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Anthropogenic Global Warming Reality or Fiction? Version 1.1 06Sep08 Francis Massen Physics Lab, LCD and meteoLCD Lycée Classique de Diekirch

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Presentation on theme: "Anthropogenic Global Warming Reality or Fiction? Version 1.1 06Sep08 Francis Massen Physics Lab, LCD and meteoLCD Lycée Classique de Diekirch"— Presentation transcript:

1 Anthropogenic Global Warming Reality or Fiction? Version Sep08 Francis Massen Physics Lab, LCD and meteoLCD Lycée Classique de Diekirch August

2 AGW.. reality or fiction? 2 Index Climate and weather Climate metrics Climate models Causes of climate change How good are the data and the models? IPCC and the so-called consensus The skeptics and their arguments Major scares, real or imagined? Cooling down? Conclusions

3 AGW.. reality or fiction? 3 Climate and weather Weather = actual state of the atmosphere, chaotic changes Climate = mean state ( min. 30 years) of the atmosphere together with its statistical variations Extreme events are a “normal” feature of every climate Climate is always changing… it never is or was constant!

4 AGW.. reality or fiction? 4 Pielke, Colorado University, 2008 The Earth’s climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilibria are the norm

5 AGW.. reality or fiction? 5 The motor of the weather Sun = engine that drives weather/climate Uneven heating by the sun of the globe causes heat flow from hot to cold regions (through convection: air movements and ocean circulation, complicated by the rotation of the globe)

6 AGW.. reality or fiction? 6 Climate change is caused by Variable inclination of earth axis Variable distance earth/sun Variable sun activity (TSI, UV and magnetic) Variable galactic cosmic rays ______________________________ Changes in land usage and land cover Changes in the composition of the atmosphere (natural, anthropogenic) long-time short time

7 AGW.. reality or fiction? 7 Climate metrics Global temperature (in °C) measured by surface weather stations, balloons and satellites (MSU, since 1978) Ocean heat content (in J) measured by ships, moores,…, floating buoys (Argo, since 2003)

8 AGW.. reality or fiction? 8 Global temperature Not many good long-time measurements (instruments only since ~1750) Past temperatures must be infered from proxies (tree rings, isotope ratios in ice cores and sea-shells) Results often dubious and uncertain Meaningful? (no uniform temperature)

9 AGW.. reality or fiction? 9 What was commonly assumed (IPCC SAR, 1995)

10 AGW.. reality or fiction? 10 The Hockey Stick (MBH 98) IPCC SAR 2001 [1] No Medieval Warm Period ! No Little Ice Age !

11 AGW.. reality or fiction? 11 The Hockey Stick (MBH 98) [2] Mann, Bradley, Hughes: temperature profile of middle age essentially derived from a couple of bristlecones Dubious statistics IPCC TAR 2001 icon, published many million times Demolished by McIntire/McKitrick (2003) Embarrassment for the IPCC (not anymore in 4AR, 2008)

12 AGW.. reality or fiction? 12 The Hockey Stick (MBH 98) [3] Ian Jolliffe, expert statistician, 2008: “It therefore seems crazy that the MBH hockey stick has been given such prominence and that a group of influential climate scientists have doggedly defended a piece of dubious statistics. “

13 AGW.. reality or fiction? 13 The Hockey Stick (MBH 98) [3] Loehle reconstruction, not using tree rings (2007): Medieval warm period (MWP) Little Ice Age (LIA)

14 AGW.. reality or fiction? 14 Divergence problem [1] Recent tree rings derived temperatures are lower than measured ones! measured tree ring

15 AGW.. reality or fiction? 15 Divergence problem [2] Wilson, GRL, 2007: No current tree ring (TR) based reconstruction of extratropical Northern Hemisphere (ENH) temperatures that extends into the 1990s captures the full range of late 20th century warming observed in the instrumental record Wilmking, 2008: This "divergence effect" seriously questions the validity of tree-ring based climate reconstructions

16 AGW.. reality or fiction? 16 Recent temperature data sources Surface: GISTEMP (GISS, Nasa) [Hansen] NCDC (US) Hadley(GB) [Jones] Satellites: MSU = microwave sounding unit UHA (US) [Christy, Spencer] RSS (US) [Mears]

