Tuvalu

Tuvalu and other Pacific islands resist sea level rise and add land area

Climate alarmists have long been predicting that global warming induced sea level rise would make low-lying Pacific islands disappear and cause thousands of “climate refugees” to seek new homes. Here are some examples:

Smithsonian.com, August, 2004: Will Tuvalu Disappear Beneath the Sea? Global warming threatens to swamp a small island nation.

Mother Jones, December, 2009: What Happens When Your Country Drowns?

Washington Post, August, 2014: Has the era of the ‘climate change refugee’ begun?

Bloomberg, November, 2017: A Tiny Island Prepares the World for a Climate Refugee Crisis.

The University of Arizona has been complicit in this hype; see my Wryheat post: University of Arizona dances with sea level.

These alarmist claims have not come to pass because of the geologic processes that build these islands.

A new paper published in Nature Communications on Feb. 9, 2018, shows that despite sea level rise, most islands are increasing in land area.

A University of Auckland study (Patterns of island change and persistence offer alternate adaptation pathways for atoll nations, Paul S. Kench, Murray R. Ford & Susan D. Owen) examined changes in the geography of Tuvalu’s nine atolls and 101 reef islands between 1971 and 2014, using aerial photographs and satellite imagery. The paper claims that local sea level has risen at twice the global average (~3.90 + 0.4 mm.yr-1). That translates to about six inches over the 43-year period. However, the study found eight of the atolls and almost three-quarters of the islands grew during the study period, increasing Tuvalu’s total land area by 2.9 percent, even though sea levels in the country rose at twice the global average. (Read Full paper in Nature).

Here is figure 3 from that paper followed by its caption:

Caption for Tuvalu fig 3 (ha = hectares): Examples of island change and dynamics in Tuvalu from 1971 to 2014.

A Nanumaga reef platform island (301 ha) increased in area 4.7 ha (1.6%) and remained stable on its reef platform.

B Fangaia island (22.4 ha), Nukulaelae atoll, increased in area 3.1 ha (13.7%) and remained stable on reef rim.

C Fenualango island (14.1 ha), Nukulaelae atoll rim, increased in area 2.3 ha (16%). Note smaller island on left Teafuafatu (0.29 ha), which reduced in area 0.15 ha (49%) and had significant lagoonward movement.

D Two smaller reef islands on Nukulaelae reef rim. Tapuaelani island, (0.19 ha) top left, increased in area 0.21 ha (113%) and migrated lagoonward. Kalilaia island, (0.52 ha) bottom right, reduced in area 0.45 ha (85%) migrating substantially lagoonward.

E Teafuone island (1.37 ha) Nukufetau atoll, increased in area 0.04 ha (3%). Note lateral migration of island along reef platform. Yellow lines represent the 1971 shoreline, blue lines represent the 1984 shoreline, green lines represent the 2006 shoreline and red lines represent the 2014 shoreline.

The reason that these islands are gaining area is that as the sea rises, coral reefs grow higher and trap coral debris and sand to build up the island. The science of coral reef atolls is not new. This process was first described by Charles Darwin in 1842: The structure and distribution of coral reefs. Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836. London: Smith Elder and Co. (Link to Darwin’s full description).

This figure from Darwin’s paper shows that coral atolls originate around a volcanic island or seamount. As sea level rises (or land sinks) the corals grow to remain in shallow water and the coral debris and sand cause an atoll island to form. That the corals were able to overcome a recent six-inch rise in sea level may not seem very much, but remember that these islands have been around a long time and dealt with a 400-foot rise in sea level since the depths of the last glacial epoch.

The findings of the new paper cited above support previous studies. For instance:

Kench et al., 2015, Coral islands defy sea-level rise over the past century: Records from a central Pacific atoll, Geological Society of America, in Geology Magazine, March 2015. (Source)

“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.”

See also:

The Sea Level Scam

UPDATE: A new paper published 19 September 2018 finds: 

Over the past decades, atoll islands exhibited no widespread sign of physical destabilization
in the face of sea-level rise. A reanalysis of available data, which cover 30 Pacific and Indian Ocean atolls including 709 islands, reveals that no atoll lost land area and that 88.6% of islands were either stable or increased in area, while only 11.4% contracted. Atoll islands affected by rapid sea-level rise did not show a
distinct behavior compared to islands on other atolls. Island behavior correlated with island size, and no island smaller than 10 ha decreased in size. This threshold could be used to define the minimum island size required for human occupancy and to assess atoll countries and territories’ vulnerability to climate change. Beyond emphasizing the major role of climate drivers in causing substantial changes in the
configuration of islands, this reanalysis of available data indicates that these drivers explain subregional variations in atoll behavior and within-atoll variations in island and shoreline (lagoon vs. ocean) behavior, following atoll-specific patterns.

