Jonathan Bamber reflects on Everest’s changing ice as radar study reveals gaps

Glaciologist Jonathan Bamber described changes to Everest’s glaciers and climbing environment in a reflection published on Phys.org on October 10, UTC. Prompted by the film Tenzing, his account draws on historical research and personal observations to examine how ice loss is reshaping the mountain landscape.

Writing for The Conversation, in an article republished by Phys.org, Bamber said: “The film made me wonder what Norgay would think if he could return to the mountain today.” His article is a mountaineer’s scientific reflection, rather than the announcement of a new monitoring campaign.

The film portrays Tenzing Norgay’s life and his first ascent of Everest with Edmund Hillary in 1953. Bamber uses that expedition as a point of comparison for conditions around the mountain 73 years later, particularly at base camp and on the Khumbu Glacier.

What Bamber describes around Everest

Bamber describes peak-season Everest Base Camp as a crowded landscape of tents, people and discarded rubbish. He contrasts that scene with the single expedition of 1953. This is his published description of the change, rather than a statistical assessment of visitor numbers or waste.

He also points to extensive lakes on the surface of Khumbu Glacier in Google Earth imagery from 2021. Bamber explains that these pools absorb more solar radiation than the surrounding ice, accelerating melting. His description links visible changes in the glacier’s surface to a physical process that can increase ice loss.

His comparison extends to the European Alps. Bamber recalls climbing the Eiger’s north face in August 1990 and says the route’s second icefield has since disappeared. That account provides a personal comparison across his climbing career, rather than a newly dated measurement of the icefield.

What radar measured beneath Everest’s glaciers

Independent research offers a more detailed view of the ice remaining around Everest. Hamish D. Pritchard and colleagues published their glacier-thickness study in Earth System Science Data on January 7, 2026. The measurements came from fieldwork conducted between October 27 and November 6, 2019.

The team used helicopter-borne, low-frequency radar to survey 11 glaciers in Nepal’s Khumbu Himal. To help interpret the radar records, the researchers developed a terrain-clutter model that distinguished reflections from surrounding terrain from echoes associated with the glacier bed.

The survey covered 119 line-kilometres, with measurements spaced approximately 40 metres apart horizontally and precision of around ±7%. The authors say that coverage approximately doubled the length of previous glacier-thickness surveys across High Mountain Asia, expanding the observations available for testing estimates of remaining ice.

Measured thickness reached 445 metres. That figure is the maximum reported across the survey, not a measurement at Everest Base Camp. The study’s geographical coverage and measurement dates matter when using its results to describe any particular part of the mountain environment.

Why estimates of remaining Himalayan ice differ

Comparing their observations with existing modelled thickness products, the researchers found substantial errors in where the models placed ice. Systematic underestimates and overestimates were equivalent to roughly half the measured thickness or more, showing that the models struggled to reproduce its distribution in these complex glaciers.

Obtaining better measurements is difficult. The researchers describe the challenges of surveying remote glaciers at high altitude, while water and debris can impede radar penetration. Their study addresses a shortage of direct thickness observations that limits understanding of the region’s remaining ice reserves.

The published study presents the dataset as a way to test model performance and improve estimates of ice distribution and future loss. Its measurements establish conditions during the 2019 survey; publication in January does not turn them into observations of glacier thickness in October 2026.

Why remaining ice matters beyond climbing

The implications extend downstream. Pritchard and colleagues explain that mountain glaciers help sustain river flows, particularly during relatively dry periods and droughts. Understanding how much ice remains therefore matters to water resources as well as to the landscapes experienced by mountaineers.

The radar dataset does not establish a date when Khumbu Glacier will disappear. The authors identify better testing and improvement of glacier models as a necessary step towards more accurate estimates of future loss. Bamber’s new reflection brings attention to the changing landscape; that independent research explains why its future remains difficult to quantify.