Global warming and extinct species: three case studies.

One of the many projected impacts of global warming, or climate change if you prefer, is species extinction. And according to the IPCC AR4, as reported in Wikipedia, the impacts of climate change on species are potentially catastrophic:

There is medium confidence that approximately 20-30% of species assessed so far are likely to be at increased risk of extinction if increases in global average warming exceed 1.5-2.5 °C (relative to 1980-1999). As global average temperature increase exceeds about 3.5 °C, model projections suggest significant extinctions (40-70% of species assessed) around the globe.

It’s also been reported that some species have already been driven to extinction by climate change, with the implication being that we’re already seeing the thin end of the wedge. But are these reports true? Are the species definitely extinct, and if so was climate change really to blame? Here we will review three of the better-known reported extinctions to see what the data tell us. In order of disappearance, the three victims are:

1. The golden toad (extinct ~1989)
2. The Aldabra banded snail (extinct ~1997)
3. The white lemuroid possum (extinct ~2005)

Here is where they lived:

And in Section 2 the real reason for the disappearance of the banded snail from Aldabra Atoll will be revealed for the first time.

1. The Golden Toad

• EXTINCT: Golden toad (Bufo periglenes). Along with the Monteverde harlequin frog (Atelopus varius), also of Central America … Last seen in 1989, the golden frog lived in mountaintop cloud forests that have disappeared due to drought and other climatic changes. (Source: IPCC AR5 Working Group II 2014 report, as quoted in National Geographic)

The IPCC’s first claim is that mountaintop cloud forests have disappeared. This is true in some areas, but the golden toad’s habitat was the Monte Verde cloud forest of Costa Rica, which is indisputably still there.

The next claim is that the extinction was preceded by drought and other climatic changes. We will begin with drought. The Global Historic Climate Network (GHCN) data base rainfall record for Monte Verde is shown below. It ends in 1986, a couple of years short of the reported extinction in 1989, but there’s no sign of drought. Also shown is the rainfall record from Puntarenas, about 20 miles south of Monte Verde, which covers 1987 and 1988 and later years. It shows no sign of drought either. (The GHCN records are available at KNMI Climate Explorer).

What about temperature? There’s no temperature record for Monteverde, but here are the records for Puntarenas and for Juan Santamaria airport, which is located about 40 miles east of Monte Verde. Apart from a few cold years in the 1960s Juan Santamaria temperatures show no significant change for a period of ~30 years before the golden toad’s extinction in 1989, and temperatures in Puntarenas were about a degree cooler in the late 1980s than they were in the early 1960s:

Clearly the extinction of the golden toad was not related to deforestation or climate change. So what caused it? The chytrid fungus, which causes a skin infection fatal to amphibians. (Interestingly, laboratory studies suggest that the infection can be cured by exposure to high temperatures.)

And the Monte Verde harlequin frog, which the IPCC also lists as extinct, isn’t. Small colonies still survive in the wild. (Note also that the golden toad will remain extinct only for so long as nobody finds one. Fifty years without a sighting is required before a species is officially listed as extinct.)


2. The Aldabra Banded Snail.

The only known population of the Aldabra banded snail Rhachistia aldabrae declined through the late twentieth century, leading to its extinction in the late 1990s. This occurred within a stable habitat and its extinction is attributable to decreasing rainfall on Aldabra atoll, associated with regional changes in rainfall patterns in the late twentieth and early twenty-first century. (Source: Gerlach 2007.)

This statement raises some questions, such as a) how did the habitat manage to remain stable during a drought severe enough to drive one of its inhabitants extinct and b) how can an extinction that occurred in the 20th century be associated with changing rainfall patterns in the 21st? But we’ll ignore them and move on. Here’s the extinction timeline:

Before 1976 – Snails abundant

After 1976 – “Dramatic drop in abundance”. Only adult snails found

1997 – Last live specimen collected

The extinction mechanism was interpreted to be a series of dry years – which if the snail population began to dwindle dramatically in 1976 must have begun around 1976 – that left the adult snails largely unharmed but killed the younger ones, leading to extinction through what is known as senescence.

Here now is the GHCN monthly rainfall record for Aldabra. Like the Monte Verde record it doesn’t quite make it to the extinction date, but there’s no sign of a series of unusually dry years beginning around 1976.

