Magara Kinji
University of Shimane
Asia and Pacific Region, occupying only about a quarter of the world's land surface, is home to the people of approximately 3.5 billion, or about 58 percent of the world's entire population as of 1994. Therefore, this region's population density is more than four-fold as high as the remaining parts of the world. Six countries in Asia, such as China, India, Indonesia, Pakistan, Japan and Bangladesh, are among the ten most populous countries in the world.
Significant economic expansion in the region, which took place in the last few decades, made people move from the rural, interior parts to more prosperous, highly populated coastal areas of many of these countries in their searches for higher income and better living conditions, typically of a western style. Such a mass migration of people has resulted in environmental destructions not only along the coastal regions, but also in the nearby seas themselves.
To improve the current situation in terms of preserving the ecology of both the coasts and seas in the region, wiser environmental management is necessary, with cooperation among local, state and international groups and governments, supported by the activities of NGOs and NPOs.
The number of people in coastal urban districts of the Asia and Pacific Region is estimated to be about 477 million (see Table 1). Because the coastal cities offer both the economic and employmentprospects, large numbers of people have moved, particularly in the People's Republic of China, from the inland rural areas to the special economic zones on the coast in the last few decades. Nearly one half of the 75 largest cities in the world are in this region, and more than half of these Asian cities are situated on or near the coast. Economic developments in the last few decades have contributed to the regional as well as national economic expansion. Unfortunately, however, the same developments have caused environmental costs.
In such Asian countries as China. Bangladesh, Indonesia, Malaysia, Pakistan, Philippines and Thailand, massive movements of their people have occurred from rural to urban districts since 1980"s (Table 2), commonly suggesting the internal migration from the interior to coastal parts of most of these countries. However, population growth of the urban districts may be caused by a combined effect of three elements, firstly, natural population increase, secondly, inward migration toward urban districts, and finally, city boundary expansion and re-classification of rural settlements.
The movement of a large number of people to the coastal cities has inevitably increased pressure on the coastal environment and its resources. The factors involved are such as 1) increased volumes of both domestic and industrial waste, 2) increased dredging, 3) increased discharges of agricultural chemicals, 4) increased sediment loads. 5) extended and widespread clearance of mangrove forests, and 6) erosion of coastal sediment and thus coastlines.
Population-related problems in China and India
With respect to the environmental problems as a result of large populations, no one would ignore two of the most populous nations in the world, namely China and India. It may not be overstated that the fates of China and India in this century depend on the paces of their population growths and their ability to stabilize them.
According to the fifth census conducted in November, 2000, the Chinese population, excluding those of Hong Kong, Macao and Taiwan, is about 1 billion 266 million (Chinese Statistics Yearbook, 2001). This number is more than 2.3 times of the population of 540 million at the time of the founding of People's Republic of China in 1949. In other words, an increase of some 720 million people has taken place in the last half century.
China's dilemma is that it has not only a huge population, but has a smaller slice of the world's natural resources. The country with roughly the same size as the USA has four and a half times as many people. With about 22 percent of the world population, China produces only 7 percent of economic output, and has only 7 percent of the cropland, 3 percent of the forest and 7 percent of fresh water (Table 3). While it has only 2 percent of oil and 11 percent of coal reserves, China produces some 16 percent of sulfur and 11 percent of carbon emissions.
Although the situation is far from uniformity, China's overall economic performance since 1978 has been impressive. Not only the productivity gains average 3 to 4 % a year, the share of trade increased from about 10% in 1978 to more than 30% in 1990. Because the prime areas for industrial production are located along the coast, there has been demographic movements from the interior to the coastal regions, or from the rural to urban districts. In China, the urban population in 1990 was estimated at about 297 million, an increase of some 90 million since 1982. The same trend from rural to urban will most likely continue in the next few decades (World Resources Institute, 1994).
India's population-related problems differ from those of China. Population growth as the result of internal migration from rural to urban dropped from about 40% in the 1970"s to about 33% in the 1980"s (Mathur, 1993). Reproduction now accounts for approximately 60% of the urban population growth. The number of cities over one million has risen from 12 in 1981 to 23 in 1991. Many of these large cities are located along the Ganges River that pours the polluted water and sediments into the Bay of Bengal.
India's census conducted in 1991 shows its population at 844 million, 160 million more people than in 1981(United Nations, 1993). Early in this century, it is expected to surpass China as the most populous country in the world
State of the Coastal and Marine Environment in Asia
There are three separate threats that are currently being faced in the coastal and ocean districts of the Asia and Pacific region; firstly, pollution from primarily land-based sources which causes direct damages to marine ecosystems, such as coral reefs, mangroves and sea grasses, secondly, damages to the biomass and ecological balance of the marine environment caused by over-fishing and unsustainable extraction of marine resources, and finally, more direct physical damages to the coastal and marine ecosystem due to urban and tourist related developments.
Because of both the domestic and industrial effluent discharges, atmospheric deposition, oil spills and other contaminants from shipping, coastal and marine pollution has become very serious in this region. Most of the pollutants which are composed of sand/silt, nutrients, toxic chemicals and oil came from land. UNEP(1999) estimated that, due to the combined effect of active tectonics, heavy monsoon rain falls, steep slopes and erodible soils of the region, more than a half of the world's total sediment transport takes place in the Asia and the Pacific. These sediments impact not only on the shallow inshore habitat but also on the deeper/wider oceanic ecosystem. Rivers running through Viet Nam, Cambodia, Thailand, Malaysia, and China deliver some 600,000 ton of nitrogen per year to coastal waters of the South China Sea(Talaue-McManus, 2000).
A range of development activities have caused direct damages to coastal habitats, particularly of the estuarine and coastal systems. They include dredging of harbors and shipping channels, construction of harbors and marinas, and reclamation of coastal wetlands for development. The effect is so wide spread in the region and it is difficult to point out one or two areas. According to the ESCAP's report in 2000, the coastal erosion has affected every state of Malaysia and a total shoreline of some 1,400 km2, or about 29% of the entire shoreline of about 4,800 km was eroded.
Flow of natural materials is being contaminated by a wide range of wastes that include organic pesticides, heavy metals such as mercury and lead, plastics, various hazardous chemicals, produced by industrial, commercial and agricultural activities. Pollution by oil spills is also serious in many parts. Out of China's four sea areas, the East China Sea was most polluted, followed by the Bohai, the Yellow and the South China seas( Government of China. 1997 and 1999). It was found that only about 19% of the coastal waters of China met Grade 1 quality standard in 1997, but this has dropped to 15% by 1999.
In 1998, Langdon et al. (1999) discovered that the increased atmospheric CO2 seems to have elevated CO2 content dissolved in sea water and thus acidity of sea water. It is known that the increased acidity slows down calcium carbonate deposition in coral communities. Coral reefs occupy only one quarter of one percent of the earth's ocean surface, but it is known that they are home to approximately a quarter of the known marine fish species. This is the principal reason why they are called the "rain forests of the marine world" (Bryant, et al., 1998). Approximately four fifths of the coral reefs in the world exist in the Asian and the Pacific region, and they with their associated plants and animals provide humans with seafood, medicine and other useful products for living. However, such human activities as coastal development, over exploitation and destructive fishing practices, in addition to both land- and marine-based pollution, have damaged the conditions of coral reefs in the region.
In many Southeast Asian countries, coral reefs are not only important in local cultures, but are also critical to the economic health. Coral reef fisheries are often vitally important in supplying food and employment. According to Burke, et al (2002), the total annual net benefit of sustainable coral reef fisheries in this region is estimated to be about $2.4 billion per year. Reefs tend to facilitate the growth of mangroves and sea grasses, by providing habitat essential to many marine species and by preventing shoreline erosion.
According to ESCAP(2000), South and Southeast Asia region has more than 40% of the world's 18 million mangrove forest, with the highest diversity of mangrove species. Mangrove is a tree growing in tropical salty/ocean water. As the mangrove tree grows, it sends down roots directly from branches and forms thickets. Mangrove thickets commonly grow in quiet ocean water and catch silts, which pile up often to form dry land. In the area near the river mouths, the mangrove roots slow down the current and help settle sands and silts. Because coral reefs can survive only in warm and clear sea water (without sands and silts), the works by mangroves are essential for the survival of coral reefs.
Unfortunately, as the result of growing population in the region, large areas of mangrove have been removed for industrial, residential and leisure developments. Most serious of all are due to the establishments of ponds for fish and prawn aquaculture. According to ESCAP's (2000) estimate, more than 60% of Asia's mangrove forests have been converted to aquaculture ponds.
Sea grasses in the tropical and temperate coastal waters and deeper waters in the region are often associated with mangrove habitats and coral reefs. They perform the ecological function of trapping sands and silts. In other words, sea grasses provide a mechanism for clearing waters with sediments - quite important to the survival of coral reefs, as mentioned earlier. They are, of course, the essential parts of marine habitats in generating oxygen through photo-synthetic reactions in the ocean. According to Heck and McCoy (1978), diversity of sea-grass species is highest in the area surrounded by Indonesia, Borneo, Papua New Guinea and northern Australia. Out of the 50 recorded species worldwide, Northeast and Southeast Asia regions have some 20 species (Sudara, et al., 1994).
According to some estimate, more than 20% of the sea grass areas of Indonesia, Malaysia, Philippines and Thailand have been damaged by a combination of coastal development, high sedimentation rate, destructive fishing, pollution from land, spills of petroleum products, dredge and fill operations (ESCAP, 2000).
Because of the economic expansions which have taken place in the last several decades, coastal and marine environments in and near the Asian countries have severely deteriorated. The concept behind the environmental conservation is rather simple, although its implementation is often difficult: firstly to preserve what is remaining, secondly to rehabilitate what has been damaged, and finally to plan the management for utilization of resources in environmentally sustainable ways. Because the Asian seas contain large percentages of the earth's marine ecosystems such as coral reefs, mangrove forests and sea grasses, it is essential to improve the coastal and marine environments of Asia in order to improve the situation of the entire world. The steps to be followed may be as follows,
Table 1. Characteristics of coastal districts of selected countries of Asia and Pacific.
| Country | Coastline length(thousand km) | Shelf to 200m depth(million km) | Coastal population(millions) |
| Australia | 25.76 | 2.26 | 13.90 |
| Bangladesh | 0.05 | 0.05 | 5.05 |
| PR China | 14.50 | 0.86 | 66.51 |
| Fiji | 1.12 | 0.02 | 0.42 |
| India | 12.70 | 0.45 | 78.25 |
| Indonesia | 54.71 | 2.77 | 58.30 |
| Iran | 3.18 | 0.10 | 1.48 |
| Japan | 13.68 | 0.48 | 88.79 |
| Malaysia | 4.65 | 0.37 | 9.15 |
| Myanmar | 3.06 | 0.22 | 7.69 |
| New Zealand | 15.13 | 0.24 | 2.83 |
| Pakistan | 1.04 | 0.05 | 12.35 |
| Philippines | 22.54 | 0.17 | 37.18 |
| Sri Lanka | 1.34 | 0.02 | 3.49 |
| Thailand | 3.21 | 0.25 | 13.54 |
| Viet Nam | 3.44 | 0.32 | 14.31 |
| Others | - | - | 64.06 |
| Total | - | - | 477.30 |
Source: World Resources Institute, 1994.
Land-based pollution is commonly caused by poor practice of human and industrial waste disposal, dredging, developments of industrial, residential and amusement sites, etc. Because of the tectonics of the Asian continent represented by high mountains such as the Himalayas and heavy rain falls by both monsoon rain and typhoon/cyclone storms, the amount of sediments transported from land and deposited in the sea is very large. Those sediments also carry a large quantity of polluted materials, because river waters in this region are contaminated by municipal sewage, industrial effluent and sediments. Although this region constitutes only about 17% of the world's total drainage area. Asian rivers carry some 50% of the sediments brought to and deposited in the oceans of the world (UNEP, 1992). Sea-based pollution is primarily originated from oil tankers, offshore oil/gas fields, and ships.
Table 1. Urban population trends in selected countries of Asia and Pacific.
| ||||||||||||||||||
| Australia | 17 | 85.8 | 85.2 | 85.5 | -0.6 | +0.3 | ||||||||||||
| Bangladesh | 114 | 11.3 | 16.4 | 22.9 | +5.1 | +6.5 | ||||||||||||
| PR China | 1153 | 19.6 | 26.2 | 34.5 | +6.6 | +8.3 | ||||||||||||
| Fiji | <1 | 37.8 | 39.3 | 42.7 | +0.5 | +4.4 | ||||||||||||
| India | 844 | 23.1 | 25.5 | 28.6 | +2.4 | +3.1 | ||||||||||||
| Indonesia | 184 | 22.2 | 28.8 | 36.5 | +6.6 | +7.7 | ||||||||||||
| Iran | 58 | 49.6 | 56.9 | 63.7 | +8.3 | +6.8 | ||||||||||||
| Japan | 124 | 76.2 | 77.2 | 79.0 | +1.0 | +1.8 | ||||||||||||
| Malaysia | 18 | 34.6 | 43.0 | 51.2 | +8.4 | +8.2 | ||||||||||||
| Myanmar | 42 | 24.0 | 24.8 | 28.4 | +0.8 | +3.6 | ||||||||||||
| New Zealand | 3 | 83.4 | 83.9 | 84.9 | +0.5 | +1.0 | ||||||||||||
| Pakistan | 118 | 28.1 | 32.0 | 37.9 | +3.9 | +5.9 | ||||||||||||
| Philippines | 62 | 37.4 | 42.7 | 48.9 | +5.3 | +6.2 | ||||||||||||
| Sri Lanka | 17 | 21.6 | 21.4 | 24.2 | -0.2 | +2.8 | ||||||||||||
| Thailand | 55 | 17.1 | 22.2 | 28.9 | +5.1 | +6.7 | ||||||||||||
| Viet Nam | 67 | 19.2 | 19.9 | 22.3 | +0.7 | +2.4 | ||||||||||||
Source: ESCAP(1995)
Table 3. China's share of world population, economic output,natural resources and some pollutants.
| Category | Share of world total (%) |
| Population | 22 |
| Economic Output (PPP) | 7 |
| Cropland | 7 |
| Irrigated Land | 19 |
| Forests and Woodlands | 3 |
| Fresh Water | 7 |
| Oil Reserves | 2 |
| Coal Reserves | 11 |
| Carbon Emission | 11 |
| Sulfur Emission | 16 |
МАГАРА Киндзи
Университет Симанэ
В соответствии с данными на 1994 год Азиатско-Тихоокеанский регион по площади занимает около 1/4 площади земной поверхности, в то время как его население составляет 3,5 миллиарда человек, т. е. около 58% населения Земли. Шесть азиатских стран - Китай, Индия, Индонезия, Пакистан, Япония и Бангладеш - входят в десятку самых густонаселенных государств планеты.
Значительный экономический рост, который имел место в этих странах в последние десятилетия, повлек за собой массовые миграции населения из центральных сельскохозяйственных районов в экономически более развитые прибрежные районы в поисках больших доходов и лучших условий жизни. Массовые миграции населения стали причиной появления в этих районах, а также в прилежащих к ним водах серьезных экологических проблем, для решения которых понадобится выработка комплекса мер по улучшению экологической обстановки в регионе при тесном взаимодействии местных и центральных властей, межправительственных групп и неправительственных общественных организаций.
Говоря о проблемах перенаселения в азиатских странах, нельзя не упомянуть о двух самых густонаселенных государствах мира - Китае и Индии. Не будет преувеличением сказать, что судьбы этих государств в этом столетии напрямую зависят от темпов роста населения и их способностей стабилизировать этот рост.
В соответствии с пятой переписью населения, проведенной в ноябре 2000 года, население Китая, включая Гонконг, Макао и Тайвань, составляет 1 млрд. 266 млн. человек. То есть за полстолетия население Китая выросло на 720 млн. человек.
Проблема усложняется еще и тем, что, обладая огромным населением, Китай имеет ограниченные запасы природных ресурсов. С численностью населения в 22% от населения мира, Китай производит только 7% от мирового валового продукта. Хотя эта ситуация далеко не однозначна, экономический рост Китай впечатляет. Темпы роста производства промышленной продукции составляют 3-4% в год, а доля Китая на мировом рынке составляет более 30% от мировой торговли. Так как центры промышленности расположены в основном в прибрежных районах, население этих районов Китая выросло с 1982 по 1990 г. на 90 млн. человек. Эта тенденция скорее всего продолжится в последующие десятилетия.
Проблемы Индии отличаются от проблем Китая. Рост населения в результате миграций из сельской местности в города резко снизился с 40% в 1970-х гг. до 33% в 1980-х. Около 60% от роста городского населения происходит за счет репродукции. Количество городов с населением более 1 млн. жителей увеличилось от 12 в 1981 г. до 23 в 1991 г. Большинство крупных городов расположены вдоль реки Ганг, которая несет свои загрязненные воды в Бенгальский залив.
Перепись населения, проведенная в 1991 г., показывает, что население Индии составляет 844 млн. человек, т.е. на 160 млн человек больше, чем в 1981 г. Предполагается, что с такими темпами роста населения в скором времени Индия превзойдет Китай и станет самым густонаселенным государством мира.
Среди наиболее явных экологических угроз, с которыми столкнулся регион, можно выделить следующие: во-первых, загрязнение воды промышленными и бытовыми стоками, наносящее вред морской экосистеме (коралловым рифам, мангровым лесам, морской растительности), во-вторых, вред, нанесенный морской биомассе и экологическому балансу вследствие чрезмерного вылова рыбы и извлечения морских ресурсов и, наконец, вред, нанесенный развитием в регионе городов и туризма.
В 1998 г. было доказано, что повышенное содержания углекислого газа в атмосфере приводит к повышению содержания углекислого газа в морской воде. Как известно, повышенная кислотность воды замедляет формирование кораллов вследствие нехватки кальция. Несмотря на то, что коралловые рифы занимают только 1% поверхности морского дна, они служат средой обитания для приблизительно 1/4 от всего количества известных науке видов морской рыбы. Около 4/5 от существующих на планете коралловых рифов находятся в АТР и являются вместе с сопутствующими им растениями и животными основными источниками пищи, сырьем для производства лекарственных препаратов и других продуктов потребления. Экономическое и промышленное развитие прибрежной зоны ведет к загрязнению воды и суши, нерациональному использованию морских ресурсов и к разрушению коралловых рифов.
В Южной и Юго-Восточной Азии сосредоточено более 40% мангровых лесов планеты. Произрастая в районах устьев рек, мангровые леса замедляют их течение и задерживают песок и ил. Как известно, рост коралловых рифов возможен только в теплой и чистой воде (без песка и ила). Таким образом, мангровые леса имеют огромное значение для сохранения коралловых рифов. Развитие региона привело к уничтожению значительной части мангровых лесов (более 60%) с целью создания на их месте искусственных водоемов.
Морские водоросли также являются важной частью морской экосистемы. Они выполняют функцию фильтра, задерживающего песок и ил, что, как упомянуто выше, является необходимым условием роста кораллов. Еще одной функцией водорослей является выделение кислорода в результате процесса фотосинтеза. Согласно некоторым оценкам, более 20% мест произрастания водорослей в регионе было уничтожено в ходе освоения прибрежных районов, загрязнения суши и воды, нерационального вылова рыбы, разливов нефти, разработки морских месторождений полезных ископаемых и т.д.
В результате экономической экспансии, имевшей место в последние десятилетия, экологическая обстановка в АТР значительно ухудшилась. Основная концепция охраны природы проста, хотя реализация ее на практике зачастую оказывается очень сложной, необходимо, во-первых, сохранить то, что осталось, во-вторых, восстановить то, что разрушено, и, наконец, решить задачу по рациональному управлению природными ресурсами и их использованию. Учитывая то, что моря Азии располагают большим разнообразием экосистем, таких как коралловые рифы, мангровые леса и морские водоросли, необходимо уделить большое внимание экологической обстановке в регионе, чтобы улучшить экологическую ситуацию в мире в целом.