Produced by and for the Hot Science - Cool Talks Outreach Lecture Series of the Environmental Science Institute. We request that the use of any of these materials include an acknowledgement of Dr. Ginny Catania and the Hot Science - Cool Talks Outreach Lecture Series of the Environmental Science Institute of the University of Texas at Austin. We hope you find these materials educational and enjoyable. Giant Ice Sheets Threaten Globe !? Climate Change and the Greenland Ice Sheet by Ginny Catania Hot Science - Cool Talks Volume 55

Title Slide Giant Ice Sheets Threaten Globe!? Climate Change and the Greenland Ice Sheet Ginny Catania Institute for Geophysics, University of Texas, Austin THE UNIVERSITY OF TEXAS AT AUSTIN

Past Climate Changes (1) Past Climate Changes IPCC (2007) Vostok Ice Core Temperature and CO 2 concentration in the atmosphere over the past 400,000 years o C 2 o C 0 o C -2 o C -4 o C -6 o C -8 o C -10 o C CO 2 concentration, ppmv3 Temperature change from present, o C Years before present 400,000350,000300,000250,000200,000150,000100,00050, ,000350,000300,000250,000200,000150,000100,00050,0000 IPCC (2007)

Past Climate Changes (2) Past Climate Changes IPCC (2007) Vostok Ice Core Temperature and CO 2 concentration in the atmosphere over the past 400,000 years CO 2 concentration, ppmv3 Temperature change from present, o C 400,000350,000300,000250,000200,000150,000100,00050, ,000350,000300,000250,000200,000150,000100,00050,0000 Today’s atmospheric CO 2 concentration: 380 ppmv o C 2 o C 0 o C -2 o C -4 o C -6 o C -8 o C -10 o C IPCC (2007) Years before present

Recent Climate Changes 1)2005 2)1998 3)2002 4)2003 5)2006 6)2004 7)2007 8)2001 9) ) warmest years since 1860 have been in the last decade. Recent climate changes Departures in temperature in o C (from the average) IPCC (2007), NASA

volcanoes orbital changes natural methane emissions car emissions industrialization What is the scientific consensus? Temperature anomalies in o C IPCC (2007) Scientific Consensus (1)

> 90% certainty: Humans are changing the Earth’s climate “Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns.” “Warming of the climate system is unequivocal” consists of people from over 130 countries, including more than 2500 scientific expert reviewers IPCC (2007) What is the scientific consensus? Scientific Consensus (2)

Impact of Warming on the Cryosphere (1) NASA Impact of warming on the cryosphere “Chance of an ice-free North Pole this summer is slightly less than 50-50” --J. Zwally (NASA); 2008 NASA NSIDC

Impact of Warming on the Cryosphere (2) Sea-level rise Changes in ocean circulation/weather Changes in habitat Impact of warming on the cryosphere Argonne National Laboratory Scott Shliebe/USFWS Business Week

Ice Sheet Mass Balance MASS BALANCE = “what goes in” - “what comes out” If more comes “out” than goes “in”, mass balance is negative Ice Sheet Mass Balance How ice comes in: snow accumulation How ice goes out: melting and calving Hugo Ahlenius, UNEP/GRID-Arendal

Satellite Image NASA

Greenland Mass Balance GRACEICESat -100 Gt per year-80 Gt per year NASA

Negative Mass Balance: Surface Melt Arctic Climate Impact Assessment R. Braithwaite Negative Mass Balance: Surface Melt

Ice Dynamics (1) NASA Landsat snow line June 14, 2001 net melting net accumulation km Ice Dynamics: Processes left out of IPCC

Ice Dynamics (2) snow line June 13, 2002 NASA Landsat km Ice Dynamics: Processes left out of IPCC

Ice Dynamics (3) June 17, 2003 snow line NASA Landsat km Ice Dynamics: Processes left out of IPCC

Rignot & Kanagaratnam, 2006 Velocity (meters/year) 100 km Jakobshavn Isbrae Kangerdlugssuaq Velocity (meters/year) Distance from ice front (km) Negative Mass Balance: Accelerating Glaciers Distance from ice front (km) Negative Mass Balance: Accelerating Glaciers (1)

NASA Earth Observatory Retreat of Jacobshavn Isbrae Negative Mass Balance: Accelerating Glaciers Negative Mass Balance: Accelerating Glaciers (2)

Northern Hemisphere temperature anomaly ( o C) Arctic Oscillation (  P between N. mid and high latitudes) Arctic Oscillation AO is similar to El Nino in the Pacific Exerts a strong influence on Arctic temperature Is cause for a lot of debate about whether or not temperature increase in Arctic is natural or human-forced Argument for Human-Induced 1920’s warming isolated in Arctic Regions in Greenland not controlled by North Atlantic Oscillation show large increases in temperature Year Negative Mass Balance: Natural Variability Hugo Ahlenius, UNEP/GRID-Arendal NOAA Negative Mass Balance: Natural Variability (1)

Negative Mass Balance: Natural Variability Climate stations showing correlation to AOClimate stations showing no correlation to AO Temperature change here is 2.2 times larger than change in global mean temperature This is predicted by global climate models Negative Mass Balance: Natural Variability (2)

IPCC on the State of the Cryosphere Dynamical processes related to ice flow [are] not included in current models but … could increase the vulnerability of the ice sheets to warming, increasing future sea level rise. Understanding of these processes is limited and there is no consensus on the magnitude. Ice dynamics are important! Since the TAR, progress in understanding how climate is changing in space and in time has been gained … Increasingly comprehensive observations are available for glaciers and snow cover since the 1960s, and for sea level and ice sheets since about the past decade. However, data coverage remains limited in some regions. IPCC IPCC on the State of the Cryosphere

internal deformation basal sliding physical controls accumulation slope bed properties  melting/calving buttressing thermal controls internal heat air temperature ocean circulation (melting & freezing) friction geothermal heat How ice moves: Controls on rate of motion: Ice Dynamics 101: How ice moves Ice Dynamics 101 (1)

If you stretch it slowly; ice thins If you stretch it quickly; ice cracks Ice Dynamics 101: How ice moves Ice Dynamics 101 (2)

= Ice Dynamics: Processes left out of IPCC Observations: Hypothesis: melting basal sliding ICESat Ice Dynamics: Processes left out of IPCC (1)

Ice Dynamics: Processes Left out of IPCC (2) NASA/JPL:Zwally et al. 2002; Janot Lamberton moulin Surface-melt induced ice sheet acceleration Ice Dynamics: Processes left out of IPCC

Greenland Melt-induced Velocity Project 1. How does surface melt drain to the ice bed? 2. How does ice respond to increased melt? 3. What will happen to rate of ice flow with further warming? Research Questions: How to proceed? Research Questions (1)

Greenland Melt-induced Velocity Project 1. How does surface melt drain to the ice bed? 2. How does ice respond to increased melt? 3. What will happen to rate of ice flow with further warming? Research Questions: ? You Have a Research Question! Integration of Research -ideas get tested and retested until they are accepted by the community -possibly included in international scientific reports (IPCC) -possibly considered for policy changes - a girl can hope! Send it to Funding Agency for Review -reviewed by 4-6 scientists by -reviewed by panel of 6-8 scientists -budget costs and proposal rank are evaluated by program manager Write a Proposal: -plan science -discuss possible results -discuss pitfalls Awarded! -planning begins Present Results -go to meetings (critiqued by your peers) -write up results (also reviewed by 2-4 scientists) Do the Work! Research Questions (2)

Tom Neumann (UVM) Julie Rumrill (UVM) Jamin Greenbaum (UTIG) Steve Price (Los Alamos) Me The Team

Getting to Greenland Kangerlussuaq Getting to Greenland

Field Preparations Food Clothing Science/Camping Equip. Field Preparations

Greenland Town Flickr: Zinnie

Iceberg Camille Seaman

Getting to the Field Site Getting to the field site

Camp Image camp

GC-1-CAMP.mov

Camping on the Ice Camping on ‘the ice’

1. How does surface melt drain to the ice bed? 2. How does ice respond to increased melt? 3. What will happen to rate of ice flow with further warming? Greenland Melt: Research Questions NASA/JPL:Zwally et al Greenland Melt: Research Questions

Ice Dynamics revisited June 17, 2003 snow line NASA Landsat Ice Dynamics: Processes left out of IPCC

Greenland Melt-induced Velocity Project Radar profiles Englacial and subglacial characteristics Water content of the ice and basal materials Greenland Melt-induced Velocity Project