17 AGW.. reality or fiction? 17 Surface temperatures heavily adjusted for UHI, instrument drift,…

18 AGW.. reality or fiction? 18 One of many problems: land-based station dropout (NOAA: GHCN) favours urban stations (UHI problem) [icecap]

19 AGW.. reality or fiction? 19 Hadley 1850 to 2007 Similar warming rate very different CO2 increase [climate4you] dCO2=+17ppm dCO2=+43 ppm

20 AGW.. reality or fiction? 20 Last 40 years… El Nino 1998 No GW since 2001 ! See difference! [climate4you]

21 AGW.. reality or fiction? 21 Global temperature = bad metric? Prof. Roger Pielke, Sr University of Colorado, Boulder: Global temperature is not a correct metric for climate change. Ocean heat content is the metric to be used.

22 AGW.. reality or fiction? 22 Barnett [Science, 2001] Observations (dubious?) Decreasing global temperatures

23 AGW.. reality or fiction? 23 Willis [GRL, 2004] upper 750m

24 AGW.. reality or fiction? 24 Hansen [Science, 2005] The observed annual mean rate of ocean heat gain between 1993 and mid-2003 was / W/m2 per year for the 93.4% of the ocean that was analyzed.

25 AGW.. reality or fiction? 25 Argo floater system (starting 2003)

26 AGW.. reality or fiction? 26 Argo floaters in use

27 AGW.. reality or fiction? 27 Argo results [Willis, JPL, 2008] Decreasing ocean heat content!

28 AGW.. reality or fiction? 28 GHG and climate forcing GHG’s (water vapour, CO2, methane,….) absorp a portion of the outgoing long wave radiation and radiate it back to the surface Earth heats up until a new equilibrium (incoming radiation = outgoing radiation) is reached Without GHG’s, earth would be at -18°C instead at +15°C

29 AGW.. reality or fiction? 29 GHG contribution to natural GH

30 AGW.. reality or fiction? 30 Climate forcing F F = hypothetical increase in TOA irradiance caused by a change of [CO 2 ] relative to pre-industrial times (280ppm) F = 5.35*ln(actual_CO 2 /reference_CO 2 ) (Arrhenius law, 5.35 from [Myrhe, 1998]) F = 3.7 Wm -2 for CO 2 doubling F = 1.7 Wm -2 today (280 → 385 ppm) The factor 5.35 is derived from historical surface temperatures, and may be grossly overestimated! [Erren, 2002] TOA = Top Of Atmosphere

31 AGW.. reality or fiction? 31 If the earth was a black body… Stefan-Boltzmann: F = σT 4 σ=5.67*10 -8 dF/dT = 4σT 3 and dT =1/(4 σ)*dF/T 3 With T = 15°C and dF=3.7 as previous gives dT = 0.68°C for a CO 2 doubling and dT = 0.31°C for today

32 AGW.. reality or fiction? 32 Climate sensitivity λ (earth ≠ black body) dT = change in global temperature caused by given change in forcing dF dF = λ*dT or λ = dF/dT [Wm -2 K -1 ] dT = dF/ λ without feedbacks dT = dF/ (λ-f1-f2..) with feedbacks f > 0 positive feedback (e.g. water vapour) f < 0 negative feedback (e.g. cloud cover )

33 AGW.. reality or fiction? 33 The data [Spencer, 2008] dT for doubling CO 2 (from 280 to 560ppm): dT = 3.7/4.5 = 0.8 °C Climate sensitivity

34 AGW.. reality or fiction? 34 The IPCC IPCC = political organisation (UNEP, WMO) Evaluates scientific literature and research and issues AR’s (assessment reports): 1990:FAR 1995:SAR 2001:TAR 2007:4AR Authors often are their own reviewers With each AR comes a SPM (summary for policy makers) written by bureaucrats and political delegates (not scientists!) AR’s had to be changed to conform to the SPM published before the AR’s !

