Defining Project Requirements
The Indonesian case study’s objective was to develop climate projections and future drought assessment for the East Java Province. The outputs were used to conduct risk assessment that will inform spatial planning.
The Ministry of Agrarian and Spatial Planning, the Local Government of East Java Province and researchers from Bandung Institute of Technology (ITB) who used the study outputs as part of their comprehensive risk assessment were identified as the stakeholders/users. Climate risk assessment for spatial planning requires climate projections and several climate hazard assessments, including drought, landslide, flood, and coastal inundation. Stakeholders’ roles included contributing to a definition of the case study’s focus, establishing context, and providing access and permission to use sources of data and information applied in the case study and training workshop.
As part of the stakeholder engagement strategy, representatives from these institutions were invited to a workshop at the beginning of the study and a training workshop at the end of the study. At the workshops, the stakeholders described the type of climate projections and climate hazard assessments required for informing spatial planning policies and contributed to the decision on the approach that was applied for the case study. At the training workshop, the researchers from ITB delivered lectures on how to develop climate projections and how to mainstream the projections into spatial planning.
The analyses were conducted for the East Java Province of Indonesia (9.125°S – 5.875°S; 125°E – 115.125°E), one of Indonesia’s major rice producing regions. Drought is one of the significant hazards affecting agricultural lands in this province.
The assessment focused on the frequency of drought, based on two drought indices: the Standardized Precipitation Index (SPI) at three- and six-month scales, and the dry spell (number of no-rain days during wet seasons). This required gridded observed and modelled rainfall data at daily, monthly, and seasonal timescales for both the baseline and projection period, and point-observed rainfall data for observed gridded data correction.
The baseline period is 1981–2010, based on the availability of observed climate data. The projection period is 2011–2040, consistent with the national spatial planning timeframe for which the assessment results can be used.
Project context was established through literature review and stakeholder engagement workshops. During this process, it was made known that Indonesia already has a Climate Change Risk and Adaptation Assessment (CCRAA) approach which is recommended for sectoral purposes (including spatial planning). The CCRAA formulates risk as a function of hazard and vulnerability. For spatial planning purposes, several hazards (i.e. drought, landslide, flood and coastal inundation) need to be assessed. However, due to resource constraints, the study focused only on the drought hazard.
The review (and step 4) revealed there were two downscaled climate simulations available that could be used: statistical downscaling model data from three GCMs (MIROC5, Nor-ESM1-M, IPSL-CM5A-MR) and dynamical downscaling from six GCMs (ACCESS1.0, CCSM4, CNRM-CM5, GFDL-CM3, MPI-ESM-LR, and NorESM1-M) using the CSIRO Conformal Cubic Atmospheric Model (CCAM).
Assessment of meteorological drought hazard was conducted by mapping the drought indices for both the baseline and projection periods. The analyses were based on statistical and dynamical downscaled climate model data stated above.