Glacier Studies during the International Geophysical Year, 1957-58
Glacier Studies during the International Geophysical Year, 1957-58
RICHARD C. HUBLEY
The International Geophysical Year (IGY), 1957-58, has a special significance to glaciologists in that it marks the initiation of glaciology as a major, important branch of the earth sciences. During and following the IGY, the interested layman can expect to read and hear more about glaciers and glacier activity the world over than ever before. It is appropriate therefore to review very briefly the present status of glaciological knowledge, particularly to point out some of the popular misconceptions associated with glacier fluctuations and what they mean, and to state some of the problems of general interest toward whose solution IGY glaciological research is directed.
It is known that at least four times in the last million years, extensive ice sheets have formed and covered much larger land areas in middle and high latitudes than are ice-covered at present. Each of these periods of extensive glaciation, with their successive interglacial periods, was associated with profound changes in climates, vegetation, geologic erosion, soil types, and sea levels the world over. It is not known, on the other hand, what caused these successive ice ages and interglacial periods. We do not even know yet what type and magnitude of change in the general atmospheric and oceanic circulations of the earth would be required to initiate a new extensive ice age, or to dissipate the present continental glaciers covering Antarctica and Greenland. The hypotheses which exist at present as possible explanations of the ice ages and their associated climatic variations are little more than interesting problems in logical reasoning in the absence of the firm, factual evidence.
In order to supply answers to the questions raised above, it is necessary to determine the exact nature of the interaction between the large polar ice masses, and the atmospheric and oceanic circulations. Particularly, we need to know how the ice masses are maintained through action of these circulations and in turn how the present ice surfaces in polar regions affect the world’s climates. Meteorological, oceanographic, and glaciological research during IGY in the Arctic and Antarctic will serve to bring solutions of these problems closer to reality. It may eventually be possible to predict if and when the world will again experience ice ages, or alternatively, if and when the present ice masses will disappear, and what types of climates may then be found in the various geographic regions of the world.
It is known that in the past several decades, alpine glaciers in some parts of the world have shrunk and retreated appreciably, and that these areas in which retreating glaciers have been observed have experienced a general climatic warming. It is not known, however, if this glacier retreat has occurred worldwide in every region where glaciers exist, nor is there sufficient data to tell if the climate of the world as a whole has warmed significantly during these past decades. In the past few years, magazine and newspaper articles have appeared which describe the glaciers of the world as retreating. Authors of these articles sometimes overzealously extrapolate this supposed world-wide shrinkage of ice bodies to a time in the not too distant future when we all shall bask in pleasant tropical climates. Actually, present data on current glacier fluctuations has been sufficient only to draw conclusions about alpine glaciers in temperate regions. Since glaciers of the temperate and equatorial regions of the world altogether make up less than two percent of the total glacier-covered area of the earth, it is not reasonable to extrapolate the behavior of this tiny sample to all of the world’s glaciers. Particularly in view of the fact that it is completely reasonable from a theoretical basis to expea that glaciers in the polar regions may not fluctuate synchronously with alpine glaciers in temperature and equatorial regions, it is quite appropriate to say that at present we have no idea at all whether the total glacier covered area of the world is growing larger, or smaller, or is virtually in equilibrium. Because the ice of Antarctica and Greenland constitutes about 95 percent of all the glacier ice in the world, it is hoped that IGY research in these two areas will supply an answer to the present status of the world’s glacier cover.
If glaciology were concerned only with amount and fluctuations of the earth’s glacier cover as a whole and the effect of this glacier cover on world climates, there would be no point in studying alpine glaciers as such, because alpine glaciers are much too small to affect climate, and represent an insignificant part of the world’s perennial ice cover. As it is, however, alpine glaciers fluctuate in size, movement, and extent in response to climatic changes, and also leave clear-cut records of these fluctuations. Alpine glaciers therefore serve to indicate and measure climatic fluctuations in the regions wherein they occur. The relationships between successive advances and retreats of these glaciers and associated climatic fluctuations are however, very complex. In order to use alpine glaciers as indicators of climatic change, it is first necessary to establish the physical relationships of changes in climate to changes in glacier mass and energy, and in turn to establish relationships between the mass and energy changes in a glacier to changes in glacier movement and position of the glacier terminus. Studies directed toward solution of these latter problems will be made as part of the U.S. IGY program, during a period including two summers and one winter, on a temperate alpine glacier in Olympic National Park, Washington; and on a polar alpine glacier in the Brooks Range of arctic Alaska.* It is expected that these IGY programs will bring new impetus to the study of glacier dynamics, which will continue after IGY and afford ample opportunity for students with good backgrounds in classical physics and a love for mountaineering to find an absorbing profession in glaciology.