Figure 1(c) of the Gerlach report linked to above contains additional annual mean rainfall data, and here’s what we get when we combine them with the GHCN data (the two data sets give the same values in years where both have a value). I’ve added the extinction timeline for reference:

The combined data sets do show an overall decline in annual rainfall after 1976, but only when we include the years after 1997, when the snail was already extinct. Between 1968 and 1997 it’s hard to detect any significant change. (I’ve assumed, incidentally, that the 1958 and 1959 data are bad. If they aren’t we can make a case that it wasn’t a lack of rain that killed the snail, but too much of it.)

Obviously the snail didn’t go extinct because of drought. What about temperature? (“longer, hotter summers” are also cited as a culprit). The closest GHCN temperature record to Aldabra is Isles Glorieuses 160 miles to the south, and here it is. The first summer that might be classified as significantly longer and hotter than average was 1998, a year after the snail’s reported demise, and the trend line shows only 0.3C of warming over the last 60 years:

In short, there’s no evidence to support the argument that climate change drove the Aldabra banded snail extinct either. But if climate change didn’t kill it, what did? There’s no evidence that it was disease, loss of food supply, predators or habitat loss. Was there any event that coincided with the beginning of the snail’s decline?

Indeed there was. The arrival of the world’s most invasive species – man.

In 1966 the Royal Society mounted an exploratory expedition to Aldabra, liked what it saw, and in 1971 it opened a research station there. As a result RS scientists counted and collected snails on and off for ten years between 1966 and 1976, with activity peaking in 1975/76. The graph below superimposes their and other available shell count data on the extinction timeline. The timing is impeccable:

And don’t be misled by the small number of counts. The scale of collection was far greater. According to a Nature article “scientists were plucking snails off fresh leaves all over the Island 30 years ago” (which dates them as Royal Society scientists) and an Island Biodiversity article states that “in the 1970s traps that were set for insects (presumably also by RS scientists) ended up with loads of snails in them”. The arrival of the first shipload of tourists on Aldabra in 1970 on board the Lindblad Explorer, which made a number of repeat visits over the next few years, probably added to the depletion rate.

Even the last living snail, found in 1997, wasn’t left in peace. It was collected too.

So now we have an explanation that fits the facts and which requires no changes in the climate or anything else. The Aldabra banded snail was collected to death, as the Masirah cowrie seems to have been. But the evidence is circumstantial, insufficient to convict. What would we need to confirm beyond a reasonable doubt that this is in fact what happened?

We would need someone to go to a remote area of Aldabra with no history of snail collection and find a snail colony alive and well.

And on August 23, 2014, someone visited a remote part of Malabar island on the north side of Aldabra, and did exactly that.

Rhachistia aldabrae wasn’t extinct at all. It was just hiding.


3. The White Lemuroid Possum

Scientists say a white possum native to the Daintree rainforest in the Australian state of Queensland has become the first mammal to become extinct due to man-made global warming. The Brisbane, Queensland, Courier-Mail reports the white variety of the lemuroid ringtail possum, found only above 3,000 feet in the mountain forests of far north Queensland, has not been seen for three years. Experts fear climate change is to blame for the disappearance of the highly vulnerable strain thanks to a temperature rise of up to 1.5 degrees Fahrenheit. (Source: Fox News.)

Unlike the golden toad and the banded snail, hemibelideus lemuroides was claimed to have been a victim of temperature, not drought, being reportedly unable to survive for more than four or five hours at temperatures exceeding 30C. So let’s go straight to the GHCN temperature record for the city of Cairns, which is at the base of the mountains in which the white lemuroid possum lives, or used to:

It’s difficult to see a sustained rise of 1.5F (0.8C) anywhere (the most distinctive feature is the ~1C upward baseline shift in 1942, without which the record would show no warming since 1907). Moreover, the hottest summers on record occurred back in the 1920s. But the “temperature rise of up to 1.5 degrees F” that supposedly did for the possum occurred during the heatwave of 2005, so let’s zoom in on the period around 2005 to see if there’s anything exceptional about it:

When people talk of the “heatwave of 2005” in the Southern Hemisphere it’s not always clear whether they mean late 2004 and early 2005 or late 2005 and early 2006, but in this case it doesn’t matter. Neither summer was in any way exceptional, and the hottest month recorded in either period – December 2005 – was still only the 12th warmest month on record – the warmest was January 1924. And once more there’s no sign of a 1.5F (0.8C) temperature rise. (Do the scientists have a weather station up in the mountains above Cairns? One imagines they would have said something about it if they did.)

