Climate Witness: Rifi Hamdani, Indonesia
I have been working as a dive guide since 2002. There are about 20 diving spots in the surrounding area of Sangalaki, Derawan, Maratua and Kakaban islands.
Uncertain and unpredictable weather
Based on my observation, the weather is now uncertain and unpredictable. Usually, strong waves occurred from mid-July to mid-September. But now, this is changing. This year, large and strong waves came early and sometimes happened during other months.
As the weather is uncertain and unpredictable, sometimes we cannot meet the needs of our guests. For example, on some days when we expect there will be no rain or strong current at certain diving spots, rain or strong current nevertheless occurs and lowers underwater visibility, making it difficult for guests to dive. Then, we have to choose other spots. As we cannot go according to our plans, we have to use more fuel to look for other locations where the visibility is good and the current is not too strong. This results in higher operational costs.
Abrupt change of weather
In addition, abrupt changes in weather also increase risks for us and our guests. This happens at times when the weather is good at the beginning of the dive, but suddenly gets worse when we are still underwater, or just about to get back on board.
Fortunately, so far there has been no significant loss for us. But, if the weather keeps changing abruptly, and is uncertain and unpredictable, there will be significant negative impacts on underwater tourism.
Scientific reviewReviewed by: Dr Heru Santoso, TroFCCA (Tropical Forests and Climate Change Adaptation) project, Indonesia
The witnesses told three natural phenomena that they considered climate related. They are increased land erosion, higher tides and unpredictable weather. Even though non-climatic factor could contribute to these phenomena, for example an increase in land erosion could be due to land mismanagement, or a higher tide could be the subsequent of regional subsidence, etc. However, in all three different locations the people observed an increase of wave energy and increasing unpredictable weather that could affect the sustainability of their villages and their livelihood.
There are very few scientific literatures to report whether the observed phenomena in this specific region are related to climate change. This region is open to Sulawesi and Sulu seas as flow paths of oceanic current from the western Pacific Ocean to Indian Ocean. Higher tides in Berau area could be related to the increase of sea surface level in the western Pacific during La Niña events. This phenomenon recently has become noticeable than in the past probably because global warming has accentuated the extent of this climate mechanism (Mimura et al. 2007).
For the same reason, unpredictable and abrupt change of weather has become noticeable. Abrupt changes are usually associated with high wind speed which could only happen if there is a significant difference in pressures between two areas. Striking heat, in particular over a heat sensitive land area, under a warmer condition could generate this high pressure difference quickly. Land sensitivity to heat is higher if the forest cover has gone or heavily degraded. The ‘widow month’, a regular phenomenon of strong southerly wind that has been disappearing, is normally associated with the monsoonal trade wind in which the easterly wind from eastern Indonesia turn northward to Asia. Global warming or higher regional temperature could alter the distribution of regional or subregional energy concentration and could also alter the scale and extent of circulation.
Therefore, global warming could have contributed to the increasing trend of recurrences of natural phenomena as reported by witnesses. However, it is quite proper to verify whether this global warming has accentuated climate mechanisms in this subregion by comparing with other climate variables. For example, during La Niña events warm waters from the east flow to the west and usually bringing more rains. The high tides in the Berau region which could be explained by this mechanism could be verified with rainfall data during that particular time of the events, preferably with a long period of observation data.
All articles are subject to scientific review by a member of the Climate Witness Science Advisory Panel.