List and describe the five factors that cause sea level to change. What will be an ideal response?
Coasts can be affected by long-term change in sea level. Five factors can cause sea level to
change. Three of these factors are responsible for eustatic change, variations in sea level that
can be measured all over the world ocean:
(1) The amount of water in the world ocean can vary. Sea level is lower during periods of
global glaciation (ice ages) because there is less water in the ocean. It is higher during warm
periods, when the glaciers are smaller. Periods of abundant volcanic outgassing can also add
water to the ocean and raise sea level.
(2) The volume of the ocean’s “container” may vary. High rates of seafloor spreading are
associated with the expansion in volume of the oceanic ridges. This expansion displaces the
ocean’s water, which climbs higher on the edges of the continents. Sediments shed by the
continents during periods of rapid erosion can also decrease the volume of ocean basins and
raise sea level.
(3) The water itself may occupy more or less volume as its temperature varies. During times
of global warming, seawater expands and occupies more volume, raising sea level.
Two of these factors produce variations in local sea level:
(4) Tectonic motions and isostatic adjustment can change the height and shape of a coast.
Coasts can experience uplift as lithospheric plates converge or can be weighed down by
masses of ice during a period of widespread glaciation. The continents slowly rise when the
ice melts.
(5) Wind and currents, seiches, storm surges, an El Niño or La Niña event, and other effects
of water in motion can force water against the shore or draw it away.
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Describe the positives and negatives of Germany's ambitious program of energy efficiency and recycling
What will be an ideal response?
Consumer owned cooperative movements
A) emerged during the "Flower Power" generation of the 1970s. B) originated with the introduction of GMOs. C) were discouraged in the United States because their ideology was counter to capitalist exploitation. D) emerged with increased product testing by consumer watch dog organizations. E) originated in the nineteenth century as an outgrowth to conditions created by the Industrial Revolution.
Growing awareness of environmental issues during the 20th century led to the creation of the U.S. Environmental Protection Agency in what decade?
A) The 1950s B) The 1960s C) The 1970s D) The 1980s