This paper will describe what it was like to map Arctic glaciers starling 62 years ago in Iceland; then in Nordaustland, Svalbard, in 1935–36; and finally in northwest Greenland and Ellesmere Island, Northwest Territories, Canada, in 1937–38. The glacier in Iceland was resurveyed by a party including me in 1992; and I made a less successful attempt to resurvey the Greenland glacier in 1993.

Glaciar Pio XI (or Glaciar Brüggen) may be the only glacier in the world currently at its Neoglacial maximum. During the 20th century, most glaciers in Patagonia have consistently retreated, whereas Glaciar Pio XI has advanced almost 10 km, most recently at rates of ≤ 1.5 m d−1. This advance cannot be explained with reference to climate alone. An explanatory model combining calving dynamics, sediment budget and fjord topography explains the main features of recent behaviour. This case-study exemplifies the climatically out-of-phase behaviour so typical of calving glaciers, and illustrates the spatial and temporal scale over which they may behave asynchronously in the southern Andes.

The Svartisheibreen glacier in northern Norway has been investigated since 1988 in connection with a proposed hydropower scheme. The scheme includes regulation of the lake into which the glacier calves. A one-dimensional flow model has been used to estimate the response of the glacier to changes in mass balance and lake level. The model predicts that a net balance, excluding calving, of 0 m a−1 will cause the glacier to retreat approximately 400 m over 50 years if lake level is maintained at 774 m a.s.l., but that the glacier front will not move significantly if lake level is lowered to 720 m a.s.l. In 1989 and 1991, lake outbursts occurred beneath the glacier. The 1991 outburst was monitored, and culminated in a peak discharge of only 3.5 m3 s−1, much less than for other reported outbursts. This outburst can be explained in a model in which the outburst tunnel passes over a subglacial threshold approximately 70 m behind the 1991 calving front. The model shows that outbursts will probably increase dramatically in size if the front retreats beyond this threshold.

Bakaninbreen is a 17 km long surge-type glacier in southern Spitsbergen, Svalbard, which began surging between the springs of 1985 and 1986, forming a surge front where fast-moving surge ice meets non-surging ice. This surge front has propagated 6 km down-glacier over the period to 1995. Instruments known as “ploughmeters” were installed into the deformable sedimentary bed close to the surge front to assess mechanical conditions year-round. Forces experienced by ploughmeters located down-glacier of the surge front are generally lower than those recorded by a ploughmeter up-glacier of the surge front. Ploughmeters installed at the bed down-glacier of the surge front show initially low applied forces, followed by increasing applied forces. We interpret this increase in applied forcing as a late-active-phase motion event. Analysis of ploughmeter data allows calculation of the yield strength of basal sediments. Yield-strength estimates at Bakaninbreen are in the range 16.6–87.5 kPa. Comparison with estimates of basal shear stress suggests that sediments up-glacier of the surge front will be actively deforming, whereas there will be only limited deformation down-glacier of the surge front. Immediately down-glacier of the surge front, calculations indicate negligible basal shear stresses. Together with the deformation of sediment from up-glacier, this implies a build-up of sediment at the surge front, offering a potential explanation for the sediment-filled thrust faults outcropping on the surge front.

Glacierized basins in the high Arctic are believed to be regions of low chemical weathering rates, despite the lack of pertinent data, because it is believed that water does not flow in significant quantities through subglacial drainage systems. We have calculated chemical weathering rates at Finsterwalderbreen, a polythermal, surge-type glacier in Svalbard. Rates of 320 and 150 meq Σ+ m−1 year−1 were measured in 1994 and 1995, respectively. The corresponding water fluxes were 4.1 × 107 and 1.7 × 107 m3. We estimate that we have measured ~72% of the total annual discharge, hence the true annual chemical weathering rates are ~440 and 210 meq Σ+ m−2 year−1, respectively This gives a mean annual chemical weathering rate of 330 meq Σ+ m−2 year−1, which approximates the continental average of 390 meq Σ+ m−2 year−1 and is intermediate between chemical weathering rates measured on cold-based glaciers (~110–160 meq Σ+ m−2 year−1) and temperate glaciers (450–1000 meq Σ+ m−2 year−1). This suggests that there may be a direct link between chemical weathering rates and thermal regime, and that glacierized basins in the high Arctic cannot necessarily be considered as regions of low chemical weathering and CO2 drawdown.

