Is Deforestation Driving Mt. Kenya’s Glacier Recession?

High above the African continent, Mount Kenya’s glaciers are rapidly receding. A new study published in the American Journal of Environmental Science and Engineering is one of the few to analyze the retreat of African glaciers, finding that forest cover has the highest correlation with Mt. Kenya’s glacier coverage. The study’s climate prediction models found that the current trend in glacier thinning will continue, although at a slower rate, until the glaciers completely disappear by 2100. In addition, the research found forest cover to be responsible for 75 percent of changes in glacier coverage during the study period, from 1984 to 2017. But can local deforestation truly be so impactful?

2017 Glacier Coverage on Mt. Kenya (Source: American Journal of Environmental Science and Engineering).

About 7 percent of Kenya is currently forested, and the average trees per person measurement is well below the global average. The country suffered from massive deforestation during the last century due to logging, charcoal burning, and agricultural expansion. In this same period, Mt. Kenya has lost roughly 92 percent of its ice cap, according to the study. Out of its once expansive 18 glaciers that reached thousands of feet beneath the 17,057-foot peak, only eight remain, with all of the remaining glaciers suffering substantial losses in both thickness and area, a change the authors attribute to the lack of forest cover.

However, earlier research conducted on other glaciers in Africa conflicts with these findings. At Mount Kilimanjaro, Africa’s highest peak lying 324 kilometers south of Mt. Kenya, glacier recession has been found to be more dependent on regional precipitation patterns than local deforestation ones, according to studies from both 2008 and 2004. A study in ScienceDirect also found that glacier recession near Mt. Kilimanjaro was not affected by local deforestation. And “long-term ice retreat at the summit of Kilimanjaro is most likely to be influenced by changes in local land-use as well as more regional free-air changes,” argues further research in Global and Planetary Change.

Without additional investigation focused on Mt. Kenya, it remains difficult for scientists to draw firm conclusions about the causes of glacier recession.

Batian Peak on Mt. Kenya (Source: Stefan Leitner/Flickr).

The government of Kenya has attempted to reverse deforestation impacts with efforts to prevent logging throughout the early 2000s, but the most recent logging ban has recently been relaxed. This places Mt. Kenya at risk of further glacial retreat, which raises concerns about water sources for the many rivers fed by Mt. Kenya’s glaciers.

“As climate variability increases, the Mount Kenya watershed becomes more important,” Kathleen Galvin, an anthropology professor and director of the Africa Center at Colorado State University told GlacierHub. “If the glaciers retreat at the same time as seasonal climate variability occurs, people, livestock, and wildlife will become more vulnerable,” she warns.

Mt. Kenya’s glaciers serve as the headwaters of the Ewaso Nyiro river watershed which provides water to the high potential agricultural communities around the mountain. The river is also important to the northern Kenyan pastoralists, including the Samburu, Somali, and Borana, according to Galvin. The study finds that the current drying out trend of rivers that have catchments in the Mt. Kenya forests will continue, leading to an increased water shortage and vulnerability for the area.

Study area on Mt. Kenya (Source: American Journal of Environmental Science and Engineering).

The researchers used Landsat and climate data from the last 33 years to find correlations between glacier coverage and forest cover, temperature, precipitation, solar insolation, and relative humidity. Forest coverage was by far the leading driver found by the authors for the glacier retreat on Mt. Kenya, with temperature also responsible for 16 percent of the changes in glacier coverage. In addition, models were used to predict future conditions until 2045.

According to Abe Goldman of the Department of Geography and Center for African Studies at the University of Florida, it would be a considerable achievement if forest cover within Mt. Kenya National Park boundaries could even be maintained at present levels in the coming years.

“Given current demographic and land use trends and conditions, there is little probability of actual forest increase (though there might be slightly more trees on farms),” he told GlacierHub.

Goldman’s concerns ran deeper, however, as he found some of the study’s assertions to be “questionable.”

“There is no causal mechanism noted that would generate increased glacial mass if ‘forest cover’ were increased,” he said. “Nor is it clear which forest cover at which location(s) might lead to glacial expansion.”

He also notes that the populations and intensive land use of Kenya and the surrounding countries, and especially close to Mt. Kenya National Park, have drastically increased, with 60 percent of the population being agricultural and reliant on biomass for energy. “The major role of population growth surrounding Mt. Kenya, especially adjacent to park boundaries, is neglected in the article,” said Goldman.

The authors of the study could not be reached for comment by the time of publication of this article. However, it is clear that further research is needed to study Mt. Kenya’s glaciers and other glaciers throughout the African continent in order to grasp the rapid changes that have heavy ties to both surrounding ecosystems and local communities.

