«The Kilimanjaro glacier will disappear, just as the glaciers of the Alps, the Andes, and even the Himalayas will melt over time.»

Douglas Hardy: “Kilimanjaro is a compelling place from both aesthetic and scientific perspectives”
Despite predictions by many 20th century scientists, the glaciers of Kilimanjaro in Tanzania still exist. However, their surface area has decreased by 91 per cent since 1912, when they were first mapped. According to Douglas Hardy, glacier and climate specialist at the University of Massachusetts Amherst (United States), their disappearance is inevitable.


Interview by Katerina Markelova
UNESCO

You’ve made over twenty expeditions to Kilimanjaro’s summit and even call it your ‘home away from home’. What first drew you to study Kilimanjaro’s glaciers?

Initially it was really luck. I was collaborating at the time with Lonnie Thompson from Ohio State University on tropical glacier research, and in 1999 he obtained permission and funding to drill ice cores at Kilimanjaro’s summit. I was invited to install meteorological instrumentation to support the ice core interpretation. Typically, such a project would last 3-4 years. Yet, 24 years later, I have logged 82 nights in the crater – far more than I ever imagined.

Kilimanjaro is indeed an incredibly compelling place from both aesthetic and scientific perspectives. Once you reach the summit, you’re struck by the contrast between bright-white vertical walls, and fins of ice sitting cleanly on dark volcanic sand. The whole scene up there is unlike anything I’ve ever seen.

From the scientific perspective, these glaciers are fascinating because they exist in a desert environment, sometimes without any snow in sight, on the African continent, at an altitude halfway through Earth’s atmosphere. Throughout the 20th century, scientists consistently predicted their demise, but have been uniformly wrong.

What preparation is required for a high-altitude research expedition?

Kilimanjaro rises 5,000 metres above the surrounding landscape. Because it’s relatively easy to climb, the most important preparation is to bring patience along. By ascending slowly, most people can adapt to the altitude and the tremendous change in oxygen concentration. This is why we usually camp about five nights on the way up, even though the entire ascent can be completed in six hours. We also try to keep in mind that we're not just climbing; we're going to the summit and then we're setting up camp and we're starting to work. It's different from a typical climb where one races back down.

Going up the mountain is a tremendous number of rapid transitions. You start on the plains, where there's a lot of villages and small farms. Then you go through the rainforest above which the environment begins drying out. By the time one reaches the summit, there's virtually no vegetation. However, it's not devoid of life, and increasingly, we're seeing birds and insects at the top.

How have the glaciers changed since you began your research in 2000?

The most obvious change is in the ice’s extent and thickness. Since Kilimanjaro’s glaciers were first mapped in 1912, 91 per cent of their area has disappeared. There have also been more subtle changes. For example, when I first visited, sharp ice features with spires and narrow fins were common. While these textures can still be found, the ice has changed. With higher humidity caused by climate change, it becomes more rounded.

What makes Kilimanjaro’s glaciers so fragile?

The summit elevation is warming. However, with collaborators in Austria and Germany we’ve shown that increasing temperature is not the main reason for the glacier retreat. Kilimanjaro’s glaciers lack an accumulation zone, and with reduced precipitation, they are really doomed.

Kilimanjaro’s climate is closely linked to sea surface temperatures in the Indian Ocean
At a much larger scale, the ocean stores a tremendous amount of heat, warming the global atmosphere. Kilimanjaro’s climate is closely linked to sea surface temperatures in the Indian Ocean and elsewhere. The strong correlation between the annual mean temperature at the summit and sea surface temperatures demonstrates the importance of the global climate system as a whole.

When did the first signs of fragility in the Kilimanjaro glaciers begin to appear?

Scientists have known about their retreat for a very long time. The German geographer Hans Meyer, who first reached the summit in 1889, noted significant ice loss by his return in 1898. He predicted they’d disappear within 20-30 years! However, his prediction was premature. A 2002 article published in the academic journal Science suggested that if climate conditions didn’t change, Kilimanjaro would likely lose all its ice between 2015 and 2020.

Despite this, although the glaciers have shrunk dramatically, with the larger Northern Icefield now more fractured, ice is still there. The glaciers’ persistence is part of Kilimanjaro’s mystique, although their eventual disappearance is inevitable.

What are the connections between these glaciers and the nearby communities?

The glaciers – and the people who are living and farming at lower levels of the mountain – are actually victims of the same problem, which is decreased regional precipitation. This is having serious implications for humans and ecosystems, creating drier conditions with more fire risk.

Kilimanjaro’s glaciers are retreating due to reduced precipitation
Kilimanjaro is Africa’s highest point, which makes it a symbolically important landmark. It’s no surprise that in 1962, Julius Nyerere, the first prime minister of independent Tanganyika, sent a torch to the top to spread light and hope throughout all of Africa. This sentiment still resonates with locals and visitors alike.

As a result, Kilimanjaro attracts a tremendous number of climbers. Many are people who don't normally spend time in the mountains, who just view the climb as a ‘bucket list’ accomplishment. However, these visits bring employment to local people and foster cultural exchanges.

To preserve Kilimanjaro’s unique environment, the National Park closely monitors ascents of the mountain. People who climb the mountain are required to bring along certain local personnel: a guide, an assistant guide, a cook, porters. Scientific research at the summit relies on this essential support.

What insights have the ice cores drilled from Kilimanjaro’s glaciers in 2000 provided?

It was a difficult project, involving challenges such as transporting tons of equipment up 5,000 meters, working at nearly 6,000 meters for a month, and carrying heavy ice cores down challenging terrain into tropical heat. In 2002, we published a paper suggesting the glaciers were almost 12,000 years old, though, if we are being honest, we knew that subsequent research was likely to modify the story. This is the normal process of science, yet today it remains the only publication on the history of Kilimanjaro’s current glaciers.

Planning for a new drilling project began in 2019 by the Ice Memory Foundation, an international initiative to obtain and preserve ice cores from the world’s key endangered glaciers. But the effort was halted due to permitting issues, leaving the project unrealized. With unrelenting ice loss it's now virtually impossible that any new ice core record will ever be recovered from Kilimanjaro’s summit.

Is there hope for preserving Kilimanjaro’s glaciers?

Optimism sprung from 2003 speculation by the Zimbabwean scientist Euan Nisbet who suggested covering the glaciers with three square kilometers of tarps, and removing them during the wet season. However, based on experience with this idea in the Alps, where ski areas on glaciers have used the same approach for decades, we know that it isn’t viable at such a scale.

Kilimanjaro glaciers will disappear. But along with them, glaciers in the Alps, Andes, and elsewhere; even glaciers in the Himalaya ultimately will disappear, with tremendous implications for water resources and flooding events. In the end, Kilimanjaro will assume new symbolism, emblematic of the myriad implications of global climate change. In the short term, I think the most important message from the glaciers is that humanity must drastically reduce our consumption of fossil fuels. That is absolutely the only solution.