Climate change

Delta faces huge flooding threat from a melting ice cap

PUBLISHED : Monday, 11 September, 2006, 12:00am
UPDATED : Monday, 11 September, 2006, 12:00am

The Pearl River Delta region will face a huge flooding threat, with many of its most developed areas being submerged as a result of the Greenland ice cap melting, a university projection shows.

The projection, simulated by the University of Science and Technology's environmental facility, shows how the region would be submerged if the sea level rose by up to 20 metres.

'The 20 metres scenario is purely for academic purposes but even at a smaller extent of one to five metres, the projection shows large areas will become sea if the sea level is to rise by five metres. The northwestern part of Hong Kong will be badly affected too,' said Alexis Lau Kai-hon, the manager of the university's environmental facility.

It is estimated that if the Greenland ice cap melts, global sea levels might rise by at least six metres, flooding most major cities, including New York and Beijing. But the scientists cannot predict when it would happen. Official estimates from the United Nations show that if the present trend of global warming prevails, in 100 years temperatures will rise by between 1.4 and 5.8 degrees Celsius and the sea level by between 9cm and 88cm.

But Professor Lau said Hong Kong had built higher sea walls to guard against high tides and typhoons and these could offer protection from rising sea levels.

Apart from rising sea levels and possible increases in infectious diseases, ecologists have also started to assess the impact on the city's country parks.

Richard Corlett, from the department of ecology and biodiversity at the University of Hong Kong, is to launch a study predicting the impact of global warming on plant distribution in Hong Kong and southern China.

In an article published in 2002, he reported that frost-sensitive plants had spread further up Tai Mo Shan, colonising areas they were once excluded from. But he agreed that assessing changes and linking them to global warming was not easy.

'The lack of local research is because global warming is an issue that we would rather not think about - too big and too difficult,' he said. 'Also, it is only in the past few years that it has become obvious that the warming is happening fast enough to study and is also too late to stop.

'We will have to adapt to at least 2-3 degrees warming and that will require local research,' Dr Cortlett said.