Why Indonesia is building an $80-billion wall against the sea
Indonesia is pressing ahead with plans to build an $80-billion sea wall along the north coast of Java, a project the government sees as a last line of defence against rising seas, sinking cities and worsening tidal floods that now threaten millions of people.
The so-called “giant sea wall” will eventually stretch hundreds of kilometres from Banten in the west to East Java, forming one of the largest coastal defence projects in the world.
Work on the Jakarta section is set to begin in September. The capital’s 19-kilometre stretch — expanded from an earlier 12-kilometre design — is expected to cost about $1 billion a year over eight years, with Jakarta asked to fund the segment because of its large regional budget.
President Prabowo Subianto revived the long-stalled plan last year by declaring it a national strategic project.
Jakarta Governor Pramono Anung said the city “fully supports the project,” arguing that extreme flooding and seawater intrusion have left officials with limited options.
Sinking Indonesia
First proposed in 1994, the wall is meant to address a convergence of crises along Java’s northern coast: climate-driven sea-level rise, chronic land subsidence and decades of unchecked groundwater extraction that have caused parts of Jakarta and other cities to sink rapidly.
A 2023 study found that several northern Javan cities are subsiding at least nine times faster than the global average rate of sea-level rise, intensifying tidal flooding and erosion in densely populated coastal areas.
For the government, the wall will protect millions of residents and key industrial zones, ports and transport links that underpin Indonesia’s economy.
Pramono said the Jakarta segment would use a hybrid design combining concrete structures with nature-based solutions, including mangrove restoration, to blunt waves and reduce erosion.
“Despite the name ‘giant sea wall’, I will still develop mangrove ecosystems along Jakarta’s sections of the wall,” he told The Jakarta Post.
Environmental groups remain unconvinced, however, warning that a massive barrier could disrupt fisheries, worsen ecological damage and serve elite economic interests. The Indonesian Forum for the Environment has called the project a “false solution” to the climate crisis.
Fisheries and marine science professor Yonvitner of Bogor Agricultural University said concrete defences were increasingly unavoidable, but stressed they would fail without ecological measures.
This story is written and edited by the Global South World team, you can contact us here.