From these results we can conclude that abnormally high temperatures were not responsible for the extinction of the white lemuroid possum. Or at least they wouldn’t have been if the possum had indeed been extinct. But it stayed extinct only until 2009, when three live lemuroid possums were spotted in their natural habitat.

But these were brown lemuroid possums, not white ones. Doesn’t matter, said some, they’re both the same species; the white possum is just an unusual color variant. Does matter, said others. The white possum is a unique evolutionary unit, whether a separate species or not. Maybe this is why the white lemuroid possum has become known as the polar bear of the Southern Hemisphere. The polar bear isn’t a separate species either, but a subspecies of the brown bear.

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30 Responses to Global warming and extinct species: three case studies.

  1. Bernd Palmer says:

    Interesting and good investigative work, thanks. Maybe some of the banded shells can still be admired in cotton lined drawers at the offices of the Royal Society. Collector’s item ….

  2. Phil Chapman says:

    I do not understand this fuss about species extinctions. The claim that we should protect all endangered species implies that the present suite of plants and animals is somehow optimal, the best that there has ever been or ever will be. The extinction of species and their replacement by new ones is the very engine of evolution: without it, life on Earth would still consist only of pond scum.

    The argument that we should preserve all existing species is human hubris, an attempted violation of the iron law of Nature, and an abdication of our responsibility to manage the planet for the benefit of our descendants. We have become of necessity the stewards of the global ecosystem, because there is nobody else, and management means making decisions. In particular, it demands triage of existing species: trying to preserve everything is just one triage policy, and one that cannot work. Of course we should preserve species that are interesting or useful or beautiful, and we should not treat animals with wanton cruelty – but these are choices based on our own ethics, or on the kind of society we would prefer, not some sort of god-given moral obligation.

    It is sometimes argued that we need to preserve every tropical rainforest because (who knows?) there may be some little unknown creeping creature there which might hold the key to some unknown pharmacological breakthrough. If on the other hand we change the ecology, some new creatures will evolve to replace those that disappear – and maybe (who knows?) they will be the ones that prove valuable.

    Nature is not nearly as as benign as Green theorists imagine. The potential ecological damage due to human activities is minor compared to the havoc that asteroid impacts, supervolcanoes, tsunami, global glaciations etc. etc. have caused in the past, and will in the future. Many megafauna went extinct at the end of last glaciation, 10,000 years ago, including the mammoth, the mastodon, the great saber-toothed cat Smilodon, the dire wolf, the large and vicious short-faced bear, the giant sloth, the giant carnivorous kangaroo, etc. I am sorry we don’t have specimens of these scary animals (preferably safe in cages), but in what way is the world worse off because they no longer exist? Do we really miss them (apart from their possible value as curiosities)? Does it matter whether they died out because of the rapid, massive climate change, or because our ancestors hunted them to extinction?

    (If you ever visit a redwood grove in California, and listen carefully, you can almost hear the cough of a Smilodon, stalking you. If you are less romantic, I recommend the La Brea Tarpits in Los Angeles and the adjacent Page Museum, which has skeletons of many of these animals that fell into and were preserved in the tarpits, long ago.)

    The fossil record offers compelling evidence that life has evolved without any purpose or ethical principle, and the struggle for survival remains a scene of unremitting carnage. Those who believe in Intelligent Design must admit that the Great Designer has been wasteful, arbitrary and ruthless: the Design, if there is one, does not involve nurturing living things but relies instead on driving them to extinction, over and over again. That is the way of the natural world: the Greens claim to respect nature, but what they are really doing is trying to impose an artificial order that is just as much a human construct as downtown Manhattan.

    The present suite of plant and animal species is a very small subset of those that have existed in times past, perhaps no more than 0.5%. All the rest have perished, including some that we might recognize as cousins if they had survived (Homo neanderthalensis, H. floresiensis, even H. erectus). The inescapable reality is that Nature is and always has been utterly merciless, and entirely indifferent about whether the world is a lush green paradise, a wasteland as barren as the Moon, or the abode of monsters (as it was in the time of the dinosaurs). Life itself is astonishingly resilient, but individual species have almost all been ephemeral, including our ancestors (and perhaps ourselves). So why should we care about the fate of the golden toad?