Increasing human disturbances, especially land reclamation and human structure construction, operated on atoll-to-shoreline spatial scales, explaining marked within-atoll variations in island and shoreline behavior. Collectively, these findings highlight the heterogeneity of atoll situations. Further research needs include addressing geographical gaps (Indian Ocean, Caribbean, north-western Pacific atolls), using standardized protocols to allow comparative analyses of island and shoreline behavior across ocean regions, investigating the role of ecological drivers, and promoting interdisciplinary approaches. Such efforts would assist in anticipating potential future changes in the contributions and interactions of key
drivers. Read paper: http://sci-hub.tw/10.1002/wcc.557

UPDATE 2: New Study, July 5, 2019:

From: University of Auckland

Pacific atolls can adapt to rising seas and extreme storms – new study

Low-lying Pacific islands in atoll archipelagos such as Tuvalu, Tokelau and Kiribati are likely to adapt to the effects of climate change rather than simply sink beneath the waves, a new study shows. Read more

University of Arizona dances with sea level

Tomorrow the University of Arizona will present some political theater.  In the evening, UA presents will feature a troupe from several South Pacific islands in a program titled  “Water is Rising.”  Preceding that on Friday afternoon is a discussion led by the UofA  Institute of the Environment titled “Vanishing Islands: Culture and Climate Change.” (See article here.)

It is unfortunate that what will probably be an entertaining evening of song and dance is being used as political propaganda posing Pacific islanders as victims of global warming-caused sea level rise that will inundate their homes.  Such propaganda is not new.  Back in 2009, Members of the Maldives’ Cabinet donned scuba gear and held a meeting under water in a publicity stunt about sea level rise.

The UA’s Institute of the Environment has also, in the past, issued alarmist articles about sea level rise flooding low-lying coastlines, see Science Fiction from the University of Arizona.

If you decide to go to the afternoon discussion, here are a few things you should know. Auckland University Professor Paul Kench has measured 27 islands where local sea levels have risen 120mm – an average of 2mm a year – over the past 60 years, and found that just four had diminished in size, the remaining 23 had either stayed the same or grown bigger, according to the research published in a scientific journal, Global and Planetary Change.

The Australian government has been monitoring sea level on Pacific islands with modern instruments since 1992.   In the case of Tuvalu, they state, “If   the   depression   of   the   1998   cyclone   is   ignored,  there   was   no   change   in   sea   level   at   Tuvalu between 1994 and 2009: 14 years. The recent slight fall would probably be related to the recent earthquake.”

Here is the Australian record of sea level for Tuvalu.  Other South Pacific islands show a similar record.

Tuvalu-sea-level

See also:

Sea Level Rising?

Sea Level Rise Declining says EU

Obama parts the waters, sea level drops

Size matters in sea level studies

Sea Level Rise in the South Pacific – None

In a previous post Pained Earth’s summer to forget: the rest of the story, I criticized an AP story printed in the Arizona Daily Star as inaccurate and alarmist.

Within that story I had written: The story states: “The melting of land ice into the oceans is causing about 60 percent of the accelerating rise in sea levels worldwide, with thermal expansion from warming waters causing the rest. The WMO’S World Climate Research Program says seas are rising by 1.34 inches per decade, about twice the 20th century’s average.” The pretended “acceleration” is the result of cherry-picking starting and ending points. The rate of sea level rise is cyclic, but the overall trend is downward. For a detailed analysis of sea level rise, and to see why the WMO statement is dissembling, see my article, Sea Level Rising? Also, a new paper in the Journal of Geophysical Research, says “The global mean sea level for the period January 1900 to December 2006 is estimated to rise at a rate of 1.56 ± 0.25 mm/yr which is reasonably consistent with earlier estimates, but we do not find significant acceleration.”

One of the commenters complained that “New Zealand has already accepted climate change refugees from Tuvalu, an island that has seen the ocean rise around it more than eight inches over the last twenty years or so.” He took this as evidence of anthropogenic global warming. (The fact that the globe has been recently warming does not speak to the cause.)

The Australian government has been monitoring sea level on Pacific islands with modern instruments since 1992. In the case of Tuvalu, they state, “If the depression of the 1998 cyclone is ignored, there was no change is sea level at Tuvalu between 1994 and 2009: 14 years. The recent slight fall would probably be related to the recent earthquake.”

Tuvalu-sea-level

Sea level at other South Pacific islands is similar. There are seasonal oscillations and variations due to cyclones and earthquakes, but the overall trend is flat.

South-Pacific-sea-level

For more detail on the Australian study, see here.