Rise in sea levels due to global warming threatens to drown at least 2,000 of the 17,000 Indonesian islands, according to Pelangi, an environmental group. Sutamihardja, head of the group and a member of the Intergovernmental Panel on Climate Change also warned that global warming could cause sea level to rise between 60 centimetres and one metre over the next 100 years. "In Indonesia, with a total maritime zone of 85,000 square kilometres, this could be bad news,' he said. It is anticipated that coastal protection and rehabilitation costs would amount to us $4 million per kilometre for every 20-centimetre rise in sea level. "In some coastal regions, every time a high tide occurs, flooding will follow,' said Sri Diharto, head of Indonesia's meteorology and geophysics agency.