Climate change claims its first species – or does it?

This post briefly reviews the demise of the Bramble Cay melomys, a rat-like mammal that is no longer to be found on Bramble Cay, a tiny coral atoll between Australia and Papua-New Guinea and the animal’s only known habitat. The acknowledged cause of the extinction – which appears in this case to be real – was a series of storm surges that inundated Bramble Cay and killed off the vegetation. There is, however, no evidence linking these storm surges to human-induced climate change. The University of Queensland’s claim that the Bramble Cay melomys ….. is the first mammal to go extinct due to human-induced climate change must therefore be considered invalid as well as grossly misleading.

For years now CAGW proponents have been relentlessly searching for an example of a species that has incontrovertibly been driven extinct by man-made climate change, but so far without success. Discredited examples have included the Harlequin Frog and the Golden Toad in Costa Rica, the European Land Leech in Europe, the White Possum in Queensland and the Aldabra banded snail (discussed earlier in this post), which after being declared extinct in a Royal Society paper was later found alive and well in a different part of Aldabra Atoll. (The RS nevertheless refused to withdraw the paper). Now, however, we have a new candidate – the Bramble Cay melomys, and this one really has the AGW people stirred up (a Google search for “Bramble Cay melomys extinct” generated 176,000 hits). There’s no shortage of hand-wringing either. As the Guardian puts it:

Farewell, Bramble Cay melomys. We killed you and you will be remembered as the first mammalian extinction caused directly by climate change: wiped off the planet by rising seas ….. It is the beginning of a new wave of loss and we need to start to prepare ourselves for the grief that will inevitably follow.

Here we will look into the question of whether “we” really did kill the unfortunate animal.

Figure 1 shows the location of Bramble Cay off the northeast tip of Queensland and the south coast of Papua-New Guinea along with the locations of four tide gauge stations discussed later:

Figure 1: Location map

And the following photos indeed make one wonder how a mammalian population could continue to survive on a postage stamp-sized (about 4 hectares), barren atoll like Bramble Cay:

Figure 2: Recent photographs of Bramble Cay. The structure in the first photo is a disused lighthouse. The second shows a trap set next to one of the last remaining patches of vegetation.

So is the melomys really extinct? No one knows for sure because there’s a possibility that it may still be present in the Papua-New Guinea rain forest. But a detailed study conducted by the University of Queensland entitled Confirmation of the extinction of the Bramble Cay melomys leaves little doubt that it is no longer present on Bramble Cay.

And what does the study say about the causes of the extinction? It looks into rainfall and temperature and concludes that neither had a significant impact:

With no trend in the annual rainfall data apparent over recent decades, this climate variable is unlikely to be a causative factor in the decline in vegetation cover on Bramble Cay during the decade prior to 2014. By contrast, the small, gradual increase in air temperature evident in the climatic record for Torres Strait could conceivably have affected plant health on Bramble Cay negatively over the past ten years, perhaps contributing to a reduction in the area of vegetation on the island. However, the relatively small change in average temperatures is unlikely to account for the large magnitude of change in vegetation extent that has taken place over such a relatively short time span.

…. goes on to identify the real cause:

The key factor responsible for the extirpation of this population was almost certainly ocean inundation of the low-lying cay, very likely on multiple occasions, during the last decade, causing dramatic habitat loss and perhaps also direct mortality of individuals.

…. and concludes by paying the requisite obeisance to human-induced climate change:

Available information about sea-level rise and the increased frequency and intensity of weather events producing extreme high water levels and damaging storm surges in the Torres Strait region over this period point to human-induced climate change being the root cause of the loss of the Bramble Cay melomys.

I’m taking the first conclusion on trust because I have no usable data on rainfall and temperature in the area around Bramble Cay, but I do have some data for sea level rise and cyclones/typhoons. First, is Bramble Cay routinely affected by typhoons and cyclones? Figure 3 leaves no doubt that it is:

Figure 3: Typhoon/Cyclone tracks, 1990-2010, data Australian Bureau of Meteorology

And has the frequency of typhoons/cyclones in and around Australia been on the increase, as one would expect if storm surges are becoming more common? According to the Australian BOM it has not:

Trends in tropical cyclone activity in the Australian region (south of the equator; 90–160°E) show that the total number of cyclones appears to have decreased to the mid 1980s, and remained nearly stable since. The number of severe tropical cyclones (minimum central pressure less than 970 hPa) is dominated by variability with periods of lower and higher frequencies of occurrence.

The data are shown in Figure 4:

Figure 4: Number of cyclones around Australia, 1970-2010.

Despite what the BOM claims there has been an obvious decrease in the total number of cyclones around Australia since 1970.

