Data Show No Danger To Pacific Atolls From Sea Level …”The Majority Have Enlarged”

Note: The NTZ site remains crippled due to WordPress upgrade from version 4.2.2 to 4.2.3.

New posts can only be viewed through the NTZ homepage. Reader comments function is also disabled by the recent upgrade. Sorry. It’s very frustrating for me as well.

As I’m not an IT guy, nor do I have time to devote to this problem right now, no solution is in sight. Now may be just as good a time to end the climate-blogging career (and just blame site assassins out to get me. /sarc)
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Sebastian Lüning and Prof. Fritz Vahrenholt recently have had a long series of excellent posts on sea level rise. Not surprisingly they show there’s nothing to worry about on that front. At many locations worldwide sea level is not even rising.

Kiribati

In their latest post Lüning and Vahrenholt write: “Good news from the Pacific: Sea level in Kiribati shows no longterm increase over the past 20 years.”

Figure 1: Kiribati sea level trend 1994-2008. Source: Aung et al. 2009.

Moreover satellite measurements also show no trend for the period.

Figure 2: Sea level rise in the region of Kiribati based on satellite measurements. Source: University of Colorado.

Also Lüning and Vahrenholt write that no region in the atolls have been found where coastal erosion is occurring. What follows is the abstract of a recent paper (emphasis added):

Coral islands defy sea-level rise over the past century: Records from a central Pacific atoll”
The geological stability and existence of low-lying atoll nations is threatened by sea-level rise and climate change. Funafuti Atoll, in the tropical Pacific Ocean, has experienced some of the highest rates of sea-level rise (∼5.1 ± 0.7 mm/yr), totaling ∼0.30 ± 0.04 m over the past 60 yr. We analyzed six time slices of shoreline position over the past 118 yr at 29 islands of Funafuti Atoll to determine their physical response to recent sea-level rise. Despite the magnitude of this rise, no islands have been lost, the majority have enlarged, and there has been a 7.3% increase in net island area over the past century (A.D. 1897–2013). There is no evidence of heightened erosion over the past half-century as sea-level rise accelerated. Reef islands in Funafuti continually adjust their size, shape, and position in response to variations in boundary conditions, including storms, sediment supply, as well as sea level. Results suggest a more optimistic prognosis for the habitability of atoll nations and demonstrate the importance of resolving recent rates and styles of island change to inform adaptation strategies.”

So why is sea level not behaving like the alarmists said it would? Lüning and Vahrenholt add:

Like in many other parts of the world, the Pacific ocean cycles play a roll in that they influence sea level in 60-year cycles. In December 2013 a team of scientists led by Jae-Hong Moon published on this subject in the Journal of Geophysical Research. The reported that the satellite data series since 1993 is much too short to allow the identification and computation of the effects of longterm ocean cycles.”

That paper’s abstract tells the whole story (emphasis added):

Multidecadal regional sea level shifts in the Pacific over 1958–2008
Altimeter data have significantly improved our understanding of regional sea level variability and trends, but their relatively short records do not allow either evaluation of the ocean state prior to 1993 or multidecadal low-frequency signals in the ocean. Here we characterize and quantify the multidecadal regional sea level rise (rSLR) and related ocean heat content in the Pacific from a non-Boussinesq ocean circulation model in comparison with data sets from altimeters, two sea level reconstructions, and in situ ocean profiles from 1958 to 2008. We show that the rSLR trends have undergone two shifts, during the mid-1970s and in the early 1990s, with an east-west dipole pattern in the tropical Pacific. In each of these phases, rSLR accelerated on one side of the Pacific, but decelerated on the other side. The multidecadal sea level shifts can be explained by the dynamical (steric) upper-ocean responses to the surface wind forcing associated with the Pacific Decadal Oscillation (PDO), with negligible contributions from internal (depth-integrated) ocean mass changes. Additional model experimentation further confirms that the Pacific wind stress trend over the recent two decades has played an important role in strengthening the rSLR in the western Pacific while suppressing the rSLR in the eastern Pacific. The climate-forced large-scale rSLR variability is likely to impose a long-term and uneven impact on coastal communities.”