 |
Our
planet. |
04 - Coastal and marine waters. |
Chapter
17 of Agenda 21 stresses the need for the protection of the oceans,
all kinds of seas, including enclosed and semi-enclosed seas, and
coastal areas, as well as the protection, rational use and development
of their living resources. The chapter covers the following programme
areas:
* The integrated
management and sustainable development of coastal areas, including
exclusive economic zones;
* Marine environmental protection;
* The sustainable use and conservation of living marine resources
of the high seas;
* The sustainable use and conservation of living marine resources
under national jurisdiction;
* The addressing of critical uncertainties for the management
of the marine environment and climate change;
* The strengthening of regional and international cooperation
and coordination;
* The sustainable development of small islands.
A wide variety
of human activities can affect the coastal and marine environment.
Population pressure, increasing demands for space and resources,
and poor economic performances can all undermine the sustainable
use of our oceans and coastal areas. The most serious problems affecting
the quality and use of these ecosystems are:
* The alteration
and destruction of habitats and ecosystems;
* The effects of sewage on human health;
* Widespread and increasing eutrophication;
* The decline of living resources, such as fish stocks;
* Changes in sediment flows due to hydrological changes;
* The impacts of climate change, including rising sea levels (GESAMP,
2001b).
Coastal Zone
Statistics for Countries Grouped by Region :
Source:
Burke et al, 2001. |
Length
of Coast (km) |
Area
of Continental Shelf, <200m (1000 km2) |
Territorial
Sea, up to 12 nm for each country (1000 km2) |
Exclusive
Fishing Zone (1000 km2) |
North
America |
398,835
|
5,107.5
|
3,484.1 |
X |
Central
America & Caribbean |
73,703
|
806.6
|
1,050.0
|
197.2 |
South
America |
144,567
|
2,203.0
|
1,030.0
|
1,814.1 |
Europe |
325,892
|
6,316.0
|
2,589.4
|
1,783.0 |
Middle
East & North Africa |
47,282
|
786.5
|
649.7
|
196.0 |
Sub
Saharan Africa |
63,124
|
987.0
|
871.9
|
3,111.1 |
Asia |
288,459
|
5,515.4 |
5,730.9
|
249.5 |
Oceania |
137,772
|
2,565.0
|
2,830.4
|
X |
World |
1,634,701
|
24,287.1
|
18,816.9
|
12,885.2 |
|
 |
31.
Species Diversity in the World's Seas, 1990 -1998 |
There is growing evidence that many marine species
are less widely distributed, and therefore more vulnerable to extinction,
than previously thought. This graphic shows the diversity of marine
mammals, sharks, molluscs, birds, and shrimps and lobsters in the
world's marine areas. |
|
32.
Changes in Marine Species Populations |
The Marine Species Population Index provides
an assessment of the average change over time in the populations of
217 species of marine mammals, birds, reptile, and fish. This graphic
shows that between 1970 and 1999, the Marine Species Population Index
recorded a decline of about 35%. |
|
33.
Global Distribution of Coral, Mangrove and Seagrass Diversity |
There are two distinct regions in which
coral reefs are primarily distributed: the Wider Caribbean (Atlantic
Ocean) and the Indo-Pacific (from East Africa and the Red Sea to the
Central Pacific Ocean). This graphic illustrates the diversity of
corals, mangroves and seagrass in the world's coastal and marine areas. |
|
34. Global Capture Fisheries and Aquaculture Production, 1950 -
1999 |
This graphic illustrates the levelling off of the
global fisheries catch from 1950 to 1999, showing a growing decline
in most major fishing areas. It also shows the amounts of aquaculture
production in marine water, freshwater and brackish water in 1998. |
|
35.
Changes in Catch Ratios of Predatory and Plankton Feeding Fish Indicating
Structural Changes in the Marine Ecosystem |
Three-quarters of fish stocks are currently exploited
to the maximum extent, if not excessively. This graphic illustrates
the decline in the catch ratios of predatory and plankton-feeding
fish from 1950 to 1995. |
|
36.
Benefits from Marine and Coastal Ecosystems and Activities |
Besides the well-known economic value of fisheries,
there are several other activities generating significant revenues
in coastal and marine areas. This graphic discusses the economic
benefits of coastal tourism, trade and shipping, offshore oil and
gas, and fisheries. It also illustrates the estimated mean value
of marine biomes such as estuaries and coastal reefs.
|
|
37.
Industrial Areas and Seasonal Zones of Oxygen Depleted Waters |
This graphic illustrates the strong link
between areas with high densities of industrial activity and zones
of seasonally oxygen depleted waters. |
|
38.
Human Actions Leading to Coastal Degradation |
Physical alteration and destruction of
habitats are now considered one of the most important threats to coastal
areas. This graphic explains the causes of coastal degradation in
estuaries, inter-tidal wetlands and open ocean. |
|
39.
Coastal Populations and Shoreline Degradation |
Coastal Populations and Shoreline
Degradation
This graphic shows that the coastal areas with the greatest population
densities are also those with the most shoreline degradation. |
|
40.
Reefs at Risk: Major Observed Threats to the World's Coral Reefs |
Major threats to the world's coral reefs
include overexploitation and coastal development. This graphic explains
which activities or conditions threaten the world's various reefs
and shows the global distribution of destroyed coral reefs. |
|
41.
What Causes the Sea Level to Change? |
The global warming that the world is beginning
to experience will likely have a major impact on coastal and marine
environments. This graphic explains the causes of sea level change
and projects the components of mean sea level rise according to Scenario
A1F1. |
Additional
graphics : |
|
A7.
Coastlines Under Threat |
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A8.
The Rising Sea |
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