About 40 per cent of the capital lies below sea level. The city has only a decade to halt the trend. Some coastal districts, like Muara Baru, have sunk up to a maximum of 4.2 metres in recent years.
Jakarta (AsiaNews/Agencies) – With climate change, the Java Sea is rising and weather in Jakarta is becoming more extreme.
Local researchers fear that temperatures could rise by several degrees over the next century. This would raise sea levels by about a metre, making the great protective wall built by the authorities useless.
Global warming is not Jakarta’s only concern. The city itself is sinking faster than any other major city on the planet, faster than sea level rise caused by climate change.
Ordinary rains regularly swamp neighbourhoods and buildings slowly disappear underground, swallowed by the earth.
The main cause of this are illegal wells, which drain the underground aquifers on which the city rests. About 40 per cent of Jakarta now lies below sea level.
Coastal districts, like Muara Baru have sunk by as much as 4.2 metres in recent years.
Hydrologists say the city has only a decade to halt its sinking. If this fails, northern Jakarta, with its millions of residents, will end up underwater along with much of the nation's economy.
The city will not be able to build walls high enough to hold back rivers, canals and the rising Java Sea.
The aquifers aren't being replenished, despite heavy rains and the abundance of rivers, because more than 97 per cent of Jakarta is now smothered by concrete and asphalt.
Open fields that once absorbed rain have been paved over. Shores of mangroves that used to help relieve swollen rivers and canals during monsoons have been overtaken by shantytowns and apartment towers.
Illegal housing, sewage and garbage now jam pumping stations that the city built because gravity no longer drains the rivers and canals naturally.
Jakarta’s former governor, Basuki "Ahok" Tjahaja Purnama, an ethnic Chinese Christian who is a geological engineer by training, tried to clear out informal settlements.
As governor, he faced and solved many of Jakarta's major problems, but failed to wrest control of water supply from private companies. He established health and sanitation services, dubbed the Orange Army, to remove sediment and garbage from rivers and canals.
His efforts have started to make a difference. Rain water that once caused flooding that lasted for days, now last only a few hours.
However, his political rivals and conservative clerics exploited local resistance to slum clearing and the feeling of piety of the poor, to stir anti-Chinese populism.
Accused of blasphemy, Ahok lost the election in April 2017 and is now serving a two-year sentence in prison.
The new governor of Jakarta, the Islamist Anies Baswedan, announced in November the re-establishment of some of the informal settlements, as one of his first acts of government.