    A personal note:
    When I was an undergraduate in Sydney (lo, these many eons ago), I had a vacation job working for the accountant for a wholesale butcher. One of my tasks was to go get the tally from the local abattoirs every day. The killing floor was a scene only Dante could have liked, with blood running in rivers across the floor, and blood-stained brutes playing soccer with a steer’s heart during their tea break. The sheep and the cattle waited dumbly in their chutes to meet their executioners, but the pigs started screaming as soon as they smelled blood. It made me think that pigs are too intelligent to eat (and I haven’t since then).

    Another formative experience: I wintered at Mawson, Antarctica during the IGY (again, many eons ago), and one of my jobs was to take a dog-team out on the sea-ice to kill a Weddell seal or two (we used their meat to feed the dogs, and sometimes ourselves). Weddells are large seals, about 700 kg, and they are unaware that humans are dangerous. I would park the dogs a hundred yards away and walk up to a group of them, basking in the sun on the ice around a breathing-hole. The one I chose would look at me with big brown soulful eyes, and I would shoot it in the head with my trusty old Lee-Enfield .303 rifle, at a range of six inches. We had to cut them up quickly into manageable pieces before they froze: I would make sure it was really dead, shooting it again if necessary, but still it shuddered when I cut into it. One time I cut out the heart, and it started beating again in my hand. It was a revolting experience, and it cured me of any interest in hunting..

    I haven’t killed any mammal since, but I have no qualms about killing fish, probably because they are less anthropomorphic. I have no pity for the scorpions and other bugs that sometimes come into our house from the desert outside (I live in Arizona) – and an Aldabra Banded Snail would certainly be endangered if I found it munching on vegetables in our garden.

    • Bernd Palmer says:

      Phil, I couldn’t agree more with this. It’s well argued.
      “the Design, if there is one, does not involve nurturing living things but relies instead on driving them to extinction,”
      I would also mention those completely useless and damageable (in our eyes) bacteria and viruses that were designed into the system (Ebola anyone), that humankind tries to extinct with all its power and intelligence. I haven’t heard of any Greens objecting.

  3. Euan Mearns says:

    Roger, another interesting post. A couple of things strike as odd. The first is that your three examples come from deep within the Tropics which I believe should be the most stable climatic belt. It is therefore very odd that “scientists” should claim climate change as the cause of the alleged extinctions especially when such obvious alternatives exist. Why do you think scientists would make such obvious mistakes?

    The second odd thing is that we had very rapid warming at the end of the last glaciation and yet we and millions of other species are still here. The reason of course is that life is robust and adaptable.

    I am in fact much more concerned about other aspects of Mans encroachment on the environment than I am about climate change. Poisons, plastics, chemicals land use changes etc I believe pose a much greater threat.

    • Euan: I think the tropics get studied a) because there is a much higher density of species there, b) because lots of species are confined to small areas, which makes it easier to show that they’re no longer there and c) because they are often attractive little animals that the public will ooh and aah over – even the Aldabra banded snail has its points.

      Climate change gets the blame because it’s widely accepted that everything bad that happens in the natural world was caused by it whether the climate has changed or not.

      And despite the false alarms the Aldabra banded snail and the white lemuroid possum are still claimed to be in imminent danger of extinction from climate change. The next time someone fails to find one we’ll hear about it all over again.

  4. A C Osborn says:

    Euan Mearns says: September 24, 2014 at 9:25 am “Why do you think scientists would make such obvious mistakes?”
    Because it fits their narrative, just like all the other so called “mistakes”
    Alpine Glaciers gone by 2025
    Millions of “climate refugees”
    Metres of Sea rise
    No Ice at either pole
    More and bigger Hurricanes, Typhoons & Tornados
    The list of things blamed on Climate Change (AGW) is now very very long and completely WRONG.

  5. It’s worth mentioning that the impacts of global warming pale into total insignificance beside the combined impacts of human activity over the last 10,000 years, which are claimed to have been responsible for the greatest mass extinction the world has ever seen:

    The Holocene extinction, sometimes called the Sixth Extinction, is a name proposed to describe the extinction event of species that has occurred during the present Holocene epoch (since around 10,000 BCE) mainly due to human activity. The large number of extinctions span numerous families of plants and animals including mammals, birds, amphibians, reptiles and arthropods. Although 875 extinctions occurring between 1500 and 2009 have been documented by the International Union for Conservation of Nature and Natural Resources the vast majority are undocumented. According to the species-area theory and based on upper-bound estimating, the present rate of extinction may be up to 140,000 species per year.