This paper compares estimates of suspended-sediment yield and discharge from two glacier basins in Svalhard exhibiting contrasting glacial thermal regimes: Austre Brøggerbreen (~12 km2), which is almost entirely cold-based, and Finsterwalderbreen (~44 km2), dominated by warm basal ice. There are marked differences in the magnitude and temporal pattern of mean daily discharge and mean daily suspended-sediment concentration from the two glacier basins. Specific suspended-sediment yields from Finsterwalderbreen (710–2900 t km−2 a−1) were more than one order of magnitude greater than at Austre Brøggerbreen (81–110 t km−2 a−1). These differences are ascribed to the influence of thermal regime upon the meltwater drainage system and the predominant sources of suspended sediment. The potential significance of glacier thermal regime is further explored using studies from other glacier basins in Svalbard. Variations in thermal regime resulting from mass-balance adjustments since the termination of the Little Ice Age are also examined.

Glaciar Upsala, a freshwater calving glacier in southern Patagonia, has been retreating since 1978, and after a drastic recession of about 700 m a−1 in 1994 the retreat seems to have stopped in 1995. A large ice-thinning rate of 11 m a−1 was obtained between 1990 and 1993, by surveying surface elevations near the terminus of Glaciar Upsala. In 1993–94, the thinning was estimated at about 20 m a−1 near the lateral margin. Some possible causes of the thinning behavior are considered.

In the ablation area of Glaciar Perito Moreno, 50 km south of Glaciar Upsala, ablation rates were measured during 110 d in summer 1993–94, and air temperature was continuously recorded throughout 1994. Using a degree-day method with temperature data at the nearest meteorological station, Calafate, annual ablation during the last 30 years was estimated to fluctuate from about 12 ± 2 to 16 ± 2 m a−1 in ice thickness, with a mean of 14 ± 2 m a−1. Thus, the temperature anomaly alone cannot elucidate the thinning of 11 m a−1 at Glaciar Upsala. As a possible mechanism of the ice-thinning, it is suggested that the considerable retreat due to calving may have resulted in reduction of longitudinal compressive stress exerted from bedrock rises and islands near the glacier front, causing a considerable decrease in the emergence flow. Thus, the ice may have thinned at a rate close to the annual ablation rate.

Measurements made during the Ross Ice Shelf Geophysical and Glaciological Survey (RIGGS, 1973–78) are used to determine the large-scale rheological conditions of the Ross Ice Shelf, Antarctica. Our method includes a numerical ice-shelf model based on the stress-equilibrium equations and control theory. We additionally perform a few tests on simplified geometries to investigate the precision of our method. Our results consist of a map of the depth-averaged viscosity of the central part of the Ross Ice Shelf to within an uncertainty of 20%. We find that the viscosity variations are consistent with Glen’s flow law. Application of a more realistic flow law in our study provides little enhancement of ice-shelf model accuracy until uncertainties associated with basal melting conditions and with temperature profiles at inflow boundaries are addressed. Finally, our results suggest a strong viscosity anomaly in the west-central part of the ice shelf, which is interpreted to be associated with changes in the dynamics of Ice Stream A or B at least 1000 years ago. This feature conforms to the prevailing notion that the West Antarctic ice streams are unsteady.

The relations between seasonal changes in ice speed, longitudinal extension rate and terminus position are investigated for Columbia Glacier, Alaska, over the period 1977–87. The lower reach of the glacier is studied using repeat aerial photography, which extends from the terminus to the base of an icefall about 14 km up-glacier. There are regular seasonal cycles in speed and stretching rate. These cycles continue after the glacier retreats off the shoal at the end of the fjord (in about 1983), indicating that factors other than backstress, such as seasonal changes in subglacial water, control the speed of the glacier. Terminus position appears to be linked with thinning induced by longitudinal extension, as predicted by the calving model proposed by Van der Veen (1996).

In order to determine the equilibrium line (EL) and the annual net mass balance over the accumulation area of Finsterwalderbreen, Spitsbergen, Svalbard (by detection of the 1962–63 radioactive peak from the 1961–62 atmospheric nuclear tests), we collected 14 ice cores, at elevations of 445–730 m, in the springs of 1994 and 1995. The corresponding samples were melted and filtered for laboratory gamma spectrometry. In the accumulation area, the 1962–63 radioactive layer is found well below the surface. The mean annual accumulation is not invariably related to altitude. The EL, averaged to 545 in a.s.l., leads to an accumulation area ratio of 0.3 and indicates a strong negative balance. The 584 Bq m−2 mean137 Cs deposition rate (1954–74 nuclear tests) for eight ice cores in the accumulation area is nearly twice the 340 Bq m−2 mean Svalbard value obtained from six other glaciers (at time of deposition).