35 AGW.. reality or fiction? 35 IPCC = 2500 scientists? Most important reports = ~50 authors Mc Lean, 2008: “Prejudiced authors, prejudiced findings”:..two of Hadley’s Centre’s contribution authors (Jones and Thorne) were among the reviewers of the chapter that they had themselves written… …the majority of scientists who are skeptical of a human influence significant enough to be damaging were unrepresented…

36 AGW.. reality or fiction? 36 IPCC and climate models IPCC relies heavily on anthropogenic GHG emissions and climate models IPCC uses scenarios (which are not predictions [Trenberth, IPCC author]) IPCC scenarios emphasize role of CO2 emissions, neglect LULC and solar influence (LULC = Land Use Land Change) SPM’s ignore the poor LOSU of many forcings (LOSU = Level Of Scientific Understanding)

37 AGW.. reality or fiction? 37 IPCC 4AR scenarios (2007)

38 AGW.. reality or fiction? 38 IPCC forcings (4AR, 2007) LOSU = level of scientific understanding high low ( Change relative to pre-industrial 1750 situation)

39 AGW.. reality or fiction? 39 Are the models reliable? [1] observation hindcast by model [Akasufo, 2007] Akasufo: former director of the International Arctic Research Center Vast difference between reality and model!

40 AGW.. reality or fiction? 40 Are the models reliable? [2] [Freeman Dyson] Freeman Dyson: FRS, physics professor at Princeton University

41 AGW.. reality or fiction? 41 IPCC critics [1a] Dr. Richard S. Lindzen, Alfred P. Sloan professor of meteorology at the Massachusetts Institute of Technology: The IPCC process is driven by politics rather than science. It uses summaries to misrepresent what scientists say.

42 AGW.. reality or fiction? 42 IPCC critics [1b] It uses language that means different things to scientists and laymen. It exploits public ignorance over quantitative matters. It exploits what scientists can agree on, while ignoring disagreements, to support the global warming agenda. And it exaggerates scientific accuracy and certainty and the authority of undistinguished scientists.

43 AGW.. reality or fiction? 43 IPCC critics [1c] The "most egregious" problem with the IPCC's forthcoming report, is that it is presented as a consensus that involves hundreds, perhaps thousands, of scientists... and none of them was asked if they agreed with anything in the report except for the one or two pages they worked on.

44 AGW.. reality or fiction? 44 IPCC critics [2] Prof. Roger Pielke Sr. University of Colorado in Boulder The IPCC is an oligarchy that is using its privileged position to advocate for a particular perspective on the role of humans within the climate system. Oligarchy = form of government in which all power is vested in a few persons or in a dominant class or clique

45 AGW.. reality or fiction? 45 IPCC critics [3] House of Lords, “ The Economics of Climate Change”, 2006: It seems to us that there remains a risk that the IPCC has become a “knowledge monopoly” in some respects, unwilling to listen to those who do not pursue the consensus line.

46 AGW.. reality or fiction? 46 Consequences of global warming: there remains no phenomen that is not caused or influenced by GW! A complete list of things caused by global warming AcneAcne, agricultural land increase, Afghan poppies destroyed, Africa devastated, Africa in conflict, African aid threatened, African summer frost, aggressive weeds, air pressure changes, Alaska reshaped, Agulhas current moves, Alps melting, Amazon a desert, American dream end, amphibians breeding earlier (or not), anaphylactic reactions to bee stings, ancient forests dramatically changed, animals head for the hills, Antarctic grass flourishes, Antarctic ice grows, Antarctic ice shrinks, Antarctic sea life at risk, anxiety treatment, algal blooms, archaeological sites threatened, Arctic bogs melt, Arctic in bloom, Arctic ice free, Arctic ice melt faster, Arctic lakes disappear, Arctic tundra to burn, Arctic warming (not), Atlantic less salty, Atlantic more salty, atmospheric circulation modified, attack of the killer jellyfish, avalanches reduced, avalanches increased, Baghdad snow, Bahrain under water, bananas grow, barbarisation, beer shortage, beetle infestation, bet for $10,000, better beer, big melt faster, billion dollar research projects, billion homeless, billions face risk, billions of deaths, bird distributions change, bird loss accelerating, bird visitors drop, birds confused, birds return early, birds driven north,… [http://www.numberwatch.co.uk/warmlist.htm]agricultural land increaseAfghan poppies destroyedAfrica devastated,Africa in conflict,African aid threatenedAfrican summer frost aggressive weedsair pressure changesAlaska reshapedAgulhas current movesAlps meltingAmazon a desertAmerican dream endamphibians breeding earlier (or not)anaphylactic reactions to bee stingsancient forests dramatically changedanimals head for the hills,Antarctic grass flourishes Antarctic ice growsAntarctic ice shrinksAntarctic sea life at riskanxiety treatmentalgal bloomsarchaeological sites threatened,Arctic bogs meltArctic in bloomArctic ice freeArctic ice melt fasterArctic lakes disappearArctic tundra to burnArctic warming (not),Atlantic less saltyAtlantic more saltyatmospheric circulation modifiedattack of the killer jellyfishavalanches reducedavalanches increasedBaghdad snowBahrain under waterbananas growbarbarisationbeer shortagebeetle infestationbet for $10,000better beer,big melt faster,billion dollar research projectsbillion homelessbillions face riskbillions of deathsbird distributions changebird loss acceleratingbird visitors dropbirds confusedbirds return earlybirds driven north

