The Greenhouse Effect

In this video Paul Andersen explains how the greenhouse effect and greenhouse gases keep our planet warm enough to be habitable. He explains how greenhouse gases keep heat closer to the surface. He finally shows how increases in greenhouse gases may lead to dangerous global warming.

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Music Attribution
Title: String Theory
Artist: Herman Jolly

All of the images are licensed under creative commons and public domain licensing:

[KarollaynneCosta]

I've been watching your videos since middle school, and I'm currently in College right now, and I couldn't find any other youtube channel that helps me so much like yours. I wish you were my professor! Great content! Thank you so much!

[grindupBaker]

The underlying heat-adjustment effect works like this:

"GREENHOUSE EFFECT", TRYING TO WARM IF THE QUANTITY INCREASES
- Solids in the troposphere have the exact same effect as the "cloud greenhouse effect" above for the exact same reason.
- Infrared-active gases in the troposphere (H2O gas, CO2, CH4, N2O, O3, CFCs) have the exact same effect as the "cloud greenhouse effect" above for the exact same reason. Non infrared-active gases in the troposphere (N2, O2, Ar) have no "greenhouse effect". The "greenhouse effect" really is that simple, and it's utterly 100% certain.

SUNSHINE REFLECTION EFFECT, TRYING TO COOL IF THE QUANTITY INCREASES
- Solids in the troposphere also absorb & reflect some sunlight and the "reflect" part has an attempt-to-cool effect, which has nothing whatsoever to do with the "greenhouse effect".
- Infrared-active gases in the troposphere (H2O gas, CO2, CH4, N2O, O3, CFCs) do not absorb or reflect any sunlight (minor note: except a tiny portion in the high-frequency ultraviolet where O2 & O3 has absorbed most of it already in the stratosphere above the troposphere).

NET EFFECT OF THE 2 ENTIRELY-DIFFERENT EFFECTS DESCRIBED ABOVE
- The net result of the 2 entirely-different "cloud" effects is that clouds have a net cooling effect of 21.1 w / m**2 as seen in the blue-hues pictorial at left on screen at either of my 2 GooglesTubes links above.
- The net result for solids in the troposphere is a net cooling effect because the change in this effect by humans is the "global dimming" atmospheric aerosols air pollution effect and that's a cooling effect (separate from its cloud change effect).
- The net result for infrared-active gases in the troposphere (H2O gas, CO2, CH4, N2O, O3, CFCs) is a warming effect because their 2nd effect above is negligible, essentially zero.

[Tschoo]

I always think of the matrix when you introduce yourself as "Mr. Anderson"

[aphidsfirst]

There was no explanation of the mechanism of the greenhouse effect. Did I miss something. You were overly focused on albedo, but no explanation of how more greenhouse gases result in a warmer atmosphere. Also, there was no warming in 1750. That industrialization had negligible effect on greenhouse emissions. It was not until the latter half of the 19th century that industrialization grew to the point where emissions began affecting global temperature.

[elk]

I would strongly encourage Mr. Anderson to consider his usage of "radiation" and "heat" which are not the same (but can be converted from one to the other). I would encourage anyone watching this video to find videos about light absorption, the definition of heat and atomic spectra to get a more fundamental picture of what is happening.

[modolief]

Why do the atmospheric molecules H2O, CO2, CH4 absorb infrared photons whereas N2 and O2 do not? I've heard it has something to do with the fact that H2O, CO2, CH4 are asymmetric molecules. But what exactly is the technical explanation of this?

[wrath]

Are you saying that planets which do not have greenhouse gases will not have not have any temperature increase as you move towards the core. A gas planet like Jupiter has much higher temperature at its core than at the edge of the atmosphere. It does not have greenhouse gases. Also you do not explain how a surface at + 15c radiates the same energy into space as a surface at - 15c. Are you saying some of the energy never gets into Space, if so then surely the Earth would just keep getting hotter and hotter?

[faelevon]

I'm making a solar oven in school and was wandering how the heat stayed in the box and this helped.

[grindupBaker]

Here's How the "Greenhouse Effect" Works (my 6th great explanation method of the same thing). Suppose there's average 345 w/m**2 of downwelling LWR radiation into the surface and 199 w/m**2 of LWR radiation heading up from the top of the troposphere. Just Suppose. The LWR is manufactured by collisions of infrared-active "Greenhouse Gas" molecules in the troposphere. The fact that the total of 345+199 = 544 w/m**2 isn't split evenly into 272 w/m**2 of downwelling LWR radiation each into the surface and out of the troposphere top means there's a "Greenhouse Effect" from those gases in the troposphere and an obvious measure of "Greenhouse Warming Effect Factor" is 345/199-1 because if they were both 272 then Factor would be 0.000 and if there was more heading up than into the surface then the Factor would be -ve (it would be a cooling Effect).

