Climate models may underestimate future warming on tropical mountains

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In few places are the effects of climate change more pronounced than on tropical peaks like Mount Kilimanjaro and Mount Kenya, where centuries-old glaciers have all but melted completely away. Now, new research suggests that future warming on these peaks could be even greater than climate models currently predict.

Researchers led by a Brown University geologist reconstructed temperatures over the past 25,000 years on Mount Kenya, Africa’s second-highest peak after Kilimanjaro. The work shows that as the world began rapidly warming from the last ice age around 18,000 years ago, mean annual temperatures high on the mountain increased much more quickly than in surrounding areas closer to sea level. At an elevation of 10,000 feet, mean annual temperature rose 5.5 degrees Celsius from the ice age to the pre-industrial period, the study found, compared to warming of only about 2 degrees at sea level during the same period.

In few places are the effects of climate change more pronounced than on tropical peaks like Mount Kilimanjaro and Mount Kenya, where centuries-old glaciers have all but melted completely away. Now, new research suggests that future warming on these peaks could be even greater than climate models currently predict.

Researchers led by a Brown University geologist reconstructed temperatures over the past 25,000 years on Mount Kenya, Africa’s second-highest peak after Kilimanjaro. The work shows that as the world began rapidly warming from the last ice age around 18,000 years ago, mean annual temperatures high on the mountain increased much more quickly than in surrounding areas closer to sea level. At an elevation of 10,000 feet, mean annual temperature rose 5.5 degrees Celsius from the ice age to the pre-industrial period, the study found, compared to warming of only about 2 degrees at sea level during the same period.

“When we run state-of-the-art climate models backward in time to this period, they underestimate the temperature changes at high elevations,” said James Russell, an associate professor in the Department of Earth, Environmental and Planetary Sciences and a fellow at the Institute at Brown for Environment and Society. “That implies that the models may similarly underestimate high-elevation warming in the future.”

The study, which Russell led with Shannon Loomis, his former graduate student, is published in the journal Science Advances.

Continue reading at Brown University

Photo: The Lewis glacier on Mt. Kenya has lost 90 percent over the last 75 years. New research suggests future warming on Mt. Kenya and other tropical peaks may happen much faster than climate models currently predict.

Credit: Hilde Eggermont