47 AGW.. reality or fiction? 47 Climate change research $$$ USA: $37 billion US$ to climate change-related activities since 2001 EUROPE: 6 th Framework : 2.0 billion Euro 7 th Framework : 9.0 billion Euro plus additional funding of 3.6 billion Euro AUSTRALIA, 2008: $2.3 billion US$ over four years for climate research Lindzen: “The research and support for research depends on the alarm”

48 AGW.. reality or fiction? 48 Dr. Gerd R. Weber Max Planck Institute, 1992 “Heute werden auf eine Weise Forschungsgelder verteilt und Berichte geschrieben, dass sich daraus eine positive Rückkopplungsschleife bildet, die allen Beteiligten Gewinne abwirft. Die Wissenschaftler bekommen mehr Forschungsgelder, die Medien neue Empörungsgeschichten..., den Politikern erschliesst sich ihr Stimmenpotential." Gerd R. Weber: Treibhauseffekt. Böttiger Verlags GmbH

49 AGW.. reality or fiction? 49 The major scares, real or imagined? Melting of glaciers and polar ice Sea level rising Hurricanes on increase Drought on increase

50 AGW.. reality or fiction? 50 Mont Blanc ice cap Vincent et al., JGR, 2007: “The most striking features of these figures are the small thickness changes observed over the 20th century. … thickness variations do not exceed ±15 m. The average changes are +2.6 m at Dôme du Goûter and -0.3 m at Mont Blanc. Considering the uncertainty interval, i.e., ±5 m, it can be concluded that no significant thickness change is detectable over most of these areas” World Climate Report

51 AGW.. reality or fiction? 51 Greenland ice Greenland's temperature record shows that the warmest year on record was 1941 while the warmest decades were the 1930s and 1940s Surface mass balance ~constant. Other sources: +11 Gt/year NOAA: Arctic Report Card 2007

52 AGW.. reality or fiction? 52 Arctic sea ice [1] -10 % [NOAA]

53 AGW.. reality or fiction? 53 Arctic sea ice [2] Polyakov (Uni. of Alaska, Fairbanks): Observations over the last 135 years show that the recent decrease is within the limits of natural variations since the 18 th century. The natural low frequency oscillation (LFO, years) related to fluctuations of the thermohaline circulation has a strong impact on ice variability.

54 AGW.. reality or fiction? 54 Antarctic: ice balance (from satellite) Wingham et al., University College of London, 2003: ice balance = [27 +/- 29 Gt/y]

55 AGW.. reality or fiction? 55 Global sea level [1] Gauges: 2.4 mm/y Satellite: 2.6 mm/y (Topex/Poseidon) [Jevreshava, JGR, 2006] ~250 mm

56 AGW.. reality or fiction? 56 Global sea level [2] Domingues et al, Nature, 2008: “…previously estimated rates for the 1990s had a positive bias as a result of instrumental errors…” “…updated estimate of near-global mean sea-level rise: 1.6 ± 0.42 mm/year for 1950 to 2003”

57 AGW.. reality or fiction? 57 Global sea level [3]: sea level change is not uniform! [Accuweather]

58 AGW.. reality or fiction? 58 Hurricane frequency increase? [1] Hurricane in the eastern Pacific (Englehart, GRL, 2008): trend is negative!

59 AGW.. reality or fiction? 59 Hurricane frequency increase? [2] US landfall hurricanes (Wang & Lee, GRL, 2008): trend is negative!

