Glacial environments are scenically and scientifically among the most exciting and complex on Earth. Apart from phenomena associated directly with moving or stagnating glaciers, fluvial, aeolian, lacustrine r.d marine processes frequently interact with ice and its deposits. Glacial environments therefore posris a wide variety of landforms and sediment associations. <...>

For most people living in temperate countries, ice is usually encountered only in small quantities on cold days or as small blocks in drinks. In this everyday form, ice appears to be a rigid, brittle and usually slippery material, but in glaciers and ice sheets ice can exhibit a wide variety of surprising and fascinating behaviour. It can flow plastically, like toothpaste, mould itself around hills and valleys, and creep and slide from high snowfields down towards lower ground. It can carve out huge troughs and alter entire landscapes, scouring away soil and other surficial material or blanketing large tracts with glacial deposits. Glaciers and ice sheets can alter the Earth’s climate, chilling the atmosphere and the oceans, and profoundly affecting the global hydrological cycle. They also preserve valuable records of past climate change locked up in ice crystals and air bubbles, and the oscillations of glacier margins provide direct indicators of recent climatic shifts. Furthermore, glaciers can store and suddenly release immense quantities of meltwater, producing catastrophic floods such as those which occurred in Iceland in late 1996 when subglacial volcanic activity melted the base of a portion of Vatnajokull. In heavily populated regions, huge volumes of glacigenic material are continuously excavated by people to use in buildings and roads, and many of the holes left behind are being filled by the ever-increasing mountains of domestic and industrial waste. Thus, either directly or indirectly, glaciers and glaciation impact upon a large proportion of the planet’s population. <...>

Glaciated alpine areas form a fascinating basis for studying environmental processes. Glaciers can be found at virtually any latitude on the globe where the mountains are high enough and the moisture supply large enough to promote permanent ice cover. Figure 1.1 provides a schematic representation of the way in which the variables of altitude, latitude and climate interact to provide regional thresholds above which glaciers may occur. Thus, in mountainous areas in maritime climatic zones and in higher latitudes, glacier snouts will frequently extend to sea level, whereas in the arid continental areas of the tropics, permanent ice and snow cover can occur only at very high altitudes. The presence or absence of glaciers in a drainage basin above the regional threshold will, of course, depend on other local factors, notably the size, orientation and slope of the basin and the way that these interact with larger scale patterns of precipitation and insolation, to control moisture inputs to the basin and losses through ablation, evaporation and runoff and thus the rate of movement and the mass balance of areas of ice or snow within the basin. The significance of these local characteristics will also vary with macro-climate as it is affected by latitude and altitude and will affect the dynamism of the glacial system. <...>

In the late 20 th century, biogeochemistry emerged as a new discipline in which the biological, physical, and human sciences collaborate (CGCR, 1999; Schlesinger, 1997). Biological, because the chemical cycles of the planet are mediated by life (Table 1). Physical, because of the strong coupling between climate and atmospheric composition so evident in the glacial-interglacial record of the ice cores (Fig. 1). And, human, because of the massive human disruption of the planet's carbon and nitrogen cycles by fossil fuel burning (which produces CO2 and a range of volatile nitrogen compounds) (Fig. 2).