Is Climate Change Threatening the Solomon Islands?

Since the first talk of an agreement between China and the Solomon Islands to establish a Chinese presence there, accusations have flown thick and fast between the Australian government and their opponents.

One of the points of contention is whether Australia’s supposed lack of urgency in addressing climate change has led to distrust of Australia by Pacific island nations, thus encouraging them to seek help from China.  Considering China’s record and plans for emissions, that is hardly likely.  However, The Guardian thinks so, saying two days ago:

There might not be a direct link between Australia’s climate policy and the security deal – Morrison certainly thinks there isn’t, dismissing such a connection as “nonsense” today – but it is without doubt that Australia’s climate policy has contributed to the dimming of Australia’s reputation in the region, especially given Australia claims to be family.

So is climate change – specifically sea level rise- threatening the Solomons?

Time for a reality check.  Here is a map courtesy of Google, showing where the tide gauge in the Solomons is in relation to Australia.

Figure 1:  Solomons tide gauge location

Not that far away.

Over the last 28 years since the BOM began monitoring sea level at Honiara, sea level has definitely risen.  Figure 2 shows monthly anomalies of mean tidal data.

Figure 2:  Monthly mean sea level, Honiara

Oh no!  Climate change!

Figure 3 shows inverted mean barometric pressure anomalies plotted with mean sea level.

Figure 3:  Monthly sea level and barometric pressure (inverted)

Hmm.  As air pressure falls, sea level rises, and vice versa.  Figure 4 shows 12 month means (from July to June, which covers most ENSO events):

Figure 4:  12 month means of monthly sea level and inverted barometric pressure

Still not a close match, but let’s include the effect of the trade winds (data from NOAA).

12 month means of trade wind anomalies, scaled down by a factor of 10 show a much better match:

Figure 5:  12 month means of monthly sea level and scaled trade winds index

Now we see the connection, and cause of the apparent trend in sea level- the combination of air pressure and trade winds.  Barometric pressure has been decreasing, and trade wind strength has increased.  These are symptoms of the El Nino Southern Oscillation (ENSO).  When atmospheric pressure is unusually high (as in very big El Ninos), sea levels are lower, mainly because the normal trade winds slacken and less water than normal is pushed westwards across the Pacific.  As trade winds strengthen, more water is pushed westwards and sea level rises.  (This also affects the eastern coast of Australia, and strengthens the East Australian current as well.) 

When we get the next big El Nino (cue droughts, bushfires, and wailing and gnashing of teeth) it is likely that the sea level trend will mysteriously flatten.

Sorry, guys, unless climate change predicts fewer and weaker El Ninos, climate change is not to blame: and certainly not the Australian government.

It’s all about the money.

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10 Responses to “Is Climate Change Threatening the Solomon Islands?”

  1. Peter Newland Says:

    Good info. What are the MSL units.

  2. Blane Coulcher Says:

    Hiya- great analysis. But what is the measure on the y axis? Presumably not metres otherwise ~20cm increase in 29 years?

  3. tonyryan43 Says:

    To me, Ken is one of the Australian 21st century heroes, not that he has much competition.

    Being a bush-bloke, most science is Chinese to me, but I am a sharp judge of people of integrity and knowledge, and he is up there.

    Well done mate.

    Being a red-neck bushie is no obstacle to logic though. I see glaciers melting as they should, following the Little Ice Age. I see *****s like Maurice Strong setting up the IPCC, and I am skeptical, knowing bullshit is the next outflow. Banker investments.

    In 2010, I read Murdoch and Rockefeller releasing an identical splurge about saving the planet and I know a snake oil salesman when I hear one.

    I want science from a scientist of integrity. Thanks, Ken.

  4. kenskingdom Says:

    Thanks, but I am not a scientist. Please don’t make defamatory comments about living famous people- they might take it out on me.

  5. Chris Says:

    It’s worth noting that the air temperature data tabulated by the BoM through the link in Ken’s post appears to be from an AWS in the capital of Honiara and is presumably influenced by UHI.

    An alternative data source is https://climateknowledgeportal.worldbank.org/country/solomon-islands/climate-data-historical which claims its temps are via the University of East Anglia Climate Research Unit and are from monitoring stations across the Solomon Islands.

    It seems about half or a slight majority of these non-Honiara stations are manual rather than AWS.

    This data averages as …

    Max
    1931-1999 : 29.83C
    2000-2020 : 29.90C

    Min
    1931-1999 : 21.39C
    2000-2020 : 21.36C

    Mean
    1931-1999 : 25.58C
    2000-2020 : 25.61C

    Might this be what happens to climate warming that isn’t influenced by automatic weather stations, concrete and bitumen?

  6. Lint Robb Says:

    Thanks Ken

    This reminds me of another Guardian article of 17 Oct, 2021, authored to promote unwarranted sea level rise concerns in the Western Pacific region.

    https://www.theguardian.com/world/2021/oct/16/my-father-will-go-down-like-the-captain-of-the-titanic-life-on-the-pacifics-disappearing-islands

    I responded to the comments section of this article with the following

    “Toruar Island is located 18 km south of Buka Town, the capital of the North Bougainville District, which has a population of about 2,000, a cathedral and a radio station and a sealed airstrip and terminal with commercial jet air services provided by Air Niugini and PNG Air. There are three, much larger inhabited islands together with the Bougainville mainland within 2,000 metres of Toruar, the closest of which is 700 metres to the northwest. Those inhabitants who choose to saturate this island do so at their own risk.

    The Solomon Islands are located on the Pacific Ring of Fire and is a very active seismic zone with more than 100 greater than Mw 7.0 events since 1900 and two events of Mw 8.0 and Mw 8.1 since 2007. The plate tectonics of the Solomon Islands region sees the Solomon Sea plate sublimating to the northeast against the south western side of Bougainville. These geological events are known to create significant tsunami activity, well capable of total island inundation.

    Local mean sea level (LMSL) data is not available for this area, the nearest tidal measurement station at Rabaul, New Britain, 300km to the north west recorded data between 1966 to 1997, the volcanic event of 1994 and subsequent subsidence required an adjustment of -130mm and later -140mm to the tidal data. Honiara lies 720km to the south east and has recorded data from 1957 until present which shows no discernible sea level change. It is evident that the claim “sea levels in the western Pacific have been increasing at a rate two to three times the global average, meaning there has been net rise of 0.3 metres in the last 30 years” is patently false, this statement predicated on IPCC modelling based on an implausible representative concentration pathway (RCP) of 8.5. Geological subsidence events, El Niño – Southern Oscillation (ENSO) and alternating La Niña (ENSO neutral) events with resulting pooling of warm waters over this region are by far the greatest threat to these locations.

    The inhabitants of Toruar Island are indeed fortunate having the opportunity to migrate less than two kilometres to the mainland if required to create a viable society”.

    The contributor comments make an interesting read and show that the vast majority accept the validity of the article content without question.

  7. Trade Winds and Australian Sea levels | kenskingdom Says:

    […] A Reality Check on Global Warming « Is Climate Change Threatening the Solomon Islands? […]

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