Photo credit: NPS.gov
Glaciers are often a nebulous concept to many people. What exactly are they? It’s often simple to conjure an image of a glacier: a large, imposing sheet of ice spreading across a landscape. What’s challenging is defining exactly what glaciers are and how they form. How do they differentiate from, say, snow pack? The answer has to deal with the formation of glaciers and how they are shaped by their surroundings.
Glaciers can be separated into two broad categories: alpine and continental. Alpine glaciers form on the slopes of mountains, while continental glaciers form on vast expanses of flatter land, allowing for greater expansion in comparison to alpine glaciers. While they are separated by their particular areas of formation, they still form in largely the same way. During colder periods of climate in the Earth’s history, snow fell quite harshly, creating immense areas of snow pack. Over time, as more snow accreted, the snow inside the dense snow pack started to compound and solidify into thick ice under the increasing pressure. That’s why glaciers have distinct layers. As the snow compacts into ice, it creates visible layers, with fresh snow at the top, thick ice at the bottom, and granular firn in between (snow in the process of becoming ice).
Glaciers are also defined by their movement. They can move as they slide down mountains with the help of gravity, or shift on the continents as they slide on their watery bases. This combination of formation and movement helps to define what a glacier is.
While it’s interesting to know what glaciers are, it’s also often unclear how they are important. Not only do glaciers hold a large percent of the Earth’s fresh water, they are also vital to global processes. Glaciers help stabilize colder temperatures in the poles and on mountains while providing a habitat for many organisms. They also hold water that would otherwise fill the Earth’s oceans if they melted. One of the most important roles of glaciers is their role as a status marker for the Earth’s climate. Scientists often look to glaciers around the world to study past and present climate, as well as to gauge possible effects of climate change in the future.
It’s important to understand the makeup and formation of glaciers because of their importance to Earth’s climate and topography. Their persistent and pervasive nature make them excellent gauges of climate change that help in understanding its impact on the planet. Even without their important climatological and ecological impacts, glaciers are still beautiful, natural structures.
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© 2020 Weather Forecaster Cole Bristow