies of their arguments were exposed. Another problem with assembling a proper discussion is that the politics surrounding this issue is sickening. Scientists are afraid to speak up with valid points against the alarmists statistics in fear of ending their careers by the orthodox establishment.
@MikkoRantalainen
Another great video, great work! I'll be sharing links to this video for sure. One suggestion for the video production: it sounds like your mic setup is prone to have sibilance issues so I would recommend adding de-esser filter to your audio post-production setup.
@emkcams
Thank you for a very informative video explaining the basic mechanism of trapping heat. Next it may be informative to get into the issue of magnitude. But, as suggested near the end, I imagine that is a very complicated topic for the lay person (such as myself).
@clivemitchell3229
I think the most important effect of a greenhouse is that it keeps the cold wind out.
@potsmkr87
I'm not really a climate denier, but i dont understand why the positives of CO2 and higher temperatures are never discussed, personally i think they far outweigh the negatives. greener planet, easier to grow food for 8+ billions, and most of the planet would have a positive effect from warming.
@MostlyIC
Dr Hossenfelder, when the sunlight hits my skin I feel it as heat, so the question is what part of the spectrum is making it through the atmosphere and causing that feeling in my skin. I think my confusion is that I tend to think it is the infrared that I feel from the sun (because that's what I think I feel for example next to a wood-fired black cast-iron stove), so in my mind the infrared shines unhindered from the sun to my skin, and therefore the "greenhouse" effect doesn't make sense to me. I also have some competing thoughts that I can't make sense of, the first is I also think that if the atmosphere does absorb heat at various wavelengths then there must be a measure, something like "cross section", that says what depth of atmosphere is required to absorb 1/2 the radiation at that wavelength, and I'd like to know both how the atmosphere's "cross section" varies with wavelength and also with altitude. the second is that water vapor clouds completely obscure visible light, and the question is what other wavelengths are similarly obscured by what atmospheric contents.
@HaydenHatTrick
Very helpful. I've done physics and chemistry and I avoid the topic. When forced to speak on it I say "Despite all the hubabub, I've never had climate change or global warming explained to me properly. I haven't recreated any models myself and if I cant model it I don't talk about it." Now, I do know a few facts here and there, but this certainly helps me point people in the right dirrection.
@robertmolldius8643
Thanks Sabine! 🇸🇪 I put this as a basis for further studies. I have long promised myself to familiarize myself with what it is that basically constitutes our global warming. It's complex to get a gripp on, but with the prevailing weather in Sweden, the holiday is best enjoyed during a scientific exploration. 🙂👍🇸🇪🇸🇪🇸🇪
@SabineHossenfelder