Satellite Image Atlas of Glaciers of the World

USGS Fact Sheet 133-99

The present volume of the Earth's glacier ice, if totally melted, represents about 80 meters in sea-level rise. From minimum (an interglacial epoch) to maximum (an ice-age epoch) volume of glacier ice on the continents, sea level has a range of 200 meters. For example, during the last glacial peak, about 20,000 years ago, sea level is estimated to have been 120 meters lower than it is today. During a warmer climatic interval in the last interglacial period, 125,000 years ago, sea level was about 6 meters higher than it is today; during an even warmer interval 3 million years ago, sea level is estimated to have been 25 to 50 meters higher. Sea-level changes, especially in low-lying coastal areas and on islands, have significant effects on human activities and facilities.

White areas show ice sheets and other glaciers around the world. The white spots in the oceans are islands where glaciers are found. Reproduced from National Geographic WORLD (February 1977, no. 18, p. 6) with permission.

A thorough global baseline study of the areal extent of existing glaciers is required if we are going to assess the magnitude of changes in glaciers that will occur worldwide during the 21st century. This research comprises a comprehensive global baseline study of the total area of glacier ice on Earth. The effort is important because present and future changes in glacier margins worldwide cannot be assessed without such a baseline study. The atlas also includes ancillary information from historical and modern ground observations by glaciologists.

One element of the Earth's cryosphere (frozen water) amenable to global inventorying and areal-change monitoring with Landsat images is glaciers. In 1978, the USGS decided to prepare an 11-chapter U.S. Geological Survey Professional Paper, Satellite Image Atlas of Glaciers of the World. In this volume, Landsat 1, 2, and 3 multispectral scanner (MSS) images and Landsat 2 and 3 return beam vidicon (RBV) images are used to inventory the areal occurrence of glacier ice on our planet within the boundaries of the spacecraft's coverage (between about 82° north and south latitudes). Between 1979 and 1981, optimum Landsat images were distributed to a team of 60 scientists, representing 25 nations and 45 institutions, who agreed to author sections of the Professional Paper concerning either a geographic area or a glaciological topic.

In addition to analyzing images of a specific geographic area, each author summarized up-to-date information about the glaciers within the area and compared their present areal distribution with historical information (from published maps, reports, photographs, and so on) about their past extent. Due to the limitations of Landsat images for delineating or monitoring small glaciers in some geographic areas (the result of inadequate spatial resolution, lack of suitable seasonal coverage, or absence of coverage), information on areal distribution is sometimes necessarily derived from ancillary sources.

Completion of the atlas in 2001 will provide an accurate regional inventory of the areal extent of glaciers on our planet during a relatively narrow time interval (1972-1982). This global "snapshot" of glacier extent is already being used for comparative analysis with previously published maps and aerial photographs, as well as with new maps, satellite images, and aerial photographs, to determine the areal fluctuation of glaciers in response to natural or human-induced changes in the Earth's climate. For example, sequential Landsat images have documented major changes in the coastal regions of Antarctica. See USGS Fact Sheet FS-050-98, Coastal-Change and Glaciological Maps of Antarctica at http://www.glaciers.er.usgs.gov/.

¹Excluding the European part of the Former Soviet Union, which is included in Chapter F (Asia)
²Web accessible: http://pubs.usgs.gov/prof/p1386h/
³Web accessible: http://pubs.usgs.gov/prof/p1386i/

Chapter A will contain introductory material, a 1:50,000,000 - scale map of Glaciers of the World, and a discussion of the physical characteristics, classification, and global distribution of glaciers. The next nine chapters, B through J, are arranged geographically (see table above) and present glaciological information on each of the geographic areas from Landsat and other data sources. The final chapter, K, discusses Monitoring and Understanding Past and Present Changes in the Cryosphere.

Selected Illustrations from the Volume

Figure 23 in Chapter B, Antarctica. Landsat 1 MSS digitally enhanced image of the Byrd Glacier where it joins the Ross Ice Shelf. Full-size image (168K GIF).	Image from Chapter J, North America. Landsat 2 MSS image of Malaspina Glacier, Alaska. Full-size image (222K GIF).
Figure 31 in Chapter I, Glaciers of South America. Salyut-6 photograph of the Southern Patagonian Ice Field, Chile and Argentina. Full-size image (205K GIF).	Figure from Chapter D, Glaciers of Iceland. Landsat 1 MSS image of Iceland's largest (8,200 square kilometers) ice cap, Vatnajökull. Full-size image (240K GIF).

Foreword to the Volume On 23 July 1972, the first Earth Resources Technology Satellite (ERTS 1 or Landsat 1) was successfully placed in orbit. The success of Landsat inaugurated a new era in satisfying mankind's desire to better understand the dynamic world upon which we live. Space-based observations have now become an essential means for monitoring global changes. The short- or long-term cumulative effects of processes that cause significant changes on the Earth's surface can be documented and studied by repetitive Landsat images. Such images provide a permanent historical record of the surface of our planet; they also make possible comparative two-dimensional measurement of change over time. Professional Paper 1386 demonstrates the importance of the application of Landsat images to global studies by using them to determine the current distribution of glaciers on our planet. As images become available from future satellites, the new data will be used to document global changes in glacier extent by reference to the image record of the 1970's. Although many geological processes take centuries or even millennia to produce obvious changes on the Earth's surface, other geological phenomena, such as glaciers and volcanoes, cause noticeable changes over shorter periods. Some of these phenomena have worldwide impact and often are interrelated. Explosive volcanic eruptions can produce dramatic effects on the global climate. Natural or culturally induced processes can cause global climatic cooling or warming. Glaciers respond to such warming or cooling periods by decreasing or increasing in size, thereby causing sea level to rise or fall. As our understanding of the interrelationship of global processes improves and our ability to assess changes caused by these processes develops further, we will learn how to use indicators of global change, such as glacier variation, to more wisely manage the use of our finite land and water resources. Professional Paper 1386 is an excellent example of the way in which we can use technology to provide needed earth-science information about our planet. The international collaboration represented by this report is also an excellent model for the kind of cooperation that scientists will increasingly find necessary in the future in order to solve important earth-science problems on a global basis. Charles G. Groat, Director U.S. Geological Survey

For more information, please contact:

 Richard S. Williams, Jr.      or           Jane G. Ferrigno

 U.S. Geological Survey                     U.S. Geological Survey
 Woods Hole Field Center                    955 National Center 
 384 Woods Hole Road                        Reston, VA 20192
 Woods Hole, MA  02543-1598    

 Tel: 508-457-2347                          Tel: 703-648-6360
 Fax: 508-457-2310                          Fax: 703-648-6524
 e-mail: rswilliams@usgs.gov                 e-mail: jferrign@usgs.gov

Supersedes Fact Sheet 94-9