So suppose I calculate how much more GHGs I need to get 1 w/m**2 extra of global heater Earth's energy budget imbalance (EEI) and mix those GHGs in the troposphere with a big spoon and INSTANTLY 2 things happen:
- LWR radiation heading up from the top of the troposphere drops from 199 w/m**2 to 198 w/m**2
- LWR radiation downwelling and penetrating the surface jumps from 345 w/m**2 to 346 w/m**2
There's been no temperature change but a global heater of 1 w/m**2, 510 terawatts, 16 Zettajoules / year, just got turned on (the total, net, heater or chiller is the sum of all heaters & chillers in operation).
The reason why LWR up from the top of the troposphere dropped from 199 w/m**2 to 198 w/m**2 is that what gets out is manufactured on average higher up than before because there are more absorbing molecules to get past, and higher air is colder so it manufactures less LWR (fewer collisions than warmer air and less violent).
The reason why LWR down from the bottom of the troposphere (into the surface) rose from 345 w/m**2 to 346 w/m**2 is that what gets out is manufactured on average lower down than before because there are fewer absorbing molecules to get past, and lower air is warmer so it manufactures more LWR (more collisions than colder air and more violent).

That was the "Greenhouse Effect". I omitted the stratosphere because it works backwards for well-mixed GHGs CO2 & O3 (but normal operation for H2O gas) causing slight cooling to offset a bit of the warming so it can't be visualized for both combined. I neglected to bookmark the scientist talk where he showed the calculations from 4 or 5 teams with the Greenhouse Effect at top of troposphere and slightly smaller Greenhouse Effect at TOA because the stratosphere works backwards (just apply my simple correct science explanation but backwards). It's a complicating detail not required to explain the "Greenhouse Effect" physics. It just means my "1 w/m**2 extra of global heater" was a slight exaggeration to keep it all simple, maybe 0.9 or 0.85 or 0.8, I dunno, it's irrelevant).

So now that I've instantly turned on ~1.0 w/m**2 extra of global heater the ocean, land & air warm over the next 2, 000 years and after 2, 000 years my 198 w/m**2 above has finally crept back up to 198.95 w/m**2 and warming stops, by which time my 346 w/m**2 downwelling into the surface has jumped to ~347.7 w/m**2 and the warming has stopped. It stopped at 198.95 instead of 199 because the "window" 9-13 microns went up by 0.05 w/m**2. As I pointed out the numbers aren't scientist accuracy because I ignored the stratosphere complication because I'm explaining how it works not calculating a quantity except in the ball park for illustration.

[kevinrichardson]

Sounds plausible, but is complete sophistry. These is no radiative greenhouse effect and CO2 doesn't warm the atmosphere. The atmosphere helps to keep the earth warmer. But that is called insulation. And it is controlled by heat capacity, convection and latent heat exchange bywayof the water cycle. Your explanation is gibberish.

[gabbiemilxa]

I might just sue my teacher for torturing my classmates by doing long 56 pages of slides on one video

[thailandlife]

during the dinosaur age, an age spanning more than 200 million years, the earth ranged from 1000-2000 ppm. Why didn't this cause an extreme earth burnup? I bet if you plugged in 2000 ppm into your program your computer would have exploded

[bakernate]

So the earth warms the atmosphere right?

[fractalnomics]

5:18 If CO2 is trapped in the ice record, and by its nature - specially  - traps heat, why doesn't it account for avalanche and snow pack instability? It is in the snowpack - at around a factor of 10 times more than the atmosphere, but no mention of it in literature or practice. If it did we'd know and we would measure monitor it. Or is it that it does cause avalanches, and I have made a great discovery. All avalanches are caused by the CO2 trapping/ changing heat in the snowpack.

[shiloahkelley]

Thank you soooo much for posting your videos. It has done wonders in helping me understand science!!!! Thanks again!

[Smiirffable]

Water vapour isn't really considered a green house gas because its concentration in the atmosphere is variable depending on air pressure and how much of it is evaporating/falling back down as rain or snow. Even if all the water in the world evaporated right now, it would all fall back down as rain because the atmosphere wouldn't be able to support its weight. 

[bartonpaullevenson]

An agricultural greenhouse works mainly by suppressing convection.

[shockey]

I don’t understand how the atmosphere is cold yet that somehow heats the surface of the earth? The higher you get into the atmosphere the colder it gets, so how can heat “radiate” from something that is cold?

[adamwilliams]

Good job man, you are really helpful and you make it all so clear! I appreciate the help and keep up the good vids

[christianalvarez]

An actual greenhouse works due to the lack of convection with outter cold air... not due to radiative reflection