    But if 140,000 species are going extinct each year how come there’s still life on Earth? (There are only 1.8 million identified species altogether). The answer is simple. The extinct species are unknown to science. We don’t notice they’re no longer there because we never knew they were there to begin with.

  6. Do you have a link to where the IPCC is making the claims you cite, Euan? I’ve search the AR5, on the IPCC web site and can’t find any of the three creatures you mentioned.

    • Euan Mearns says:

      Mike, the article is authored by Roger Andrews who lives on the west coast of Mexico. Usually gets active late afternoon UK time. I will let Roger answer.

    • A C Osborn says:

      Roger’s article actually says AR4, not AR5.

    • The IPCC was cited (indirectly) as the reference only in the case of the golden toad. If you had a problem finding it it was because the link didn’t work. Apologies. Now fixed.

    • My apologies for attributing the article incorrectly and thanks to Roger and A C for replies.

      I see that the first quote was from AR4 but that didn’t concern specific species. As Roger stated, the only attribution to the IPCC was for the Golden Toad, with AR5 mentioned. However, there is no mention of the Golden Toad (either the common name or the scientific name) in AR5 that I could find. The reference to the IPCC was through a National Geographic article but that article did not state that the IPCC thought that the Golden Toad had gone extinct through climate change. It referred to Bob Scholes and Hans-Otto Pörtner making the claim, though they also state that there were other confounding factors in the extinction.

      So I’m still confused as to why this article seems to imply that the IPCC has made claims about specific extinctions caused (entirely or partially) through climate change, or why Roger chose those particular extinctions. Are there other ones you’ve looked at where climate change is a clear factor in the extinction? With climate zones moving poleward quite quickly, it seems likely that it will cause extinctions, especially in connection with other human behaviours that tend to destroy habitat.

      In some ways, it doesn’t matter whether it is climate change or other human behaviours that are causing the highly elevated estimated rate of extinctions. A 6th extinction event would be most unwelcome whatever the causes.

      • A C Osborn says:

        mikeroberts2013 says: September 26, 2014 at 6:32 am “With climate zones moving poleward quite quickly”

        What Climate Zones are moving Poleward at all let alone “quickly”?

        • All of them. Try a search on “climate zones moving polewards ” (without quotes) for more info.

          • Euan Mearns says:

            This suite of analyses generates ‘very high confidence’ (as laid down by the IPCC) that climate change is already affecting living systems.

            The Nature paper you link to is dated 2003 and so I imagine there analysis is dominated by the period of warming leading up to 2000. I find it astonishing that Nature finds the claim “climate change is already affecting living systems” to be worthy of publication since Earth’s climate is in a state of continual flux that has affected living systems since the dawn of time.

            The crux of the argument lies in attribution of the causes of late 20th century warming. My view is that perhaps 50% of that warming is natural, perhaps more.

            Where I live in NE Scotland in the 90s and early 00s we had a run of mild winters with little frost or snow. We were told snow was a thing of the past. It did look possible then that the forecasts were proving correct. But then the NAO switched and we returned to snowy and cold conditions more reminiscent of the 70s.

          • Euan, that was just one reference to climate zones moving polewards but if it was happening up to 2003, why do you think that such movement suddenly stopped thereafter, since there is still warming, albeit at a slower pace? Hansen’s book (2009) also mentions the phenomenon.

            Anecdotal evidence about your local weather is neither here nor there. I could mention that here in New Zealand, north island, summers seems to be producing more droughts or that we’ve had a couple of mild winters in a row, including the hottest June (a winter month here) on record. But that wouldn’t constitute evidence of anything, either, as I’m sure you’re aware. It is remarkable, though, that, globally, we haven’t had a month that was colder that the average of the 20th century, for over 30 years.

            Is your feeling that humans have only contributed half of warming just a feeling? I recall Judith Curry recently also had this feeling but (as far as I’m aware) couldn’t provide any evidence. Conversely, the IPCC AR5 report states that the science shows humans have probably caused all of the warming since 1950.

