Why does CO2 cause the Greenhouse Effect? | Climate Chemistry


So just a few days ago, I had a date… Wait is this meant to be a date?? Yes, it’s November 3rd. You know that’s not what I meant— Oo good idea, let’s talk about climate change. But I didn’t even — So probably my favourite thing about the greenhouse effect… Oh now there’s a point. … is that it’s got such a cool name! Or should that be warm name..? No, but seriously there is something I’ve always wondered about the greenhouse effect. Now I know what the greenhouse effect is. Ah the greenhouse effect. Light energy from the sun passes through our atmosphere, and gets absorbed by the Earth’s surface. But some of the lower frequency light the Earth reemits gets trapped by greenhouse gases like CO2. The more of these gases, the more energy gets trapped, and the warmer the world gets. I said I knew what the greenhouse effect was! But what I don’t understand is why this happens! What is it about carbon-dioxide that only traps the light on its way out? What is it about these tiny CO2 molecules that make them work like this?? That’s a good question. And I’ll explain everything… … in due course. Why are you talking so ominously? What’s going on? Why is it fading to black?? Experiment time! Our experiment starts with carbon sleeping in the ground in the form of fossil fuels. It’s been sleeping there for millions of years. But then… we dig it up. I said… WE DIG IT UP! Oh my god what is happening? We’re learning how carbon causes the greenhouse effect… like you wanted! Now you’re fossil fuel carbon and we’re digging you up. Oh… OK..? OK so I am fossil fuel carbon and you’ve just dug me up. When does this start having anything to do with the greenhouse effect? Well for the greenhouse effect, we first need to add two oxygen atoms to our carbon atom to form CO2. I’m not picking up those incredibly bulky weights. Well that’s understandable… Just like in a power plant or a car, to go from fossil carbon to carbon dioxide, we first need to… burn it! OK, OK! I’ll take your stupid oxygen atoms. Now you’re carbon-dioxide: a gas! This gas gets released into the atmosphere. And that’s where the greenhouse effect happens! The atmosphere..? Come on.  Shoo. Out. Out into the atmosphere! C’mon! So here we are. The atmosphere! OK so this is where the greenhouse effect happens? And this is where the magic… I mean, the greenhouse effect happens! So light energy from the sun passes straight by carbon dioxide without much effect. *HIGH VOICE* Come on CO2. *HIGH VOICE* Aren’t you going to do anything?? So the light energy from the sun zips past CO2 and nothing very exciting happens. But the light energy the Earth re-emits… that’s a different story. This has a different, lower frequency and that really gets CO2 moving! *DEEP VOICE* Come on carbon-dioxide! *DEEP VOICE* Let’s see what you can do, maggot! As you can see the lower frequency light from the Earth really gets carbon-dioxide moving. That’s because this light has just the right frequency for CO2 to absorb it. When CO2 absorbs it the molecule starts wiggling. And there’s one wiggle that’s especially
important. *DEEP VOICE* Come on! *DEEP VOICE* Up – down – up – down – up – down! This wiggle is special, because Earth emits lots of energy with just the right frequency to get it going. Every time a wiggle’s kicked off, it absorbs energy at this special frequency. It’s only because of the two oxygen atoms that the molecule can absorb low [frequency] light so well. A carbon atom on its own… … doesn’t really do anything! Y’see: *DEEP VOICE* Up – down – up – down – up – down! No. So, the CO2 molecules aren’t really bothered by the light that the sun emits, which just passes through the atmosphere and heats up the Earth’s surface. But the light that the Earth re-emits has just the right frequency to get the CO2 molecules moving. That means carbon dioxide absorbs this energy, keeping the world warm. The greenhouse effect is completely natural – and important! Without it the world would be way too cold for comfort. But we’re adding more and more CO2 into the atmosphere, and this is making the globe warmer and warmer… There should really be a name for that… You mean.. global warming..? Y’know carbon atoms can’t actually talk. I can’t believe you dragged me out of bed for this! Thanks a lot for watching. This was the first of a two part series I’m making on the chemistry of climate change. The second part will be all about methane and why it’s different to carbon dioxide. If you don’t want to miss that make sure
to subscribe. And while you’re here why don’t you give
this video a like and leave a comment. Until next time… Bye!

Comments 9

  • CO2 isn't the only greenhouse gas we've got to worry about. So don't miss the follow up to this episode – all about methane:
    https://youtu.be/a_hKx7EuHek
    Cos nothing's hotter than a gas produced by rotting garbage!

