Geography Reference
In-Depth Information
the fi rst over the past 6000 years. But the name
Little
Ice Age
certainly was more dramatic than “Minor
Glaciation,” and it stuck.
In his topic
The Little Ice Age
(2000), archaeolo-
gist Brian Fagan described how the Franz Josef Glacier
on New Zealand's South Island “thrust downslope into
the valley below, smashing into the great rainforests . . .
felling giant trees like matchsticks.” In North America,
our growing understanding of the Little Ice Age helps
explain why the Jamestown colony collapsed so fast, a
failure attributed by historians to ineptitude and lack
of preparation. The chief cause may well have been
environmental. Geographer David Stahle (1998) and
his team, studying tree ring records that go back eight
centuries, found that the Jamestown area experienced a
seven-year drought between 1606 (the year before the
colony's founding) through 1612, the worst in nearly
eight centuries. European colonists and American
Indians were in the same situation, and their relations
worsened as they were forced to compete for dwindling
food and falling water tables. The high rate of starva-
tion was not unique to the colonists. They, and their
American Indian neighbors, faced the rigors of the
Little Ice Age as well.
As the Little Ice Age continued into the 1800s, a
large-scale volcano had a major impact on human soci-
ety. On April 5, 1815, the Tambora Volcano on the island
of Sumatra in what was then the Dutch East Indies,
located not far east of Bali, rumbled to life. Less than
a week later it was pulverized in a series of explosions
that could be heard a thousand miles away, killing all
but 26 of the island's population of 12,000. When it was
over, the top 4000 feet of the volcano were gone, and
much of what is now Indonesia was covered by debris.
Darkness enveloped most of the colony for weeks, and
tens of thousands died of famine in the months that fol-
lowed. Colonial reports describe fi elds covered by poi-
sonous ash and powder, waters clogged by trees and
cinders, and air rendered unbreathable by a fog of acid
chemicals.
Since the 1850s, when the Little Ice Age waned
and a slow but nearly continuous warming phase
began, climatologists and other scientists have sought
answers to crucial questions relating to climate change:
what causes alternating cycles of global warming and
cooling? Given the enormous quantities of pollution
poured into the planet's atmosphere as the Industrial
Revolution gathered momentum, how large is the
human contribution to the associated
greenhouse
effect
(that results when greenhouse gases trap heat
and raise temperatures)? This worldwide, interna-
tional effort to answer such questions involves the use
of sophisticated computers and complicated models,
and as discussed below, it has achieved an alarming
consensus.
Take time to search the Internet and read about what has
happened to Phuket, Thailand, since the Indian Ocean tsu-
nami hit in December 2004. Look for before and after images
of Phuket—how did it look before the tsunami hit and after?
Research how Phuket has been rebuilt and determine why
Phuket has been rebuilt the way it has.
HOW HAVE HUMANS ALTERED
EARTH'S ENVIRONMENT?
Biologists estimate that as many as 25 million types
of organisms inhabit Earth, perhaps even more. Most
have not yet been identifi ed, classifi ed, or studied. No spe-
cies, not even the powerful dinosaurs, ever affected their
environment as strongly as humans do today. An impact
by comets probably made the dinosaurs and many other
species extinct. Some biogeographers suggest that the
next great extinction may be caused not by asteroids but
by humans, whose numbers and demands are destroying
millions of species.
The natural environment is being modifi ed and
stressed by human activity in many obvious and some less
obvious ways. Some
environmental stress
is more obvi-
ous because it takes place around human habitats, such
as cutting forests and emitting pollutants into the atmo-
sphere. Less obvious environmental stress takes place
away from dense concentrations of humans, including
mountain top mining, burying toxic wastes that contam-
inate groundwater supplies, and dumping vast amounts
of garbage into the oceans. Humans have built seawalls,
terraced hillslopes, dammed rivers, cut canals, and modi-
fi ed the environment in many constructive as well as
destructive ways. All of these activities have an impact
on environment and have given rise to a number of key
concerns. Among these are the future of water supplies,
the state of the atmosphere, climate change, desertifi ca-
tion, deforestation, soil degradation, and the disposal of
industrial wastes.
Water
Resources that are replenished even as they are being
used are
renewable resources
, and resources that are
present in fi nite quantities are
nonrenewable resources
.
Water, essential to life, is a renewable resource. But the
available supply of fresh water is not distributed evenly
across the globe. Figure 1.11 shows the world distribution
