Kiribati – adapting to climate change
NIWA has been working closely with the Kiribati Government for over two years, contributing to the Kiribati Adaptation Program (KAP II) initiative to plan for climate change. Our role has included assessing hazards such as drought, high intensity rainfall, extreme sea levels, and wave conditions for the islands that make up Kiribati.
We have also provided projections of how changing climatic conditions over the next 100 years could affect these conditions.
In November this year, NIWA’s Doug Ramsay paid a third visit to Kiribati as part of KAP II. He ran a further series of workshops and training activities for staff of the Government of Kiribati .
The training developed the experience of staff within various government departments in:
• deriving and applying climate and coastal extreme information
• assessing how climate change will affect these extremes
• using the information derived in a process of risk assessment for adaptation decision-making.
The Kiribati coastal calculator
NIWA has undertaken hydrodynamic modelling of waves and water levels to assess the variability in extreme waves and water levels around both the lagoon and ocean shoreline on Tarawa; also to assess how climate change and sea-level rise will affect these conditions. We have incorporated the information into a spreadsheet-database and calculator that can be used for site-specific calculations. Users can compare present day and future conditions, based on selected climate change scenarios and timeframes (see screenshot and information below).
Workshop participants use the tool on a number of demonstration case studies including assessing areas of potential inundation, minimum ground levels, and storm wave overtopping change.
What can the calculator do?
The calculator's database contains:
- Extreme offshore significant wave heights around each island in Kiribati and at 23 locations around the Tarawa lagoon shoreline
- Extreme storm tide locations at 23 locations around the Tarawa lagoon shoreline and representative parts of Tarawa’s ocean shoreline
- Joint occurrence of extreme wave heights and storm tide levels at 23 locations around Tarawa lagoon shoreline (and off the east and south Tarawa ocean coast)
- Annual Mean Level of the Sea (MLOS) data from the University of Hawaii and SEAFRAME tide gauges from 1974 to present
- 5% central estimates and 95% range of sea-level rise for the six emission scenarios used by the IPCC AR4 and allowance for additional ice sheet discharge based on IPCC AR4 guidance.
The calculator enables site-specific calculations to be made, and comparison between present-day and potential future values of:
- Mean and high tide levels
- 10%, 2%, 1% Annual Exceedance Probability conditions for:
– storm tide levels
– wave set-up levels over the fringing reef flat (on ocean shoreline)
– wave heights at the shoreline
– wave run-up levels on beaches or sloping seawalls
– wave overtopping volumes for a range of different seawall types.
The Kiribati Adaptation Program is supported by the World Bank, the Global Environmental Facility, AusAID and NZAID, the Japan PHRD Climate Change Fund, UNDP, and a parallel project by the EU. The hydrodynamic modelling was conducted in collaboration with the Pacific Applied Geoscience Commission (SOPAC).
Doug Ramsay, [email protected]