And what about sea level rise? Figure 1 showed the locations of four PSMSL tide gauge records on the northern tip of Queensland, about 250km away from Bramble Cay and the closest I can find. From west to east they are Booby Island, Goods Island, Turtle Head and Ince Point. All of them have data from 2000 through 2013 and Figure 5 plots them up:

Figure 5: The four tide gauge records

Figure 6 shows the average of the four records:

Figure 6: Average of the four tide gauge records

If one can believe a trend line drawn through data like these then relative sea levels in the area rose by 65mm, or about 2 ½ inches, between 2000 and 2014, the period over which the melomys died out. Clearly this would not have inundated Bramble Cay, which reaches a height of nine feet above sea level. Not even the +/- 400mm seasonal range – note that sea levels are highest in the cyclone season – would have made that much difference, and being in the open ocean the seasonal range at Bramble Cay could well be lower than this. Yet there is abundant evidence that the island was inundated, and more than once, in recent years. From the University of Queensland report:

A significant weather system in July 2005 during which “waves were reported being thrown up over the cay as a result of gale force winds pounding the cay for several days coupled with very high tides” was probably responsible for, or at least contributed to, the 49% reduction in vegetation cover on the island in December 2011, as compared to the previous assessment in November 2004…. seawater inundation resulting from one or more extreme weather events over the two and a quarter years following December 2011 (was) the most likely cause of the further 94% loss of vegetation cover that occurred by March 2014. Observations made during the August–September 2014 visit provided strong evidence of additional episodes of seawater inundation or wave penetration of the cay’s interior during the five-month period between the two trips made to the island in 2014.

So there you have it. The demise of Melomys rubicola had nothing to do with temperature, rainfall or sea level rise. The animal was a victim of storm surges that progressively destroyed its habitat. No evidence – not even a climate model – is presented to support the claim that these storm surges had anything to do with increasing atmospheric CO2. It’s also questionable whether storm surges at a remote atoll even qualify as “climate change” – note that they are described in the above quotes as “weather events”. Yet in its press release the University of Queensland has no compunction in confirming that the extinction was a result of man-made climate change:

University of Queensland and Queensland Government researchers have confirmed that the Bramble Cay melomys – the only mammal species endemic to the Great Barrier Reef – is the first mammal to go extinct due to human-induced climate change.

Usually I like to conclude a post with a pithy comment, but in this case words fail me.

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24 Responses to Climate change claims its first species – or does it?

  1. erl happ says:

    Nicely potted. Let’s hope this post is in the file when the researchers responsible for this nonsense present their next application for funding.

  2. Russ Finley says:

    “…The animal was a victim of storm surges that progressively destroyed its habitat…”

    Then why didn’t storm surges drive this mouse to extinction millennia ago? Sea levels have risen, storms have become more energetic (both observed and predicted by climate models). Respectfully, I’m not convinced it wasn’t the victim of climate change.

  3. “…The animal was a victim of storm surges that progressively destroyed its habitat…”

    Then why didn’t storm surges drive this mouse to extinction millennia ago? Sea levels have risen, storms have become more energetic (both observed and predicted by climate models). It’s a reasonable hypothesis that this subspecies was the victim of climate change.

    • Graeme No.3 says:

      The Cay may not have existed in the past. There is a report from 1927 claiming that the land was rising.

      Alternately the species was wiped out by storm surges in the past, and repopulated the Cay when it was carried down on vegetation by the Fly River in flood.

    • It isn’t a reasonable hypothesis when you have no evidence to back up the claim only supposition and conjecture. Do we know that the creature has lived there for millennia? If so, has it always been present on that island? Sea levels have been rising for considerably longer than we have been pumping CO2 into the atmosphere.

    • Javier says:


      Despite the name you don’t know much about species. Do you? This is life at the edge. A small patch of land appears, and gets quickly colonized by a few species. Through founder effect, genetic drift, and specific conditions they quickly diverge, but their life is precarious. If conditions become slightly worse the population is wiped out, and this is not a loss to the parent species. This is evolution in action, and has nothing to do with us.

      On the other hand island endemic species are high risk. Of all the mammal and bird species gone extinct during civilized man watch, the great majority have been island species. And the main cause is invasive species. Despite this being our responsibility, we don’t seem to be too worried about the loss of these species. Perhaps because it is not due to climate change. If we discount these island species that we are losing, the idea of a mass extinction becomes silly.

      Since 1500 we have lost 61 mammal species, 3 of them in continents and 58 in islands and Australia. And we have lost 129 bird species, 6 of them in continents and 126 in islands and Australia. Can you see a pattern?

      As a biologist I am concerned that instead of dedicating our efforts to the protection of wild populations and ecosystems all over the planet, as we have been doing in the developed world, we dedicate the money to fight a climate change that it is having surprisingly little effect on the biology and most of it positive.

      Climate change has helped more UK species than it has harmed

      Agricultural management and climatic change are the major drivers of biodiversity change in the UK
      Burns, F. et al., 2016. PLoS ONE 11(3): e0151595

      “Climatic change has had a wide range of impacts on species, with more species impacted positively than negatively in the short-term at least.

      Climatic change accounted for the second largest percentage of impact, 14 [-6 ; +8], though its impact on species trends was more balanced between positive and negative, and thus was the largest positive impact.”