          • Roger Andrews says:

            The Parmesan & Yohe paper rears its ugly head again. I’m unable to make head nor tail of the methodology, but even if the results are correct I find it difficult to get worked up about 279 of the world’s 1.8 million species moving poleward at 0.00004 miles per hour.

  7. mikeroberts, you ask: Are there other ones you’ve looked at where climate change is a clear factor in the extinction?

    I thought about including this one, although it isn’t extinct.

    European blood-sucker falls victim to global warming (Reuters)
    Xerobdella lecomtei land leech

    OSLO – A rare European leech seems to be headed towards extinction as global warming dries out the Austrian forest home of the tiny blood-sucker, scientists said on Wednesday.
    Researchers at German and Austrian universities found only one juvenile leech in birch forests near Graz, Austria, in searches from 2001-2005. Scientists had found 20 specimens, up to 4 cms (1.6 inches) long, in the same forests in the 1960s.

    “Recent human-induced warming may have led over past decades to the almost complete extinction of a local population of this rare animal species,” they wrote in a study to be published in the journal Naturwissenschaften.
    A rise in average summer temperatures in the region of 3 Celsius (5 Fahrenheit) since the 1960s, widely blamed on greenhouse gases from burning fossil fuels, had apparently dried out the forests where leeches lived on moist bark and leaves.

    Here are the temperature and rainfall records for Graz, Austria, supplied without comment.

    Note also that the European land leech is one of the rarest animals on Earth. It wasn’t discovered until 1868.

    • Roger, that wasn’t really an example of an extinction where climate was clearly a cause (in your view). Are you suggesting that there are no cases where a species has become extinct probably due to recent climate change? Concerning your “example”, you reference an article, rather than a scientific paper (though the article mentions a paper, without a link or proper reference, or names of the researchers) but that article states that the average summer temperature has risen 3C over the last 50 years. Your charts do appear to show an increase but it’s difficult to tease out exact numbers from those charts.

      Can you point to scientists making the claims you’ve chosen to highlight in your piece? I’m having difficulty tracking such claims down.

      • Roger Andrews says:

        Are you suggesting that there are no cases where a species has become extinct probably due to recent climate change?

        The European land leech is the only example I can find of a claimed extinction that’s associated with an actual change in climate, except that the leech isn’t extinct and the change in climate was subtle, as you note.

        Can you point to scientists making the claims you’ve chosen to highlight in your piece? I’m having difficulty tracking such claims down.

        All of the text quotes are correctly attributed. If you believe they aren’t, well, please provide details.

        However, it now occurs to me that I should have included the full abstract from Pounds et al, 2005, which as an example of pseudoscience in action is hard to beat. And no fewer than fourteen “scientists” signed off on it:

        Widespread amphibian extinctions from epidemic disease driven by global warming

        As the Earth warms, many species are likely to disappear, often because of changing disease dynamics. Here we show that a recent mass extinction associated with pathogen outbreaks is tied to global warming. Seventeen years ago, in the mountains of Costa Rica, the Monteverde harlequin frog (Atelopus sp.) vanished along with the golden toad (Bufo periglenes). An estimated 67% of the 110 or so species of Atelopus, which are endemic to the American tropics, have met the same fate, and a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) is implicated. Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with ‘very high confidence’ (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable.

        • Bernd Palmer says:

          From the Pounds et al. citation:
          (i)Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with ‘very high confidence’ (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances.(/i)
          Correlation is not causation. Have they checked the temperatures and precipitation locally, in the American tropics?

        • The complete Pounds et al paper is here:

          Its key claim is that the growth of the fungus that killed the amphibians was caused by increasing cloud cover: “At Monteverde, regardless of the season, the daily minimum is rising while the daily maximum is falling (Fig. 4a). These trends imply increasing cloud cover that contributes to warming at night but diminishes it during the day.”

          This claim is based on data from an earlier paper by Gomez & Fernandez entitled “Interannual variations in temperature in Costa Rica”. G&F, however, concluded that “In the absence of cloud data correlations were obtained between diurnal temperature range and sunlight and rainfall. These correlations are weak and do not allow the reduction in diurnal temperature range to be attributed to an increase in cloudiness.” (My translation from the Spanish.)

