CLIMATE CHANGE IN ARCTIC AND ALPINE AREAS

Transcription

1 CLIMATE CHANGE IN ARCTIC AND ALPINE AREAS 1. Introduction 2. Data sources: glaciers 3. Data sources: ice cores 4. Patterns and mechanisms 5. Feedbacks and surprises

2 Striations (evidence of glacial erosion)

3 U-shaped valley (evidence of glacial erosion)

4 Glacial moraines (evidence of glacial depositional)

5 Glacier retreat above Manang, Nepal

6 Holgate Glacier, Alaska, Source: National Snow and Ice Data Center glacier rephotography collection.

7 Holgate Glacier, Alaska, Source: National Snow and Ice Data Center glacier rephotography collection.

8 McCall Glacier, Alaska, Source: National Snow and Ice Data Center glacier rephotography collection.

9 McCall Glacier, Alaska, Source: National Snow and Ice Data Center glacier rephotography collection.

10 Franz Josef Glacier, New Zealand, 1951 Source: National Snow and Ice Data Center glacier rephotography collection.

11 Franz Josef Glacier, 1952 Source: National Snow and Ice Data Center glacier rephotography collection.

12 1954 Source: National Snow and Ice Data Center glacier rephotography collection.

13 1956 Source: National Snow and Ice Data Center glacier rephotography collection.

14 1957 Source: National Snow and Ice Data Center glacier rephotography collection.

15 1958 Source: National Snow and Ice Data Center glacier rephotography collection.

16 1960 Source: National Snow and Ice Data Center glacier rephotography collection.

17 1961 Source: National Snow and Ice Data Center glacier rephotography collection.

18 1964 Source: National Snow and Ice Data Center glacier rephotography collection.

19 Antarctic ice shelf collapse: Larsen-B ice shelf, 2002

20 Antarctic ice shelf collapse: Larsen-B ice shelf, 2002

21

22 Location of Vostok station, Antarctica. Todd Sowers, Lamont Doherty Earth Observatory/ NOAA Paleoclimatology Program. Source:

23 Location of Vostok station, Antarctica. Todd Sowers, Lamont Doherty Earth Observatory/ NOAA Paleoclimatology Program. Source:

24 How ice coring works

25

26 OXYGEN ISOTOPE ANALYSIS 8 electrons (-) Nucleus: 8 protons (+) 8 neutrons

27 OXYGEN-16 ( 16 O): 8 protons, 8 neutrons OXYGEN-18 ( 18 O): 8 protons, 10 neutrons

28 WHY IS THIS USEFUL FOR CLIMATE RECONSTRUCTION? Fractionation!

29 Two isotopes of oxygen: 16 O 18 O Which water molecules fall as snow near the poles? H 2 16 O H 2 18 O Which water molecules rain out more easily? Which water molecules evaporate more easily?

30 Bigger ice sheets separate out the isotopes More 16 O locked up in the ice sheets More 18 O remains in the oceans

31 Source: Peter Sloss, NOAA/NGDC, NOAA Paleoclimatology Program.

32 Quelccaya ice cap. Source: Lonnie Thompson, Ohio State University/ NOAA Paleoclimatology Program.

33 Packing in to the Quelccaya ice cap. Source: Lonnie Thompson, Ohio State University/ NOAA Paleoclimatology Program.

34 Qori Kalis glacier, Quelccaya ice cap, Source: Byrd Polar Research Station, Ohio State University.

35 Qori Kalis glacier, Quelccaya ice cap, Source: Byrd Polar Research Station, Ohio State University.

36 Recent behaviour of twenty mountain glaciers worldwide. Source: Oerlemans, 2001.

37 Tsaa Glacier, Alaska, Source: Rozell, 2007, Icy Bay Glaciers Get up and Go, Alaska Science Forum, UAF.

38 Tsaa Glacier, Alaska, Source: Rozell, 2007, Icy Bay Glaciers Get up and Go, Alaska Science Forum, UAF.

39 Efforts to keep the Pitztal Glacier (Austria) from melting. Source: National Geographic.

40 Surface melting on Greenland, 1992 and Source: Arctic Climate Impact Assessment, 2004.

41 New melt extent on Greenland, Source: Koni Steffen.

42 Change in mass, , cm water. Source: NASA

43 Source: The Cryosphere Today/NSIDC

44 Source: The Cryosphere Today/NSIDC

45 Source: NASA/The New York Times Average minimum

46 Site of Vostok station, Antarctica. Todd Sowers, Lamont Doherty Earth Observatory/ NOAA Paleoclimatology Program. Source:

47

48 The northern hemisphere at 18,000 BP. Source: Christopherson, 2003.

49

50 The first Milankovitch cycle: a change in the shape of Earth s orbit around the sun

51 The second Milankovitch cycle: a change in the angle of tilt of the Earth s axis

52 The third Milankovitch cycle: a change in the timing of summer

53 Delta O-18 (per mil) The Last Deglaciation GISP-2 Oxygen Isotope Data WARM COLD Years Before Present

54 Delta O-18 (per mil) The Last Deglaciation Dansgaard-Oeschger Events GISP-2 Oxygen Isotope Data WARM Younger Dryas COLD Years Before Present

55

56 General temperature trends over Earth s history derived from fossil evidence Growth of large ice sheets possible COLD WARM

57 WARMER COLDER Climate change over last ~60 million years. (Source: Raymo.) Time before present (million years) ICE SHEETS Temperature estimated from benthic foraminifera ICE FREE

58

59 Time (million years BP) Temperature changes over the last 60 million years COLDER Cold enough for permanent ice sheets WARMER Too warm for permanent ice sheets

60 Last 1000 years Last 400,000 years COLDER WARMER Last 60 million years WARMER COLDER COLDER WARMER

61

62 Carbon dioxide concentration (ppm) Carbon dioxide changes over time Atmospheric CO 2 recorded in the Vostok ice core, Antarctica, and measured at Mauna Loa, HI. Years before present Source: data from WDC Paleoclimatology and NOAA Mauna Loa CO 2 records.

63 Preindustrial and anthropogenic carbon dioxide. Source: Ruddiman, 2001, p. 396.

64 Atmospheric carbon dioxide concentration recorded at Mauna Loa, Hawaii

65 Atmospheric carbon dioxide concentrations over the last 1000 years. Source: IPCC, 1996.

66 Source: Arctic Climate Impact Assessment, 2004.

67

68 The Arctic is warming at twice the global rate. Source: Arctic Climate Impact Assessment, 2004.

69 Temperature changes for relative to Source: IPCC, Degrees Celsius

70 Temperature changes for relative to Source: IPCC, Degrees Celsius

71 Changing sea ice extent derived from satellite images, Source: NASA and The New York Times

72 Source: NOAA/GFDL Visualization Gallery.

73 Last 1000 years COLDER WARMER Last 400,000 years WARMER COLDER Last 60 million years COLDER WARMER Too warm for permanent ice sheets Cold enough for permanent ice sheets