Kerry Emanuel Department of Earth Atmospheric and Planetary Sciences MIT Common Misperceptions about Climate and Climate Science Earths climate is inherently s table Climate science is very young ID: 999971
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1. What We Know About Climate ChangeKerry EmanuelDepartment of Earth, Atmospheric, and Planetary Sciences, MIT
2. Common Misperceptions about Climate and Climate ScienceEarth’s climate is inherently stableClimate science is very young Human activities can have only a minuscule effect compared to natureThe idea that we are altering climate is based exclusively on complex, unreliable models
3. Common Misperceptions about Climate and Climate ScienceEarth’s climate is inherently stableClimate science is very youngHuman activities can have only a minuscule effect compared to natureThe idea that we are altering climate is based exclusively on complex, unreliable models
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6. Last 450 Thousand Years
7. The Snowball Earth, 650-750 mya
8. Common Misperceptions about Climate and Climate ScienceEarth’s climate is inherently stableClimate science is very youngHuman activities can have only a minuscule effect compared to natureThe idea that we are altering climate is based exclusively on complex, unreliable models
9. John Tyndall (1820-1893)Jean Baptiste Joseph Fourier(1768-1830)
10. Climate Forcing by Orbital Variations (1912)Milutin Milanković, 1879-1958
11. Last 450 Thousand Years
12. Black: Time rate of change of ice volumeRed: Summer high latitude sunlightStrong Correlation between High Latitude Summer Insolation and Ice VolumeP. Huybers, Science, 2006
13. Svante Arrhenius, 1859-1927“Any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4°; and if the carbon dioxide were increased fourfold, the temperature would rise by 8°.” – Världarnas utveckling (Worlds in the Making), 1906
14. Guy Stewart Callendar (1898 - 1964)
15. Carbon Dioxide and Climate:A Scientific AssessmentReport to the National Academy of SciencesJule G. Charney and co-authors1979When it is assumed that the CO2 content of the atmosphere is doubled and statistical thermal equilibrium is achieved, the more realistic of the modeling efforts predict a global surface warming of between 2°C and 3.5 °C, with greater increases at high latitudes.
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17. Common Misperceptions about Climate and Climate ScienceEarth’s climate is inherently stableClimate science is very youngHuman activities can have only a minuscule effect compared to natureThe idea that we are altering climate is based exclusively on complex, unreliable models
18. John Tyndall (1820-1893)
19. Tyndall’s Essential Results:Oxygen (O2 ) and nitrogen (N2), though they make up ~98% of the atmosphere, are almost entirely transparent to solar and terrestrial radiationWater vapor (H2O), carbon dioxide (CO2), nitrous oxide (N2O), and a handful of other trace gases make the lower atmosphere nearly opaque to infrared radiation, though still largely transparent to solar radiation (but clouds have strong effects on radiation at all wavelengths)
20. Water Vapor (H2O) is the most important greenhouse gas, but responds to atmospheric temperature change on a time scale of about 2 weeksClimate is therefore strongly influenced by long-lived greenhouse gases (e.g. CO2, CH4, N2O) that together comprise about 0.03% molar fraction of the atmosphere
21. Common Misperceptions about Climate and Climate ScienceEarth’s climate is inherently stableClimate science is very youngHuman activities can have only a minuscule effect compared to natureThe idea that we are altering climate is based exclusively on complex, unreliable models
22. Paleoclimate
23. Last 450 Thousand Years
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25. Paleo reconstructions of temperature change over the last 2000 yearsYearInstrumental Record“Hockey Stick”
26. Arctic air temperature change reconstructed (blue), observed (red) The long-term cooling trend in the Arctic was reversed during recent decades. The blue line shows the estimated Arctic average summer temperature over the last 2000 years, based on proxy records from lake sediments, ice cores, and tree rings. The shaded area represents variability among the 23 sites use for the reconstruction. The red line shows the recent warming based on instrumental temperatures. From Kaufman et al. (2009).