An in situ gamma-ray detector was lowered down each borehole, and137 Cs levels were recorded. The counting rate is proportional to the apparent deposition rate and the specific activity. The laboratory measurements perfectly match the in situ determinations. In the ablation area, a dust layer and the associated nuclear test deposits are concentrated close to the bare ice surface of the glacier, under the winter snow layer and present maximum 137 Cs and 210 Pb contents. The dust layer acts like a filter for radioactive materials removed from the glacier and its basin by melting and water flow. The original specific activities and deposition rates at a given location are enhanced by adsorption of additional radioactivity on the dust particles. A linear relationship exists between 137 Cs and 210 Pb deposition rates. This process is almost constant for all studied ice cores. The apparent 137 Cs deposition rate for seven ice cores in the ablation area is 465 Bq m−2 (at date of measurement: 1 July 1995).

Changes in planimetric area, elevation and volume were calculated for Athabasca Glacier, Alberta, Canada, below 2400 m elevation for the period 1919–79 from maps produced using aerial or terrestrial photogrammetry. Map contours were digitized and converted into raster digital elevation models (DEMs). Comparison of the models allowed changes in volume and elevation to be estimated. In the time of record, the glacier lost 2.344 × 108 m3 of volume and downwasted significantly.

There are several sources of error associated with DEM generation and construction: source maps have spatially variable uncertainty in vertical estimation, associated with the photogrammetric process used; small errors are introduced in the creation of raster DEMs as a result of fitting surfaces to digitized contours; errors of registration, leading to errors in estimation of vertical change over time, can be of significance, especially when comparing maps produced by different photogrammetric techniques.

These errors are quantified and displayed in transect and map form. Especially with maps only 2 years apart in time, errors are often greater than actual changes in surface elevation. The magnitude of the errors involved in the comparison of maps made with a 2 year interval would suggest that 5 or 10 years between successive mappings might have been more scientifically justifiable and more cost effective.

Glaciar Pio XI, the largest glacier in South America, has experienced an advance during the 20th century, unlike virtually all other glaciers in Patagonia, which are retreating rapidly. Climatological records of the last 80 years are analyzed together with ice-velocity and meteorological measurements collected during November 1995 near the tidewater front of Glaciar Pio XI. Ice speeds of up to 50 m d−1 were measured, the maximum occurring during a period when air temperatures were high.

Vatnajökull, Iceland, is the Earth’s most studied ice cap and represents a classical glaciological field site on the basis of S. Pálsson’s seminal glaciological field research in the late 18th century. Since the 19th century, Vatnajökull has been the focus of an array of glaciological studies by scientists from many nations, including many remote-sensing investigations since 1951. Landsat-derived positions of the termini of 11 outlet glaciers of Vatnajökull were compared with frontal positions of six of these 11 outlet glaciers determined by field observations during the period 1973–92. The largest changes during the 19 year period (1973–92) occurred in the large lobate, surge-type outlet glaciers along the southwestern, western, and northern margins of Vatnajökull. Tungnaárjökull receded −1413 ± 112 m (−1380 ± 1 m from ground observations), and Brúarjökull receded −1975 ± 191 m (−2096 ± 5 m from extrapolated ground observations) between 1973 and 1992. Satellite images can be used to delineate glacier margin changes on a time-lapse basis, if the glacier margin can be spectrally discriminated from terminal moraines and sandur deposits and if the advance/recession is larger than maximum image pixel size. “Local knowledge” of glaciers is critically important, however, in the accurate delineation of glacier margins on Landsat images.

We use a time-dependent ice-cap model to predict the pattern of growth and decay of the Patagonian ice cap during a simulated glacial cycle. The purpose is to illuminate the internal system dynamics and identity thresholds of stability related to the underlying topography. This is a necessary step if former ice-cap behaviour is to be linked to climatic change. The model, which is fully described elsewhere, portrays ice extent and surface altitude at intervals of 1000–5000 years. The modelling suggests that there are two stable ice-cap states largely influenced by topography, namely, the present distribution of upland ice fields and the long, linear ice cap along the Andes as represented by the Last Glacial Maximum. Both states can coexist in equilibrium with a climate similar to that of the present day. There is a third, larger variable state in which a more extensive ice cap extends into the adjacent plains, as occurred during early Quaternary glaciations. Warmer and/or drier conditions are required to remove all these ice caps. There are five ice centres during ice-cap growth.

