NSF: Natural and Anthropogenic Climate Impacts as Evidenced in Ice Cores

Transcription

1 LIVE INTERACTIVE YOUR DESKTOP NSF: Natural and Anthropogenic Climate Impacts as Evidenced in Ice Cores Presented by: Dr. Joseph McConnell and Linda Morris May 2, 2012

2 Natural and Anthropogenic Climate Impacts as Evidenced in Ice Cores Joe McConnell :

3 Where is the Arctic? Permafrost Permanent and seasonal sea ice Glaciers and ice sheets

4 What is the basic role of the Arctic in global climate? Earth s radiator! Source: PhysicalGeography.net

5 How is the Arctic changing today?... Air temperatures are rising! Year Year Source: IPCC, 2007

6 ... Sea ice extent expands and shrinks the overall trend is strongly downward! Sea ice extent anomalies Loss of permanent sea ice predicted by 2030 (or earlier!) Year Source:

7 ... The edges of Greenland s ice sheet are melting and flowing faster! 1993 to 1999 changes in Greenland ice sheet thickness from repeated altimetry measurements Sea level would rise by >23 ft if Greenland melted (>200 ft if Antarctica melted) Greenland Warm colors = up Cold colors = down Krabill et al., 1999.

8 What drives climate change? Trapped solar energy (radiative forcing) Source: IPCC, 2007

9 Indicators of natural and human impacts are transported to ice sheets through the atmosphere

10 Forming the glaciochemical archive of the environment Ice Core accumulation zone flow lines depth [m] age [yrs BP] equilibrium line ablation zone Example: Central Greenland bedrock in 3028 m reached in July 1992 Courtesy of B. Stauffer

11 Hidden evidence of past climate in the ice: Falling Snow Surface Layer Isotopes Pollutants Sea salts Dust Firn (old snow), with trapped air Firn to ice transition 60 to 110 m Ice 2000 to 5000 m, with bubbles of gas Courtesy Z. Courville Radioactive fallout CO2 CH4 Isotopes Chemistry Volcanic Tephra

12 Let s stop for two questions from the audience

13 Sampling the Archive Deep (Millennial-Scale) Ice Coring Deep coring at Siple Dome, West Antarctica K. Taylor K. Taylor

14 Sampling the Archive Intermediate (Century-Scale) Ice Coring L. Long

15 Sampling the Archive Shallow (Decade-Scale) Ice Coring Commuter Coring Home in time for dinner!!

16 Ice cores are shipped back to many laboratories for analysis Tronstad, 2008 McConnell, 2007 A large variety of measurements have been made, leading to important discoveries. For example

17 Analysis of snow accumulation and isotopes in ice cores tells an amazing tale Climate change can occur abruptly, in less than 10 years!! Alley, 2000

18 My research focuses on aerosols; droplets and particles in the air Ice cores provide long term records of multiple sources: Desert dust Sea spray Burning from wildfires, agriculture, industry (soot) Industrial emissions (e.g., lead) Volcanic emissions (sulfur) Aerosols impact climate and ecosystem health

19 DRI s unique analytical system for ice core aerosol measurements

20 Desert Dust 2007 satellite image of Patagonian dust plumes over the South Atlantic Image courtesy of S. Gassó (U. Maryland)

21 Desert dust in the Antarctic Peninsula & air temperature *Dust Al Flux *Measured in ice core *Dust Al Concentration Southern Hemisphere Air Temperature (Jones et al., 1999) Southern Patagonia Air Temperature (Masiokas & Villalba, 2004) McConnell et al., PNAS, 2007.

22 20 th century increases in dust in the Antarctic Peninsula resulted from extensive desertification & climate warming. Extent of Desertification in Patagonia del Valle et al., 1998.

23 Burning Aerosols Soot (black carbon) emissions come from forest fires & fossil fuel combustion big climate impact! Photo A. Stohl

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25 Not from biomass burning! Biomass burning dominated 1788~1860 and after ~ Year McConnell et al., Science, 2007.

26 Coal burning dominated ~1850 to 1951 Sulfur from industrial emissions

27 Let s stop for two questions from the audience

28 Industrial emissions (e.g. lead) Annual average 5 year average Clean Air Act 2 nd Industrial Revolution Lead Ghengis Kahn dies Columbus crosses the Atlantic 1 st Industrial Revolution Declaration of Independence Year Great Depression

29 Sulfur Aerosols Sulfur aerosols come from many sources including volcanic and industrial emissions both sources have big climate impacts (cooling)! June 12, 2009 eruption of Sarychev seen from the International Space Station

30 Volcanic Emissions (sulfur) Huaynaputina, 1600 Tambora, 1816 Katmai, 1912 Sulfur Annual average 5-year average Year

31 What about the future? Different industrial activities lead to different pollution aerosols with important differences on climate and the environment Aerosols are short-lived (days to weeks) Black Carbon Lead Sulfur Annual Average: light 5-year Average: heavy Year McConnell & Edwards, PNAS, 2008.

32 Long-lived greenhouse gases will warm the Arctic (and the globe) for decades to come. The longer we wait for the inevitable switch to renewable fuels, the greater the climate impact. IPCC, 2007

33 (1) (4) Let s see what you ve learned!!! What happened Greenland Sulfur (2) Greenland Lead at the arrows? Year (3)

34 Conclusions The Arctic is a critical component of the global climate system Earth s radiator Arctic environment is changing rapidly As documented in ice cores, humans have had a very significant impact on Arctic climate and environment for at least 150 years The future of the Arctic depends on us

35 IDPO Classroom Resources Let s do a quick web tour Morris for NSTA

36 CLIMATE EXPEDITIONS Polar Detectives Activity Ice Drilling Program

37 A Discrepant Event Our question: What caused the Year Without a? A hypothesis: Evidence archived in ice cores Morris for NSTA

38 Investigating physical properties: What do you observe? Summer (Sugar) Winter (Salt) Examples: Size, color, crystal shape Morris for NSTA

39 SEM Images of the Real Thing Morris for NSTA

40 Annual Layers in a Snow Pit Morris for NSTA Credit: Z. Courville

41 Modeling An Ice Core Snow builds in visible layers, the oldest on the bottom. Aerosols, dust and ash are trapped as layers turn to ice. Morris for NSTA

42 Morris for NSTA Recent Core From WAIS

43 Analyzing Chemical Data Summit S West Antarctic S Greenland data; 3 blue peaks Antarctic data; 2 pink peaks Ash from 2 equatorial events in both cores Critical thinking: How did this weather fit with climate norms? Morris for NSTA

44 For further information, please contact: Additional resources are available at: Morris for NSTA

45 Thank you to the sponsor of tonight's Web Seminar: This web seminar contains information about programs, products, and services offered by third parties, as well as links to third-party websites. The presence of a listing or such information does not constitute an endorsement by NSTA of a particular company or organization, or its programs, products, or services.

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47 National Science Teachers Association Dr. Gerry Wheeler, Interim Executive Director Zipporah Miller, Associate Executive Director Conferences and Programs Al Byers, Assistant Executive Director e-learning NSTA Web Seminars Paul Tingler, Director Jeff Layman, Technical Coordinator Brynn Slate, Program Coordinator LIVE INTERACTIVE YOUR DESKTOP