USGS report: global warming responsible for vanishing Northwest glaciers

Research has shown that North American glaciers have been melting steadily for the past 50 years. A report just released by the U.S. Geological Surveyunder the Obama administration focused on three Northwest glaciers that are representative of a thousand others.

The glaciers in the study were the South Cascade in Washington, and the Wolverine and Gulkana in Alaska. Although the glaciers are approximately 1500 miles apart, the report found that all three glaciers had begun melting at the same eccelerated rate. This indicates the warming is happening across the board, even in different climate regimes. Particularly in the past 10-15 years.

The average surface loss rate for the South Cascade glacier grew from 1m annually to an average of 1.75 to 2m per year. If this rate continues, the glacier could disappear in the next 50 years.

According to Ed Josberger, the report’s lead author, Glaciers in the Northwest have gained or lost mass from year to year since the agency began collecting data in 1957, due tof changes in winter storm patterns tied to shifts in Pacific Ocean currents. However, the cumulative decline since 1989 suggests that global warming has overcome those seasonal variations.

What’s so important about glaciers? Melting glaciers add to the rise of sea level, threatening low-land and coastal communities. The loss of glaciers in the Northwest also affects rivers and streams where species such as bull trout and salmon live, Josberger said. Those fish prefer the colder, highly oxygenated water that runs off the glaciers in the spring and summer. Lack of glacial spring run-off can trigger droughts like the one currently plaguing California.

“More than 99 percent of America’s thousands of large glaciers have long-documented records of an overall shrinkage as climate warms,” agency scientist Bruce Molnia said in a statement.

Geologists can track the growth and decline of glaciers by taking photographs from the same position each year and by taking snow core samples. Core samples allow the researchers to measure the height of the annual snowfall. The data is used to estimate the net balance of a glacier and its average mass over a year.

Furthermore, disappearing glaciers have been happening on a global scale since 1980 as significant global warming has led to increasing glacier retreat. To the extreme that some glaciers have disappeared altogether, and the existence of a great number of the remaining glaciers of the world is threatened. In locations such as the Andes of South America and Himalayas in Asia. The demise of glaciers in these regions will have potentially increasing impact on available water supplies.

Water shortages are already of concern in many areas of the world. Particularly India, China, and parts of the middle east where conflicts over water rights are increasingly likely, with the anticipation that water will eventually become more precious than oil.

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***For photo credit run cursor over photograph * Copyright Jean Williams 2009 * Author also writes under pen name DelilahStarling. Permission to reprint up to three paragraphs with a direct “read full story” back to this page. Contact creatinggreenpiece@juno.com