Indonesia signed the Climate Change Convention (UNFCCC, United Nation Framework Convention on Climate Change) in Rio in 1992, which was then ratified in 1994 through Law no. 6/1994. Under this framework, Indonesia, which is a non-Annex 1 country, is committed to fully implementing the convention. Under one of the requirements of the convention, Indonesia has to report its activities aimed at addressing the climate change to the UNFCCC through the National Communication on Climate Change. The National Communication contains information on national circumstances, GHG inventory and projection, mitigation action plan (including related cost, expected funding and relevant policies), vulnerability and adaptation assessment (including action plan for adaptation, related costs, expected funding and relevant policies), institutional arrangement, and plan for improvement of future national communication.
Sea level rise is one of the most potentially serious impacts of global warming and climate change. The sea level rise, however, cannot be projected with high confidential level using the physical models due to dynamics of ice sheets and glaciers and to a lesser extent of the oceanic heat uptake that is not sufficiently understood (Vermeer and Rahmstorf, 2009). Moreover, Vermeer and Rahmstorf (2009) also explained that the limited understanding was seen, e.g., in the fact that observed sea-level rise exceeded the predicted ones by models (best estimates) by ˜50% for the periods 1990–2006 and 1961–2003. Eventually, Intergovernmental Panel On Climate Change (IPCC) assessment report did not include rapid ice flow changes in its projected sea-level ranges, arguing that they could not yet be modeled, and consequently did not present an upper limit of the expected rise (IPCC, 2007).
The mass balance of the ice sheets is a topic of considerable interest in the context of global warming and sea level rise. If totally melted, Greenland and West Antarctica would raise sea level by approximately 7m and 3m to 5 m, respectively. Thus, even a small amount of ice mass loss from the ice sheets would produce substantial sea level rise, with adverse societal and economic impacts on vulnerable low-lying coastal regions (Cazenave and Llovel, 2010).
The IPCC projection is based upon the mass difference of ice melted and ice formed. Since the mass of the melting ice is bigger than that of the ice forming, Greenland ice sheet does contribute to the rise of sea level (Ridley, et al., 2005). On the contrary, Antarctica is projected to freeze more and undergo increased ice forming, thus the ice forming in Antarctica and the ice melting in Greenland will cancel each other, with no net contribution to the sea level rise. Thus most of the contribution to the changing mass (the difference between ice melted and ice formed) is limited to the melting of glaciers and mountain ice cover (Meehl, et al., 2007).
Rahmstorf (2007) used the relationship between the rise of the sea level and surface temperature to predict the sea level rise in the end of the 21st century. His estimate ranges from 50 cm to 140 cm, relative to the sea level in 1990. This prediction is higher than the projection of IPCC 4th Assessment Report (AR4). Moreover, the sea level rise before 1990, due to mass changing, is purely dominated by the glacial melting (Bindoff et al., 2007), thus Rahmstorf (2007)’s prediction excludes the changing of sea level due to the ice melting in Antarctica and Greenland. Abdalati (2006) argued that the glaciers and ice sheets of the world contain enough ice to raise sea level by approximately 70m if they were to disappear entirely, and most of this ice is located in the climatically sensitive polar regions. Fortunately changes of this magnitude would probably take many thousands of years to occur, but recent discoveries indicate that these ice masses are responding to changes in today's climate more rapidly than previously thought (Abdalati, 2006). To avoid the impact of ice melting, Bryan (1995) calculated the thermosteric sea level rise using the ocean model. The model results explained that average rise in sea level of approximately 15±5cm by the time atmospheric carbon dioxide doubles for 80 years model running. Furthermore, the thermosteric and halosteric sea level rise from 1955 to 2003 are estimated to be 0.31±0.07mm/yr and 0.04±0.01mm/yr, respectively (Ishii et al., 2006).
Due to the high sea level rise in the Indonesian Seas (Sofian, 2010), the estimation of contribution of ice melting (CIM) is inevitable to project the sea level rise in the future. The CIM estimation is conducted using the nested HYbrid Coordinate Ocean Model (HYCOM) on the global model. The nested Regional Ocean Modelling Systems (ROMS) has the spatial resolution of 5km, while the global HYCOM model has 16km of spatial resolutions.
The climate change not only affects on the sea level characteristics, but also affect on the other ocean parameter, such as ocean acidification, temperature, desalination and others. Due to the lacking of ocean data, it is inevitable to simulate the ocean climate from 1960 to the present by using the ROMS. The model will be nesting on the Simple Ocean Data Assimilation (SODA) and HYCOM model output, and driven by the NCEP reanalysis and ECMWF interim data. Furthermore, the reconstruction of ocean climate not only limited on the physical parameters such as salinity, temperature and ocean currents, but also the biogeochemical data such as nitrate, phosphate, chlorophyll-a and others. Finally, the biogeochemical model output can be used to analyses the ocean acidification impacts on the coral reef as the one of the most important habitat in the coastal regions.
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