1 / 64

The Science of Climate Change

The Science of Climate Change. Explaining why we need to act NOW. Prepared with material from NPL (UK), IPCC, BOM (Aus). Australian Institute of Physics (Vic branch) Education Committee. The Science of Climate Change. What is climate change?

tasha-richard
Download Presentation

The Science of Climate Change

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Science of Climate Change Explaining why we need to act NOW Prepared with material from NPL (UK), IPCC, BOM (Aus) Australian Institute of Physics (Vic branch) Education Committee

  2. The Science of Climate Change What is climate change? Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer).1 Australian Institute of Physics (Vic branch) Education Committee

  3. The Science of Climate Change • Has Climate change occurred before? YES! Australian Institute of Physics (Vic branch) Education Committee

  4. The Science of Climate Change How do we know Climate Change has occurred before? • The Foot-print of Glaciers • Geologists wondered why large boulders occurred in landscapes were they didn’t belong • The shapes of some valleys were U shaped rather than V shape. • Striations (scratches) on rocks Australian Institute of Physics (Vic branch) Education Committee

  5. The Science of Climate Change So why do Ice Ages Occur? The ice ages are believed to be caused by a phenomena called ‘Orbital Forcing’. Australian Institute of Physics (Vic branch) Education Committee

  6. The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  7. The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  8. The Science of Climate Change Why are Ice Ages important in this discussion? The ice ages are part of a cycle where the Earth warms and then cools. Ice ages and CO2 in the atmosphere follow each other Australian Institute of Physics (Vic branch) Education Committee

  9. Ice Ages The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  10. Ice Ages The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  11. The Science of Climate Change How do we know about the atmosphere 100,000 years ago? Australian Institute of Physics (Vic branch) Education Committee

  12. Maximum Value 300 ppm Minimum Value 180 ppm The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  13. The Science of Climate Change • So if this has been happening for ages why are we worried now? Australian Institute of Physics (Vic branch) Education Committee

  14. YOU ARE HERE! Current value 389 ppm variation in the last 400,000 years The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  15. The Science of Climate Change So what makes CO2 so important? CO2 is a greenhouse gas And what is a greenhouse gas? Well I’m so glad you asked! Australian Institute of Physics (Vic branch) Education Committee

  16. The Science of Climate Change The Earth’s atmosphere keeps heat in like a green house. To understand how a green house works we need to take a step back and look at the light energy that keeps us all alive………. Australian Institute of Physics (Vic branch) Education Committee

  17. The Science of Climate Change We use the wave model to help us explain light. Different colours are produced by different wavelengths of light. Australian Institute of Physics (Vic branch) Education Committee

  18. The Science of Climate Change Not all the light that comes from the sun is in the visible spectrum. Australian Institute of Physics (Vic branch) Education Committee

  19. The Science of Climate Change How hot does an object get hot when placed in front of a fire? Australian Institute of Physics (Vic branch) Education Committee

  20. Light from the Sun The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  21. Light reflected from Earth Average Value 100 watts per square metre Light from the Sun Average Value 340 watts per square metre The Science of Climate Change

  22. Average Value 240 watts per square metre Average Value240 watts per square metre The Science of Climate Change Without an atmosphere what would be the average surface temperature? -18 °C

  23. Earth Light from the Sun The Science of Climate Change Light from the sun heats the Earth The Earth then radiates heat away… Australian Institute of Physics (Vic branch) Education Committee

  24. The Science of Climate Change The Earth’s surface temperature is determined by energy in and energy out Heat lost from the Earth by radiation Heat input from the Sun Australian Institute of Physics (Vic branch) Education Committee

  25. The Science of Climate Change The energy in and the energy out determines the Earth’s temperature. So why is the Earth warmer than -18oC Energy gets trapped in our atmosphere and starts to heat the surface up Australian Institute of Physics (Vic branch) Education Committee

  26. The Science of Climate Change • The Atmosphere consists of Australian Institute of Physics (Vic branch) Education Committee

  27. Illustration of atmospheric composition • About 100 molecules • N2 • O2 • Ar

  28. Illustration of atmospheric composition • About 1200 molecules • Water(H2O)

  29. Added in 20th Century Increase in CO2 concentration • About 10000 molecules • Concentration in 19th century • Carbon dioxide (CO2)

