Importance of coastal zones to humans

1. The total length of the world’s coastlines is about 504,000 km, enough to circle the Equator 12 times.

2. Coastal areas comprise 20% of the Earth’s surface yet contain over 50 percent of the entire human population. By the year 2025, coastal populations are expected to account for 75% of the total world population.

3. More than 70% of the world’s megacities (greater than 8 million inhabitants) are located in coastal areas. Half of the world’s cities with more than one million people are sited in and around estuaries.

4. Average human population density in coastal areas is about 80 persons/km2, twice the global average polulation.

5. About one-third of the European Union population is concentrated near coasts.

6. It is projected that western and Central African coastal populations will double to 50 million over the next 25 years, leading to a continuous chain of cities along the 1000-km Gulf of Guinea.

7. Coastal ecosystems yield 90 % of global fisheries and almost 80 % of known species of marine fish (13,200 species).

8. Reefs cover an estimated 284 300 km2, or just 1.2 per cent of the world’s continental shelf area.

9. Coral reefs are among the most biologically rich ecosystems on earth. About 4,000 species of fish and 800 species of reef-building corals have been described to date.

10. Reefs and mangrove protect the shoreline by absorbing at least 70-90 per cent of the energy of wind generated waves.

11. Worldwide, over 1,200 major estuaries, lagoons and fiords have been identified covering an area of about 500,000 km2. They account for approximately 80% of the world’s freshwater discharge. 62% these major estuaries occur within 25 km of cities with 100,000 or more habitants.

12. Global mangrove forest cover is estimated between 16 and 18 million hectares. 64% of all the world’s mangroves occur within 25 km of cities with 100,000 or more habitants.

13. More than a billion people rely on fish as their main or sole source of animal protein, especially in the coastal zone of developing countries.

14. Tourism plays an important role in the economy of many coastal nations (25% of total export earnings in the Pacific and 35 % in the Caribbean islands).

15. The total annual economic value of reefs has been estimated at between US$100 000 and US$600 000 per km2 (according to areas and national evaluations) and the value of mangroves at more than US$900 000 per km2.

Sources

N°2; 3; 4; 7; 14: World Summit on Sustainable Development 2002 – A Guide to Oceans, Coast and Islands
N°5: Europe Environmental Agency – State and Pressure of the marine and Coastal Mediterranean Environment / Environmental Issues Series Nº 5
N°8; 10; 15: “In the Front Line – Shoreline protection and other ecosystem services from mangroves and coral reefs” – UNEP/ICRAN/IUCN
N°9: UN Ocean Atlas
N°11; 12; 13: « Marine and Coastal Ecosystems and Human Well-being” Synthesis report based on the findings of the Millennium Ecosystem Assessment/UNEP

Loss or degradation of coastal habitat

16. 1/3 of coastal regions run a high risk of degradation, especially from infrastructure development and pollution. In 4/7 of coastal regions, the degradation is increasing.

 17. The most threatened regions are Europe with 86 per cent and Asia with 69 percent of their coastal ecosystems at risk.

18. 60% of the Pacific and 35% of the Atlantic Coast shoreline are eroding at a rate of a meter every year.

19. About 30 per cent of the world’s reefs are seriously damaged and 60 % of reefs could be lost by 2030.

20. In Southeast Asia, more than 80 % of the most species-rich coral reefs of the world are threatened by coastal development and fishing pressures, and over half are at high risk. Nearly two thirds of Caribbean reefs are at risk (especially Jamaica, Barbados and Dominica). Pacific reefs are the least threatened, with 40 % at medium or high risk of damage.

21. An estimated 35 per cent of mangrove forest has disappeared, and some countries have lost 80 per cent of cover.

22. In south-east Asia, 20 to 60 % of sea-grass beds have been lost.

Impacts

23. The leading human activities that contribute to mangrove loss are: 52% aquaculture (38% shrimp plus 14% fish), 26% forest use, and 11% freshwater diversion.

24. Mangrove mortality may be caused by a 3-5 degrees Celsius increase in ambient water temperature in the tropics and the diversity and mass of associated fauna may diminish by 90%.

25. World-wide since 1950, some 30,000 dams have been built (over half of them in China), diverting or damming 13 percent of global river flow to the sea.

26. Shoreline and recreational activities account for nearly 55 % of all the trash found on the coastline.

27. Tourism contributes to 7% of all pollution in the Mediterranean (industrial and urban waste, polluted rivers draining to the sea, crude oil dumped, etc.) and a hugely water scarcity.

28. One study of a cruise ship anchor dropped in a coral reef for one day found an area about half the size of a football field completely destroyed, and half again as much covered by rubble that died later. It was estimated that coral recovery would take fifty years.

29. A 1991 survey of 26 remote Great Barrier Reef islands found 5,656 items of rubbish, including 725 glass bottles, 1 066 plastic fragments, 247 aluminium cans and plastic cups, 919 thongs and one bar fridge.

30. A fee specially leveled on visitors of the Great Barrier Reef National Park produced over 28% of the revenue of the authority managing it in 1999.

31. The global economic cost related to pollution of coastal waters is $16 billion annually, much of which is due to human health impacts.

32. The price to pay for maintaining marine coastal ecosystems is much lower than the benefit received. For example, the estimated average operational management cost of a marine protected area is US$775 per km2, or less than 0.2 per cent of the estimated global value of a square kilometre of reef or mangrove.

33. In Indonesia, the social costs of activities that damage coral reefs are estimated to be 50 times greater than their benefits.

Sources

N° 23; 31: “Marine and Coastal Ecosystems and Human Well-being” Synthesis report based on the findings of the Millennium Ecosystem Assessment/UNEP
N° 24: GESAMP (Group of Experts on Scientific Aspects of Marine Environmental Protection) Report 71 – Protecting the Oceans from Land-based Activities-2001
N° 25: UN Ocean Atlas
N° 26: Ocean Conservancy- International Coastal Cleanup
N° 27: Europe Environmental Agency – Europe’s environment: the third Assessment 2003 –Environmental assessment report n°10
N° 28: Ocean Planet Smithsonian Institution
N° 30: GESAMP (Group of Experts on Scientific Aspects of Marine Environmental Protection) – Report 70-A sea of trouble – 2001
N° 32: “In the Front Line – Shoreline protection and other ecosystem services from mangroves and coral reefs”