Many of the impacts of climate change will be experienced by communities as changes in the hydrological cycle; and will exacerbate existing stresses on water resources (pollution, population growth) (Pahl-Wostl and Knieper 2014; Mukheibir 2010).
In the Gilbert Islands, the average recorded temperatures have increased by 1 °C from 1950 to 2009, while maximum temperatures have increased by 0.18 °C per decade over the past 60 years (PCCSP 2011b) (Fig. 17.1).
While annual rainfall in the Gilbert Islands can be described as highly variable, due mainly to El Nino and La Nina events, a gradual increase in rainfall can be observed for the traditionally wet seasons (PCCSP 2011b). The average rainfall is approximately 2100 mm with just over 900 mm received between May and October (Fig. 17.2).
Fig. 17.1 Average annual temperatures (PCCSP 2011b)
Fig. 17.2 Average annual rainfall (PCCSP 2011b)
Melting ice in the polar regions and snow-capped mountains due to the increase in temperature has led to a global increase in the sea level. At the Gilbert Islands the sea level has risen by 1-4 mm per year since 1993—10-40 mm per decade (PCCSP 2011b).
Future climate change scenarios for Kiribati are based on projections undertaken by the Pacific Climate Change Science Program (PCCSP 2011b), using 18 different models that best represent the climate of the western tropical Pacific region, specifically the Gilbert Islands.
The projections for Kiribati are based on three of the IPCC emissions scenarios for the periods around 230 and 2055 (IPCC 2007):
- • Low impact on GHG emissions (B1)—due to a rapid change in economic structures toward a service and information economy, with reductions in material intensity, and the introduction of clean and resource-efficient technologies.
- • Medium impact on GHG emissions (A1B)—due to very rapid economic growth, global population that peaks in mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies, with a balance of between fossil and non-fossil energy sources.
- • High impact on GHG emissions (A2)—due to continuously increasing global population and per capita economic growth and technological change are more fragmented and slower than in other scenarios.
Under these scenarios, the following changes can be expected: