Glacier change in the American West 1946 The Mazama legacy of f glacier measurements
The relevance of Glaciers Hazards: Debris Flows Outburst Floods Vatnajokull, 1996 White River Glacier, Mt. Hood
The relevance of Glaciers Climatic Indicator: past and present Landscape Modification Information in the ice
The relevance of Glaciers Water Flow: Frozen Reservoirs Alpine Streams Global Sea Level Rise Robert Stallard Digital Vision
Global Changes in Air Temperature and Sea Level From the IPCC SPM-3, 2007
Causes of Global Sea Level Rise 3.5 3 Antarctica Greenland Dotted line uncertainty in estimates Grey - observed Sea level rise mm yr -1 2.5 2 1.5 1 0.5 Glaciers and ice caps Thermal Expansion observed Blue contribution Of melting ice Red - thermal expansion of ocean water due to atmospheric warming 0 1961-2003 1993-2003 From the IPCC SPM report 2007
USGS Surveys of the West USGS explorations make the first scientific observations of glaciers King Survey, Watkins photographer
CLARENCE KING Mount Shasta, CA September 11, 1871 discovered the first glacier in the western states C.E. Watkins, 1871 Hague discovered glaciers on Mt. Hood Arnold Hague
Glaciers in the American West 1 : 24,000 3079 450 1158 68.6 8303 glaciers 463 208 42.5 2.6 1 0.09 1475 73.3 141 4.8 688 km 2 (266 miles 2 ) 1778 46.2 US Forest Service lands National Park Service lands Glaciers
Examples of glacier change over the past 100 years Eliot Glacier, Mount Hood, OR 1901 2006 Provided by Darryl Lloyd
Benson Glacier Wallowas, OR 1920 (H. Richardson) 1992 (D. Jensen) (courtesy USDA)
Grinnell Glacier Lewis Range, Montana Glacier National Park 1938 1998 T.J. Hileman D. Fagre
1907 Darwin Glacier Sierra Nevada Kings Canyon Nat. Park August 14, 1907 G.K.Gilbert 2003 August 2, 2003 Hassan Basagic
Andrews Glacier Colorado Front Range Rocky Mountain National Park 1938 1962
South Cascade Glacier, WA 1960 USGS 2004 John Scurlock
Current (2007) USGS topographic map and its depiction of South Cascade Glacier
Current (2007) aerial photograph of South Cascade Glacier. The map on the previous image is really about 40 years out of date andhas not kept up with climate change.
South Cascade Glacier Cummulative Mass Change (m weq) 0-4 -8-12 -16-20 -24 1955 1965 1975 1985 1995 2005 US Geological Survey
How glaciers work Winter Snow Summer melt Mass Change + -
Trends in Winter Snowpack since 1950 (Mote et al., 2005) Red thinning April 1 snow packs Blue thickening April 1 snowpacks. Consequently, we expect glaciers to retreat except in the high Sierra.
Total Glacier Area Changes 10 100% 1.0 8 80% 0.8 Area (km 2 ) 6 4 2 Fractional Area 60% 0.6 40% 0.4 20% 0.2 Oregon Cascades Sierra Nevada Lewis Range ` 0 1900 1925 1950 1975 2000 0% 0.0 1900 1925 1950 1975 2000
Glacier Area Change 1900-2003 5000 Elevation (m) 4000 3000 2000 1000 0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Sierra Glacier Nat Pk Mt Hood Mt Rainier Olympics Local effects: Glaciers in the Northwest (Rainier) with high elevations are receding more slowly than others. Effect of increased snow above the local freezing level. Sierra have different local effects. Area Change Decrease
Article from a California newspaper in 1940 8 SEP 2004 Basagic IC Russell 1883 R.H. Anderson 1940 geologists believe that within 50 years these ancient ice masses may disappear completely. Have to be careful with predictions. The glaciers in the Sierra are very small and have retreated into protective Niches (cirques) which contribute extra snow via avalanches and reduces
Fraction of Glacier Area Lost since 1900 31% 24% 66% 30% 40% 60% The 60% loss in the Sierra despite local snow gains in the region indicates that Other processes are at work.
Global Glacier Change Kaser et al., 2006
Global Sea Level Rise 3.5 3 Antarctica Greenland Sea level rise mm yr -1 2.5 2 1.5 1 Glaciers and ice caps Thermal Expansion observed Now about the contribution to global sea level from Greenland. 0.5 0 1961-2003 1993-2003 IPCC SPM report 2007
Melting on the Greenland Ice Sheet 2005 The red/orange indicates the extent of melting on the Greenland Ice Sheet. Arctic Impacts of Arctic Warming, Cambridge Press, 2004 Koni Steffen, University of Colorado
A new response: INCREASED ICE FLOW TO THE OCEAN From Alley, EGU 2006 Howat et al., 2005, GRL, Helheim Glacier, Greenland
Melting Melting & Ice Flow Its not just melting and water flow to the oceans, now it includes rapid ice flow to the oceans.
SEA LEVEL RISE
How do we know the cause is humans and not natural causes? Through computer models, which are becoming increasingly accurate. IPCC
Web page on the glaciers we study. www.glaciers.us
Appearances Time/ABC/Stanford poll: About 85% of Americans say global warming is happening right But 65% think scientists disagree about global warming wrong The community of climate research scientists are in broad agreement that humans are warming the planet.