Support for assessing climate change impacts in Tonga
Friday, 15 October 2010 10:54

Agriculture, GTZ, and Meterology officers with CLIMsystems trainerCustomised software for assessing the effects of climate change was demonstrated to government technical staff in Tonga recently.

The climate modelling software is being provided through the Secretariat of the Pacific Community (SPC)/ German Technical Cooperation (GTZ) Programme on Adaptation to Climate Change in the Pacific Island Region (ACCPIR).

A three-day (4–6 October) training session on using the TongaSimCLIM software was held at the Forestry Division in Tongatapu for technical officers from the Ministries of Environment and Climate Change, Agriculture and Food, Forests and Fisheries, Lands, Survey and Natural Resources and the Meteorology Department. The training focused on the software application to examine and assess impacts of climate variability and change in Tonga. Participants were also introduced to a customised version of PlantGro 4.0, which can be used to explore possible alternative crops and trees for islands in Tonga. The training was conducted by CLIMsystems, the developer of TongaSimCLIM.

CLIMystems said that the software has been customised for use by Tonga with a local, very high resolution (30 metre), digital elevation model for the islands of Tongatapu, Vava’u, Ha’apai and Niuatoputapu. Also available are other data specifically collected for application in the island kingdom. The high resolution TongaSimCLIM includes 21 general circulation models (GCMs) and tools for generating ensembles, analysing various climate change scenarios, including extreme weather events, and running rainwater tank simulations. The latter showed that although annual precipitation is projected to increase in Tongatapu as a result of climate change, the dry period is actually expected to get drier.

Kolovai shoreline (lowest point), TongatapuThe TongaSimCLIM sea-level rise simulation is the only climate impact assessment tool of its kind that accounts for local trends in sea-level rise in combination with vertical land movements, over a period of time, in looking at potential scenarios. The Tonga tidal station shows a 9.21 mm sea-level rise a year, whilst satellite data records indicate a rise of 6.29 mm a year. This has led to the conclusion that the area around the tidal station is sinking at a rate of 2.92 mm per year. Projections generated under a high climate sensitivity scenario and worse case story line for global greenhouse gas emissions (A1F1) show a possible sea-level rise of 952 mm for Tongatapu by the year 2100. The worst case from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change for the world is 590 mm. The fact that the area is slowly sinking worsens the real rate of sea-level rise. It is important to note that this is just one scenario for possible sea-level change and that the data record is not very long.

However, sea-level rise is not the most critical concern for the reefs of Tonga. In a much shorter time period, rising sea surface temperatures and ocean acidification are likely to impact on the health and vitality of the fringing reef. Reef degradation will affect the productivity of coastal fisheries and marine ecosystems.

Deputy Director of the Ministry of Agriculture and Food, Forests and Fisheries, Mr Tevita Faka’osi, commended the training saying that it also facilitated better understanding of the science behind climate change.

The SPC/GTZ ACCPIR programme is supporting Tonga in the development of effective land use planning processes, adaptation strategies, and supporting databases to help the land-based sector better cope with climate change.

For more information please contact the SPC Land Resources Division helpdesk: This e-mail address is being protected from spambots. You need JavaScript enabled to view it