Glaciers—Understanding Climate Drivers

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 Across the globe, glaciers are decreasing in volume and number in response to climate change.  Glaciers are important for agriculture, hydropower, recreation, tourism, and biological communities. Loss of glaciers contributes to sea-level rise, creates environmental hazards and can alter aquatic habitats.  These are among the cascading effects linked to glacier loss which impact ecosystems and human populations.


Predicting and preparing for the wide-ranging consequences of glacier change requires science that helps stakeholders and decision-makers understand connections between glaciers, the environment, and human populations. USGS scientists work collaboratively across climatically diverse glacierized regions to advance our understanding of physical glacier systems and implications of glacier change.

Aerial photo of Grinnell, Salamander and Gem Glaciers

The three visible glaciers in this photo, Grinnell, Gem and The Salamander Glaciers, have unique rates of retreat, but all have decreased in volume and area since their mid-19th century maximum extent (Credit: John Scurlock (Photographer & Pilot), USGS. Public domain.)

GLACIERS RESPOND TO CLIMATE: Glaciers are intrinsically linked to climate because ice mass gain or loss depends on temperature and precipitation, elements of climate that can be impacted by human actions. Currently, Earth’s glaciers are decreasing in response to climate warming driven largely by increased greenhouse gas emissions. USGS data documenting the extent of glaciers and other mountain cryosphere (frozen) features are available in these published studies by the Climate Change in Mountain Ecosystems (CCME) group.

IMPACTS OF GLACIER LOSS: Loss of glaciers alters habitats in measurable ways. Glacier loss reduces the input of cold freshwater to streams, particularly during late summer months when streamflow is otherwise low. Though studies show that many endemic aquatic species can persist after glaciers have disappeared, the fragmentation and loss of critical habitat may impact genetic diversity and ultimately lead to extinction. In some places, glaciers provide essential drinking water to communities and sustain local livelihoods where meltwater contributes to agricultural practices and recreational use.  Glacial melt also contributes to sea level rise  and can create flood hazards.    

CCME GLACIER RESEARCH: For decades, USGS scientists have studied the physical processes of glaciers, laying the foundation for understanding glacier ecological connections and impacts to society.  As glaciers retreat in response to warming temperatures, the USGS Climate Change in Mountain Ecosystems (CCME) group supports a robust glacier research program to study the relationship between climate change and glaciers.  Use of both field-based techniques and emerging technologies, like remote sensing, are the hallmarks of continental scale mass balance research at Sperry Glacier.  CCME’s focused studies of the glaciers of Glacier National Park  provide visitors with understanding of the namesake features and inform management decisions in this protected region. 

TRACKING GLACIER LOSS IN GNP: In Glacier National Park (GNP), Montana, average annual temperature warmed over the 20th century by almost double the global average temperature warming. CCME scientists use a variety of methods to track glacier retreat in GNP and have documented a reduction in area of all named glaciers between the Little Ice Age glacial maxima, mid-19th century and 2015.

REPEAT PHOTOGRAPHY: A growing collection of paired glacier images documents glacier loss through the lens of a camera. The USGS’ Repeat Photography Project has been collecting and repeating historic photos of glaciers for over two decades. This photo gallery displays a subset of the collection featuring glaciers across Glacier National Park. 



Boulder Glacier Repeat Photo

Repeat photography documents the retreat of Boulder Glacier, 1910 – 2007. (Credit: 1910 photo by Morton Elrod, GNP Archives, 2007 photo by Dan Fagre, USGS. Public domain.)

 Why study glaciers in Glacier National Park? Glacier National Park

attracts visitors from around the world. Across this glacier-carved landscape, several dozen small mountain glaciers still cling to mountain tops. Glacier National Park is one million acres, protected and recognized internationally as a UNESCO World Heritage Site, an International Peace Park, and a United Nations Biosphere Reserve, indicating the physical and ecological value within its boundaries. The hydrologic, ecologic, and economic impacts linked to glaciers will be measured by loss of habitat, loss of biodiversity, and reduced streamflow for agriculture and recreation. National Park managers, tasked with conserving the landscape and its features for future generations, rely upon USGS science to make informed management decisions and communicate accurate evidenced-based information to the public.



Related Links:

USGS Glacier Retreat Fact Sheet 

Global Land Ice Measurements from Space

Randolf Glacier Inventory

World Glacier Monitoring Service