Assessment report concluded that Arctic
summer sea ice extent has decreased by nearly 27 per
cent in the past 50 years due, at least in part, to
warming temperatures. In the past 30 years, Arctic sea
ice loss has accelerated by 20 per cent compared with
previous rates. In the past two decades, sea ice thickness
also has decreased at a rate of seven to nine per cent
Climate models predict that if current warming trends
continue, the Arctic Ocean could be ice-free during
the summer by the end of this century.
Honduras is second only to Ecuador
in the production and export of cultured shrimp from
Latin America. Vast areas of the delta have been converted
into farms for the cultivation of shrimp.
The rapid growth of shrimp aquaculture
in Honduras has caused both environmental and social
problems. Shrimp farmers are depriving fishers, farmers
and others of access to mangroves, estuaries and seasonal
lagoons; destroying mangrove ecosys-tems, altering the
hydrology of the region, destroying the habitats of
other flora and fauna and precipitating declines in
biodiversity; contributing to degraded water quality;
and exacerbating the decline in Gulf fisheries through
the indiscriminate capture of other species caught with
the shrimppost larvae that are used to stock ponds.
These two images provide a visual comparison
of the increase in coverage by shrimp farms in the Gulf
of Fonseca over time. It is evident from the images
that between 1987 and 1999, a period of about 12 years,
the total area under shrimp farming has increased tremendously.
Iguazú National Park, located
in Argentina near its borders with Brazil and Paraguay,
contains remnants of the highly endangered Paranaense
Isolated from other rain forests by
natural barriers, the Paranaense developed a distinct
and highly diverse ecosystem with thousands of species
of mammals, birds, reptiles, and amphibians unique to
the area. The famous Iguazú Falls are located
within the boundaries of the National Park and are shared
by Argentina and Brazil.Between1973 and 2003, dramatic
changes to the landscape occurred in this region.
In 1973 the forested area spread across
the borders of the three nations. By 2003, however,
large areas of the forest in Paraguay and Brazil, and
smaller amounts in Argentina, had been converted to
other forms of land cover, creating a mosaic of differently
colored land use areas. Note the variation in land cover
patterns among the different countries—reflections
of different land use polices and practices.
Iran’s Lake Hamoun is fed primarily
by water catch-ments in neighboring Afghanistan. In
1976, when rivers in Afghanistan were flowing regularly,
the amount of water in the lake was relatively high.
Between 1999 and 2001, however, the lake all but dried
up and disappeared, as can be seen in the 2001 satellite
The “dry phase” of Lake Hamoun is a striking
example of how competition for scarce water resources
can transform a landscape. When droughts occur in Afghanistan,
or the water in watersheds that support Lake Hamoun
is drawn down by other natural or human-induced reasons,
the end result is a dry lakebed in Iran. In addition,
when the lake is dry, seasonal winds blow fine sands
off the exposed lakebed. The sand is swirled into huge
dunes that may cover a hundred or more fishing villages
along the former lakeshore. Wildlife around the lake
is negatively impacted and fisheries are brought to
a halt. Changes in water policies and substantial rains
in the region saw a return of much of the water in Lake
Hamoun by 2003.
Las Vegas is the fastest growing metropolitan
area in the United States. Its growth was fairly slow
during the first half of the 20th century, but as the
gaming and tourism industry blossomed the population
increased more rapidly. In 1950, Las Vegas was home
to 24 624 people.
Today, the population of the Las Vegas
Valley tops one million, not including the tourists.
According to one estimate, it may double by 2015. This
population growth has put a strain on water supplies.
Satellite imagery of Las Vegas provides
a dramatic illustration of the spatial patterns and
rates of change resulting from the city’s urban
sprawl. Las Vegas is shown in the central portion of
these images from 1973 and 2000. Note the profound modifications
to the landscape—specifically the proliferation
of asphalt and concrete roads and other infrastructure,
along with the displacement of the few vegetated lands.
By 2000, Las Vegas’ growth had
sprawled in every direction, with the greatest expansion
to the northwest and southeast. As the city expanded,
several new transportation networks emerged to serve
the city’s inhabitants.
This pair of satellite images shows
the impact of massive and rapid agricultural development
in Almeria Province along Spain’s southern coast.
In the earlier image, the landscape reflects rather
typical rural agricultural land use.
In the 2000 image, much of the same
region—an area covering roughly 20 000 hectares
(49 421 acres)—has been converted to intensive
greenhouse agriculture for the mass production of market
produce. (Greenhouse-dominated land appears as whitish
In order to address increasingly complex
water needs throughout Spain, the government adopted
the Spanish National Hydrological Plan (SNHP) in 2001.
Initially, this water redistribution plan involved the
construction of 118 dams and 22 water transfer projects
that would move water from parts of the country where
it was relatively abundant to more arid regions.
In 2004, the Spanish government announced
it would begin exploring more environmentally friendly
water-saving technologies, such as wastewater recycling
and seawa-ter desalinization.
Copsa Mica is a large industrial city
located in the very center of Romania and is classified
as an “environmental disaster area.” The
environmentally damaged area covers hundreds of square
kilometres of land. The main industries in Copsa Mica
are non-ferrous metalworking and chemical processing
plants, and their effect on the environment has been
devastating. Air pollution by heavy metals is 600 times
the allowed levels.
To make matters worse, a lead-smelting
facility emitted fumes containing sulfur dioxide, lead,
cadmium, and zinc on the town and surrounding area for
50 km2 (19 square miles). The entire town and much of
the surrounding area were covered with a blanket of
black soot daily until the facilities were forced to
close in 1993.
In 1989 Copsa Mica was exposed as one
of the most polluted places in Europe. It has the highest
infant mortality rate in Europe, 30.2 per cent of children
su?er reduced “lung function” and 10 per
cent of the total popula-tion of 20 000 su?er “neurobehavioral
problems.” The soil and the local food chain probably
will remain contaminated for at least another three
For decades, heavy demands have been
placed on the land-locked Dead Sea to meet the needs
of growing populations in the countries that border
it. Both Israel and Jordan draw water from rivers that
flow into the Dead Sea, reducing the amount of water
that would naturally replenish it. The amount of area
devoted to evaporation ponds for producing salt has
greatly expanded over the past three decades. The creation
of salt works tends to accelerate evaporation, further
contributing to the reduction in water level. Currently,
it is estimated that the water level of the Dead Sea
is dropping at a rate of about one metre (3 feet) per
year.These two images, from 1973 and 2002, reveal dramatic
changes in the Dead Sea over a period of about 30 years.
Declining water levels, coupled with impoundments and
land reclamation projects, have greatly increased the
amount of exposed arid land along the coastline. The
near-complete closing off of the southern part of the
Sea by dry land (2002 image) reveals the severity of
water level decline.
The Huang He (Yellow River) is the
muddiest river on Earth and is China’s second
longest river, running 5 475 km (3 395 miles) from eastern
Tibet to the Bohai Sea.
The Huang He’s yellow color is
caused by its tremen-dous load of sediment, composed
primarily of mica, quartz, and feldspar particles. The
sediment enters the water as the river carves its way
through the highly erodable loess plateau in north-central
China. (Loessial soil is called
huang tu, or “yellow earth,” in Chinese.)
Centuries of sediment deposition and dike building along
the river’s course has caused it to flow above
the surrounding farmland in some places, making flooding
a critically dangerous problem.
Where the Huang He flows into the ocean,
sediments are continuously deposited in the river delta,
where they gradually build up over time. Between 1979
and 2000—as these satellite images show—the
delta of the Huang He expanded dramatically. Several
hundred square kilometres of newly formed land were
added to China’s coast during this period.