Guest essay by John McLean
Barry Brill’s report on Fiji’s relocation of a village doesn’t mean that it’s the only opportunistic Pacific island country when it comes to COP23. It’s near neighbour, Kiribati, is likewise trying to get its hands on some of that money to reimburse it for the NZD10 million paid to Fiji for 15,000 acres of land on which to resettle refugees from rising sea level.
The Permanent Service for Mean Sea Level (PSMSL) database shows that the only tidal gauge currently operating in Kiribati is at Betio (Lat. 1.365 S, Long. 172.933 E), on the island of Bairiki, which is ENE of Nauru, almost due north of New Zealand. The gauge has only been operational since January 1993 and the first two years can be ignored because data is missing for nine months of that period.
The trend in monthly average sea level at Betio from January 1995 to December 2016 shows a rise of 4.7mm/year, which is almost three times the global average calculated from tidal gauge data.
Sea level at many Pacific Islands rises and falls according to the El Nino-Southern Oscillation. The strong El Nino of 1997-8 saw sea level at Betio fall about 250mm and only slowly rise back to its old level. With this event so early in the sea level record the relatively high trend is hardly surprising.
Skipping the period of the El Nino and the slow recovery and calculating the trend from January 2000 to December 2016 shows just 1.9mm/year.
At that rate it will take over 50 years to exceed 100mm, which is about the width across the palm of an adult male’s hand. A mass exodus due to rising seas to Fiji or anywhere else any time soon seems highly unlikely.
The sea level response at Betio to the 1997-8 El Nino was very unusual because most El Nino events cause a rise rather than fall. In fact sea level at Betio corresponds very well to the Nino 3.4 ENSO index of about three months later.
The close relationship between sea level and the ENSO indicates that the ENSO is the primary driver of Betio’s sea level. This of course is hardly likely to stop the Kiribati government claiming otherwise and begging for money, such is the attraction of supporting the UNFCCC’s beliefs.
While researching the reports of rising sea level it was found that the data for Pago Pago (American Samoa) has an upward step in 2010. A check of GPS data from the Nevada Geodetic Laboratory (see http://geodesy.unr.edu) reveals a gradual fall at station ASPA, near the Pago Pago airport, that began in that year and still continues, being about 120mm at the present time. It appears that the PSMSL data for Pago Pago has not been corrected for the fall in the tidal gauge. Tidal gauge data for Honolulu also seems in need of adjustment, which raises the question of how much PSMSL data is in need of correction and the impact those adjustments might have on the global average sea level trend.