[samcday]

Not sure if you've seen the following statement from University of Sydney, but they're standing by the estimate: https://sydney.edu.au/news-opinion/news/2020/01/03/a-stateme...

In fact, they've pointed out the 500 million figure is a conservative estimate, and is likely to be much higher: "... The true loss of animal life is likely to be much higher than 480 million. ..."

[mistermann]

> The authors deliberately employed highly conservative estimates in making their calculations. The true mortality is likely to be substantially higher than those estimated.

It's a shame the University of Sydney doesn't have access to this study such that they could have included a link so skeptical people could see for themselves the specifics of this alleged conservatism. Not doing that causes my intuition to question the truthiness of these claims, so I will file this item under "Unknown-Suspicious".

[nl]

The report[1] (which is trivial to find) has a section on their estimation methodology and includes reasons why it is conservative (section 2.3):

Many species were excluded from estimates because there is insufficient information on their abundance. The largest omission is the entire NSW bat fauna (37 species), for which no information on density could be found.

Many small mammals in semi-arid and arid regions exhibit large fluctuations in density depending on the prevailing weather. For example, historical accounts of the long-haired or plague rat (Rattus villosissimus) suggest that densities well in excess of 1000 animals per hectare can be attained after years of good rain31, with the species virtually disappearing again during drought. For such eruptive species, only the low-density population estimates were used.

The densities of several common species, such as the brown antechinus (Antechinus stuartii), agile antechinus (A. agilis), yellow-footed antechinus (A. flavipes) and brushtail possum (Trichosurus vulpecula) have been measured in several studies, with most yielding low to moderate densities but small numbers of studies yielding very high estimates. To reduce bias arising from these rare high values, means for each species were first calculated as log- transformed densities and then back-transformed to produce normal values. This method was used also by Cogger et al.

As noted, the usually lower densities obtained from studies carried out in the tablelands, western slopes and plains were used in preference to the higher estimates obtained in surveys further east. my note: these bushfires are in the East, so the higher estimates would be more appropriate here

Several species were omitted from consideration due to uncertainty about how vegetation clearing would affect them.

[1] https://www.researchgate.net/publication/318029981_Impacts_o...

[mistermann]

> has a section on their estimation methodology

>> 1.5 METHODOLOGY

>> Calculation of wildlife impacts

>> Given Australia’s megadiversity of species and our comparatively small human population and research base, the density (ie number of individuals in a given area) of relatively few species has been determined with precision. In addition, the number of different species, or species richness, occurring in a given area is not known in great detail for many habitats. Estimates of these values must necessarily be extrapolated from a relatively small number of detailed studies. Therefore the authors have deliberately employed highly conservative estimates in making their calculations. The true mortality is likely to be substantially higher than those estimated in this report.

The authors seem fairly straightforward in admitting that these numbers should be considered unreliable, so no criticism from me on that. However: does this (un)certainty attribute accompany (with appropriate emphasis) the data into subsequent news articles and social media conversations, and ultimately millions of human minds?

>> 2.3 HOW HAVE THESE NUMBERS BEEN ESTIMATED?

(No excerpt because I have nothing particular to highlight.)

Again, from a science perspective, I have no complaints about the study itself, but I do have complaints about how it is being used as the basis of broadcasting a manufactured version of reality into the public psyche, dressed up as reality itself.

Take the University of Sydney article itself...

Headline: "A statement about the 480 million animals killed in NSW bushfires since September"

Article content: "Professor Chris Dickman estimates that 480 million animals have been affected since bushfires in NSW started in September 2019. This statement explains how that figure was calculated. "

See the differences?

a) "killed" --> "affected"

b) "480 million animals [have been] [killed]" --> "it is [estimated that] 480 million animals have been [affected]"

And this is the University of Sydney article, an "authoritative" (able to be trusted as being accurate or true; reliable) institution. Now imagine the hyperbolic distortions of content and certainty that the MSM, Twitterverse, and Reddit hivemind layer on top of this, which is then consumed repeatedly by hundreds of millions of people who consider it to be factual reality. [0] [1]

So, is this a big problem? I have no idea. How would one even estimate the magnitude of risk involved in the general public walking around with (unnecessarily) inaccurate internal representations of reality in their heads? Again, I have no idea. But with human behavior getting stranger by the day, I have a feeling that widespread adamant opposition to even considering this very real aspect of reality may turn out to be not a wise approach. Time will tell I suppose, although it's completely possible no one ever sees this perspective even if it does ultimately result in negative outcomes.

[0] https://www.frontiersin.org/articles/10.3389/fpsyg.2014.0158...

[1] https://www.nature.com/articles/474446a

[nl]

Sydney Uni has posted an updated link: https://sydney.edu.au/news-opinion/news/2020/01/08/australia...

They use "killed" and "affected" interchangeably. The exact quote is:

Professor Chris Dickman has revised his estimate of the number of animals killed in bushfires in NSW to more than 800 million animals, with a national impact of more than one billion animals.

I'm not an expert in this area, but from my reading over the past few hours it appears the distinction between "killed" and "impacted" is not something ecologists think about a lot. It appears that they expect most of those "impacted" which do not immediately die, to die soon after (from predators or from habitat loss), or if they don't die they expect them not to be able to reproduce successfully (the young are too vulnerable in destroyed habitats).

I'd note this from the report (part you quoted):

The true mortality is likely to be substantially higher than those estimated in this report.

Edit: here's the interview where he makes the updated number claim: https://www.kosu.org/post/1-billion-animals-have-died-austra...

Edit 2: But it is true I'd like to see some more rigour around the estimates. I'd note that estimates for the 2009 Black Friday bushfires were for 1M animals killed with 400K hectares burnt. These fires have already burnt 8.5M hectares, but taking the 2009 death rate produces a number roughly an order of magnitude less.

[mistermann]

Thanks for that update.

> It's not clear why you keep picking it over looking for reasons not to believe it.

Because that's what lots of people do - at best, and I believe a solid argument can be made that this seemingly simple fact of human nature actually brings with it significant and unrealized risk.

Maybe it's worth pointing out explicitly: I'm not accusing the University or the professor of significant wrongdoing, intentional or not. Rather, my concern is with the effects our various styles of reporting the news (aka describing reality) has on the beliefs that individuals hold in their heads, and in turn the cascading/recursive unintended consequences that result from that.

HN is a relatively sane place, but look around at some of the other conversations taking place on planet earth - is it terribly innacurate to say that signs of fairly severe delusional thinking and insanity are becoming increasingly widespread?

An alien from another planet might reasonably predict that an increasing occurrence of (plausibly) climate-related calamities would result in massive widespread/unanimous concern among humanity for the health of the planet....and yet, what do we actually observe?

The same alien might reasonably predict, considering what's at stake, that the response to this unexpected outcome would be widespread concern among officials and intelligent people about what the hell is going on with people's thinking, and perhaps even a few initiatives to figure it out and rectify it while there's still time. But instead, we seem passionately satisfied with "groups x,y,z are stupid, and if they'd just stop we'd be all sorted....end of discussion!".

If our alien had a sense of humor, he might find this situation rather humorous.

[nl]

I actually deleted the but you are responding to because I don't think it was particularly useful. But thanks for responding.