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USGS Report Shows a “Dramatic” Decline in U.S. Glaciers

South Cascade Glacier in Washington State

The South Cascade Glacier in 1928 (top) and now (bottom)

“Fifty years of U.S. Geological Survey (USGS) research on glacier change shows recent dramatic shrinkage of glaciers in three climatic regions of the United States. These long periods of record provide clues to the climate shifts that may be driving glacier change.”

Thus begins a report (pdf) released on Thursday by the U.S. Geological Survey showing a “dramatic decline” in three “benchmark” glaciers the agency has studied for five decades.

Beginning in 1957, the USGS has taken annual measurements of the South Cascade Glacier in Washington state, and followed shortly thereafter monitoring the Gulkana Glacier on the coast of Alaska and Wolverine Glacier in Alaska’s interior.

All three glaciers have shrunk and thinned, the report says, with the mass loss rapidly accelerating over the past 15 years. The South Cascade Glacier has lost nearly 25% of its weight, and the two Alaskan glaciers about 15%.

Between 1987 and 2004 all three glaciers consistently lost more snow and ice each summer as compared to years prior, the report says. Combined with less snowfall the loss has led to the net decline of the glaceirs.

The three benchmark glaciers tell the story for most of the many thousands of glaciers across the country and worldwide.

In addition to these three glaciers, more than 99 percent of America’s thousands of large glaciers have long documented records of an overall shrinkage as climate warms,” said USGS scientist Bruce Molnia.

The study raises concerns about diminishing freshwater runoff and the future availability for fresh drinking water in areas that depend on the glaciers for water supply as they continue to shrink – some possibly disappearing entirely. The shrinkage also changes water temperatures, effecting the habitat of fish, insects, and other animals downstream, says USGS scientist Shad O’Neel.

The ongoing study demonstrates the value of long-term research by enabling scientists to discern the difference between natural variations and man-made global warming. In the 60’s and 70’s, for example, researchers tracked the two coastal glaciers were able to determine a coincidental link between their growth and decline and natural changes in temperature of the Pacific Ocean. In recent decades, that link has weakened considerably, overtaken, researchers say, by the overall rise in global temperatures.

There is no doubt that most mountain glaciers are shrinking worldwide in response to a warming climate,” said USGS scientist Edward Josberger, “Measuring changes in glacier mass provides direct insight to the link between glaciers and climate, ultimately helping predict glacier response to anticipated climate conditions.”

Image courtesy of ClimateWire, USGS

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Comments

  1. […] Quote: Originally Posted by IanC Quote: Originally Posted by Old Rocks Quote: Originally Posted by IanC Thanks Old Rocks. Your site didn't actually address my question but I will look it over more carefully when I have time. The one graph that did bother me was the one that called the increase in CO2 levels 'exponential'. The line itself does not show the typical severe increasing rise associated with graphs of that nature, although I suppose that CO2 production is proportional to the human population which is 'exponential' in growth. Is population control one of the main platforms for amelioration of global warming? Ok, I think this is what you are looking for. Greenhouse Gas Absorption Spectrum thanks again Old Rocks. this site was much better at describing the absorption spectra of CO2, H2O and other gasses. it is interesting to see the windows for energy reaching the earth, and the windows for black body radiation which allows energy to escape. Basically, CO2 stops infrared at 3 spectral regions. At present concentrations of CO2 it takes 10metres (33ft for you Americans) to completely absorb those wavelengths. If you double the amount of CO2 then it only takes 5m. If you halve the CO2 then it would take 20m (66ft) to absorb all the IR. Obviously practically no heat is leaving the earth at these wavelengths no matter what the concentration of CO2 is. I am simplifying the absorbtion of IR/re-emmission of black body radiation but there is no catastrophy even possible here. Not only are you simplifying it, you have it completely wrong. There is a section in the American Institute of physics site, the History of CO2, that addresses what your are speaking of. And it does not work the way you describe at all. The Carbon Dioxide Greenhouse Effect Old Rocks- you seem like a thoughtful, reasonably well educated guy. Have you really thought a bunch of this stuff through? The hockey stick is a joke. A joke that has been verified by many, many other scientists. Yes, the latest graphs are a bit more bumpy than the first, reflecting better data, and better interpretation of the proxies, but the conclusion is the same. When you make a statement such as this, you had best be able to back it up with real data from real scientists. Even with satellites, measuring the earth's temp to the nearest one degree is difficult. Can you really trust the estimates for 100, 500 and 1000 years ago? Why are you so sure that the same cyclical climate changes that have been going on since history was recorded are caused (THIS TIME) by mankind? We have a pretty good understanding of the forces driving the cyclical changes, from the short ones like the La Nina, El Nino cycles, to the long ones such as the Milankovic Cycles. By those very cycles, we should be experiancing a slow descent into another ice age. Our climate, by those cycles, should be much more like that of the Little Ice Age, than what we presently see. I totally agree that we have made an impact by burning fossil fuels, agriculture and industrial polution. But the scale is small… No, Ian, the scale is not small. I wish it were. But you can see the scale simply by looking at the melt rate for the major glaciers worldwide. A rate that is accelerating. SOTC: Glaciers Retreat of Glaciers in Glacier National Park | Northern Rocky Mountain Science Center (NOROCK) USGS Report Shows a "Dramatic" Decline in U.S. Glaciers | Global Warming is Real […]

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