Trends in extreme daily temperature and rainfall have been analysed from 1961 to 1998 for Southeast Asia and the South Pacific. This 38-year period was chosen to optimize data availability across the region. Using high-quality data from 91 stations in 15 countries, significant increases were detected in the annual number of hot days and warm nights, with significant decreases in the annual number of cool days and cold nights. These trends in extreme temperatures showed considerable consistency across the region. Extreme rainfall trends were generally less spatially coherent than were those for extreme temperature. The number of rain days (with at least 2 mm of rain) has decreased significantly throughout Southeast Asia and the western and central South Pacific, but increased in the north of French Polynesia, in Fiji, and at some stations in Australia. The proportion of annual rainfall from extreme events has increased at a majority of stations. The frequency of extreme rainfall events has declined at most stations (but not significantly), although significant increases were detected in French Polynesia. Trends in the average intensity of the wettest rainfall events each year were generally weak and not significant.

This paper examines traditional ecological knowledge of weather and climate in Samoa, a Polynesian community in the South Pacific. The research found Samoans have their own unique seasonal calendar. The Samoan seasonal calendar is predominantly based on the observations of local environmental changes, which are in turn influenced by weather and climate. Monitoring changes in plants and animal behaviour, for example, are key indicators used by the Samoans to forecast changes in weather and climate. In addition, their communal and family social activities like hunting, fishing and feasting are driven by the seasonal calendar. The Samoans knowledge of cloud formation, conditions conducive to the formation and onset of severe weather systems and seasonal changes in climate, helped them anticipate, plan and adapt to extreme weather and climate events. The ability and knowledge of the Samoans to forecast the onset of extreme weather and climate events, relying predominantly on local environmental changes are vital tools that should be incorporated in the formulation of human induced climate change adaptation strategies.

Abstract. It is widely accepted by the international scientific community that human activities have increased atmospheric concentrations of greenhouse gases (GHG) and aerosols since the pre-industrial era. This increase has contributed to most of the warming (0.6±0.2°C) observed over the 20th century, land areas warming more than the oceans, with the 1990s very likely to be the warmest decade of the 20th century (IPCC, 2001). How this warming influences the occurrence, severity and frequency of ENSO episodes remains highly uncertain. The IPCC (2001) assessment of the scientific literature found insufficient evidence to suggest any direct attribution between increase in ENSO events that occurred in the last 20 to 30 years of the 20th century and global warming (IPCC, 2001). However, assessments carried out since then (e.g. IPCC Fourth Assessment Report (AR4), in preparations) suggest El Niño events have become more frequent, persistent and intense during the last 20 to 30 years compared to the previous 100 years. Attribution to global warming, however, remains highly uncertain. Efforts to simulate and model past, present and future behaviour of ENSO under a warming world due to enhanced GHG concentrations produce conflicting results. Since substantial internally-generated variability of ENSO behaviour on multi-decadal to century timescales occurs in long, unforced atmospheric-oceanic general circulation model (AOGCM) simulations, the attribution of past and future changes in ENSO amplitude and frequency to external forcing like GHG concentrations cannot be made with certainty. Such attribution would require extensive use of ensemble climate experiments or long experiments with stabilised GHG forcing. Although there are now better ENSO simulations in AOGCM, further model improvements are needed to simulate a more realistic Pacific climatology and seasonal cycle of the key modes influencing the climate of the region, as well as more realistic ENSO variability. More research is needed to further enhance scientific understanding of possible teleconnections between ENSO and global warming. It is worth noting the IPCC AR4 due to be release in September 2007, would provide a more detailed assessment of ENSO and global warming than what is being covered in this paper.

No abstract

No abstract