Jakarta –
Researchers at Ohio State University analyzed ice cores from Nevado Huascarán, the world’s highest tropical mountain, located in the central Peruvian Andes. The ice of these mountains reveals important climate data.
This study, which is the first to examine ice cores from this mountain peak, provides unprecedented insight into the climate history of the Amazon basin over the past sixty years.
Research focus
The research, supported by the National Science Foundation, focused on the analysis of four ice samples. Two of them come from the “pole” of the mountain, that is, from the lowest point between two ridges, and two others come from its summit, almost 7,000 meters above sea level.
As cited by Earth.com, the research team then compared records of stable oxygen isotopes found in glacial ice at different elevations on the mountain.
Stable isotopes of oxygen are used by scientists as a proxy to infer temperature changes over time. However, interpreting this data in tropical regions can be difficult due to the complexity of the climate in these regions.
Critical intuition
The results reveal that the isotopic record has a statistically significant relationship with sea surface temperatures in the Pacific and precipitation in tropical regions of South America.
In particular, peak isotopes show greater sensitivity to large-scale changes in tropical Pacific sea surface temperature, compared to isotopes at lower altitudes. These differences are important because they suggest that isotope records at different altitudes may reflect different aspects or mechanisms of regional climate history.
The study shows an increasing influence of the tropical Pacific climate on the recorded isotopic peaks, most likely caused by rapid climate change in recent times.
The Year of Nino
“From a paleoclimate perspective, the data tells us that these cores could be useful for looking at the history of El Niño in the tropics,” said Austin Weber, lead author of the study and a doctoral candidate at the Byrd Polar and Climate Research Center. . “And we don’t have a good history of it because there aren’t many observational datasets or historical records about the tropics.
El Niño years, characterized by unusually warm sea surface temperatures in the equatorial Pacific, impact the Amazon basin by weakening trade winds and reducing precipitation. These climate changes in turn affect how isotopes are broken down.
Impact of climate change
The study, published in the Journal of Geophysical Research, also highlights the impact of climate change on the region. Over the past 60 years, rising temperatures have significantly contributed to accelerating ice retreat on Nevado Huascarán.
The reduction in ice is concerning, said Lonnie Thompson, one of the study’s authors and a senior research scientist at the Byrd Polar and Climate Research Center.
He said tropical ice core samples could serve as important evidence for understanding Earth’s complex ocean-atmosphere system.
“The beauty of these ice cores is that they give perspective on natural variability before humans started changing the climate system,” Thompson said.
Historic result
The recovery of these ice cores in July 2019 marked a historic achievement, overcoming decades of challenges posed by avalanches and snow-covered crevasses.
The team managed to reach the southern summit of the mountain and found glacial ice cores 471 meters long, both from the drilling site on the hill (6,050 meters above sea level) and at the summit (6,768 meters above sea level).
“This is a very difficult and dangerous place to recover ice cores and the expedition will probably not be repeated,” Thompson said.
“This paper is the first published study of what I believe will be a series of papers on what may be the most unique collection of ice cores collected in my career,” he concluded.
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(rn/rn)
2024-01-21 07:03:28
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