          The ISCCP satellite data also show no significant change in cloud cover in Costa Rica since 1983:

        • Thanks for that, Roger. From the link in the abstract, I could find the paper, though I don’t have access to the full text. I did find this paper which does suggest that it was more likely dry periods caused by El Nino that influenced the demise of the golden toad.

          Sorry for missing the links in the other two cases. The paper covering the possible demise of the snail shows annual rainfall under 1023mm might be a factor and such years did increase prior to the estimated demise of the snail. For the possum, it seems that it didn’t become extinct in the year of the linked article but may be ecologically extinct now. It’s actually not near Cairns (a three hour drive north) and 300 metres up. This article states that there was a heat wave in 2005, there, and temperatures over 30C for a few hours could kill them off.

          My impression, then is that you’ve not really presented conclusive evidence that global warming isn’t implicated in any extinctions, only that one of the ones mentioned probably wasn’t caused by AGW, though may have been “helped” by climate change via ENSO, which is not known to be tied to AGW.

          • My impression, then is that you’ve not really presented conclusive evidence that global warming isn’t implicated in any extinctions,

            How do I prove I didn’t take out a life insurance policy on my wife?

            Sorry, but the onus is on you guys to prove that global warming IS implicated in extinctions, but despite many determined efforts no one has yet been able to identify a single case. I think that speaks for itself.

            The Anchukaitis and Evans paper you link to is also interesting. We started off with this in Pounds et al:

            … we conclude with ‘very high confidence’ (99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the (amphibian) disappearances … With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable.

            And now we’re down to this:

            There is no evidence of a trend associated with global warming. Rather, the extinction of the Monteverde golden toad (Bufo periglenes) appears to have coincided with an exceptionally dry interval caused by the 1986–1987 El Niño event.

            After going through the data yet again I can find no good evidence that the extinction had anything to do with the 1986-87 El Niňo event either, but even if it did it’s widely accepted that El Niňos aren’t caused by man-made greenhouse gases.

  8. A C Osborn says:

    279 of 1700 Species that might be moving (With very high confidence as laid down by the IPCC, which is meaningless in Scienctific terms), does not represent Climate Zones.
    Merely 16% of those studied, did they bother to look for any moving in the opposite direction?
    This is as bad as the Tree Line predictions.

  9. Hey, Roger, I’m not sure what you mean by “you guys” but I guess you’re admitting that I’ve chanced upon a climate skeptic web site (I just followed a link from TheOilDrum to see what Euan was up to, these days). Looking through some prior posts, that seems to be confirmed. What I find with these sorts of sites is similar to what I see with climate doom sites – a distinct cherry picking of articles and science papers that could possibly support a particular view and an ignoring of all other.

    You say there is no good evidence of El Nino being implicated in the demise of the Golden Toad and yet a science paper got published in a peer reviewed publication with good evidence. Of course, not all science papers turn out to be accurate but peer review is the best filter we have.

    So, you have decided that scientists have made claims about specific species being affected by climate change. You found one where the species is generally considered extinct and you reasonably find that climate change probably wasn’t a factor, just as a later paper also found (so maybe that wasn’t such a good example, as there is clearly some difference of opinion in scientific circles). A second example misrepresents the referenced paper in terms of what constitutes too dry weather for the snail. The third example relies on weather records from a place 3 hours drive south and much lower in elevation.

    So it was you who made the claim about what climate scientists were saying and then proceeded to debunk it with three examples, only one of which you seemed to have a good case for (though you then try to briefly debunk another view that actually supported your position – do you believe that climate conditions can’t possibly have any impact on life?). Now you say that I need to prove something that you were claiming.

    Personally, I like to think I take a critical position, and criticise some more alarming reasoning (like 200 species a day becoming extinct – not just through climate change – or drastic methane emissions in the Arctic) as well as positions like Curry’s who thinks that because of the uncertainty, we should wait until taking action (even though uncertainties can work both ways). Paleoclimate data alone show that we have some real problems to deal with, but the general thrust of most recent climate and emissions related science is that we have a serious problem. Of course, one could just ignore all the evidence (or mischaracterise it as “no evidence”) and hope for the best. As with peak oil, that doesn’t seem to be an intelligent approach.

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  11. Gin says:

    Is that possum an albino (pink eyes)? Don’t albinos have inherent problems? Just saying…

  12. Pingback: Recent Energy And Environmental News – September 29th 2014 | PA Pundits - International

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