Opinion: Jakarta's vulnerability to global warming
- The Jakarta Post, 28 Apr 2007:
Jakarta's vulnerability to global warming
Deden Rukmana, Jakarta
The United Nations' Intergovernmental Panel on Climate Change
presented a new report on global warming earlier this month. The
report was prepared by more than 200 scientists and was endorsed by
officials from more than 120 countries.
The world is irrefutably warming and the panel predicted a rise of
between one and three degrees Celsius over the next century, which
could lead to the inundation of coasts and islands inhabited by
millions of people all over the world, including Jakarta.
Sea-level rise is not the only threat to the vulnerability of Jakarta
due to climate change. February's floods in Jakarta, which inundated
more than 70 percent of Jakarta and sent about 450,000 fleeing from
their homes is strong evidence that torrential rain could be a
serious threat for the city.
Bigger storms make Jakarta even more vulnerable because the city lies
in the lowlands, near the sea, and is crossed by 13 rivers flowing
down from the south.
The vulnerability of Jakarta will be even worse if the exploitation
of groundwater and the conversion of water catchment areas into urban
settlements in the city's peripheral areas can not be reduced.
Both factors contribute to issue of land subsidence, which was first
identified by researchers when the Sarinah bridge at Jl. M.H. Thamrin
cracked in 1978.
Since then, land subsidence abuse Jakarta has been increasing over
the years, particularly in the northern part of the city.
The Jakarta Mining Agency reported variances over a 12 year period,
from 1993 to 2005 -- with the largest rate of land subsidence
occurred in Central Jakarta.
It was reported the above sea-level height of Central Jakarta was
3.42 meters in 1993. This dropped by 102 cm in 2005.
The height of North Jakarta was only 1.46 meters above sea level in
2005, dropping from 2.03m in 1993.
During the same period, West Jakarta, East Jakarta and South Jakarta
have sunk by 2.11, 11.45 and 28.46 centimeters respectively.
According to the Jakarta Mining Agency, the main causes of the land
subsidence in Jakarta include the construction of new buildings,
particularly high-rise towers, and water usage.
Due to limited piped water supply, the majority of the population
relies on groundwater for their water needs.
The Jakarta Mining Agency estimated about 66,000 gallons of water is
extracted from the Jakarta's aquifer every year. Such intensive
groundwater withdrawal accelerates the problem.
Land subsidence has also been exacerbated by the decreasing water
catchment areas both in Jakarta and its outskirts. This will reduce
the volume of water that sinks into the ground for recharging the
The mismatch between the intensive groundwater withdrawal and
recharge of groundwater is the major cause of land subsidence.
Jakarta is just one of many coastal cities in the world that needs to
adapt to survive global warming.
Some major coastal cities have taken action to mitigate the impact of
sea-level rise. The most commonly used action is building hard
structure such as dikes and sea walls such as in the Netherlands,
London and Beijing.
The Netherlands is preparing to raise the North Sea defenses from and
London is preparing to add 12 inches of protection on top of the
existing floodgates to keep ocean-storm surges from flooding the
Jakarta needs not only to protect the city from sea-level rise but
also from the land subsidence.
In addition to building dikes and sea walls, Jakarta needs to reduce
significantly the use of groundwater as its main source of water for
As many water reservoirs as possible need to be built to conserve the
The conversion of land use in water catchment areas also needs to be
prevented. Water catchment areas should be protected.
Such protection will allow more water to sink into the ground and
recharge the groundwater. Reducing the use of groundwater and
protecting water catchment areas will decelerate the land subsidence
and decrease the vulnerability of Jakarta.
The writer is an assistant professor of urban studies at Savannah
State University in the U.S. He can be reached at