East African Glaciers at Risk from “Global Drying”

In the tropical climate of East Africa, glaciers are an unexpected, yet vitally important part of the ecosystem. Since 1900, African glaciers have lost a staggering 80 percent of their surface area, contributing to regional water shortages.

While rising temperatures may seem like an obvious cause of global glacier retreat in many regions, the glaciers of east Africa are a unique exception. A study published in Cryosphere earlier this year has found that the largest glacier on Mount Kenya, the Lewis Glacier, is melting because of decreasing atmospheric moisture rather than increasing temperatures.

Snow-capped peaks of Mount Kenya (Source: Valentina Strokopytova)
Snow-capped peaks of Mount Kenya (Source: Valentina Strokopytova)

African glaciers have all but disappeared, except for three locations in East Africa: Mount Kilimanjaro in Tanzania, Mount Kenya in Kenya, and the Rwenzori Range in Uganda. Scientists have been studying the few remaining African glaciers in hopes of preserving what is left of the rapidly melting ice. While headway had been made in understanding the causes of melting on Kilimanjaro, the melting on Mount Kenya, Africa’s second tallest mountain, has remained a mystery until now.

The complex climatic features of Mount Kenya, combined with the lack of observational data, has made it difficult to pinpoint an exact cause of Lewis Glacier’s retreat. Lindsey Nicholson, a researcher at the Institute of Atmospheric and Cryospheric Sciences, led a study in 2013 that concluded a combination of causes was responsible for the melt, rather than one factor in particular.

Building on  her previous work, the team, led by University of Graz’s Rainer Prinz and Lindsey Nicholson, set out to collect the data they needed to gain a more accurate understanding of why Lewis Glacier was melting. They installed an automatic weather station on the glacier at an elevation of 4,828 meters, and collected 773 days of data over the course of two-and-a-half years.

Glacier lake on Mount Kenya (Source: Cheyenne Smith)
Glacier lake on Mount Kenya (Source: Cheyenne Smith)

In conjunction with the data from the weather station, the team used a model to predict how much Lewis Glacier would melt under a range of different scenarios. By manipulating variables, including precipitation, air temperature, air pressure, and wind speed, in the model, the team was able to see which factors played the biggest role in glacier melt.

The team found that moisture had the biggest impact on Lewis Glacier’s surface area, rather than air temperature or a combination of other climatic factors. Despite differences in location and elevation, the glaciers of Mount Kenya and Kilimanjaro are melting for the same reason: East Africa is getting progressively drier, and the lack of water is impacting much more than just the glaciers.

The glaciers on the peak of Kilimanjaro lie significantly above the regional freezing point—year round, the peak is cold enough to maintain its ice levels, even as surface temperatures in East Africa have steadily increased. Yet, Kilimanjaro’s glaciers continue to retreat and are projected to disappear completely by 2020. Temperature changes fail to explain the severity of the mountain’s glacier retreat.

Observational studies have showed that Kilimanjaro is receiving less cloud cover that leads to increased radiation from the sun, and less precipitation, causing infrequent snowfall. The IPCC has projected a 10% decrease in rainfall during the already dry season from June through August, amplifying the impacts of regional dryness and drought.

crop fields at the foot of Mount Kenya--the mountain serves as a major watershed for surrounding agriculture and livestock (Source: Cheyenne Smith)
crop fields at the foot of Mount Kenya–the mountain serves as a major watershed for surrounding agriculture and livestock (Source: Cheyenne Smith)

The impact of a drying climate has greatly impacted Kilimanjaro, and caused its glaciers to retreat from sublimation–a process by which the ice changes directly into water vapor rather than melting into water. The theory that moisture is the main factor impacting glacier melt on Kilimanjaro has, up until now, been assumed to be a product of the mountain’s height and not generalizable to all East African glaciers. Prinz and Nicholoson’s findings suggest that drying may be the main reason for glacier melt throughout the region as a whole.

Mount Kenya’s glaciers are at lower elevations compared to Kilimanjaro’s, and lie much closer to the regional freezing level. It was therefore expected that rising temperatures would affect the glaciers of Mount Kenya, and no scientific studies had proved or disputed this assumption.

Droughts, desertification, and crop failure have become increasingly common in tropical Africa, and according to the study this is primarily caused by shifting ocean conditions that are preventing moisture from circulating over East Africa. The lack of moisture means there is not enough precipitation—either as rain over the savannas or snow on the mountain peaks—to sustain the glaciers or the populations that rely on them. In order to preserve the last remaining African glaciers, it will be necessary to understand and prevent changes in water, rather than only changes in temperature.