Figure 1: Carbon dioxide (C02 ) concentrations associated with three IPCC emissions scenarios: low (B1- blue), medium (A1B - green) and high (A2 - purple). The PCCSP has analysed climate model results for periods centred on 1990, 2030, 2055 and 2090 (shaded). Source: www.pacificclimatechangescience.org

How do scientists develop climate projections?

Climate impacts almost all aspects of life in Kiribati. Understanding the possible future climate of Kiribati is important so people and the government can plan for changes.

Global climate models are the best tools for understanding future climate change. Climate models are mathematical representations of the climate system that require very powerful computers. They are based on the laws of physics and include information about the atmosphere, ocean, land and ice.

There are many different global climate models and they all represent the climate slightly differently. Scientists from the Pacific Climate Change Science Program (PCCSP) have evaluated 24 models from around the world and found that 18 best represent the climate of the western tropical Pacific region. These 18 models have been used to develop climate projections for Kiribati.

Figure 1: Carbon dioxide (C02 ) concentrations associated with three IPCC emissions scenarios: low (B1- blue), medium (A1B - green) and high (A2 - purple). The PCCSP has analysed climate model results for periods centred on 1990, 2030, 2055 and 2090 (shaded). Source: www.pacificclimatechangescience.org

Figure 1: Carbon dioxide (C02 ) concentrations associated with three IPCC emissions scenarios: low (B1- blue), medium (A1B – green) and high (A2 – purple). The PCCSP has analysed climate model results for periods centred on 1990, 2030, 2055 and 2090 (shaded). Source: www.pacificclimatechangescience.org

The future climate will be determined by a combination of natural and human factors. As we do not know what the future holds, we need to consider a range of possible future conditions, or scenarios, in climate models. The Intergovernmental Panel on Climate Change (IPCC) developed a series of plausible scenarios based on a set of assumptions about future population changes, economic development and technological advances. For example, the A1B (or medium) emissions scenarios envisages global population peaking mid-century and declining thereafter, very rapid economic growth, and rapid introduction of new and more efficient technologies. Greenhouse gas and aerosol emissions scenarios are used in climate modelling to provide projections that represent a range of possible futures.

The climate projections for Kiribati on this website are based on three IPCC emissions scenarios: low (B1), medium (A1B) and high (A2), for time periods around 2030, 2055 and 2090. Since individual models give different results, the projections are presented as a range of values.

Information on this page has been sourced on behalf of the Kiribati Meteorology Service and with kind permission from Australian Bureau of Meteorology and CSIRO, 2011.Current and future climate of Kiribati. Visit www.pacificclimatechangescience.org to download information brochures.

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