  30. The Science of Climate Change What would happen if we only had Nitrogen N2 and O2 (which represents 99%) in our atmosphere? Australian Institute of Physics (Vic branch) Education Committee

  31. Average Value 240 watts per square metre Average Value240 watts per square metre The Science of Climate Change With an atmosphere of only Nitrogen & Oxygen, what would be the surface temperature? -18 °C

  32. +15 °C 33 °C -18 °C The Science of Climate Change Average Surface Temperature Temperature for atmosphere of O2 and N2 Greenhouse Effect

  33. The Science of Climate Change Although they make-up less than 1% of our atmosphere the green house gases of water, H2O and carbon dioxide CO2 are able to contribute 33oC to our surface temperature. So how can these gases have such an effect?? Australian Institute of Physics (Vic branch) Education Committee

  34. The Science of Climate Change Lets look at these gases as a chemist would.. Hydrogen, H2 Oxygen, O2 Greenhouse gasses: Water H2O Carbon Dioxide CO2 Australian Institute of Physics (Vic branch) Education Committee

  35. The Science of Climate Change What is special about H2O and CO2? • Their molecules havethreeatoms • Their natural frequencies of vibration are in the infra-red Australian Institute of Physics (Vic branch) Education Committee

  36. The Science of Climate Change It is this difference which has a huge effect on how they absorb and reflect light energy. Nitrogen, N2 and Oxygen, O2 are able to absorb high spectrum light energy like UV. They protect us from these harmful rays, but they allow visible and infrared through Greenhouse gases like Water, H2O and Carbon Dioxide CO2 are able to absorb lower spectrum light energy like infrared. Australian Institute of Physics (Vic branch) Education Committee

  37. Ultra Violet Visible Infra Red

  38. Others <1 °C CO22 °C H2O31 °C What determines the Earth’s surface temperature? Greenhouse Warming 33 °C

  39. The Science of Climate Change So greenhouse gasses drive our planet warming which is good because we’d all be pretty cold at -18oC. But our 15oC average depends on our greenhouse gases level remaining constant, that is our energy in and energy out stabalises Australian Institute of Physics (Vic branch) Education Committee

  40. On Average 240 W/m2 On Average less than 240 W/m2 Average Value 240 W/m2 150 W/m2 sent back to Earth Light energy sent back to Earth Light Energy sent back to Earth Light Energy sent back to Earth On Average 240 W/m2 On Average 280 W/m2 On Average 320 W/m2 On Average 390 W/m2 The Science of Climate Change • In balance at + 15 °C…

  41. The Science of Climate Change The Earth’s surface temperature is determined by energy in and energy out which in turn is determined by the greenhouse effect Heat lost from the Earth by radiation Heat input from the Sun Australian Institute of Physics (Vic branch) Education Committee

  42. YOU ARE HERE! Current value 389 ppm variation in the last 400,000 years The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  43. The Science of Climate Change CO2 is a particular problem because it hangs around, unlike water that cools in the atmosphere and then precipitates as rain and snow. Australian Institute of Physics (Vic branch) Education Committee

  44. The Science of Climate Change CO2 does get used up by green plants but the amount we are pumping in is more that the amount used. Australian Institute of Physics (Vic branch) Education Committee

  45. The Science of Climate Change CO2 does get absorbed into the oceans but this makes them more acidic which has implications for marine life. Australian Institute of Physics (Vic branch) Education Committee

  46. The Science of Climate Change Looking to the future…. Scientists use mathematical models of the climate to try to work out where this might lead. These models are extremely complicated as small changes have flow on effects. We test the accuracy of these models by applying them to the past and seeing if they will give results that match known data. Australian Institute of Physics (Vic branch) Education Committee

  47. The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  48. The Science of Climate Change Australian Institute of Physics (Vic branch) Education Committee

  49. The Science of Climate Change But what about reports that say the average temperature has dropped since 2000….. Australian Institute of Physics (Vic branch) Education Committee

  50. Observed Temperature changes But its not just average temperature that matters http://www.cru.uea.ac.uk/cru/climon/data/themi/g17.dat

More Related