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Current and future climate of the

> Fiji Meteorological Service > Australian Bureau of Meteorology > Commonwealth Scientific and Industrial Research Organisation (CSIRO) Fiji’s current climate

Across Fiji the annual average temperature is between 20-27°C. Changes Fiji’s climate is also influenced by the in the temperature from season to season are relatively small and strongly trade winds, which blow from the tied to changes in the surrounding ocean temperature. east or south-east. The trade winds bring moisture onshore causing heavy Around the coast, the average night- activity. It extends across the South showers in the mountain . time temperatures can be as low from the Solomon Fiji’s climate varies considerably as 18°C and the average maximum Islands to east of the from year to year due to the El Niño- day-time temperatures can be as with its southern edge usually lying Southern Oscillation. This is a natural high as 32°C. In the central parts near Fiji (Figure 2). climate pattern that occurs across of the main islands, average night- Rainfall across Fiji can be highly the tropical Pacific Ocean and affects time temperatures can be as low as variable. On Fiji’s two main islands, weather around the world. There are 15ºC. The country has two distinct and Vanua Levu, rainfall is two extreme phases of the El Niño- seasons – a warm wet season from strongly influenced by high mountain Southern Oscillation: El Niño and La November to April and a cooler dry peaks up to 1300 m. On the south- Niña. There is also a neutral phase. In season from May to October (Figure 1). eastern slopes of Viti Levu, near Suva, Suva, El Niño events tend to bring dry Much of Fiji’s rainfall is associated with the average annual rainfall is about seasons that are drier and cooler than the movement of the South Pacific 3000 mm. In contrast, the lowlands on normal, while La Niña events usually Convergence Zone which is closest the western side of Viti Levu, near Nadi, bring wetter than normal conditions. to Fiji in the wet season. This band of are sheltered by the mountains and heavy rainfall is caused by air rising have an annual average rainfall of 1800 over warm water where winds mm with a well-defined dry season converge, resulting in thunderstorm favourable to crops such as sugar cane. Floods and droughts Maximum temperature Average temperature Minimum temperature Sea surface temperature River flooding occurs almost every wet season and occasionally 35 35 Suva, Fiji 178.45°E, 18.15°S in the dry season during La Niña events. Major floods tend 400 to be associated with severe weather events, such as tropical 30 depressions and cyclones that

300 bring high intensity rainfall.

Most meteorological droughts

25 since 1920 are associated

200 with El Niño events. Recent severe droughts occurred Temperature (ºC)

Monthly rainfall (mm) in 1987, 1992, 1997-98,

20 2003 and 2010 (Figure 5). 100 0 15 Jan Apr JulOct Figure 1: Seasonal rainfall and temperature at Suva. Fiji Meteorological Service Fiji Meteorological 2003 drought, Yaqara, northern Viti Levu.

2 N H o N 20 o Federated States of o n e I n t e r t r o p i c a l C o n v e r g e n c e Z 10 o W a 0 r m p Tra de W inds o o l S o u M o t h Tu valu n S s o P o East o n a c i f i c C o n v e r g Fiji e n c e

S 10

Z o o To nga Cook Islands n e S 20 H o

0 500 1,000 1,500 2,000 30 Kilometres o E E E E E E E W W W W o o o o o o o o o o o 0 180 11 12 0 13 0 14 0 15 0 16 0 17 0 17 0 16 0 15 0 14 0 Figure 2: The average positions of the major climate features in November to April. The arrows show near surface winds, the blue shading represents the bands of rainfall convergence zones, the dashed oval shows the West Pacific Warm Pool and H represents typical positions of moving high pressure systems. Tropical 6 Tropical cyclones 11-yr moving average 5 cyclones

4 Tropical cyclones usually affect Fiji between November and April, 3 and occasionally in October 2 and May in El Niño years. In the 41-year period between 1 1969 and 2010, 70 tropical No. of tropical cyclones 0 cyclones passed within 400 km of Suva, an average of one to two cyclones per season. Over 1969/701971/72 1973/74 1975/76 1977/78 1979/80 1981/82 1983/84 1985/86 1987/88 1989/90 1991/92 1993/94 1995/96 1997/98 1999/00 2001/02 2003/04 2005/06 2007/08 2009/10 this period, cyclones occurred Figure 3: Number of tropical cyclones passing within 400 km of Suva. more frequently in El Niño years. Eleven-year moving average in purple.