27. Instrumental Record
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30. Distribution of temperature change, 1901-2005
31. High vs Low Temperature Records2011- 2.7:1
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33. Credit: National Snow and Ice Data Center courtesy Stroeve et al. 2012 September Arctic Sea Ice Extent
34. Carbon Dioxide from Ice Cores and Direct Measurements
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36. Variation in carbon dioxide and methane over the past 20,000 years, based on ice core and other records
37. Simple Models
38. MIT Single Column Model
39. Global Climate Models
40. 20th Century With and Without Human Influences
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42. Sources of UncertaintyCloud FeedbackWater Vapor FeedbackOcean ResponseAerosols
43. Source: 100000 PAGE09 runs Our best estimate of how much global climate will warm as a result of doubling CO2: a probability distributionChris Hope, U. Cambridgecourtesy Tim Palmer
44. Climate RouletteCredit: MIT Center for Global Change Science
45. Atmospheric CO2 assuming that emissions stop altogether after peak concentrationsGlobal mean surface temperature corresponding to atmospheric CO2 aboveIPCC 2007: Doubling CO2 will lead to an increase in mean global surface temperature of 2 to 4.5 oC. Courtesy Susan Solomon
46. Consequences
47. (Source: WBGU after David Archer 2006)Past and Projected Sea Level vs. Temperature
48. Hydrological Extremes Increase with Temperature Floods
49. Drought
50. Hurricanes
51. Projected Global Tropical Cyclone Power DissipationGlobal annual tropical cyclone power dissipation averaged in 10-year blocks for the period 1950-2100, using historical simulations for the period 1950-2005 and the RCP 8.5 scenario for the period 2006-2100. In each box, the red line represents the median among the 5 models, and the bottom and tops of the boxes represent the 25th and 75th percentiles, respectively. The whiskers extent to the most extreme points not considered outliers, which are represented by the red + signs. Points are considered outliers if they lie more than 1.5 times the box height above or below the box.
52. Severe Thunderstorms
53. Tornadoes
54. Hail Storms
55. 55The Oceans are Turning SourAcidification through CO2 threatens marine lifePlanktonCoral Reefs
56. “Climate change could have significant geopolitical impacts around the world, contributing to poverty, environmental degradation, and the further weakening of fragile governments. Climate change will contribute to food and water scarcity, will increase the spread of disease, and may spur or exacerbate mass migration.”-- Quadrennial Defense Review, U.S. Department of Defense, February, 2010
57. Dealing with Climate ChangeReduce emissionsgasification of coal—potential CO2 capturealternative sources– nuclear, wind, etc.unlikely to effect major reductionsfocus on non-CO2 greenhouse gasesCarbon capture and sequestrationOther geoengineeringtechnically feasible, $20-30 billion/yearside effects, e.g. reduced precipitationAdaptation
58. Climate Politics
59. The New York Times December 9th 1953
60. NY Times article on smoking-cancer connectionBeginning of industry disinformation campaign
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62. 1991 the Western Fuels Association established the Information Council for the Environment (ICE) to “demonstrate that a consumer-based media awareness program can positively change the opinions of a selected population regarding the validity of global warming.”[1] The Council planned an ad campaign that would “directly attack the proponents of global warming by relating irrefutable evidence to the contrary, delivered by a believable spokesperson” and would “attack proponents through comparison of global warming to historical or mythical instances of gloom and doom.” The campaign specifically targeted older, less-educated males and younger, lower-income women. 1991: Western Fuels Association establishes the Information Council for the Environment (ICE) to “demonstrate that a consumer-based media awareness program can positively change the opinions of a selected population regarding the validity of global warming.” Ad campaign that “will directly attack the proponents of global warming by relating irrefutable evidence to the contrary, delivered by a believable spokesperson”, and “will attack proponents through comparison of global warming to historical or mythical instances of gloom and doom.” The campaign specifically targeted “older, less-educated males and younger, lower-income women”.
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64. RESULTS:
65. Summary of Main PointsSeveral aspects of climate science are well establishedProjections remain highly uncertain, particularly at the regional scaleIll effects felt mostly through weather extremes and through indirect fallout, such as global armed conflict
66. Summary of Main PointsHighly asymmetric risk functionRational response to risk impeded by well-funded and highly effective marketing campaign
67. Atlantic Sea Surface Temperatures and Storm Max Power Dissipation(Smoothed with a 1-3-4-3-1 filter)Years included: 1870-2011Data Sources: NOAA/TPC, UKMO/HADSST1
68. Annual power dissipation of North Atlantic tropical cyclones downscaled from AGCMs and the NCAR/NCEP reanalysis using the technique of Emanuel et al. (2008), compared to estimated actual tropical cyclone power dissipation. The series have been smoothed using a 1-3-4-3-1 filter.
69. Sandy?
70. An exampleIt’s getting warmer!....Time
71. It’s getting warmer!....No, it’s not! Warming stopped at 13! In fact, 13 was warmer than at any time since then!Time
72. Note: We can forecast that summer will be warmer than winter, even though we cannot forecast the weather beyond a few days