Page 291 - Fundamentals of Geomorphology

274 PROCESS AND FORM

HUMANS AND GLACIAL
ENVIRONMENTS

Human impacts on glacial landscapes
Glacial landscapes are productions of frigid climates.
During the Quaternary, the covering of ice in polar
regions and on mountain tops waxed and waned in
synchrony with swings of climate through glacial–
interglacial cycles. Humans can live in glacial and
periglacial environments but only at low densities. Direct
human impacts on current glacial landscapes are small,
even in areas where tourism is popular. Indirect human
impacts, which work through the medium of climatic
change, are substantial: global warming appears to be
melting the world’s ice and snow. Over the last 100 years,
mean global temperatures have risen by about 0.6 C,
◦
about half the rise occurring in the last 25 years. The
rise is higher in high latitudes. For example, mean winter
temperatures at sites in Alaska and northern Eurasia have
risen by 6 C over the last 30 years (Serreze et al. 2000),
◦
which is why glacial environments are so vulnerable to
the current warming trend.
Relict glacial landscapes, left after the last deglacia-
tion some 10,000 years ago, are home to millions of
people in Eurasia and North America. The relict land-
forms are ploughed up to produce crops, dug into for
Plate 10.16 Small kettle-hole lake in end-moraine sand and gravel, and covered by concrete and tarmac.
complex of Saskatchewan Glacier (seen in background) Such use of relict landscape raises issues of landscape
in the Canadian Rockies.
(Photograph by Mike Hambrey) conservation. The other side of the coin is that knowl-
edge of Quaternary sediments and their properties can
aid human use of relict glacial landscapes (Box 10.3).

Box 10.3

WASTE DISPOSAL SITES IN NORFOLK, ENGLAND

An understanding of the Quaternary sediments aids applied for planning permission to create an above-
the designing of waste disposal sites in south Norfolk, ground or ‘landraise’ waste disposal site of 1.5 million
England (Gray 1993). Geologically, south Norfolk is cubic metres at a disused US SecondWorldWar airfield
a till plain that is dissected in places by shallow river at Hardwick. The proposal was to dig a 2–4-m-deep
valleys. It contains very few disused gravel pits and pit in the Lowestoft Till and overfill it to make a low
quarries that could be used as landfill sites for munic- hill standing up to 10 m above the surrounding plain.
ipal waste. In May 1991, Norfolk County Council The problem of leachate leakage from the site was to be