3 Fiji’s changing climate

Temperatures No rainfall change tide gauges are used to measure sea level. Satellite data indicate sea level have increased Data for Suva and Nadi Airport has risen in Fiji by about 6 mm per (Figure 5) since 1950 show no year since 1993. This is larger than the Annual maximum and minimum clear trends in annual or seasonal global average of 2.8–3.6 mm per year. temperatures have increased in both rainfall. Over this period, there This higher rate of rise may be partly Suva (Figure 4) and Nadi since 1950. has been substantial variation related to natural fluctuations that take In Suva, maximum temperatures in rainfall from year to year. place year to year or decade to decade have increased at a rate of 0.15°C caused by phenomena such as the per decade and at Nadi Airport the El Niño-Southern Oscillation. The natural rate of increase has been 0.18°C Sea level has risen variation in sea level can be seen in per decade. These temperature As ocean water warms it expands Figure 7 which includes the tide gauge increases are consistent with the causing the sea level to rise. The record since 1972 and the satellite data global pattern of warming. melting of glaciers and ice sheets since 1993. also contributes to sea-level rise. Instruments mounted on satellites and Ocean acidification has been increasing 27 El Niño La Niña About one quarter of the carbon dioxide 26.5 emitted from human activities each year is absorbed by the . As the extra 26 carbon dioxide reacts with sea water 25.5 it causes the ocean to become slightly more acidic. This impacts the growth emperature (ºC) 25 of corals and organisms that construct their skeletons from carbonate minerals. 24.5 These species are critical to the balance

Average T of tropical reef ecosystems. Data 24 show that since the 18th century the 23.5 level of ocean acidification has been slowly increasing in Fiji’s waters. 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 4: Annual average temperature for Suva. Light blue bars indicate El Niño years, dark blue bars indicate La Niña years and the grey bars indicate neutral years.

3500 El Niño La Niña 3000 2500 2000 1500

Rainfall (mm) 1000 500 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 5: Annual rainfall for Nadi Airport. Light blue bars indicate El Niño Taking rainfall observations, years, dark blue bars indicate La Niña years and the grey bars indicate Bay Meteorology Office. neutral years.

4 Fiji’s future climate

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

How do scientists develop climate projections?

Global climate models are the best tools or scenarios, in climate models. The for understanding future climate change. Intergovernmental Panel on Climate Climate models are mathematical Change (IPCC) developed a series of representations of the climate system plausible scenarios based on a set of that require very powerful computers. assumptions about future population They are based on the laws of physics changes, economic development and 2090 and include information about the technological advances. For example, 800 atmosphere, ocean, land and ice. the A1B (or medium) emissions scenario envisages global population peaking 2055 700 There are many different global climate 600 mid-century and declining thereafter, 2030 tion (ppm) models and they all represent the a

very rapid economic growth, and t r climate slightly differently. Scientists from 1990 500 rapid introduction of new and more e n the Pacific Climate Change Science 400

efficient technologies. Greenhouse on c Program (PCCSP) have evaluated 24 300 C

gas and aerosol emissions scenarios 2

models from around the world and O are used in climate modelling to found that 18 best represent the climate C provide projections that represent of the western tropical Pacific . Figure 6: Carbon dioxide (CO ) a range of possible futures. 2 These 18 models have been used to concentrations (parts per million, ppm) develop climate projections for Fiji. The climate projections for Fiji are based associated with three IPCC emissions on three IPCC emissions scenarios: low scenarios: low emissions (B1 – blue), The future climate will be determined (B1), medium (A1B) and high (A2), for medium emissions (A1B – green) and by a combination of natural and human time periods around 2030, 2055 and high emissions (A2 – purple). The factors. As we do not know what the 2090 (Figure 6). Since individual models PCCSP has analysed climate model future holds, we need to consider a give different results, the projections results for periods centred on 1990, range of possible future conditions, are presented as a range of values. 2030, 2055 and 2090 (shaded).

Rain clouds, Coral Coast, Viti Levu. Coral Coast, Viti Levu.

5 Fiji’s future climate

This is a summary of climate projections for Fiji. For further information refer to Volume 2 of Climate Change in the Pacific: Scientific Assessment and New Research, and the web-based climate projections tool – Pacific Climate Futures (available at www.pacificclimatefutures.net).

