I want to start with a hypothetical set of questions. What if someone built a dam that shut down the iconic Niagara Falls? What if a large engineering project was designed to fill the Grand Canyon? The thought of such detrimental actions for two of the world's greatest treasures is unthinkable. My family takes an epic road trip every summer. Yes, think Chevy Chase and the Vacation movies. If you are under the age of 30, Google them or find them on your favorite movie service. They are hilarious, but I digress.
Something that is not funny motivated our destination this summer. I asked my family if we could visit Glacier National Park in Montana. I literally said, "I want to see a glacier there before they are gone." While I was basing that statement on some science, I was probably being a bit hyperbolic at the time (or perhaps not). Glacier National Park is actually losing its glaciers.
It really only struck me how dire things are once I started researching the trip a bit more and trying to get my nerve up to drive on the Road to the Sun. Recent video of the Park clearing snow along the road didn't help. The Glacier National Park social media feeds recently shared the following information that put into perspective the dramatic loss of glaciers in the park,
In 1910, the park had over 100 glaciers but by 1966 only 35 remained. Today, rising temperatures are shrinking every glacier in the park. In 2015, 26 met the size criteria to be designated active glaciers.
One of the more iconic glaciers in the park is Sperry Glacier. According the National Park Service. Dr. Lyman B. Sperry of Oberlin College (Ohio) led the first European exploration group to the glacier around 1896. Known as the "Gentleman Explorer," Sperry is credited with building the first trail to this glacier. The current route to the glacier is basically the same pathway as that original trail. Ground, airborne, and satellite (see image above) analysis has revealed just how much the Sperry Glacier shrank. In 1966 its areal extent was 331 acres, but in 2015, it was estimated to be around 198 acres.
With such sobering news, let's take a step back and do a little science. What exactly is a glacier? The National Park Service website has a succinct and useful definition:
Glaciers are masses of ice, snow, water, rock and sediment that move under the influence of gravity. They are formed when snow and ice accumulation exceeds summer melting. They "retreat" when melting outpaces snowfall.
Glaciers move because large accumulations of snow are compacted into ice. The weight of the snow above causes the layers of ice beneath to become viscous (sort of a mix of liquid and solid). They slide downhill. According to the United States Geological Survey Climate Change in Mountain Ecosystems Program, the minimum size criterion for a glacier is 100,000 m² or roughly 25 acres. A common misconception is that glaciers "bulldoze" the landscape. In reality, the glacier redistributes materials through a series of melt - freeze episodes. A better analogy, as suggested by the National Park Service scientists, is a "downhill conveyor belt."
In Glacier National Park, the glaciers are at least 7,000 years old and probably peaked in size during the Little Ice Age around the mid 1800s. Because climate changes naturally, there have been other significant changes as well. During the Pleistocene Epoch, millions of years ago, ice covered the Northern Hemisphere and lowered sea levels by 300 feet or so. According to the National Park Service website, ".......In places near the park, ice was a mile deep. The Pleistocene Epoch ended around 12,000 years ago...."
Oh wait, did anyone notice that a climatologist acknowledged that climate changes naturally? I jest about this because it is amusing to most of us that study the climate that skeptics often mention to us that climate changes naturally. We know. I promise. Since the Industrial Revolution, the climate has been changing at a rate much faster than the rather slow changes in the naturally-varying climate system. A "victim" of this pace of warming is the set of glaciers in Glacier National Park and other around the world. The National Snow and Ice Data Center has a good discussion on the linkages between climate change and glaciers.
That is why I am taking my family to Glacier National Park this summer. The prospect that most of the parks iconic glaciers could disappear in my lifetime or my kids' places great urgency on this vacation. We'll have fun too. While there, we will look for all of the calling cards on the landscape that glaciers leave behind. U-Shaped valleys are carved out by the aforementioned melt-freeze conveyor belts. When a smaller glacier feeds into a large, deep glacier, the undercutting can result in a hanging glacier. Aretes can be seen where two glaciers carve on both sides of a ridge. They tend to be saw-toothed shaped. Horns are mountain tops that result from vertical scraping by glaciers on at least 3 sides. Amphitheaters carved by glaciers on a slope are called cirques. Often described as ice cream scoop-like, they hold glaciers, snow, or lakes (tarns). Paternoster lakes resemble rosary beads and are a chain of small lakes formed during glacial retreat. Moraines are accumulated ares of glacial debris.
