Natural climate phenomena like El Niño are leading to a dramatic melting of tropical glaciers, according to a recent study.
A recent study reveals that natural climate happenings, such as El Niño, are causing tropical glaciers to significantly lose their ice.
El Niño is an event that typically happens every two to seven years, leading to unusually warm ocean temperatures in the eastern Pacific, which greatly influences weather patterns worldwide.
The Quelccaya Ice Cap (QIC) in the Peruvian Andes has proven to be particularly responsive to these climatic changes, but the exact impact of El Niño on its ongoing shrinkage has remained unclear until now.
By examining images from NASA Landsat satellites collected over the last forty years, researchers have established that the periodic warming associated with El Niño has led to a significant decrease in the area covered by snow on the glacier. This study, led by Kara Lamantia, a graduate student at the Byrd Polar and Climate Research Center at The Ohio State University, indicates that between 1985 and 2022, the QIC has lost approximately 58% of its snow cover and about 37% of its total area.
“Our findings offer insight into the health of the glacier,” explained Lamantia. “The Quelccaya glacier experiences significant imbalance during these short-term climate fluctuations.”
Published today (October 8, 2024) in the journal The Cryosphere, this study pioneers the automation of detecting snow-covered areas on the QIC. Traditionally, determining this has required extensive field measurements or manually tracing clear satellite images to distinguish between snow and ice.
To address this, the research team created an algorithm that processes images utilizing near-infrared technology, which uses wavelengths outside the visible spectrum. “By setting a threshold for the differences in reflectance between snow and ice, we can get consistent and much more reliable measurements,” said Lamantia.
Glaciers and ice caps gain mass by collecting ice and snow, but they lose mass when less is accumulated or more is melted than gained. By assessing the ratio of the snow-covered area to the total area, researchers can determine whether the QIC is gaining, losing, or stabilizing its mass.
The research uncovered that during El Niño events, the ratio of snow cover decreases significantly from the average, indicating a considerable reduction in the area snow-covered.
This significant change in the ratio can be linked to the stark contrasts between the dry and wet seasons in southern Peru, according to Lamantia.
“All snowfall occurs during the wet season, but during an El Niño, southern Peru experiences warmer and drier conditions than usual, leading to a dry wet season,” she explained. “Consequently, snow cover continues to decline, with potentially far less snowfall to replenish it.”
As climate change rapidly transforms the Earth’s atmosphere, it is anticipated that El Niño events will become more prolonged and intense, which will hasten ice loss. This raises concerns that the QIC may not recover its snow cover during La Niña periods, when ocean temperatures are generally lower.
“The ice cap is experiencing a steady linear decline due to human-induced warming,” Lamantia noted. “It may not matter how strong future La Niña events are; as the freezing elevation rises and snow cover dwindles, the Quelccaya is expected to keep declining.”
If conditions persist, some forecasts indicate that the snow cover on the QIC could vanish by 2080, turning it into a desolate ice field similar to Kilimanjaro. By the century’s end, the study suggests that the ice cap could completely disappear.
Understanding how other temporary weather phenomena might affect glacier vulnerability is challenging, and similar studies could explore these dynamics in the future. What is evident is that ice loss threatens high-altitude communities that rely on these glaciers, as diminished snow coverage can quickly reduce essential water supplies.
The damage inflicted on the atmosphere and oceans cannot be undone quickly, Lamantia emphasized. However, leveraging the data on their complex interactions may better equip researchers to monitor and mitigate the planet’s climate challenges.
“The prevailing opinion is that we should expect intensified and prolonged El Niños to create more challenges for the QIC,” said Lamantia. “We need to become smarter in our approach to water resource usage and conservation.”
This research was funded by the National Science Foundation, the Heising-Simons Foundation, and the Volo Foundation. The other co-authors included Lonnie Thompson and Bryan Mark from Ohio State, and Laura J. Larocca of Arizona State University.
