How do we know glaciers are shrinking?

In addition to qualitative methods like Repeat Photography, USGS scientists collect quantitative measurements of glacier area and mass balance to track how some glaciers are retreating (Glacier Monitoring Studies). For example, ablation stakes show the seasonal gain and loss of snow, snow-pit analyses measure density of snow, and precision GPS measurements document the glacier margin. Also, because on-site GPS measurement of individual glaciers is expensive and labor intensive, aerial photograph analysis is used to determine glacier area through digitization of glacier margins.

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Does the USGS monitor global warming?

Not specifically. Our charge is to understand characteristics of the Earth, especially the Earth's surface, that affect our Nation's land, water, and biological resources. That includes quite a bit of environmental monitoring. Other agencies, especially NOAA and NASA, are specifically funded to monitor global temperature and atmospheric phenomena...

What is the difference between global warming and climate change?

Although people tend to use these terms interchangeably, global warming is just one aspect of climate change. “Global warming” refers to the rise in global temperatures due mainly to the increasing concentrations of greenhouse gases in the atmosphere. “Climate change” refers to the increasing changes in the measures of climate over a long period...

Are today's glaciers leftovers from the Pleistocene ice age?

Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and...

How many glaciers currently exist in Alaska?

Based on the most recent comprehensive survey in 2011, there were about 27,000 glaciers in Alaska. However, the number of glaciers is a misleading statistic. Scientists are more interested in total glacial land coverage as a measure. The number of glaciers is less important since large ones can split up into several as they retreat. The amount of...

How old is glacier ice?

The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire...

Was all of Alaska covered by glaciers during the Pleistocene Ice Age?

No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation. This ice-free corridor also provided one route for humans to move into North America.

Is glacier ice a type of rock?

Yes – glacier ice, like granite, is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2 O). It forms through the metamorphism of tens of thousands of individual snowflakes into crystals of...

How much of the Earth's water is stored in glaciers?

About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers...

How does present glacier extent and sea level compare to the extent of glaciers and global sea level during the Last Glacial Maximum (LGM)?

The Last Glacial Maximum (LGM) occurred about 20,000 years ago, during the last phase of the Pleistocene epoch. At that time, global sea level was more than 400 feet lower than it is today, and glaciers covered approximately: 8% of Earth’s surface 25% of Earth’s land area 33% of Alaska Beginning about 15,000 years ago, continental glaciers...

How would sea level change if glaciers melted?

If all of the glacier ice on Earth were to melt, sea level would rise ~ 80 m (~ 265 ft), flooding every coastal city on the planet. If all of Earth’s temperate glaciers melted, sea level would rise ~ 0.3–0.6 m (~ 1-2 ft). If all of Greenland’s glaciers melted, sea level would rise ~ 6 m (~ 20 ft). If all of Antarctica’s glaciers melted, sea level...

Is there a size criterion for a glacier?

While there is no global standard for what size a body of ice must be to be considered a glacier, USGS scientists in Glacier National Park use the commonly accepted guideline of 0.1 square kilometers (about 25 acres) as the minimum size of a glacier. Below this size, ice is generally stagnant and does not have enough mass to move.
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Date published: May 10, 2017

Glaciers Rapidly Shrinking and Disappearing: 50 Years of Glacier Change in Montana

The warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent, according to data released by the U.S. Geological Survey and Portland State University.

Date published: September 28, 2016

Fifty Years of Glacier Change Research in Alaska

ANCHORAGE, Alaska — This year marks the 50th anniversary of one of the longest continuous glacier research efforts in North America.

Date published: March 18, 2015

From Icefield to Ocean - What Glacier Change Might Mean for the Future of Alaska

Frozen bodies of ice cover nearly 10 percent of the state of Alaska, but the influence of glaciers on the environment, tourism, fisheries, hydropower, and other important Alaska resources is rarely discussed.

