Environmental Engineering Reference
In-Depth Information
sensitivity to limit human population levels yet, paradoxically, stimulate a substantial
tourist industry.
2
Mountains occur either as narrow orogens, the product of crustal shortening and
isostatic uplift in response to tectonic compression and subduction, or more general
areas of epeirogenic uplift. Three Phanerozoic orogens representing two
supercontinental cycles form Earth's principal mountain systems today. Continuing
uplift in American, Eurasian and New Zealand Cenozoic orogens coincides with
Quaternary glaciation to provide spectacular alpine landsystems.
3
Mountains intrude into the mid-troposphere and generate major weather disturbances,
especially in Earth's jet streams. Global Rossby wave disturbance and its associated
mid-latitude and monsoon climate impact are attributed to the Rocky Mountains,
Andes and Tibetan plateau. Locally, the extension of topographic surfaces into the
mid-troposphere alters energy and moisture balances compared with the free
atmosphere and channels topographic winds.
4
Steep topographic, meteorological and edaphic gradients in mountains stimulate steep
ecologic gradients and local diversity. Arctic-alpine tundra is sandwiched between a
forest-montane forest belt on lower slopes and a cryonival belt around high mountain
summits. The forest-tundra ecotone is primarily of Holocene age, as alpine glaciers
receded from the timberline.
5
Alpine landsystems represent the integration of glacier, cryonival and slope processes
above the timberline, which buffers them from lower-lying fluvial landsystems. High
potential energy, continuing uplift in many orogens and Pleistocene glaciation ensure
that the modern glacier-cryonival-slope landsystem is a high-energy, unstable slope
and high sediment transfer system. Surviving alpine glaciers, icefields and many other
facets of mountain environments and human occupation are threatened by global
warming.
forest and mineral resources at a distance. Tourism exploits dramatic mountain scenery
and alpine snowfields, bringing welcome income to poorer indigenous communities. Yet
it conflicts with their traditional life style and is driven by short-term economic interests
inimical to the sensitivity and stability of their physical environment. Sustainable
management of global mountains requires us to understand first the character and
operation of their physical systems.
FURTHER READING
Barry, R. G. (1992)
Mountain Weather and Climate
, second edition, London and New York:
Routledge. This detailed text may be too advanced for many but there are few topics which can
match the specialist attention paid to its subject. It is still possible to derive a greater
understanding of mountain weather and climate without being drawn into its mathematical
explanations.
Gerrard, A. J. (1990)
Mountain Environments: an examination of the physical geography of
mountains
, London: Belhaven Press. It is worth retaining this topic for its comprehensive
review of the ecology and geomorphology of mountains and Earth's principal mountain
systems, which are less well covered in contemporary applied texts. Aspects of mountain
