2 One form of the sea level rise impact is tidal flood. Tidal flood may occur due
to high tide wave overflowing coastal land. Today about 50 of the worlds population lives in this critical interface between land and water, where 13 of the
worlds 20 largest cities are located at the coastal regions. Cohen et al 1997 estimated that in 1994 about 2.1 billion people 37 of the worlds population lived
within 100 km of a coast. However increasing populations and development of the largest cities are placing significant stresses on the losses and other resources
destruction, when the disaster caused by the rise of sea level appeared. In Indonesia, tidal flood occurred almost on all of Northern region of the Java
Islands Pantura, such as Jakarta, Subang, Cirebon, Semarang, and Surabaya. Sofian 2008 reported that rapid sea level rise in Jakarta, Semarang, and Surabaya,
predicted causing the inundation flood in area having elevation between 0 and 4 meter above sea level. Moreover the dynamic climate anomaly of the climate
hazards could also raise the amount of the tidal flood. Surabaya as the second largest Indonesian city has more valuable to the
study; it is driven by the economic rationalities with PDRB Domestic Bruto Regional Product in million about 154 billion rupiahs and population about 3
million BPS, 2009. Tidal flood may cause diseases, economical loss and also damage to the infrastructure corrosive. Wuryanti 2002 said there is an indication
of the sea level rise in Surabaya; the tidal flood for 12 ~ 48 hours in 2002 had caused inundation level in range between 5 to 100 cm. In last January and 19th February
2010 there was tidal flood in some area of Surabaya with inundation level ranging from 20 to 160 cm within 30 minutes to 6 hours Iwa, 2010.
This research is study about the prediction of the sea level rise in common and extreme conditions on the basis of MRI-CGCM data model, and examining
vulnerable area which affected by tidal flood in coastal region of Surabaya city.
1.2. Objective of Research
The objective of this research is to establish a hazard map on the basis of the prediction inundation area in 2030 and 2100; in which 2010 data were used as
reference year.
1.3 Research Output
Tidal flood extent hazards map and loss estimation.
3
I I . L I T E R A T U R E R E V I E W
2.1 Sea Level Rise
There are a lot of observations shows that the sea level has been rising over the past several decades. The recent report of the Intergovernmental Panel on
Climate Change IPCC estimates that in response to rising temperatures 1.0°-3.5°C higher than 1990 levels in 2100, sea level will have risen from 15 to 95 cm by the
year 2100. Moreover global sea level could rise: between 75 to 190 cm Vermeer, 2009. Nunn 2001 noticed, since the 1800’s, sea level in the Pacific has been rising
then in the last century this rise has been recorded at about 15 cm and it is predicted that this rise will be at least twofold in the next century, meanwhile the projected sea
level rise in Java Sea Indonesia is ranging from 60 to 78 cm until year 2100 Sofian, 2008.
Figure 2.1: Global of Mean Sea Level source from White 2009
The Figure 2.1 shows the evidence report of annual sea level based on reconstructed sea level fields since 1870. Since 1993, the sea level are estimated
using satellite altimeter data red, while since 1880 the sea level rises were estimated by combining in situ sea level data from coastal tide gauges and the spatial
patterns of variability determined from satellite altimeter data blue.
4 A new scientific study warns that sea level could rise faster than previously
projected. Since 1990 sea level has been rising at 3.4 millimetres per year, twice as fast as on average over the 20th century. Those condition were linked affected the
rate of sea level by global temperature rise. The temperature is getting warmer causing faster sea level rises.
Many experts declared that global warming is the main factor that contributes to the sea level rise. Thermal expansions which come from greenhouse gases as trap
heat energy in the atmosphere, transferred to the ocean and it may increasing the ocean volume. As impact of global warming, the rising temperature may cause
mountain glaciers and ice sheets to melt and then sending the resulting melting water into the sea. Added by Gardiner et al 2004, effect of the global warming can cause
ocean current variations which move vast quantities of water from one side of the southern Pacific to the other ocean area El Nino.