In 1978, the first detailed glaciological studies were carried out on the small glacier AX010 in a glacier inventory of Dudh Kosi region, in the Nepal Himalaya. Its length, area and highest and lowest elevations in 1978 were 1.7 km, 0.57 km2, 5360 and 4950 m a.s.l., respectively. Two resurveys of its terminus position and/or surface elevations were carried out in 1989 and 1991. The glacier retreated by about 30 and 28 m during the periods 1978–89 and 1989–91, respectively.

In 1995, annual monitoring of this glacier by means of ground survey, stake method and topographical mapping began, in order to obtain its mass balance, surface flow velocity and extent, and link them with climatic conditions. The results obtained in 1995 are summarized as follows: (1) During the period 1991–95, the glacier retreated by 12 m. (2) Associated with the ice-thickness loss in the lower part of the glacier, the horizontal surface velocities along the center line in 1995 (June–October) showed a remarkable decrease on the glacier tongue, to about 50% of those in 1978.

Shrinkage of the glacier in the near future is predicted from a simple model calculation for the case that climatic conditions remain unchanged from 1995. The results show that the present shrinkage should continue and accelerate.

Analysis of five surges of Variegated Glacier, Alaska, indicates that they all terminated with their surge fronts in the terminal lobe of the glacier, and that different surges penetrated into the terminal lobe by different amounts. Of the five surges, the one that occurred in 1905–06 penetrated furthest into the terminal lobe. The 1964–65 surge affected a greater proportion of the glacier than either the 1947–48 or the 1982–83 surge, caused greater total ice displacements than the 1982–83 surge and appears to have resulted in larger total displacements down-glacier than the 1982–83 surge. Overall, the 1964–65 surge was a significantly larger event than either the 1947–48 or the 1982–83 surge.

The retreat of Wurtenkees, a glacier of about 1 km2 in the European East Alps, is described by measurement of frontal change, interpretation of maps and a computed mass-balance series. Since 1850, Wurtenkees has been one of the most strongly retreating glaciers in this region. Mass balance has been measured since 1982. Measured values of the accumulation area ratio and the equilibrium-line altitude as well as a degree-days model are used for the description of the activity conditions of the glacier. Under present climatic conditions Wurtenkees would need a lowering of the mean air temperature during the summer season of 1–1.5° C to return to a balanced mass budget. With predicted global warming, the glacier is likely to disappear early in the 21st century.

Most glaciers in Patagonia are retreating rapidly. Glaciar O’Higgins, a freshwater calving glacier, has experienced the largest retreat rate of all, as measured from 1945 to 1986 (Aniya and others, 1992). Based on historical maps, early exploration reports and recent aerial photography, the front-position record of Glaciar O’Higgins is extended to cover the period 1896–1995). Climatic warming, in combination with the detaching of the glacier front from an island, is believed to be the cause of the rapid retreat.

Equilibrium-line altitudes (ELAs) are reconstructed for Hintereisferner, Tyrol, Austria, using temperature and precipitation records for the period from 1859 to the present. The basic idea is to calibrate simple statistical models using observations of the ELA over the period 1964–92. Results are compared with those of Kuhn’s glacial–meteorological model of ELA fluctuations. Correlation coefficients between observed and predicted ELAs arc 0.91 for the glacial–meteorological model and 0.98 for the multiple regression model. The calibrated model allows backward extrapolation of the ELA from the longer climatic records (‘Austrian Temperature Series” since 1775; precipitation at Marienberg, South Tyrol, since 1858). ELAs after the glacier maximum of the 1850s were rather high until the 1870s, when they show a trend towards lower values. The lowest values, about 200 m lower than the “1850” average, were finally reached in 1912–14. During the years 1907–26, the ELA of Hintereisferner was lower than the “1850” average in 13 out of 20 years. This led to the widespread glacier advance of the 1920s in the Alps. After this, the ELA rose constantly, reaching its highest value in 1947. From the early 1950s until 1980 there was a trend towards lower ELAs again, which has been succeeded by a period of very high ELAs. The period from the late 1920s to the early 1960s was the longest period of almost constantly high ELAs since the middle of the 19th century.