Outdoors Issue 2019: Science Still Shows Glaciers On Retreat

Along with the polar bear, Glacier National Park’s vanishing ice masses have long been the most startling example of climate change’s devastating environmental effects, serving as a visual cue to the park’s 3 million annual visitors as researchers study the phenomenon of glacial retreat.

Dan Fagre, a research ecologist and climate change research coordinator for the U.S. Geological Survey’s Northern Rocky Mountain Science Center, has studied Glacier’s glaciers for three decades, and likens them to “a checking account for the climate,” an ecological balance sheet trending decidedly downward.

According to scientists and historic research, there were roughly 150 glaciers present when the park was established 1910. As of today, estimates show 25 remaining glaciers. In 2003, a report co-authored by Fagre described the melt rate under current climate scenarios and estimated the remaining glaciers will disappear by 2030.

Earlier observations pegged their full recession even earlier, however, leading to the installation of an interpretive display at the St. Mary Visitor Center reading “Goodbye to the Glaciers” and explaining that “computer models indicate the glaciers will all be gone by the year 2020.”

With 2020 right around the corner, and 25 glaciers still remaining, park officials received funding to replace the display at St. Mary Visitor Center with new signage explaining that the glaciers are “rapidly shrinking due to human-accelerated climate change. When they will completely disappear, however, depends on how and when we act.”

Climate skeptics perceived the new display swap as an about-face, and the move prompted a flurry of articles accusing the National Park Service of “quietly removing the display.”

“Officials at GNP seem to be scrambling to hide or replace their previous hysterical claims while avoiding any notice to the public that the claims were inaccurate,” wrote Roger Roots, a former Libertarian candidate for Montana Secretary of State, in a blog post that received viral attention.

Lauren Alley, a spokesperson for Glacier National Park, said the 2020 sign was based on earlier projections that showed glaciers were shrinking more quickly than a computer model predicted they would, and wasn’t a covert attempt at covering up a mistake.

“Subsequently, larger-than-average snowfall over several winters slowed down that retreat rate and the 2020 date used in the National Park Service display does not apply anymore,” Alley said. “The park works closely with the U.S. Geological Survey to understand glacial retreat and how it impacts the park ecosystem. The National Park Service does not typically issue press releases for new interpretive displays or park signage.”

The park continually updates its interpretive material including exhibits based on the latest research available for multiple park resource topics, Alley said. This winter, the park was able to fund an update to the St. Mary Visitor Center glacier exhibit to reflect the latest modeling.

In presentations to the public, and in his research publications, Fagre provides a more nuanced explanation of glacial retreat, and has maintained predictions that the park’s namesake glaciers will likely vanish by 2030.

The retreat of glaciers in Glacier National Park has received such widespread attention because it is a clear and poignant indicator of change in the northern Rocky Mountains. But as climate science evolves, so too have the predictions made by climate scientists trying to understand how a warming world will respond to human-accelerated circumstances.

According to recent research published by the U.S. Geological Survey and Portland State University, Montana’s glaciers have, on average, shrunk by 39 percent since 1966 and only 25 glaciers are now larger than 25 acres, which is used as a guideline for deciding if bodies of ice are large enough to be considered glaciers.

The agency’s data include scientific information for the 37 named glaciers in Glacier National Park and two glaciers on U.S. Forest Service land.

Scientists used digital maps from aerial photography and satellites to measure the perimeters of the glaciers in late summer when seasonal snow melted and revealed the extent of the glacial ice. The areas measured were from 1966, 1998, 2005 and 2015/2016, marking approximately 50 years of change in glacier area.

But why should a visitor to Glacier Park care?

According to Fagre, establishing rates of glacier retreat, using the decreasing area of glacier ice, is key to understanding the Glacier National Park ecosystem and future state of the park’s resources.

“For instance, glacial meltwater supplies critical meltwater habitat for endangered stream insects,” Fagre wrote in the study. “More broadly, retreating glaciers are indicative of long-term climate change and have hydrologic and ecologic importance to many park resources. Glaciers and their retreat are of great interest to park visitors and the American public and are part of Glacier National Park’s appeal. This is important because Glacier National Park is a major driver of the regional economy.”

As its name suggests, Glacier Park is well suited for the study of glaciology.

Massive valley glaciers up to 1,000 meters thick originally carved the landscape into saw-tooth peaks and hanging valleys, forming its present identity. The glaciers that did survive were reduced in size and have been actively retreating to varying degrees, evidenced in a seminal research paper published in 2003 and co-authored by Fagre and Myrna H. P. Hall.

For example, Sperry Glacier lost nearly 35 percent of its surface area between 1966 and 2005, according to Fagre’s study.

The results of Fagre’s field research have reaffirmed that the glacier hugging the north slopes of Gunsight Mountain, once one of the largest in the national park, is continuing to recede and lost 9 percent of its surface area between 2005 and 2015, or roughly 861,112 square feet. The glacier, which spanned 216 acres in 2005, lost about 4.37 meters of water equivalent averaged across the entire formation in that span of time.