Green chemistry: webquest

1. Ben Lapworth Green chemistry: webquest

2. Global warming… • The increase in average temperature of the earths surface caused by an enhanced greenhouse effect due to increased concentration of greenhouse gasses in the atmosphere.

3. How do the greenhouse gasses do it? • Well, its quite simple really. It all starts at the sun. due to the sun’s immense ferocity of heat it emits huge masses of energy in the ultraviolet, visible light and infrared regions of electromagnetic radiation. • To try and regain some sort of balance the earth has to re-emit some of this energy, but as it’s a fair bit cooler than the sun it only has enough energy to re-emit infra-red radiation.

4. Yeah, finished there, simple really? • Not quite. In the earths atmosphere there is some gasses (known as greenhouse gasses) determined to make it more confusing, annoying and warmer (not to mention prolonging this homework!). • The 3 main suspects in the stratosphere and troposphere are; water vapour, methane and carbon dioxide.

5. But what do these 3 gasses have to do with anything? • Quite a lot actually. They affect the re-emission of infra red radiation by preventing It from leaving our atmosphere. • As the earth emits this radiation trying to get rid of it, these gasses absorb it thus keeping it locked in our atmosphere.

6. Actually, that’s not a fair comment. Its not the fault of the atoms within the gas molecules, but the bonds holding these atoms together that are to blame! • The c=o bond (carbon dioxide), the o-h bond (water) and c-h bond (methane) are all to blame. They can stretch, twist or bend to receive the energy from the infrared radiation.

7. This is a very large contributing factor in what we call global warming. If the earth cannot emit this extra energy, then it remains in our atmosphere, thus increasing the temperature (because these molecules will reemit some of the energy- back to the earths surface!).

8. The greenhouse effect… • The ‘greenhouse effect’ of a given gas is how gasses can absorb infrared radiation emitted from the earths surface and then re-emit some of this energy back too the earths surface. • This greenhouse effect is present on water, carbon dioxide and methane molecules. It can be increased dependant on atmospheric concentration and ability to absorb radiation.

9. concentration • Concentration is basically how much of a species there is per unit volume. • If there is more ‘stuff’ in less space, there is a high concentration. • The concentration of greenhouse gasses affects the emission of infrared radiation from earth. With more greenhouse gasses filling up space in the atmosphere, there are more opportunities for radiation to be absorbed.

10. Due to humans (and some other natural occurrences) constantly dishing these greenhouse gasses into the atmosphere, there are more and more of them filling up the same amount of space. • This just means that radiation is more likely to be emitted and re-emitted (back to earth) increasing global warming one molecule at a time.

11. Ability to absorb infrared radiation. • Carbon dioxide has a relatively small ability to absorb radiation (infact it has a greenhouse factor of one) but due to its huge concentration in the atmosphere it still contributes to 60% of the greenhouse effect. • Methane has a larger ability to absorb radiation (factor 30) but is less concentrated in the atmosphere so contributes to 15-20% of the greenhouse effect.

12. Something needs to be done, right? • This could end up quite messy. There's a chain of events leading from the ignition key on your car, to the polar ice caps melting and the end of the earth as we know it. Okay, maybe a little dramatic for now, but whilst its possible…

13. But we can just about salvage our fate! • We need to work collectively, as the great human race, to do something about this global warming (leading from atmospheric increases in greenhouse gasses). • Whilst there are many natural excretions of these harmful gasses into the atmosphere, there are also many unnecessary ones being pumped out into the atmosphere by humans.

14. We CAN, we MUST, we NEED, to do something about it. • Limiting the amount of fossil fuels burned by us, is the most obvious answer. These are the things that emit shed loads of carbon dioxide into our atmosphere, where it sits there, stealing the infrared energy and chucking it back at us.

15. First step is too use this as little as possible. Why drive a car when you can walk or cycle (or even lift shares and busses limit the amount being burned)? Why get a ferry when you could swim to Australia? Okay, maybe slightly exaggerated but you get the point. Stop unnecessarily burning fossil fuels! We know where you live….

16. The key thing to do, however, is to find an alternative bio source of energy. I don’t mean a hamster running in a wheel to spin a turbine, I mean a proper source of energy. • We are grasping the concepts of solar energy, wind energy, hydroelectric energy and even geothermal energy. We have an understanding of how these make energy, but now we need to make them more efficient.

17. Global warming is happening; LOOK!

18. Carbon storage • This is a way of collecting potentially harmful carbon dioxide, piping it underground and storing it between rock formations below the earths surface. The carbon dioxide could react with substances under the surface to make carbonates, this would make them easier to store below the earths surface as solids aren't as likely to escape as gasses.

19. And finally! • The Kyoto protocol was made so nations could agree to fight global warming. Countries agreed to limit there emissions of greenhouse gasses. • It’s a start, but major nations such as America, Australia, china and India refused to sign it.