Environmental Engineering Reference
In-Depth Information
Never before have so many humans lived so close
to the coasts. More than 100 million people worldwide
live within 91 centimeters (36 inches) of mean sea
level—roughly equal to the highest projected sea level
rise by the end of this century. According to a 2004
UN-funded study by Janos Bogardi, the number of
people who are vulnerable to floods is expected to
double to 2 billion worldwide by 2050 due to a combi-
nation of global warming, rising sea levels, deforesta-
tion, and population growth in flood-prone areas.
One comedian jokes that he plans to buy land in
Kansas because it will probably become valuable
beachfront property. Another boasts that she is not
worried because she lives in a houseboat—the “Noah
strategy.”
According to the IPCC, the largest burden from
the harmful effects of moderate global warming (Fig-
ure 16-10) will fall on people and economies in poorer
tropical and subtropical nations that lack the economic
and technological resources needed to adapt to those
harmful effects. According to a 2030 UN study by Paul
Reiter and Alistair Woodward, climate change cur-
rently prematurely kills about 150,000 people per year
and this number could double by 2030. By the end of
this century, the annual death toll from global warm-
ing could reach 6 million or more. Some analysts say
these estimates are exaggerated. Even if the actual toll
is lower, this remains a serious and largely preventable
human tragedy.
Beech
Future
range
Overlap
Present
range
Figure 16-11 Natural capital degradation: possible effects of
global warming on the geographic range of beech trees based
on ecological evidence and computer models. According to
one projection, if CO 2 emissions doubled between 1990 and
2050, beech trees (now common throughout the eastern United
States) would survive only in a greatly reduced range in north-
ern Maine and southeastern Canada. Similarly, native sugar
maples would likely disappear in the northeastern United States
in a scenario of increased atmospheric warming. Conversely,
the ranges of other tree species adapted to a warm climate
would spread. Critical thinking: what difference does it make if
the range of beech trees changes? (Data from Margaret B.
Davis and Catherine Zabinski, University of Minnesota)
a rise in sea level of 88 centimeters (35 inches)—would
produce some dire effects:
Threatening half of the world's coastal estuaries,
wetlands (one-third of those in the United States), and
coral reefs
Disruption of many of the world's coastal fisheries
Flooding low-lying barrier islands and causing
gently sloping coastlines (especially along the U.S.
East Coast) to erode and retreat inland by about 1.3
kilometers (0.8 mile)
Flooding agricultural lowlands and deltas in parts
of Bangladesh, India, and China, where much of the
world's rice is grown
Contaminating freshwater coastal aquifers with
saltwater
Submerging some low-lying islands in the Pacific
(Figure 16-12) and Caribbean
Flooding coastal areas with large human popula-
tions, including some of the world's megacities (Fig-
ure 7-13, p. 141)
Figure 16-12 Natural capital degredation: for a low-lying island na-
tion like the Maldives, even a small rise in sea level could spell disaster
for most of its 265,000 people. About 80% of the 1,180 islands making
up this country, which are strung out across a large area of the Indian
Ocean, lie less than 1 meter (3.3 feet) above sea level. Most islands in
the Maldives would be flooded and disappear if the highest sea level
rise projected by 2100 as a result of global warming proves correct.
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