3. (continued) Ice under fire, rising seas: Geophysical changes
Research Papers and Documents
For information on the Larsen ice shelf breakup of 2002, see National Snow and Ice Data Center, http://nsidc.org/iceshelves/larsenb2002/.
Glaciologist Ted Scambos' studies of this and other shelves "provide a solid link between climate warming and the recent extensive disintegration..." (article 16 January 2001 on this site).
Eugene Domack, et al. "Antarctic Peninsula Climate Variability: A Historical and Paleoenvironmental Perspective"
A conference sponsored by the National Science Foundation April 2002, Hamilton College New York. Abstracts available at; http://academics.hamilton.edu/workshops/antarctica/Abstracts/
See also Domack et al, Cruise Reveals History of Holocene Larsen Ice Shelf. EOS (American Geophysical Union) Vol. 82/2 pg 13-17 (2001)
Serreze, M.C. et al. (includes Chapin and Osterkamp) "Observational Evidence of Recent Change in the Northern High-Latitude Environment" Climatic Change 4:159-207 (2000)
Reports up to 6° C increase in winter temps since 1966 in large areas of Siberia and North America, lesser amount in summer, but the warming in winter can slowly increase temp of permafrost, making it easier to thaw into the active layer. Also snow depth may increase.
See also Overpeck, J., K. et al. "Arctic environmental change of the last four centuries"<italic> Science</italic>, 278, pg 1251 (1997).
Rothrock et al., "Thinning of the arctic sea-ice cover" Geophysical Research Letters, Vol. 26, pg 3469 ; and Vinnikov et al., "Global warming and northern hemisphere sea ice extent" Science, Vol. 286, pg 1934 (1999)
Data from satellites show that perennial ice (ice that survives all year) declined by 14 per-cent between 1978 and 1998, while data from submarine cruises show that ice thickness has declined by about 40 percent over the last 20-40 years. A related study estimated only a slight chance that the observed trends were due to natural variability, suggesting that human activities probably contribute to the loss of Arctic sea ice
Another measure of Arctic Sea Ice was created from satellite microwave data from 1978 to 2000, by Josefino Cosimo et al in Geophys. Res. Letters 29, pg 1956 (2002). The area covered by the ice has decreased at a rate of 9% per decade, and at this rate will disappear later in the present century. The data also show the surface temperature of the sea ice is increasing every ten years by 1.2 o Kelvin
W. Krabil et al., "Greenland ice sheet: High-elevation balance and peripheral thinning"Science, Vol. 289, pg 428 (2000) and R. Thomas et al., "Mass Balance of the Greenland Ice Sheet at High Elevations"Science, same volume
Data from a comprehensive survey of the ice cap suggest that although the high elevation portions of the ice sheet are unchanged, the outlet glaciers are changing. Radar and lidar measurements indicate many glaciers reaching tidewater are moving faster and thinning. Information on the NASA Greenland mapping project can be found at: http://aol.wff.nasa.gov/aoltm.htm
"Trouble in Polar Paradise" section of News and Reviews, Science 297 pg 1489-1514, (30 August 2002). Includes:
Richard Moritz et al "Dynamics of Recent Climate Change in the Arctic" pg 1497-1501
Eric Rignot and Robert Thomas "Mass Balance of Polar Ice Sheets" pg 1501-1506
Josefino Comiso in Journal of Climatology v 16, pg 3498 (2003) compared satellite thermal infrared temperature data from 1981 to 2001 and found that Temperature increases across the Arctic were steeper during the 1990s than the decade before, and were 8 times more rapid than the 100 year average. Melt season increased by 10 to 17 days per decade
The most dramatic melting of the Arctic was reported in 2002 by Mark Serreze and Konrad Steffen of University of Colorado. Greenland showed the greatest area of surface melt ever measured, and the Arctic Ocean reached record minimum extent. In Sept 2002 the sea ice extent was 400.000 sq miles less than the long term average. See Serreze et al "A record minimum Arctic Sea ice extent and area in 2002" Geography Research Letters 30(3) pg 1110; and Steffen "Greenland Maximum Melt Extent" at http://cires.colorado.edu/steffen/melt/index.html.
