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
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