Date published: January 20, 2015

Melting Glaciers Increase the Flow of Carbon to Downstream Ecosystems

ANCHORAGE, Alaska Melting glaciers are not just impacting sea level, they are also affecting the flow of organic carbon to the world’s oceans, according to new research that provides the first ever global-scale estimates for the storage and release of organic carbon from glaciers.

Date published: December 4, 2014

Rare Insect Found Only in Glacier National Park Imperiled by Melting Glaciers

The persistence of an already rare aquatic insect, the western glacier stonefly, is being imperiled by the loss of glaciers and increased stream temperatures due to climate warming in mountain ecosystems, according to a new study released in Freshwater Science.

Date published: August 25, 2010

Washington’s Benchmark Glacier Still Shrinking

TACOMA, Wash. — Washington’s only “benchmark” glacier continues to lose mass as a result of changes in climate, according to a report by the U.S. Geological Survey.

Attribution: Land Resources
Date published: August 25, 2010

Glaciers Retreating in Asia

Many of Asia’s glaciers are retreating as a result of climate change.

Attribution: Land Resources
Date published: August 10, 2009

Salazar Releases Long-Term Report Detailing Glaciers Shrinking in Alaska and Washington

A report on long-term glacier measurements released today by Secretary of the Interior Ken Salazar shows that glaciers are dramatically changing in mass, length and thickness as a result of climate change.

Date published: October 6, 2008

Most Alaskan Glaciers Retreating, Thinning, and Stagnating, Says Major USGS Report

Most glaciers in every mountain range and island group in Alaska are experiencing significant retreat, thinning or stagnation, especially glaciers at lower elevations, according to a new book published by the U.S. Geological Survey. In places, these changes began as early as the middle of the 18th century.

Date published: May 29, 2002

Decline of World's Glaciers Expected to Have Global Impacts Over This Century

The great majority of the world’s glaciers appear to be declining at rates equal to or greater than long-established trends, according to early results from a joint NASA and United States Geological Survey (USGS) project designed to provide a global assessment of glaciers. At the same time, a small minority of glaciers are advancing.

Date published: December 13, 2001

Melting Glaciers to Methane Gasses

Nearly 300 scientists from the U.S. Geological Survey will present papers and posters describing their earth-science research, during the annual meeting of the American Geophysical Union (AGU), at the Moscone Convention Center in San Francisco, December 10 – 14. 

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Animated gif of Grinnell Glacier Rdige 1910 - 2017
June 15, 2018

Grinnell Glacier Ridge animation

Animated gif of Grinnell Glacier Rdige 1910 - 2017

This image shows the perimeter of Sperry Glacier in Glacier National Park in 1966,1998, 2005, and 2015.
December 31, 2017

Sperry Glacier perimeter: 1966,1998, 2005, 2015.

This image shows the perimeter of Sperry Glacier in Glacier National Park in 1966,1998, 2005, and 2015. 

This image shows the perimeter of Chaney Glacier in Glacier National Park in 1966, 1998, 2005, and 2015.
December 31, 2017

Chaney Glacier perimeter: 1966, 1998, 2005, 2015.

This image shows the perimeter of Chaney Glacier in Glacier National Park in 1966, 1998, 2005, and 2015.

Rainbow Glacier perimeter: 1966, 1998, 2005, 2015.
December 31, 2017

Rainbow Glacier perimeter: 1966, 1998, 2005, 2015.

This image shows the perimeter of Rainbow Glacier in Glacier National Park: 1966, 1998, 2005, 2015. 

Swiftcurrent Glacier 1910 - 2016 animation
November 2, 2017

Swiftcurrent Glacier 1910 - 2016 animation

Swiftcurrent Glacier 1910 - 2016 animation

July 27, 2017

USGS Public Lecture: Warm Ice—Dynamics of Rapidly Changing Glaciers

  • Glacier Numerology – The how big, how long, how thick, how much, how often, of glacier science.
  • Glacier Photography – While a picture may be worth a thousand words, a collection of images may tell a complete forensic story.
  • Glacier Geophysics – How new technologies are being introduced to reexamine and refine decades old glacier analyses.