Ice-penetrating Radar (1) Survival bag Spares/seat Receiver Generators Transmitter Sled antennas transmitter tow rope GPS unit 1MHz Antenna deployment Greenland Melt: Ice-penetrating radar

Ice-penetrating Radar (2) Ice thickness Siple Dome, Antarctica Greenland Melt: Ice-penetrating radar

Ice-penetrating Radar (3) Siple Dome, Antarctica Changes in bed properties Siple Dome Greenland Melt: Ice-penetrating radar

Ice-penetrating Radar (4) Siple Dome, Antarctica interpretation of internal layer shapes Greenland Melt: Ice-penetrating radar

GC-4Snowmobile.mov

Greenland Melt-induced Velocity Project Revisited Radar profiles Englacial and subglacial characteristics Water content of the ice and basal materials Greenland Melt-induced Velocity Project

Greenland Melt: Ice-penetrating radar Radar Profile (1)

Greenland Melt: Ice-penetrating radar Radar Profile (2)

 hypothesize these are moulins  very complex and variable  some may not reach the bed all the way  some associated with dipping layers (*implies vertically oriented*) Greenland Melt: Ice-penetrating radar Janot Lamberton Radar Profile (3)

Greenland Melt: Ice-penetrating radar Locations of moulins snow line Moulin Locations

Modeling Crevassing Critical tensile stress required for crevassing ~100 kPa (Nath & Vaughan, 2001) Greenland Melt: Modeling Crevassing cracking? cracking! 100kPa

Greenland Melt: Crevasse locations snow line Crevasse Locations (1)

Greenland Melt: Crevasse locations snow line Crevasse Locations (2)

evidence for moulins; allow rapid drainage of surface water to the bed well correlated to surface cracking 1. How does surface melt drain to the ice bed? Greenland Melt: Research Questions NASA/JPL:Zwally et al How does ice respond to increased melt? 3. What will happen to rate of ice flow with further warming? NASA/JPL:Zwally et al Research Conclusions (1)

Location of GPS units Greenland Melt-induced Velocity Project

GPS Deployment solar panel ablation pole GPS antenna battery GPS receiver May 15, 2006 October 20, 2006 Greenland Melt: GPS deployment

GPS Results Greenland Melt: GPS results abrupt, tripling in velocity over a few days asynchronous elevation increase at some station but draw-down at others is indicative of some stretching of the ice basal sliding

water lubricates the bed and allows ice to move faster internal deformation basal sliding Greenland Melt: Research Questions 1. How does surface melt drain to the ice bed? 2. How does ice respond to increased melt? some of the ice is thinning because it is stretching over time, speeds reduce indicating that the drainage system may adjust to accommodate water input NASA/JPL:Zwally et al What will happen to rate of ice flow with further warming? Research Conclusions (2)

Greenland Melt: Research Questions 3. What will happen to rate of ice flow with further warming? Process left out of IPCC need to be modeled melting basal sliding Possible scenario: -increased melting causes increased velocity = positive feedback Research Conclusions (3)

Lamont-Doherty Earth Obs. Vanity Fair 2006 Giant Ice Sheets Threaten Globe!! 5m sea-level rise 3m sea-level rise Giant Ice Sheets Threaten Globe

uncertainty in how the system behaves is very large Greenland Melt: Research Questions 3. What will happen to rate of ice flow with further warming? Process left out of IPCC need to be modeled melting Possible scenario: -increased melting can be accommodated by formation of subglacial conduits Uncertainty in System Behavior

News Media Policy Experts News media wants a good (dramatic) story Greenland Melt: Future Predictions Bourg Government wants certainty before policy is dictated Future Predictions (1)

Future Predictions: What we need BOTTOM LINE NEEDS: 1.more data in particular areas 2.better understanding of important processes 3.better integrated global climate models (that include ice sheets) But until then, this is what we know… FACT: Earth is warming due to greenhouse gases FACT: Ice melts! FACT: CO2 has a lifetime of ~100 years (ACT NOW!) wili wikipediaNASA Future Predictions (2)

Future Predictions (3) Eco-friendly integrated world Moderately eco-friendly Business as usual Note: 3 o C = 5.4 o F Future Predictions: The BIG experiment WHICH FUTURE DO WE CHOOSE?