Temperature will Changing rainfall Less frequent continue to increase patterns but more intense Projections for all emissions There is uncertainty around rainfall tropical cyclones scenarios indicate that the annual projections as model results are not On a global scale, projections indicate average air temperature and sea consistent. However, projections there is likely to be a decrease in the surface temperature will increase in generally suggest a decrease in dry number of tropical cyclones by the the future in Fiji (Table 1). By 2030, season rainfall and an increase in end of the 21st century. But there is under a high emissions scenario, this wet season rainfall over the course likely to be an increase in the average increase in temperature is projected of the 21st century. Increased wet maximum wind speed of cyclones by to be in the range of 0.4–1.0°C. season rainfall is expected due to the between 2% and 11% and an increase projected intensification of the South in rainfall intensity of about 20% within Pacific Convergence Zone. Drought More very hot days 100 km of the cyclone centre. projections are inconsistent for Fiji. Increases in the average temperature In the Fiji region, projections tend to will also result in a rise in the number More extreme show a decrease in the frequency of hot days and warm nights and of tropical cyclones by the late a decline in cooler weather. rainfall days 21st century and an increase in the Table 1: Projected annual average Model projections show extreme rainfall proportion of the more intense storms. air temperature changes for Fiji days are likely to occur more often. for three emissions scenarios and three time periods. Values represent 90% of the range of the models and changes are relative to the average of the period 1980-1999.

2030 2055 2090 (°C) (°C) (°C) Low 0.2–1.0 0.5–1.5 0.7–2.1 emissions scenario Medium 0.2–1.2 0.9–1.9 1.3–2.9 emissions scenario

High 0.4–1.0 1.1–1.7 2.0–3.2 National Oceanic and Atmospheric Administration emissions Tropical Cyclone Tomas (Category 4) scenario struck Fiji in March 2010 causing Bridge across the River significant damage. partially destroyed by severe flooding in January 2009.

6 Sea level will Ocean acidification continue to rise will continue Sea level is expected to continue to rise Under all three emissions scenarios The impact of increased acidification in Fiji (Table 2 and Figure 7). By 2030, (low, medium and high) the acidity on the health of reef ecosystems is under a high emissions scenario, this level of sea waters in the Fiji region likely to be compounded by other rise in sea level is projected to be in will continue to increase over the 21st stressors including coral bleaching, the range of 3-16 cm. The sea-level century, with the greatest change storm damage and fishing pressure. rise combined with natural year-to-year under the high emissions scenario. changes will increase the impact of storm surges and coastal flooding. As 90 there is still much to learn, particularly how large ice sheets such as Antarctica 80 Reconstruction and Greenland contribute to sea-level Satellite altimeter 70 rise, scientists warn larger rises than Tide gauges (3) currently predicted could be possible. 60 Projections

50 Table 2: Sea-level rise projections for Fiji for three emissions scenarios 40 and three time periods. Values represent 90% of the range of the 30 models and changes are relative to 20 the average of the period 1980-1999. 10 2030 2055 2090 Sea level relative to 1990 (cm) (cm) (cm) (cm) 0

Low 5–16 10–27 16–47 −10 emissions scenario −20

Medium 5–15 9–31 20–59 −30 emissions 1950 2000 2050 2100 scenario Year High 3–16 8–31 21–62 Figure 7: Observed and projected relative sea-level change near Fiji. emissions The observed sea-level records are indicated in dark blue (relative tide- scenario gauge observations) and light blue (the satellite record since 1993). Reconstructed estimates of sea level near Fiji (since 1950) are shown in purple. The projections for the A1B (medium) emissions scenario (representing 90% of the range of models) are shown by the shaded green region from 1990 to 2100. The dashed lines are an estimate of 90% of the range of natural year-to-year variability in sea level.

7 Changes in Fiji’s climate

> Temperatures have > Rainfall at Suva and > By the end of this > Sea level near > Ocean acidification warmed and will Nadi Airport shows no century projections Fiji has risen and has been increasing continue to warm clear trend since 1950. suggest decreasing will continue to in Fiji’s waters. It will with more very hot Rainfall patterns are numbers of tropical rise throughout continue to increase days in the future. projected to change cyclones but a this century. and threaten coral over this century with possible shift reef ecosystems. more extreme rainfall towards more days expected. intense categories.

The content of this brochure is the result of a collaborative effort between the Fiji Contact the Fiji Meteorological Service and the Pacific Climate Change Science Program – a component Meteorological Service: of the Australian Government’s International Climate Change Adaptation Initiative. This web: www.met.gov.fj information and research conducted by the Pacific Climate Change Science Program email: [email protected] builds on the findings of the 2007 IPCC Fourth Assessment Report. For more detailed information on the climate of Fiji and the Pacific see: Climate Change in the Pacific: phone: +679 672 4888 Scientific Assessment and New Research. Volume 1: Regional Overview. Volume 2: Country Reports. Available from November 2011. © Pacific Climate Change Science www.pacificclimatechangescience.org Program partners 2011.