AHY: Giant Sea Wall Not a 'Roro Jonggrang' Project

Coordinating Minister for Infrastructure and Regional Development Agus Harimurti Yudhoyono (AHY) has stated that the Giant Sea Wall programme is not a ‘Roro Jonggrang’ project, but rather a collective effort. AHY said the construction of the sea wall must utilise a scientific and technocratic approach to ensure it is built correctly. ‘We need to involve everyone and, once again, a collective awareness to make this a success. This is not a Roro Jonggrang project; this is a project based on evidence, science, and technocracy,’ AHY said at Bappenas, Jakarta, on Monday (13/7/2026). AHY previously stated that the giant sea wall construction is a long-term project spanning 10 to 20 years, as it requires a substantial budget and a careful construction process. He added that although the construction will be carried out in stages, specifically in Jakarta and Semarang, including the Kendal and Demak areas, the giant sea wall construction must be accelerated because these areas are in the most severe condition, where the ground surface is already below sea level. AHY explained that the danger of rising sea levels is occurring due to the effects of global warming, which is causing Antarctic ice to melt. While sea levels are rising, AHY said there is another threat in the form of land subsidence. ‘In Jakarta Bay, including Semarang, Demak, and Kendal, the average subsidence per year can be 5, 10, or even 15 to 20 cm,’ AHY stated. ‘So, in 10 years, our land could be lower by up to 2 metres,’ he continued. AHY explained that this land subsidence phenomenon is suspected to be caused by residents still extracting groundwater for clean water. On the other hand, the demand for water in urban areas will become increasingly heavy as the population is projected to concentrate in cities. ‘There are still tens of millions of families or households that take their clean water from the ground, and there is a heavy burden from urban development. It is projected that 70 per cent of Indonesia’s population will live in large cities. This is what we need to mitigate together,’ he said. Based on data from the IPCC, the Intergovernmental Panel on Climate Change, AHY stated there are several scenarios resulting from rising sea levels. First, if the sea level rise reaches 0.6 metres, Indonesia’s coastline that is affected and potentially submerged by seawater could reach over 22,000 square kilometres. ‘An even worse scenario is if the sea level rise reaches 1.2 metres. It can be seen that more than 49,000 square kilometres of land area would be affected. This is a long-term projection for the next 2,100 years,’ AHY said. Meanwhile, over the next 50 years, Indonesia could experience land subsidence of 0.74 cm per year, which is worse than the global average of 0.4 cm per year. ‘That is possibly for Indonesia. The global average is 0.4 cm per year. For Southeast Asia, it is 0.5 to 0.7 cm per year. Indonesia could also experience up to 0.74 cm on several islands over the next 50 years,’ AHY explained.