Crisis in the Andes: 1,600 years of ice melts in just 25 years

Rick Docksai | Science Recorder | April 06, 2013

Crisis in the Andes: 1,600 years of ice melts in just 25 years

Glaciers continue to melt, according to the latest study.

It’s a stunning development in the world of climate change. Masses of ice that took South America’s Andes mountain range 1,600 years to form have reportedly melted in full in the last 25 years, another consequence of warming temperatures worldwide, according to a study published April 4 in the journal Science.

The study, led by Ohio State University glaciologist Lonnie Thompson, documents the massive ice loss that the Quelccaya ice cap in Peru has suffered in recent decades. The formation, they report, is now the smallest it has been in 5,200 years.

Quelccaya, located in far eastern Peru, is the largest tropical glacier on Earth, but it’s been withering under as global temperatures rise, in particular by El Niño — a temporary climate shift driven by wind and ocean patterns in the Pacific. Members of Thompson’s team have spent time photographing the glacier since 1978, and year by year photographs show steady glacial retreat and the emergence of plant life in what had been frozen ground years before.

One landmark discovery was a mass of plants that the team found near a lake formed from the meltwater. These plants turned out to be 4,700 years old, which meant that when the glacier’s margin had stopped at their location, it was at its lowest point in nearly 5,000 years.

And yet it’s at an even lower point today.

Thompson’s group later found another crop of exposed plants that turned out to be 6,300 years old. The 1,600 years that separate the first plant group from the second, the researchers explained, indicate 1,600 years of ice that melted since 1978,

Thompson and his colleagues back up their visual collage with their data that they compiled from ice-core samples that they extracted over a period of years. Through analyses of the samples, they have been able to reconstruct the region’s last 1,800 years of climate history. They could also discern the age of the glacier’s margins by carbon-dating of plant matter—in eons past, when the glaciers were expanding, they submerged and froze over plant life, remains of which are once again exposed as the glaciers now withdraw.

And what’s happening to Quelccaya is happening to many other tropical glaciers around the world. The researchers noted that its ice cores showed strong similarities to ice cores that other groups had obtained from the Himalayas and the mountains of Tibet. All the core samples bear similar chemical compositions, and their glaciers are likewise losing ground at continuous rates.

Meanwhile, the findings are especially devastating for Peru, which has played witness to an extraordinary decline in its glacier area. According to scientists, the 1970 at least 22 percent of the country’s glacier area has melted, and ice is said to be retreating at average rate of 200 feet per year. As a result, the country has taken unprecedented measures to curb the effects of warming, even going as far as covering large swaths of its glaciers in white paint.

The discovery is likely to only add fuel to the debate over the effects of global warming. According to researchers, rising global temperatures will speed the melting of glaciers and ice caps and cause early ice thaw on rivers and lakes. Over the course of the past decade, a number of massive ice shelves have felt the impact of rising temperatures. After existing for many millennia, the northern section of the Larsen B ice shelf in Antarctica — a section larger than the state of Rhode Island — collapsed between January and March 2002, far sooner than scientists had predicted. Meanwhile, a series of studies released by the National Oceanic and Atmospheric Administration (NOAA) shows the Earth continuing to warm at an alarming rate. According to NOAA scientists, 2012 was the warmest year since global instrumental temperature records began over 130 years ago.

Still, a number of climate skeptics have questioned whether the effects of global warming will play out as predicted. According to a series of recently released studies, scientists are already discovering evidence that seems to show unpredicted changes. For example, a recent study examined how glacial retreat could present penguins with larger nesting areas. With more room to hatch babies, the Ross Sea Adélie penguins may ultimately benefit from a warming planet, said researchers.

The Quelccaya ice-core samples remain in deep-freeze—i.e., -30 degrees Celsius—storage. Thompson and his colleagues hope that further analysis of the samples will aid climate researchers worldwide in better understanding Earth’s climate history—and its future.


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