Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists have discovered.
Researchers visiting Peru’s Quelccaya Ice Cap have released a stunning pair of images to show the dramatic change.
They were also able to obtain ice core samples from the area and track plant life as it moved into previously glacial areas.Two annually dated ice cores drawn from the tropical Peruvian Andes reveal Earth’s tropical climate history in unprecedented detail—year by year, for nearly 1,800 years.
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What a difference This 2002 photo of Quelccaya Ice Cap Right) is, taken from the same spot as a previous photo in 1977, and clearly shows the retreat of the ice wall’s vertical margins.
Researchers at The Ohio State University retrieved the cores from a Peruvian ice cap in 2003, and then noticed some startling similarities to other ice cores that they had retrieved from Tibet and the Himalayas.
‘These ice cores provide the longest and highest-resolution tropical ice core record to date,’ said Lonnie Thompson, distinguished university professor of earth sciences at Ohio State and lead author of the study.
‘In fact, having drilled ice cores throughout the tropics for more than 30 years, we now know that this is the highest-resolution tropical ice core record that is likely to be retrieved.’The cores will provide a permanent record for future use by climate scientists, Thompson said.
This is very important, as plants captured by the advancing ice cap 6,000 years ago are now emerging along its retreating margins, which shows that Quelccaya is now smaller than it has been in six thousand years.
‘The frozen history from this tropical ice cap—which is melting away as Earth continues to warm—is archived in freezers at -30ºC so that creative people will have access to it 20 years from now, using instruments and techniques that don’t even exist today,’ he said.
Patterns in the chemical composition of certain layers matched up, even though the cores were taken from opposite sides of the planet.
The cores provide a new tool for researchers to study Earth’s past climate, and better understand the climate changes that are happening today.
The new cores, drilled from Peru’s Quelccaya Ice Cap, are special because most of their 1,800-year history exists as clearly defined layers of light and dark: light from the accumulated snow of the wet season, and dark from the accumulated dust of the dry season.
They are also special because of where they formed, atop the high Andean altiplano in southern Peru.
Most of the moisture in the area comes from the east, in snowstorms fueled by moist air rising from the Amazon Basin.
But the ice core-derived climate records from the Andes are also impacted from the west—specifically by El Niño, a temporary change in climate, which is driven by sea surface temperatures in the tropical Pacific.
‘We have been able to derive a proxy for sea surface temperatures that reaches back long before humans were able to make such measurements, and long before humans began to affect Earth’s climate,’ Thompson said.