KATHMANDU, July 28: Human activities at the world's highest mountaineering camp are contributing to the melting of the Khumbu Glacier, according to a landmark scientific study that, for the first time, has quantified the local impacts of expedition operations on the glacier beneath Everest Base Camp (EBC).
The study, published in the peer-reviewed journal Regional Environmental Change, estimates that cooking, heating, electricity generation and even human urine discharged directly onto the glacier during the 2023 spring climbing season generated enough heat to potentially melt about 2,492 (±528) tons of glacier ice and snow.
While this amount is negligible compared to the glacier's overall mass loss, researchers say the heat is concentrated within the heavily used base camp area and may contribute to localized glacier instability.
The findings add a new dimension to growing concerns over the future of Mount Everest as climate change continues to shrink Himalayan glaciers and mountaineering activity reaches unprecedented levels.
"Our study examines how local human activity, together with climate change, is affecting the Khumbu Glacier and explores a sustainable future for Everest Base Camp," said lead author Gautam.
First quantitative assessment
Although scientists have long documented the retreat of the Khumbu Glacier due to global warming, few studies have attempted to measure the direct impact of human activities associated with Everest expeditions.
The researchers collected field data during the 2023 spring climbing season, documenting expedition activities and waste management practices. They combined those observations with more than three decades of Landsat satellite imagery to examine long-term surface temperature trends around Everest Base Camp.
The study found that fossil fuels used for cooking, heating tents and generating electricity accounted for the overwhelming majority of the estimated heat released at the camp.
According to the researchers, expedition operators used 824 LPG cylinders, 18,935 liters of kerosene and 5,130 liters of petrol during the 2023 climbing season. After accounting for combustion efficiency, the fuels released enough heat to theoretically melt approximately 2,338 tons of glacier ice. Human urine discharged directly onto the glacier added another 154 tons of potential ice melt, bringing the total estimate to nearly 2,500 tons.
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Researchers estimated that human activities at the base camp released approximately 849,174 megajoules of heat energy during the roughly 50-day expedition season.
Base camp warming faster
Beyond estimating the heat released by expedition activities, the study found that the Everest Base Camp area has been warming significantly over the past three decades.
Using Landsat satellite data covering the period from 1991 to 2023, researchers found that land surface temperatures at the campground increased by 0.28 degrees Celsius per year, compared with 0.15 degrees Celsius per year over the adjacent snow-covered section of the Khumbu Glacier.
The warming rate at the base camp was also higher than that recorded over nearby debris-covered terrain. All warming trends were statistically significant.
However, the researchers caution that satellite observations alone cannot conclusively attribute the additional warming at the campground solely to human activity because the observed difference remains relatively small and falls within the statistical confidence intervals. Higher-resolution thermal observations and field measurements would be needed to isolate the human contribution more precisely.
Climate change remains the dominant driver
Importantly, the researchers stress that their findings should not be interpreted as suggesting that climbers are responsible for the retreat of the Khumbu Glacier.
The paper concludes that the estimated anthropogenic melt represents only a very small fraction of the glacier's overall ice loss. Instead, it identifies expedition-related heat as an additional localized stress on a glacier already undergoing rapid changes because of global climate change.
The authors also acknowledge uncertainties in their calculations, noting that several potential heat sources—including helicopter operations, pack animals and human metabolic heat—were not included because sufficient data were unavailable.
Likewise, not all heat generated at the base camp is transferred directly into the glacier, meaning the estimates should be regarded as first-order approximations rather than exact measurements.
A seasonal city on ice
Everest Base Camp has evolved into what the researchers describe as a temporary seasonal city.
During the spring climbing season of 2023, approximately 2,127 climbers, guides and support staff occupied nearly 1,600 tents spread across 26.5 hectares of the Khumbu Glacier for about 50 days while preparing for summit attempts on Everest and neighboring peaks, including Lhotse, Nuptse and Pumori.
As the number of expeditions has grown over recent decades, so too has the environmental footprint of the camp, including increased fuel use, waste generation and infrastructure built directly on glacier ice.
Relocation of Everest Base Camp
One of the study's most significant recommendations is the possible relocation of Everest Base Camp from the glacier to nearby stable, ice-free ground.
The researchers identified two potential sites southwest of the existing base camp that could provide safer and more sustainable alternatives. Both locations are situated on stable terrain rather than moving glacier ice and are considered less vulnerable to glacier instability.
According to the authors, relocating the camp could reduce human pressure on the Khumbu Glacier, eliminate the need to reconstruct camp infrastructure every climbing season, improve safety, facilitate helicopter operations and reduce long-term environmental impacts.
The study also notes that Everest Base Camp has not always occupied its current location. Early Everest expeditions in the 1950s established their camps farther southwest near Gorakshep, suggesting that relocation would not be unprecedented.
The researchers acknowledge that moving the base camp would require careful planning and consultation with expedition operators, local communities and conservation authorities because of the logistical, ecological and economic implications.
Nevertheless, they argue that proactive adaptation measures are becoming increasingly necessary as climate change accelerates glacier loss across the Himalaya and human activity on Everest continues to increase.
They conclude that relocating Everest Base Camp could help reduce localized human-induced glacier melting while promoting a more sustainable future for mountaineering and preserving one of the world's most iconic high-altitude environments.
Gautam noted that Nepal relies heavily on high-altitude expedition tourism, while Himalayan glaciers provide vital water resources to millions of people living downstream. He expressed hope that the findings would inform policies to protect the Khumbu Glacier without compromising Nepal's mountaineering industry.
"We hope this study can contribute to sustaining mountaineering tourism and high-altitude expeditions," he said.
The study, led by Gautam, involved scientists from the U.S. Geological Survey (USGS), the Department of Environmental Science at Tribhuvan University and the Nepal Academy of Tourism and Hotel Management (NATHM).
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