The Jokobshavn Icestream research was reported by Bea Csatho, research scientist at Ohio State University's Byrd Polar Research Center and Waleed Abdalati, a program manager at NASA. Abdalati presented the results at the December 2003 meeting of the American Geophysical Union.For more information on ice roads and oil exploration related to climate change, see "Broken Promises: The reality of big oil in America's Arctic" by Pamela Miller, Arctic Connections (The Wilderness Society, Washington DC, 2003) Available at http://www.wilderness.org/newsroom/release/20030408
Bruce Peterson, Robert Holmes and James McClelland of the Ecosystem Center at the Marine Biological lab in Woods Hole report increasing flow of water from major Eurasian rivers into the Arctic Ocean.
In their study they collaborated with Russian scientists to show these six rivers, including the Lena and the Ob, discharged 7 percent more water in 1999 than in 1936. This increase is enough to raise concern that the amount of fresher water in the Arctic will reach the point that it affects the generation of Atlantic Ocean currents. "Increasing River Discharge to the Arctic Ocean" Science 298 page 2171-2173 (13 December 2002).
Gagosian, Robert B. "Triggering Abrupt Climate Change" Perspective article by the President and Director of Woods Hole Oceanographic Institution, at http://www.whot.edu/home/about/whatsnew/abruptclimate.html.
"Insight: Climate and Water" a series of articles on the hydrologic and atmospheric cycles in Nature 419 pg 187-232 (12 Sept 2002)
John Magnuson et al Science 289 pg 1743 (8 Sept 2000)
Northern hemisphere lakes freezing later, thawing earlier over 150 years. From Wisconsin to Siberia, average freeze date change is 5.8 days per 100 years; thaw date averages 6.5 days earlier.
Also, Sagarin and Michili in Nature 294 pg 811 (26 oct 2001) indicate the 84 year record of the spring break up of the Nenana River near Fairbanks Ak shows a 5.5 day advancement of the date when the ice disintegrates. This time is known to the minute because locals place bets on it.
David Easterling, et al "Climate Extremes: Observations, Modeling, and Impacts" Science 289, pg 2068, (22 Sept 2000)
This review article lists recorded changes in high temperatures, fewer frost days, more heavy precipitation, more intense storms, droughts, etc. Mentions study by E Cooter and S LeDuc in Internat. Journal of Climatology (1995, Vol 15 pg 650) that the start of the frost free season in the northeastern US occurred 11 days earlier in the 1990s than in the 1950s
Eric Rignot, Jet Propulsion Laboratory, Personal Communication
"Global sea level rise is between 1.5 and 2.5 mm/yr over the last century. There is obviously still considerable debate about the exact value.... I however do not believe the conclusions that all of the signal is due to the thermal expansion of the oceans. Glaciers are melting throughout the world, the trend seems to be increasing, and that includes Greenland and even parts of Antarctica."
Dan Fagre, USGS Glaciologist, Glacier National Park, Montana,
http://www.mesc.usgs.gov/glacier/glacier_retreat.htm and personal communication Sept 2000.
Of the 34 named glaciers in the park, and total of 83 perennial ice and snow areas, all have been receding for most of the century. Only five glaciers remain larger than 1 sq Km and two others are slightly smaller. Total permanent snow and ice in the park is now 36 sq Km, with less than 26 sq Km being true glaciers. Reduction since mid 19th C is between 77 and 46 percent on fully-mapped glaciers. Grinnell Glacier (photo) has shrunk 63 percent and receded about 1 km since about 1850.
I received information about Cascade Range glacier recession from Dr. Robert M. Krimmel , USGS - ICP, Tacoma, WA
Alcides Ames, Peruvian glaciologist, personal communication, July 1999, including directions up to Ururashraju and Broggi glaciers near Huaraz, Cordillera Blanca
Also see http://unisci.com/stories/20011/0117013.htm "Small glaciers of the Andes may vanish in 10-15 years" 17 January 2001, about studies conducted on the Chacaltaya glacier in Bolivia and the Antizana glacier in Ecuador. B. Francou, et al in Ambio, vol.29, No 7, Nov. 2000.
