Green Open Space Scenarios in Reducing CO2 Emissions in Malang City, Indonesia: A Dynamic System Approach

Abstract

Purposes of this study were (1) to contruct model of Green Open Space as sequester CO2 emissions in Malang City, and (2) to design scenarios of Green Open Space policies in order to optimize the absorption of CO2 emissions in Malang City. This study envolved the quantitative and qualitative approaches, using modeling software tools of "Powersim Constructor". Procedures in this study included (1) the collection, presentation and analysis of data, (2) developing dynamic models by using software of Powersim Contructor : system analysis; developing dynamic models; evaluating several scenarios, (3) development of policy alternatives model. Based on the developed model, it is suggested that declining trend of Green Open Space (GOS) in Malang city; at beginning of simulation periode (2010), areas of GOS about to 5,259.83 ha, whereas at the end of simulation periode (2060) only 1,940.56 ha. Absorption of CO2 emissions about 158,620.98 tons/year at 2010, and decreased to 78,976.37 tons / year at 2060. This was due to the significant decreasing of GOS areas in Malang City. CO2 emissions continue to increase, which at the beginning of simulation periode (2010) amounted to 124,630.06 tons/year and increased to 677,651.20 tons / year at the final periode simulation (2060). CO2 emissions increase annually in line with the increasing number of vehicles in Malang City. The increasing number of vehicles and fuel oil consumption result in the CO2 emissions. The Addition of trees population in Malang City as many as 28,491 trees (2016), and at the end of the simulation (2060) must be about 3,508,743 trees. Policy analysis model of GOS in Malang City formulated three scenarios, namely independent, moderate and sustainable scenario. Simulation results of the independent scenario, showed that areas of green open space at the end of simulation periode (2060) only 587.83 ha (with total CO2 emissions amounted to 1,020,768.97 tons / year, the absorption of C02 emissions by 32,997.29 tons / year, and the addition of trees population about 5,785,882 tree). The moderate scenario suggested that at the end of simulation periode (2060) the Green Open Space areas about 2,028.30 ha (with total CO2 emissions amounted to 391,930.80 tons / year, the absorption of CO2 emissions by 132,694.84 tons / year, and the addition of trees population about 1,518,477 tree). While the sustainable scenario showed the areas of Green Open Space about 3,324.14 ha (the total CO2 emissions of only 283,035.18 tons / year, the absorption of CO2 emissions amounted to 183,574.93 tons / year, and the addition of trees population about 582,589 tree). With the increase of land coverage of urban trees, a more amount of CO2 are absorbed, and the residual of CO2 emissions getting lower. The recommended ways in reducing CO2 emissions in Malang City are : saving fuel oil (diesel fuel and gasoline fuel), restriction ownership of private vehicles, especially motorcycles and private cars, efforts to use LPG, improving qualities of existing public transportation systems. The sustainable scenario can be implemented as an effective policies in development of urban GOS in Malang City.