  • Theres no evidence that co2 is pollution. There are computer models with co2 as the only variable. And every single one has been wrong…. As for actual science.

    The idea that CSP is invariant is absolutely wrong. Radiation physics, specifically the SB Law requires that the Ts^4 relationship between temperature and emissions be honored, thus dTs/dP is 1/(4eoTs^3), which is the SB Law integrated with respect to Ts and then inverted and which has a 1/Ts^3 dependence on the surface temperature and definitely not temperature independent. Since in the steady state, total forcing is equal and opposite to total emissions across any Gaussian surface surrounding the planet, P == F, thus the steady state dTs/dP and dTs/dF are the same at each such surface. Only the equivalent emissivity, e, will be different starting at 1 at the surface whose temperature is Ts decreasing to about 0.61 at TOA.

    What confuses some is that 1 calorie raises the temperature of 1 gm of water 1C, which is a linear, invariant relationship between temperature and stored energy. However; this relationship assumes that the water is receiving energy at a far greater rate than it’s radiating energy away while the Earth is radiating energy at the same rate that it’s receiving it. If the energy radiated by the Earth did not change in response to to a change in forcing, then Ramathan’s estimate of CSP would be closer to being correct. The planet responds very quickly to changes in forcing, the evidence being the difference between night and day.

    The IPCC adds confusion by calling the sensitivity an incremental metric and fails to acknowledge that all of the accumulated forcing from the Sun must have the same effect, thus the incremental sensitivity and the absolute sensitivity must be the same. The absolute sensitivity is 1.6 W/m^2 of surface emissions per W/m^2 of solar forcing corresponding to about 0.3C per W/m^2. That the incremental gain (which climate science incorrectly refers to as the sensitivity) and the absolute gain must be the same is one of the necessary conditions for Bode’s feedback analysis to be valid and that Hansen/Schlesinger ignored when fabricating their bogus feedback claims based on Bode’s amplifier analysis.

    It’s absurd to think that the next W/m^2 can increase surface emissions by 0.8C corresponding to an increase in emissions of 4.3 W/m^2 while each of the 240 W/m^2 of prior forcing only added 1.6 W/m^2 to the surface emissions. If each of the 240 W/m^2 of solar forcing resulted in 4.3 W/m^2 of surface emissions, the surface temperature would be close to the boiling point of water! Moreover; the 1/T^3 dependence of the sensitivity means that the incremental sensitivity expressed as degrees per W/m^2 must be less than the average for all W/m^2 that preceded.

    They add more confusion by obfuscating the Joules deficiency supporting their absurd sensitivity by expressing sensitivity as degrees of surface temperature per W/m^2 of forcing, rather than the proper, linear gain metric of W/m^2 of surface emissions per W/m^2 of forcing.

    More confusion is added by referring to increased atmospheric absorption as forcing. Only the Sun forces the system and at best you can say that increased atmospheric absorption is EQUIVALENT to an increase in solar forcing while keeping the atmosphere constant. They also tend to apply the equivalent forcing to a modified system counting the effect twice. If the Sun emits nothing, no amount of CO2 will make a bit of difference to the surface temperature, thus it’s concentration can not be considered forcing. This leads to another level of obfuscation which recasts sensitivity as the effect of doubling CO2.

    Yet more obfuscation arises from the bogus RCP scenarios. There are so many levels of obfuscation and misrepresentation leading to confusion, I’m not at all surprised that so many on both sides are so incredibly confused.

  • Hello Adam – may I ask, do you live near London?

  • I recognise those bins!

  • Absolutely love it ClimateAdam!
    You have a talent for this!
    Trump and his "friends" in Russia and Saudi Arabia should listen to this! 🙂

  • 3:27 the symmetric stretch is not IR active.

  • I appreciated your clever explanation. You could have gone into a bit more detail as to how the increased wiggling of the CO2 molecule is converted into heating the general atmosphere. The wiggling represents heating of the molecule which transfers its thermal energy to the surrounding atmospheric molecules. That heats the lower atmosphere and in turn keeps the surface of the earth warm.

    Many climate science deniers have come to believe that the mechanism is that the CO2 molecules serve as a reflector of the infrared energy and as a result it reflects it back to the earth in a radiative heat transfer process.

  • CO2 as a primary cause for Climate Change is nonsense. CO2 is too fractional in atmosphere & too limited in its IR bands that can respond. "If" AGW exists,, it is certainly NOT caused by CO2 ; unless you're gullible and want a new religion with a crusade.

  • This channel has potential 🙂 keep it up.

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