Although as yet we are not able to make complete interpretations of glacier fluctuations in terms of climatic fluctuations, it is still of great importance to collect all possible observations on glacier activity, present and past. This, because, as our methods for interpreting glacier fluctuations in terms of climatic fluctuations improve and become more accurate, data as complete as possible will be needed to reconstruct the climatic history of glacier-covered regions. For this reason IGY also includes plans to make observations of present activity of alpine glaciers. Quantitative data will be obtained on some glaciers by using photogrammetric surveys to prepare successive maps of glaciers over a period of years, from which changes with time in glacier volumes can be computed.
Valuable qualitative data will also be obtained very simply by photographing glacier termini, icefalls, etc., repeatedly over a period of years from fixed marked photo-points near, but not on the glacier. This type of data can easily be collected by non-professionals. Because there are too few professional glaciologists to make observations of glacier activity in all areas from which they are needed, it is to be hoped that as time goes on, and particularly during IGY, more mountaineers will become actively interested in making qualitative photographic records of glacier activity and thereby supply valuable data needed by the glaciologist to obtain a correct picture of glacier activity in various geographic regions.
Examples of this type of qualitative observation are shown in the accompanying photographs. Figure 1 shows two composite photos made ten months apart of the advancing terminus of the Coleman Glacier from a single, fixed station. The growth of the glacier terminus is clearly shown in these photographs by the downslope advance of the terminus, the heightened skyline of the ice, and the burial by avalanche ice of rocks appearing in the foreground of the 1954 picture.
Figures 2 and 3 show the lower part of the Chocolate Glacier, on Glacier Peak, as photographed from the air in September 1955 and September 1956. Because they are taken from a moving plane, these pictures do not represent photos repeated from a fixed station. On the other hand, sufficient distinctive features appear in both photographs, particularly around the glacier terminus, so that the advance of the terminus during the intervening year is clearly marked.
A large number of photographs made both from the ground and from the air of glaciers in the Cascades and Olympics in the past few years have allowed the following qualitative conclusions to be drawn concerning present glacier activity in western Washington:
1. Out of a total of 116 glaciers checked by the end of summer 1956, 98 are advancing. The remaining 18 glaciers show evidences of growth, but currently are not advancing, presumably because either they are as yet too thin to move, or because an impulse of accelerated ice-flow originating in the upper accumulation region of each of these glaciers has not yet had time to reach the glacier terminus.
2. The general glacier advance is most pronounced in the northern Cascades, from Glacier Peak to the Canadian border, where some glaciers are advancing at rates in the order of 300 feet per year. To the south on Mount Rainier, glacier growth and advance is pronounced, but less so than in the northern Cascades. In the Olympics, glacier growth is also occurring, but at present is considerably less pronounced than in the Cascades.
These qualitative observations, together with much more technical detailed observations being made on a few selected glaciers in the area are affording a documentation of glacier activity comparable to that which has been obtained for some time in the European Alps, and which it is hoped will eventually be obtained for other glacier areas in the world.
This current advance of glaciers in northwestern United States, along with the recent information that glacier retreat in the European Alps appears to have ended and been replaced by a period of growth suggests that glacier observations in other areas at this time may yield results of exceptional interest, inasmuch as this may be a turning point in glacier activity in other glacier areas in the world.
Any interested mountaineer visiting an area having glaciers can make a valuable contribution to these studies by observing the following simple instructions:
Take photographs of glacier termini, icefalls, lateral contacts between ice and bedrock or moraines, and of peaks or nunataks rising out of the ice.
Try to include as many bedrock features in the photographs as possible for identification points.
Make a record of the date each photograph was taken, the features appearing in the photograph, the type and focal length of the camera used, and a description of the spot from which the photograph was made. If possible, mark the photo-point with a cairn or other identification so it can be found easily in later years.
A list of the photos, or preferably copies of the photos themselves with the above pertinent data should be turned in to the Department of Exploration and Field Research, American Geographical Society, Broadway at 156th Street, New York 32, New York, care of W. O. Field
*A temperate glacier is one whose mean temperature in summer is at the melting point. A polar glacier is one in which the mean temperature is always below the melting point.