From Jennifer Marohasy

 By jennifer

I was at John Brewer reef earlier in the month, and so I checked the AIMS (Australian Institute of Marine Science) water temperature data for this location.  The most up-to-date information is to February 7, 2024, and has been measured at 9 metres.  It begins February 1, 2016, thus giving us some information on the last 8-9 summers.    This location specific temperature data indicates that this last summer has not been particularly warm at John Brewer reef considering the last few summers and it does not show temperatures increasing.  Temperatures cycle within a relatively narrow band from 23C to 30C with the seasons.

This is just one location, and one relatively short data series.  And it is consistent with what I observed when I visited this and four other coral reefs in the central Great Barrier Reef earlier this month.  There was some coral bleaching, but overall corals in the central region of the Great Barrier Reef appear to have been more impacted by Tropical Cyclone Kirrily, than warmer than average water temperatures this summer.

Given all the negative media about widespread bleaching from unusually elevated water temperatures I was expecting to jump-in and see lots of stark white corals.

The first reef that I dived was Wheeler reef, some distance to the south of John Brewer.  When I did jump in and looked down, the first thing that I saw was a large stand of dark brown branching Acropora some many metres below the boat.  It was so heartening to see those corals, to see they were replete with zooxanthellae.

Damage from cyclone Kirrily has been devastating in the shallower sections of some of these mid-shelf reefs offshore from Townsville, and I have written about this previously, CLICK HERE.

It is nevertheless possible to find beautiful corals, and so many fishes, once you do get down below about 7 metres, and even at the reef crest at Wheeler reef that does not appear to have been impacted by the cyclone.

The photograph featured at the top of this blog post is from about 9 metres, from the reef front at John Brewer taken when I visited on April 4, 2024.

I decided to post this photograph with the water temperature data from about the same depth, and the same reef, at my official Facebook page.

Well, some of my many Facebook friends liked it and shared it, but others posted very critical comment suggesting I had cherry-picked data, that I should admit that the oceans are warming.

I have written at length explaining why I prefer location specific data.  I went through some of the issues with global average temperatures last year, you may remember my blog post considering location specific data for Mawson in Antarctica versus what could be considered a contrived global average, CLICK HERE.

How can we know if the oceans are warming from location specific data?  This is a question some have asked me.

It could be the case that some parts of the ocean are warming, and others are cooling.  If this is the case, then global averages are not useful, even misleading.

One of my favourite books is titled ‘The Oceans and Climate’ by Grant R. Bigg, published in 1996 by Cambridge University Press.  It includes a chart of sea level pressure differences near Iceland, and showing how there is some correspondence with sea surface temperatures.  They don’t show a linear increase for the period shown that is 1870 to 1990.   Rather there are cycles.

This may not be an accurate representation of global temperatures.  But it may be an accurate representation of temperatures for that part of the world for that period.

Books nowadays tend to reproduce remodelled ocean and land temperatures to be sure they show trends that are consistent with expected narratives and with as little regional variation as possible.   It is global trends that are fashionable.  (Of course fashion is not politically neutral and some claim it to be the lowest form of ideology.)

The equatorial Pacific Ocean – the region far to the east of the Great Barrier Reef and a little further north – has been unusually warm this last year.   At least that is what the satellite data indicates, presented to us as coloured maps.  I prefer time series data.  And even if much of the Pacific has been very warm this does not mean it has been unusually warm at the Great Barrier Reef.

Credible time series data that I have sourced for the Great Barrier Reef does not show a warming trend.

Just this afternoon I had a look for the temperature data for Myrmidon to the east of John Brewer reef and it shows this last summer to be unusually mild, at the three different depths for which there is up-to-date AIMS temperature data.

I am not holding up this data as evidence the entire world is cooling, or that our cities are cooling, but this data is certainly inconsistent with what the Climate Council and others are claiming, even just this morning and even just for the Great Barrier Reef.