Climate Science

1. This presentation is designed for those who wish to provide a reasoned argument against the ever proliferating confusion over climate science. Newer versions of this presentation and others can be found at: www.vicphysics.org Follow the link from the ‘Climate Change’ link on the ‘Home’ page. Be sure to look at the ‘Notes pages’ (below) for added comments to help in presenting and for more information and sources. Please feel free to email me with suggestions for improvements or useful comments. This presentation is designed for around an hour (or more with expansion of some of the points) Latest version 23 Feb 2010 Climate Science Keith Burrows Science Teachers for Climate Awareness

2. Countering Climate Confusion What to say to ‘sceptics’ Download from www.vicphysics.org

3. CCC – Main Points Countering Climate Confusion • The basic reason for concern is the fundamental science (not rising temperatures or sea levels). • CO2 captures heat radiation from the ground and sends it back. • The greenhouse effect is well understood. It is crucial to life on Earth. • We know we are increasing the greenhouse effect. The question is by how much and what will happen. • We know the Earth is capable of wild swings of climate from ‘Snowball Earth’to‘Hothouse Earth’.

4. CCC – Basic science • First counter: Why won’t adding more CO2 to the atmosphere increase the greenhouse effect? • Virtually all major scientific bodies have stated that continued anthropogenic CO2 emissions will ‘almost certainly’ cause damaging climate change. • Here’s a partial list...

5. Some scientific bodies who have issued statements stressing the need for action on climate change – USA only • National Academies of Science • National Research Council • American Association for the Advancement of Science (AAAS) • National Oceanic and Atmospheric Administration (NOAA) • National Center for Atmospheric Research (NCAR) • NASA's Goddard Institute of Space Studies (GISS) • American Institute of Physics • Woods Hole Research Center • Union of Concerned Scientists • Federal Climate Change Science Program • American Geophysical Union • Geological Society of America • American Chemical Society - (world's largest scientific organization) • Federal Climate Change Science Program - commissioned by Bush! • American Association of State Climatologists • US Geological Survey • Environmental Protection Agency (EPA) • Pew Center on Climate Change

6. Some scientific bodies who have issued statements stressing the need for action on climate change – Rest of World • UN Project on Climate Variability and Predictability • United Nations Framework Convention on Climate Change (UNFCCC) • United Nations Environment Program • World Meteorological Organization • International Council on Science • The Royal Society (UK) • The Institute of Physics (UK) • Canadian Meteorological and Oceanographic Society (CMOS) • Geological Society of London • The Australian Academy of Sciences • The Institution of Engineers Australia • The Australian Meteorological And Oceanographic Society • … and many more!

7. CCC – Basic science • Second counter: • It is easy to create confusion, about climate science, but much harder to clarify it. • Denier arguments often ‘look reasonable’, but always fall downon close inspection. But all they need to do is create confusion. • This is strong evidence that climate change is serious!

8. CCC – Risk management • Third major counter:

9. Would you get on this aeroplane if 1 out of 10 engineers found dangerous cracks in the wings?

10. How about if 9 out of 10 engineers said there were dangerous cracks in the wings but 1 said they didn’t matter?

11. That’s about the proportion of climate scientists saying climate change is dangerous!

12. That’s about the proportion of climate scientists saying climate change is dangerous! “This image was digitally altered!” Actually it is more like over 95%

13. CCC – Risk Management • Normally we don’t take risks where lives are at risk.

14. CCC – Risk Management www.gregcraven.org

15. CCC – Risk Management www.gregcraven.org

16. CCC – Risk Management Disaster!

17. CCC – Risk Management “What if we create a better world and it turns out we didn’t need to?”

18. CCC – Risk Management Do the ‘sceptics’ ask themselves this question? www.gregcraven.org

19. CCC – Risk management • Third major counter: Genuine sceptics will answer this by saying we should take precautions. Deniers simply don’t seem to hear the question! What if you are wrong?

20. ‘Climate sceptics’ and ‘climate deniers’ Climate sceptics • Scepticism is an important part of science. Scientists always try to question and test their theories. • Scientific sceptics discuss their questions with other scientists through the peer reviewed journals. Climate deniers • Deniers take the supposed ‘debate’ to the public – inappropriately. They avoid discussions with the scientific community. • Deniers express no doubt about their position – or they would have to take action in case they are wrong.

21. Countering Climate Confusion • So: • Basic science says adding CO2 must warm the Earth. • Confusion is easy, but hides a potential catastrophe. • Why on Earth would we risk the only planet we have? • A little more on each of these...