60 AGW.. reality or fiction? 60 Hurricane intensity increase? [3] [Swanson, GRL, 2007] Variable intensity, no trend!

61 AGW.. reality or fiction? 61 Increasing Drought ? [1] [Simmon, Nasa] NPP = net primary productivity [kgC/m 2 ] NPP change

62 AGW.. reality or fiction? 62 Increasing Drought ? [2] : NDVI increases…the Sahel is greening! NDVI = normalized difference vegetation index, measured by satellite [Ollson, encyclopedia of earth]

63 AGW.. reality or fiction? 63 Outlook: cooling down? Several recent changes point to a future cooler, not warmer climate There has been no warming since at least 2001, despite rising atmospheric CO2 Sun activity is unusal low, Aug08 was the first month since 1913 without any sunspots Solar cycle 24 is late, and is predicted to be calm (idem for SC 25)

64 AGW.. reality or fiction? 64 Cooling down? [temperature & CO2] Global temperature and CO – 2000 only period where dCO2 ~ dT > 2000: CO2 rising, temperature decreasing

65 AGW.. reality or fiction? 65 Cooling down? [temperature & CO2] [icecap]

66 AGW.. reality or fiction? 66 Cooling down? [temperature & water vapour] Satellites show lower troposphere cooling; atmospheric water vapor trend is negative [NOAA, 2008]

67 AGW.. reality or fiction? 67 Cooling down? [permafrost] Alaska [Akasofu, 2008] Permafrost temperature remains constant!

68 AGW.. reality or fiction? 68 Cooling down? [sunspots] Sunspot number and global temperature There have been more sunspots since the 1940s than at any other period (of same duration) in the past 1150 years [New Scientist, 2003]

69 AGW.. reality or fiction? 69 Cooling down? [magnetic activity] Sun activity increased dramatically over last century, but now is on decrease [Motl, 2007] Cycle 23 Electromagnetic flux

70 AGW.. reality or fiction? 70 Cooling down? [solar cycle length, 1] Longer solar cycle → cooler temperature [Lassen, Danish Meteorological Institute ]

71 AGW.. reality or fiction? 71 Cooling down? [solar cycle length, 2] SC22: 9y8m SC 23: >12y4m Will the very long cycle yield lower global temperatures? (SC24 has still not started; Aug08 first month since 1913 without sunspots) [www.dxlc.com/solar/]

72 AGW.. reality or fiction? 72 Papers announcing coming cooling or reduced warming [1] Zhen-Shan, L. and S. Xian Multi-scale analysis of global temperature changes and trend of a drop in temperature in the next 20 years. Meteorology and Atmospheric Physics, 95, 115– [cooling] Keenlyside, N. S., M. Latif, J. Jungclaus, L. Kornblueh, and E. Roeckner: Advancing Decadal-Scale Climate Prediction in the North Atlantic Sector. Nature, 453, [reduced warming] Landscheidt, Th: New Little Ice Age instead of Global Warming? Schröter Institute [cooling] V. S. Bashkirtsev and G. P. Mashnich: Will We Face Global Warming in the Nearest Future? Institute of Solar–Terrestrial Physics, Siberian Division, Russian Academy of sciences. August 28, 2002 [cooling] Pyilai Ch, : Predicting Solar Cycles with a Dynamo Model. Indian Institute of Science, Bangalore [weak cycle 24]

73 AGW.. reality or fiction? 73 Papers announcing coming cooling or reduced warming [2] [Dilley, 2008]

74 AGW.. reality or fiction? 74 Conclusions The past century warmed by ~0.7°C. The contribution of AGW to this warming is probably much smaller than that given by the IPCC consensus. The influence of GHG’s, especially CO2, is overstated, the natural variability (of the sun) is understated. Climate models are still unreliable and should not be trusted as a political decision aid. Climate and energy are separate problems: climate change scares should not be used to push a particular energy agenda! Future research and funding should be focused on energy problems; useless and costly global treaties like Kyoto should be avoided.

75 AGW.. reality or fiction? 75 Anthropogenic Global Warming Reality or Fiction? Thank you for your attention! Fiction: most of the recent warming is anthropogenic Reality: most of the recent warming is natural


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