Figure 2.2: Causes of sea level rise from climate change Source from Griggs 2001
5 A significant sea level rise is one of the major anticipated consequences of
climate change. The Figure 2.2 explains the causes of sea level change according to the Intergovernmental Panel on Climate Change IPCC. It explains the IPCCs A1
scenario family, which consists of three scenarios on future use of fossil energy sources, including scenario A1F1, which involves the use of fossil-intensive energy
sources. This resource also includes the graphic Components of Mean Sea Level Rise for the Scenario A1F1 which shows the projected sea level rise in metres by
2050 and by 2100 for Greenland, glaciers, expansion, the Antarctic, and the total sea level rise Griggs, 2001.
Rolalisasi 2008, divides the sea level rise impacts into; physical impact and socio economic impact. The physical impact includes inundation and displacement of
lowlands and wetlands; coastal erosion intensification of storm flooding, increase in salinity of estuaries, salt-water intrusion into freshwater aquifers, and degradation of
water quality, change of tide in rivers and bays, change of sediment deposition patterns. The socio-economic impact includes; the increased loss of property and
fisherman settlements, increased flood risk and potential loss of life, damage to coastal protection works and other infrastructure.
Mcgranahan et al., 2007 noted that approximately 10 of the world’s population, or about 600 million people, are live in low land areas which vulnerable
of being flooded. The sea level rise impact may cause change the border of the country due to the sinking of the outer islands which used as reference for ZEE
Economic Exclusive Zone. In Indonesia may cause reduction of inland area and more than 3000 islands will be sinking in future when the 25 meter of the shoreline is
declined then will cause the lost of 202.500 Ha of coastal area by the end of 2100 Diposaptono, 2002; Rais, 2007; Salim, 2008.
The following are the data of submerged islands due to sea level rise, according SMT, 2010:
• Lohachara, India – 10,000 residents • Bedford, Kabasgadi and Suparibhanga islands near India – 6,000 families
• Chesapeake Bay in Maryland, USA – 13 islands • Kiribati – 3 atolls
• Half of Bangladesh’s Bhola Island permanently flooded – 500,000
6 The following table, are recorded data of the sinking islands and or at risk
from rising sea levels:
Table 2.1: Sinking Island and Vulnerable Area Caused by Sea Level Rise
Location Description
Tuvalu 12,000 residents with no more fresh drinking water
and vegetable plots have washed away. Ghoramara near India
23 submerged as of 2006 with 7,000 residents already relocated.
Neighboring island of Sagar 250,000 residents also threatened, some 50 other
islands were jeopardized in the India-Bangladesh Sundarbans, with a population of 2 million.
Kutubdia in southeastern Lost over 200,000 residents
Bangladesh 150,000 likely soon to depart.
Maldives 369,000 residents in the Indian Ocean, whose
president wants to relocate the entire country. Marshall Islands
60,000 residents. Kiribati
107,800 residents, approximately 30 islands submerging.
Tonga 116,900 residents.
Vanuatu 212,000 residents, some of whom have already been
evacuated and coastal villages relocated. Solomon Islands
566,800 residents. Carteret Islands in Papua
New Guinea 2,500 residents whose land no longer supports
agriculture. Shishmaref in Alaska, USA
600 residents. Kivalini in Alaska, USA
400 residents. Indonesia
Over 2,000 islands sink. Dubai
1.2 million residents in the United Arab Emirates considered at risk.
Source from: SMT 2010
The sea level is not rising uniformly around the world, in some regions, rates are up to several times the global mean rise, while in other regions sea level is falling,
7 mostly due to non-uniform changes in temperature and salinity and related to
changes in the ocean circulation. As-syakur 2007 noted, that Indonesia is belong to this condition where occurrence of main convergence of two main world circulation
walker and hardly. Location of Indonesia is between 2 continents and ocean so that has a circulation monsoon due to sun movement and of course the occurrence of
ENSO el-nino and la-nina. Variation of topographic in all region of Indonesia, mountains, forests, valley, etc causing variation of climate and sea level condition.
2.2 Sea Level Projection According IPCC Model