22. CCC – Some basic science • Why is the Earth at just the right temperature for us?

23. The Big Picture

24. The Big Picture EARTH: Atmosphere: N2 , O2 , H2O and a little CO2 Mean temperature: +15oC Just right! Why?

25. CCC – Some basic science Earth’s energy balance

26. So what determines the Earth’s temperature? • The balance between the energy coming in • ... and that going out.

27. CCC – Some basic physics • Earth’s energy balance • Two simple laws of physics enable us to figure out the energy balance: • The Stefan-Boltzmann law... I = εσT4 • Wien’s law... λmax = 0.0029/T • S-B just tells us how much heat a hot object radiates. • Wien tells us what sort of radiation it will be. (but fortunately others have done the hard work for us!)

28. CCC – Some basic physics • Svante August Arrhenius worked it out in 1896

29. CCC – Some basic physics ? • Svante August Arrhenius worked it out in 1896 “The Earth’s average temperature should be about –18oC”

30. CCC – Some basic physics • Svante August Arrhenius worked it out in 1896 “Ah! The atmosphere must be trapping the heat”

31. CCC – Some basic physics ? • Svante August Arrhenius worked it out in 1896 “But Oxygen and Nitrogen can’t absorb the infrared radiation”

32. CCC – Some basic physics • Svante August Arrhenius worked it out in 1896 “It must be the water vapour and carbon dioxide!”

33. CCC – Some basic physics • Svante August Arrhenius worked it out in 1896 “Together they absorb heat and re-emit enough back to Earth to raise the temperature by +33degrees!” “Doubling CO2 should raise the Earth’s temperature about 5°C”

34. CCC – Some basic physics • Earth’s energy balance: • Not all the IR radiation from the surface escapes immediately... • or the average temperature would be a freezing –18°C • No liquid water or clouds • And no life! • This is very well established physics!

35. CCC – Some basic science So how does the atmosphere keep us +33°C warmer?

36. CCC – Some basic science • How do air molecules ‘trap’ the IR radiation? Oxygen (O2): 21% Nitrogen (N2): 78% Carbon dioxide (CO2): 0.04% (was 0.03%) Water vapour (H2O): 0% – 1%

37. CCC – Some basic science • Nitrogen (N2) and oxygen (O2) molecules: • Two atoms ‘tightly bound’

38. CCC – Some basic science • Water (H2O) and carbon dioxide (CO2) molecules: • Three atoms ‘loosely bound’

39. CCC – Some basic science • Nitrogen and oxygen molecules: • Light ‘photons’ (visible and IR) go right through N2 and O2

40. CCC – Some basic science • Water and carbondioxide molecules: • Infrared photons get absorbed by H2O and CO2 molecules (and give them energy)

41. CCC – Some basic science • Water and carbondioxide molecules: • The H2O and CO2don’t keep the energy... • they ‘re-radiate’ it.

42. CCC – Some basic science • Some of this re-radiated IR goes back down and warms the surface – a little like a greenhouse... • The so called “Greenhouse Effect” • This keeps the Earth at a warm +15oC (average) instead of that freezing –18oC

43. Countering Climate Confusion • In other words we understand the basic science very well. • The two key questions are: • By how much will our CO2 emissions increase the temperature? • What will be the effect of that increase?

44. Countering Climate Confusion • By how much will our CO2 emissions increase the temperature? • This is complex, but there are a number of different approaches– • Look at the physics (climate models) • Look at the past (palaeoclimate) • Look at the effect of recent changes (volcanoes etc) • Measure it ...

45. CCC – Some basic science • Car +70 ppm +0.6°C 1°C per 50 years

46. CCC – Some basic science • But it is a lot more complicated than that! • Thermal inertia (delayed action) • Non-linear problem (2 + 2 = 4!) • Feedback effects (positive and negative) • This is the big one! • But most reliable estimates are around 2°C – 5°C per doubling of CO2 Most likely ~3°C • Deniers have to find ways to claim that this is less than 1°C! (Usually by dodgy calculations) X

47. CCC – Some not so basic science • This is where computer models come in handy!

48. IPCC

49. (IPCC graph) The basic data needed is measured in various ways and is well known. Notice that overall, incoming equals outgoing (342 = 107 + 235). Also, that large amounts of energy are absorbed and re-radiated by greenhouse gases.

50. CCC – Some not so basic science • Scientists put all the laws of physics and chemistry into computer models which can do the vast numbers of calculations needed. • Some of the basic equations: