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Tanzania: Global Warming Threatens Indian Ocean Islands
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Business Daily (Nairobi)
12 May 2008
Posted to the web 12 May 2008
Zephania Ubwani
Scientists are issuing an alert that the islands of Zanzibar and Mafia in Tanzania are likely to disappear under water in the next century due to global warming.
The islands off the Tanzania mainland coast could be submerged by the ocean by 2100 following a catastrophic rise in sea-level caused by the melting of polar ice, said scientists meeting in Arusha during the launch of the International Year of Planet Earth for Africa.
The scenario is "very possible," they reiterated, saying there were cases of islands that had disappeared or faced the danger of being submerged.
This means Tanzania could be among the countries that may be hardest hit by climate change, a phenomenon associated with global warming due to increased emissions of greenhouse gases.
Islands known to have been submerged include Maziwi, near Pangani in Tanga Region, and Fungu la Nyani, on the Rufiji River estuary.
Other threatened sites are Ras Nungwi, at the northern tip of Zanzibar island, which has lost almost 100 metres of its beach to sea water, and Bongoyo and Mbudya islands near Dar- es- Salaam.
Eric Mugurusi, the director of environment in the Vice-President's Office, says Tanzania has started feeling the impact of climate change, and gave the example of the melting of the snowcap on Mt Kilimanjaro.
The experts have called for "bold measures" as the only way to save the islands, which are among the leading tourist sites in the country.
"This period is not a long time at all, especially for people who care much about the future of their grandchildren. That would depend on how we address global warming and climate change," one expert said.
Increased emissions of greenhouse gases, notably carbon dioxide, methane and nitrous oxide, have been blamed as being the major causes of global warming.
Experts from the Zanzibar-based Institute of Marine Sciences of the University of Dar- es- Salaam said the rising sea level posed a grave danger to the economy of Zanzibar and coastal areas of the mainland.
"Our concern is not what would happen in 2100, but the gradual rise in sea level taking place now," said a marine scientist who pointed out tourism, fisheries and seaweed farming would be adversely affected.
It could not, however, be established if the Maziwi and other islands which have disappeared were inhabited in the past.
The Government stopped people from settling on the Bongoyo and Mbudya islands in the early 1990s, but they remain leading tourist attractions.
Scientists say the icecap volume on Mt Kilimanjaro has dropped by 80 per cent in the last 100 years; from 12.1 square kilometre in 1901 to only 2.2 square kilometre in 2000.
The loss, Mr Mugurusi said, quoting experts, was a cause for worry since the 1970s.
Carlos Mbuta, a senior environmental management officer with the National Environment Management Council (NEMC) has, however, said there were other factors behind the sea level rise.
For instance, he said, the studies by NEMC covering between 1988 and 2000 showed the Bongoyo and Mbudya islands were reduced largely by strong wave actions.
Another study carried out 15 years ago by a German scientist indicated that out of every 1,000 tonnes of water from Kilimanjaro, 400 tonnes came from the ice-caps and the rest from the forest belt, he said.
Mr Mbuta cautioned that observation of climate change depended on the equipment used and the parameters guiding the whole exercise.
He said it has been difficult to quantify the amount of carbon dioxide, one of the greenhouse gases blamed for global warming, because there were many sources of such gases other than the factories.
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He added that methane is released in big quantities by ant-hills, other animals, and is linked to rice farming.
One big ant-hill, he explained, can produce four litres of methane every five hours. Considering the number of ant-hills across the globe the amount of gas released to the atmosphere could be enormous.
Also contestable was the amount of carbon dioxide that can be absorbed by forests, amid suggestions that exotic vegetation may not be effective as the carbon sinks compared with indigenous trees.
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