Cabanes et al Science 294 pg 840 (26 Oct 2001
This study reports a 150mm (6 inch) average sea level rise over 100 years and also confirms the IPCC estimate that about 2/3 of this is due to climate change & glacial melting. But for 1993-98 the rise is more than double this rate, over 3 mm /yr, all most all of which is accounted for by the thermal expansion of sea water. This would mean a SL rise of 1 foot over the next 100 years.
Mark Meier, presentation at the 2002 American Assn for the Advancement of Science meeting, Boston Mass, February 16, 2002
Glacier and ice cap retreat now is "unprecedented," and will result in a greater sea level rise than estimated last year by the IPCC. "The rate of ice loss since 1988 has more than doubled," he told the meeting. His calculations are that glacier contribution to sea level will be at least .65 foot, double the IPCC estimate. (IPCC estimate of thermal expansion of sea water is .36 to 1.4 feet by 2100.)
In "How Alaska Affects the World", Science 297 pg 350 (19 Jul 2002) Meier and Mark Dyurgerov review these estimates and say that Alaskan glaciers contribute half the rise.
Anthony Arendt etal "Rapid Wastage of Alaska Glaciers and Their Contribution to Rising Sea Level" Science (same issue pg 382).
The authors state that the amount of glacial ablation, about 96 km3/year, is double that reported from Greenland and that glacier thinning was twice as fast as measured before. They used airborne laser altimetry to estimate volume changes of 67 glaciers. A few large glaciers (Columbia, Malaspina, Bering, LeConte etc) accounted for 75% of the change.
For more information about glacier melt and contribution to sea level, see State of the Cryosphere http://nsidc.org/sotc/
I am indebted to Dr. Mauri Pelto of Nichols College for field information about shrinking NW glaciers. His long-term studies of Cascade Range ice may be viewed at http://www.nichols.edu/departments/Glacier/nccent.htm
The Climate Impacts Groups of the University of Washington's Center for
Science in the Earth System may be accessed at http://www.jisao.washington.edu/PNWimpacts/
Principal researchers are Edward Miles, Philip Mote, Nathan Mantua,
and others.
Dr. Hector Galbraith, "Potential effects of sea level rise on intertidal habitat for migrating shorebirds" presentation to the Ecological Forecasting session, Estuarine Research Federation Conference, March 2002.
"Over the next few decades global warming is predicted to result in an acceleration in the current rate of sea-level rise, potentially inundating many low-lying estuarine areas and intertidal habitats. This could have important implications for shorebirds that depend on these areas for feeding habitat during their migrations. ... Even assuming a conservative global warming scenario (2°C within the next century), we predict major habitat loss at four of the sites (Willapa Bay, Humboldt Bay, San Francisco Bay, and Delaware Bay)" from the abstract. (Study was by Galbraith; S.H. Julius; D. Park; R. Jones; J. Clough; B. Harrington; G. Page, GES; EPA; Ecomodelling; Stratus Consulting; Ecomodelling; Manomet Center for Conservation Sciences; Point Reyes Bird Observatory)
Rising sea level effects on Chesapeake and Delaware Bay marshes were addressed by Michael Kearney et al in Eos (American Geophysical Union) April 16, 2002. More than 70 percent of of marshland in both estuaries is affected. (ENS report April 11, 2002)
The Jokobshavn Icestream research was reported by Bea Csatho, research scientist at Ohio State University's Byrd Polar Research Center and Waleed Abdalati, a program manager at NASA. Abdalati presented the results at the December 2003 meeting of the American Geophysical Union.
An overview of Greenland ice science may be found in Nature 42, 11 March 2004 pg 114, "A rising tide," by Quirin Schiermeier. It is reported that all studies show Greenland's ice sheet losing mass and rapidly flowing out and ablating along the coasts. The bulk of Greenland's ice, about 3,000 m thick in the center, is a remnant of the great ice age of 20,000 years ago, say scientists, and contains enough water to raise sea levels by seven meters.
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