Glaciers have gotten a lot of buzz in recent years as global warming has accelerated, threatening the existence of the world’s land ice. Scientists expect several of the world’s glaciers to disappear in the coming years, with some having already perished from climate change.
The fate of Montana’s Glacier National Park, however, is somewhat less certain. The park recently removed signs stating that the park’s glaciers will disappear by 2020, replacing them with ones making more general statements about glacier melt and climate change.
The new signs
The older signs, posted earlier this decade at the St. Mary Visitor Center, were based on earlier scientific assessments of glacier recession. A display at the center which read “Goodbye to the Glaciers” explained that computer models indicated the loss of all of the park’s glaciers by 2020.
Yet, with 2019 coming to a close, some of the glaciers remain.
While they’ve continued to shrink and are on course to disappear, recent years of plentiful snowfall has slowed down their rate of depletion. This prompted park officials to replace the signs.
These new signs say that glaciers are still melting bit by bit due to climate change, although researchers are unable to make an accurate prediction of when exactly glaciers at the park will disappear. “When they completely disappear, however, will depend on how and when we act,” the new sign reads.
Climate denialists pounce
The news was not formally announced on the park’s website, but has drawn the attention of climate denial sites in the past few weeks. The Daily Caller quoted the US Geological Survey, which stated that glacier retreat can fluctuate due to changes in local microclimates. “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,” the agency said.
Watts Up With That, a hub for climate denialist commentary, also covered the signage change. It sited Roger I. Roots, founder of Lysander Spooner University, who said the park’s Grinnell and Jackson Glaciers have actually grown since 2010. They believe the Jackson Glacier may have expanded by as much as 25 percent in the last decade.
Both stories, among others, suggest that recent increases in glacier mass demonstrate that previous accounts of glacier retreat were alarmist.
Scientists have recognized, however, that glacier retreat is not a linear process. Climate variability sometimes causes more snow to accumulate on glaciers, causing them to grow. Yet the mass trend in the northern Rockies, where Glacier National Park is located, and in nearly all mountain ranges in the world is on a steady decline.
Caitlyn Florentine, a post-doctoral research fellow at the USGS Northern Rocky Mountain Science Center, spoke to GlacierHub about the glacier retreat at Glacier National Park and the influence of local microclimate on melt rates. She is currently working on projects focused on the relationship between mountain glaciers and regional climate, using Sperry Glacier as a benchmark for regional climate change at Glacier National Park.
Florentine said it’s important to look at the ways local factors, such as avalanching, shading, and wind drifting of snow, affect mass balance on glaciers.
Florentine referenced a recent study published in the journal Earth System Science Data, which monitored seasonal mass balance on the park’s Sperry Glacier since 2005. “There are some years where there’s a positive mass balance, and that was true in 2008, 2011, 2012, and 2016,” said Florentine, “But, overall, the net loss from each year offset the mass added, leading to a cumulative decline.”
The study team examined one model that suggests Sperry Glacier will not disappear until 2080 under current climate and glaciological conditions at the park. Scientists have tracked a steady, progressive retreat of Sperry since the mid 20th century.
“If you look at glacier change and Glacier National Park based on the footprint of the glaciers, with data going all the way back to 1966, you’ll see that the footprint of the glaciers has definitely shrunk over time,” Florentine said.
Although Glacier National Park has received a significant amount of snow in recent years, the glaciers are continuing to retreat, with a third of the park’s ice having already disappeared in just the last 50 years.
Informing the public
Lauren Alley, a management assistant at Glacier National Park, said it’s difficult to capture how the longevity of the park’s glaciers will affect tourism.
She stressed the importance of incorporating accurate information about climate science and melt rates at the park. Climate change is one of the things that the public really wants to learn more about, she said.
“There’s no doubt that for some, a component of their trip may be to see a glacier,” she commented. “That said, typically things like wildfire, exchange rates, gas prices, and the economy overall can all have a pretty big overall effect on national park visitation.”
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