What is a Benchmark Glacier?

Benchmark Glacier” refers to four North American glaciers that have been selected for long-term glacier monitoring that investigates climate, glacier geometry, glacier mass balance, glacier motion, and stream runoff. They are Gulkana Glacier and Wolverine Glacier in Alaska, South Cascade Glacier in Washington, and Sperry Glacier in Montana.

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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: 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.

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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. 

Photograph of the Wolverine Glacier, Kenai Mountains, Alaska taken at sunrise in the fall of 2013.
April 8, 2016

Photograph of the Wolverine Glacier, Kenai Mountains, Alaska taken at sunrise in the fall of 2013.

Photograph of the Wolverine Glacier, Kenai Mountains, Alaska taken at sunrise in the fall of 2013.

Sperry Glacier margin map.
April 5, 2016

Sperry Glacier margin map.

This is a map of the margin of Sperry Glacier in 1998 and 2005.

August 25, 2011

PubTalk 8/2011 — Through the Lens of Time

Repeat Photography in an Era of Global Change

by Robert Webb, Hydrologist

  • Repeat photography remains an essential and cost-effective technique for scientists and researchers working to track and study changing environmental conditions
  • Scientists worldwide are exploring methods to apply this technique in various
...
Repeat oblique photographs of Gulkana glaciers in Alaska.
December 31, 1967

Repeat oblique photographs of Gulkana glaciers in Alaska.

Repeat oblique photographs of Gulkana glaciers in Alaska.  1967, Unknown USGS photographer. 2016, L. Sass, USGS.

Repeat oblique photographs of Wolverine glacier in Alaska.
December 31, 1966

Repeat oblique photographs of Wolverine glacier in Alaska.

Repeat oblique photographs of Wolverine glacier in Alaska.  1966 image by unknown USGS photographer; 2015 image by L. Sass, USGS.

Image: 2006 South Cascade Glacier

2006 South Cascade Glacier

2006 black-and-white vertical aerial photo of South Cascade Glacier, northwestern Washington State. Top of photo is south.

Image: 2006 South Cascade Glacier

2006 South Cascade Glacier

2006 oblique-angle aerial photo of South Cascade Glacier, northwestern Washington State, looking approximately south-southeast.

Image: 1958 South Cascade Glacier

1958 South Cascade Glacier

1958 black-and-white vertical aerial photo of South Cascade Glacier, northwestern Washington State. Top of photo is south.