      This was totally predictable. An increase in temperatures produces an increase in energy and water and together with an increase in CO2 produces more productive ecosystems. Some species might respond negatively to the changes, but most species will respond positively.

      Anthropogenic effect on species is greatly negative, but not due to climate change.

      “As we describe, the net impact of climatic change on UK species in our sample is positive, but it is not clear whether this will always be the case.”

      Typical non-scientific bullshit. We find that the impact of climatic change is positive, but since we know it has to be negative, this has to change.

      • Javier: Thanks for that excellent response. I believe there are a number of biologists like you who take an objective view of species extinction but whose voices are rarely if ever heard in the mainstream media, which never saw a climate change disaster it didn’t like no matter how absurd the reasoning behind it.

  4. Euan Mearns says:

    Bramble Cay is effectively a sand bar in the estuary of the Fly River, PNG. Top image is dated 2008 and shows how the cay was eroded between 2002 and 2004. This cannot be considered a permanent feature, though it does sit atop a coral atoll. On Google Earth it appears as a tiny smudge.

    The Melomys probably shouldn’t be there in the first place and probably arrived on floating debris or on ships. Captain Cook may have lost a couple of his pet Melomys when he claimed the territory for Britain.

    Here’s a 20 page report prepared by the Queensland Government on how to save the Bramble Cay Melomys. Obviously they failed. Perhaps setting hundreds of traps and trampling all over the island was not such a good idea after all!

    From what I can gather, the melomys is common on islands in the region and is therefore not even extinct.

    • Thanks for the pics,Euan. While coral atolls have a self-regulating mechanism that maintains them at or around sea level sandspits are notorious for coming and going. And the fact that your 1935 paper refers to driftwood from the Fly River arriving on the beach at Bramble gives us a plausible explanation for how the melomys got there in the first place. If so, we might expect to find a thriving colony of Melomys Rubicola in the Fly River delta.

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  6. Graeme No.3 says:

    Ah, but Euan, this is a special melomys found only by those looking for an example of Climate Change extinction. None of the other melomys have become extinct so they lack the essential distinguishing feature.
    I notice that no-one checked if the ones from the Cay would interbreed with those from the mainland or from the as yet unlooked for relatives in Papua New Guinea.
    If this is a true indication of the scientific abilities of the “researchers” then they should be marooned on Bramble Cay.

  7. Craig Austin says:

    My understanding is that most island extinction events like this are caused by the introduction of cats. May be a cat drifted out there and has since drifted on. As ridiculous as my suggestion is, it makes more sense than their explanation.

  8. To correct a mistake I made in the text, Bramble Cay is not an atoll but, as other commenters have noted, a sandspit probably created by outwash from the Fly River delta.

    It is also clearly not part of the Great Barrier Reef:

    The UQ claim that the melomys was the only mammal species endemic to the Great Barrier Reef is therefore also invalid.

  9. JerryC says:

    Sure would be interesting to know what characteristics separate this rodent from similar species on the PNG mainland.

  10. Jimmy says:

    Nicely written article, thank you for a free lesson on climate change, i do agree that many times people do unfounded research just to earn money :v

  11. mosomoso says:

    Can we first know what ferals have made their way to this sand spit? If cats are there, no need to build whirlygigs in California or install solar panels in Brandeburg at 50+ N to avert further extinctions.

    I live in a declared koala habitat where there are no koalas. Tabby (and Rover) can clean out more native fauna in a night than a year of floods or droughts.

    Not that our modern activist researchers would ever obscure such an obvious causative factor just to get an appreciative moo from the herd.

  12. steve says:

    I am not qualified in graph analysis but the Figures for sea level rise do not seem to show a 65mm trend. Drawing a series of points from Y2000 to the end, the line falls, rises a bit then falls again. Re- averaging this line gives a different line to the trend chosen to prove extinction. Can someone who understands how they do it explain please.

  13. Morten Jødal says:

    Small sandy islands like Bramble Cay are unstable. They are not long-existing, and are shaped by sand transportation from nearby rivers, plus wind and currents. On such a place, no animal or plant can evolve into a separate species. They will not have the required time. It must have been brought there by floating debris or by humans. Which means: the species must exist another place.

  14. Any discussion involving millenniums in this area near the Great Barrier Reef should reflect the enormous changes that occur following each 100.000-year glacial period. In a very brief period (~8,000 years) sea level rose over 400 feet, and suddenly (in geological terms) there was a Great Barrier Reef, and sea mounts supported coral growth that easily maintained itself at or near the surface as sea level rose rapidly. Only 6,000 years ago, during the Holocene Climate Optimum, sea level was 10 feet higher than now, and if Bramble Cay broke the surface at that time, it probably was even less suitable for mouse habitat than now. In the light of these vast changes, the Australian researchers have been inspired to arrive at half-vast conclusions. They seem not to understand the environment they work in.

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