the past 40 years or more. Decreases in the snow pack have also been documented in several regions worldwide based upon annual time series of
mountain snow water equivalent and snow depth. Permafrost and seasonally frozen ground in most regions display large
changes in recent decades. Temperature increases at the top of the permafrost layer of up to 3°C since the 1980s have been reported. Permafrost warming has
also been observed with variable magnitudes in the Canadian Arctic, Siberia, the Tibetan Plateau and Europe. The permafrost base has been thawing at a rate
ranging from 0.04 myr in Alaska to 0.02 myr on the Tibetan Plateau. The complete summary that shows contribution of each parameter majority to
sea level rise based on upon observations as compared to model can be seen in table 2.2.
Table 2.2. Contribution to SLR Sea Level Rise
Sea Level Rise mmyear 1961-2003
1993-2003
Source of SLR Observed
Modeled Observed
Modeled
Thermal expansion 0.42 + 0.12
1.5 + 0.7 Glaciers and ice caps
0.50 + 0.18 0.5 + 0.3
Greenland ice sheets 0.05 + 0.12
0.21 + 0.07 Antarctic ice sheet
0.14 + 0.41 0.21 + 0.35
Sum of individual climate contributions to SLR
1.1 + 0.5 1.2 + 0.5
2.8 + 0.7 2.6 + 0.8
Observed total SLR 1.8 + 0.5
Tide gauges
3.1 + 0.7 Satellite
altimeter Differences observed total
minus the sum of observed climate contribution
0.7 + 0.7 0.3 + 1.0
Source: IPCC 2007. Notes: means prescribed based upon observation
2.5 Sea Level Change Phenomenon in Indonesia
Climate change has and will continue to impact Indonesia where one of the impacts is sea level change in term of rising. All Indonesia’s coastal area will be
impacted by sea level rise with different scale of impact because the rate of increase varies with locations Sofian in ICCRS, 2009. A recent mapping
vulnerability assessment shows that the western and eastern areas of Java Island including Jakarta are at particular threat to droughts, floods, landslides, and sea-
level rise. Jakarta as one of the most densely populated areas in Southeast Asia is at high
risk of climate impacts because it is frequently exposed to significant flooding and subsided. The wet season in Jakarta has become wetter, mean sea level rising by
the time, and therefore the city experiences more flooding, which is compounded by clogged drainage and the fact that major part of the city is at or near sea level.
Previous floods as the combination from all of those factors have occurred in Jakarta where major flood events in 1996 and 2007 submerged 5,000 hectares of
land with losses from infrastructure damage and state revenue estimated at US572 million. These two floods also killed at least 85 people and forced about
350,000 people from their homes WWF, 2009. More specific, the impact of sea level change also threaten human life because peak tide has reached it usual peak
tide level. Governor of DKI Jakarta in KOMPAS 2011 states that peak tide has reached 2.5 meters or 30 cm higher than it normal so that tidal flood inundated
some area in North part of Jakarta. Clear example can be seen in Pantai Muara and it surrounding area that has been inundated up to 80 cm by this occurrence.
Banjarmasin City as the capital of South Kalimantan Province with 72 km
2
area of land where some part of land is low lying area and it City crossing by Barito river that becomes ship route to reach Java Sea also impacted by sea level
change. When level of ebb tide is lower than normal, ship can come inout from Banjarmasin. The impact of sea level rise for specific time period also has been
projected by Susandi et.al. In 2010 sea level will be emerge area that lower than 0.37 m land area loss around 0.53 km
2
, in 2050 will emerge land area that lower than 0.48 m land area loss around 1.039 km
2
, and will emerge land area that lower than 0.934 m in 2100 land area loss around 2.581 km
2
. They also counted
the economic loss of each land area loss where in 2010 the economic losses will reach 0.03x10
6
, in 2050 economic losses will reach 0.14x10
6
, and in 2100 economic loss will reach 0.69x10
6
.
2.6 Land Subsidence
Land subsidence is a gradual settling or sudden sinking of the Earth’s surface owing to subsurface movement of earth Materials. Land subsidence is merely the
surface symptom of a variety of subsurface displacement mechanisms. Not all of these mechanisms are well understood. Subsidence processes are hiding below
ground, their development to the point of surface deformation may involve long periods of time, and for at least some mechanisms, significant evidence may lie
outside the area directly beneath the surface subsidence. Furthermore, at some sites more than one condition favorable to subsidence occurrence may be present
and require consideration in analyzing causal mechanisms and devising remedial procedures USGS, 2000.
Subsidence is a familiar accompaniment of a variety of natural events that comprise the geologic history of many areas. For practical reasons geologic
processes that are accompanied by subsidence have been examined for evidence that the range in their rates of progress extends into a time frame that may produce
damaging effects in terms of man’s time scale. The processes investigated are those that remove or withdrawal subsurface materials to produce void space or
significant volume reduction-solution, underground erosion, lateral flow, and compaction-or, in the case of tectonic activity, deep-seated downward
displacement. For all of these naturally occurring geologic processes, examples of related surface subsidence have been found, though some are rare Allen, 1970.
The incidence of subsidence is greater where some of these geologic processes are set in motion or accelerated by man’s engineering activities that involve
excavation, loading, or changes in the ground-water regime. The term subsidence is used because it representing the sinking in a broad
sense to include both slows downwarping and the collapse of discrete segments of the ground surface. Displacement is principally downward, although the
associated small horizontal components have significant damaging effects. The
