Kerry Emanuel Department of Earth Atmospheric and Planetary Sciences MIT This Evenings Program Overview of climate and climate change Effect of global warming on extreme weather Common Misperceptions about Climate and Climate Science ID: 1041549
Download Presentation The PPT/PDF document "Climate Change and Extreme Weather" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Climate Change and Extreme WeatherKerry EmanuelDepartment of Earth, Atmospheric, and Planetary Sciences, MIT
2. This Evening’s Program Overview of climate and climate change Effect of global warming on extreme weather
3. 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 modelsAnthropogenic climate change is controversial among climate scientists
4. 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 modelsAnthropogenic climate change is controversial among climate scientists
5.
6.
7. Penobscot “Bay”, 10,000 years ago
8. Last 450 Thousand Years
9. The Snowball Earth, 650-750 mya
10. 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 modelsAnthropogenic climate change is controversial among climate scientists
11. John Tyndall (1820-1893)Jean Baptiste Joseph Fourier(1768-1830)
12. Climate Forcing by Orbital Variations (1912)Milutin Milanković, 1879-1958
13. Last 450 Thousand Years
14. Black: Time rate of change of ice volumeRed: Summer high latitude sunlightStrong Correlation between High Latitude Summer Insolation and Ice VolumeP. Huybers, Science, 2006
15. 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
16. Guy Stewart Callendar (1898 - 1964)
17. 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.
18.
19. 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 modelsAnthropogenic climate change is controversial among climate scientists
20. John Tyndall (1820-1893)
21. Tyndall’s Essential Results:Oxygen (O2 ), nitrogen (N2), and argon (Ar), though they make up ~99% 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). Together they increase the Earth’s surface temperature from about 0oF to around 60oF.
22. Atmospheric CompositionThe orange sliver (can you see it?) makes the difference between a mean surface temperature of 0oF and of 60oF.
23. Water Vapor (H2O), about 0.25% of the mass of the atmosphere, 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 0.04% of the mass of the atmosphere. Concentration of CO2 has increased by 43% since the dawn of the industrial revolution
24. 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 modelsAnthropogenic climate change is controversial among climate scientists
25. Paleoclimate
26. Carbon Dioxide from Ice Cores and Direct Measurements
27.
28. Variation in carbon dioxide and methane over the past 20,000 years, based on ice core and other records
29. Paleo reconstructions of temperature change over the last 2000 yearsYearInstrumental Record“Hockey Stick”
30. 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).
31. Instrumental Record
32.
33.
34. Distribution of temperature change, 1901-2005
35. Based on bathythermograph and ARGO (post-2004) dataImage credit: NOAA
36. Tropospheric temperature trend from 1979-2012 based on satellite measurements (RSS)Top of the stratosphere (TTS) 1979-2006 temperature trend.
37.
38. Credit: National Snow and Ice Data Center courtesy Stroeve et al. 2012 September Arctic Sea Ice Extent.2012
39. 39The Oceans Are Becoming More AcidicAcidification through CO2 threatens marine lifePlanktonCoral Reefs
40. Simple Models
41. MIT Single Column ModelIPCC Estimate:2-4.5 oC
42. 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 modelsAnthropogenic climate change is controversial among climate scientists
43.
44. The Future
45. Source: 100000 PAGE09 runs Estimate of how much global climate will warm as a result of doubling CO2: a probability distributionChris Hope, U. Cambridgecourtesy Tim Palmer
46. Sources of UncertaintyCloud FeedbackWater Vapor FeedbackOcean ResponseAerosols
47. CO2 Will Go Well Beyond DoublingDouble Pre-Industrial
48. Consequences for Weather
49. 49observationsHadCM3 Medium-High (SRES A2)20032040s2060sTemperature anomaly (wrt 1961-90) °CHeat
50. High vs Low Temperature Records2011- 2.7:1
51. Adaptation Limit:Maximum Tolerable Wet Bulb Temperature12o increase in mean global TSherwood and Huber, PNAS, 2010
52. (Source: WBGU after David Archer 2006)Past and Projected Sea Level vs. Temperature
53. Hydrological Extremes Increase with Temperature Floods
54. Drought
55. Severe Thunderstorms
56. Tornadoes
57. Hail Storms
58. Hurricanes
59. 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.
60. Trends in Thermodynamic Potential for Hurricanes, 1980-2010
61. Haiyan was Boosted by Warmer Seas
62. Global Warming Effects:Increase in frequency of intense hurricaneIncrease in tropical moistureIncrease in wind and storm surge damageIncrease in incidence of hurricane-induced freshwater floods
63. Projections of climate change effects on weather extremes vary a great deal depending on type of event and model projectionsIncidence of floods increases fairly rapidlyIncidence of drought also increases rapidly
64. Frequency of intense (destructive) hurricanes projected to increaseVery little currently known about response of severe thunderstorms to climate change
65. Summary of Main PointsSeveral aspects of climate science are well establishedProjections remain somewhat uncertain, particularly at the regional scaleIll effects felt mostly through sea level rise, 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 by fossil fuel interestsRational measures possible when many begin to notice tangible climate change
67. Scientific organizations that endorse the consensus position that "most of the global warming in recent decades can be attributed to human activities":
68. Academies of Science
69. “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
70. Why We Need to Act Now
71. 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
72. 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