In the Mountains of the Moon, a trek to Africa’s last glaciers

The changes here also pose a challenge to climate scientists. Inside the Rwenzori’s receding glaciers are specks of pollen and dust that could unlock secrets about past climatic upheavals. But there’s a problem: no one has managed to access the glaciers amid the daunting terrain. Seven years ago, Lonnie Thompson - the well-known US scientist who has sampled high-altitude tropical glaciers worldwide and uncovered evidence of dramatic pre-Incan climate swings from ice core samples high in the Andes - was scheduled to work in the Rwenzori. But he had to cancel his trip because of security concerns in East Africa at the start of the Iraq war.

Time is running short.

“The whole atmosphere is warming in the tropics,” Thompson told Science News. “But the greatest risk is taking place at the highest elevations - on the order of 0.3 C (0.5 F) per decade.”

Ice in the Rwenzori is disappearing so swiftly that much critical information may have already been lost. “There is a lot of concern about whether there is even a viable [ice] core,” said Richard Taylor, a hydrologist at University College in London. Without such solid evidence, he added, scientists can’t even determine the age of the range’s glacial cover.

Taylor is the lead author of a 2006 study in Geophysical Research Letters that links the melting glaciers in the Rwenzori more directly to rising temperatures than the shrinking snowcap on 19,340-foot Mount Kilimanjaro.

“The ice fields on Kilimanjaro are substantially higher” than the Rwenzori and therefore less prone to melting, Taylor told me by phone from London. “The glaciers that still exist in the Rwenzori reside somewhere between 4,800 meters and 5,050 meters” - 15,750 to 16,570 feet - making them “more vulnerable to fluctuations in temperature.”

By contrast, the shrinking snowcap on Kilimanjaro is likely due to decreasing humidity, not rising temperatures, he said, adding, “The Rwenzori mountains are the icon of global warming - not Kilimanjaro.”

But as I climb higher into the Rwenzori, it’s clear that getting close to even one African glacier is going to be more of an ordeal than I expected. And it’s not just the steep trails and thin air that conspire to halt my progress. It’s the mud. Never have I seen mud in such quantity or variety. Sludge-like in places, syrupy in others, it filled two enormous high-altitude bogs. In spots, a boardwalk helped. But where it ended, chest waders would have come in handy, too.

Finally, after scrambling up a nearly vertical wall of rock and moss, I stepped onto a ledge at 14,400 feet, where a century ago Abruzzi encountered a nine-story-high wall of ice known as the Speke glacier, named for the British explorer - John Hanning Speke - who discovered the source of the Nile at Lake Victoria.

In Abruzzi’s day, the glacier snaked down the side of 16,080-foot Mount Speke for 1,600 feet before ending abruptly near the rocky cliff face where he - and now I - stood. A century ago, the glacier covered about 540 acres, and de Filippi recounts listening to the roar of gigantic columns of ice crashing into the valley below.

In the thickening mist, I searched for ice but saw none. Instead, I looked out on the ghost of a glacier, a rubble of smooth slate-gray stone sloping up from a small green lake, formed by glacial melt. Here and there, giant groundsels were starting to grow between rocks that not long ago were entombed in ice.

Then the sky opened up to reveal a narrow band of silver and white more than 1,000 feet up the mountain - the last receding remnant of the Speke glacier, which has now shrunk to just a few dozen acres.

A few seconds later, the clouds zippered back up and it was gone.