RollingThunder
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- Mar 22, 2010
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Anthropogenic global warming is rapidly melting most of the world's mountain glaciers. This threatens the water supplies for billions of people and also threatens the irrigation water supplies for large agricultural regions. The loss of these mountain glaciers will almost certainly result in great suffering and mass starvation within the next few decades. Regional conflicts over shrinking water supplies are probable in a number of areas around the world, as Pentagon reports have warned.
Here's the latest scientific study of just one of those disappearing glaciers that highlights just how fast these changes are occurring.
In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years
The New York Times
By JUSTIN GILLIS
Published: April 4, 2013
(excerpts)
Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance. The evidence comes from a remarkable find at the margins of the Quelccaya ice cap in Peru, the worlds largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago. Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheets margins. Lonnie G. Thompson, the Ohio State University glaciologist whose team has worked intermittently on the Quelccaya ice cap for decades, reported the findings in a paper released online Thursday by the journal Science. Dr. Thompson and his team have expanded on previous research involving long-dead plants emerging from the melting ice at the edge of Quelccaya, a huge, flat ice cap sitting on a volcanic plain 18,000 feet above sea level.
Several years ago, the team reported on plants that had been exposed near a meltwater lake. Chemical analysis showed them to be about 4,700 years old, proving that the ice cap had reached its smallest extent in nearly five millenniums. In the new research, a thousand feet of additional melting has exposed plants that laboratory analysis shows to be about 6,300 years old. The simplest interpretation, Dr. Thompson said, is that ice that accumulated over approximately 1,600 years melted back in no more than 25 years. If any time in the last 6,000 years these plants had been exposed for any five-year period, they would have decayed, Dr. Thompson said. That tells us the ice cap had to be there 6,000 years ago. Global warming, which scientists say is being caused primarily by the human release of greenhouse gases, is having its largest effects at high latitudes and high altitudes. Sitting at high elevation in the tropics, the Quelccaya ice cap appears to be extremely sensitive to the temperature changes, several scientists said. Throughout the Andes, glaciers are now melting so rapidly that scientists have grown deeply concerned about water supplies for the people living there. Glacial meltwater is essential for helping Andean communities get through the dry season.
Here's the latest scientific study of just one of those disappearing glaciers that highlights just how fast these changes are occurring.
In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years
The New York Times
By JUSTIN GILLIS
Published: April 4, 2013
(excerpts)
Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance. The evidence comes from a remarkable find at the margins of the Quelccaya ice cap in Peru, the worlds largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago. Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheets margins. Lonnie G. Thompson, the Ohio State University glaciologist whose team has worked intermittently on the Quelccaya ice cap for decades, reported the findings in a paper released online Thursday by the journal Science. Dr. Thompson and his team have expanded on previous research involving long-dead plants emerging from the melting ice at the edge of Quelccaya, a huge, flat ice cap sitting on a volcanic plain 18,000 feet above sea level.
Several years ago, the team reported on plants that had been exposed near a meltwater lake. Chemical analysis showed them to be about 4,700 years old, proving that the ice cap had reached its smallest extent in nearly five millenniums. In the new research, a thousand feet of additional melting has exposed plants that laboratory analysis shows to be about 6,300 years old. The simplest interpretation, Dr. Thompson said, is that ice that accumulated over approximately 1,600 years melted back in no more than 25 years. If any time in the last 6,000 years these plants had been exposed for any five-year period, they would have decayed, Dr. Thompson said. That tells us the ice cap had to be there 6,000 years ago. Global warming, which scientists say is being caused primarily by the human release of greenhouse gases, is having its largest effects at high latitudes and high altitudes. Sitting at high elevation in the tropics, the Quelccaya ice cap appears to be extremely sensitive to the temperature changes, several scientists said. Throughout the Andes, glaciers are now melting so rapidly that scientists have grown deeply concerned about water supplies for the people living there. Glacial meltwater is essential for helping Andean communities get through the dry season.