Sustainable Dairy Farming – Eutrophication and Greenhouse Gas Mitigation

This is my first foray into posting a paper that I originally produced for my studies, something I hinted at doing in a previous post.

This paper was written as part of a subject exploring the human effect on the natural environment.

I chose to explore the prospect of sustainable dairy farming; particularly, the obstacles top sustainability created by nutrient run-off from dairy farms into waterways (eutrophication) and greenhouse gas emissions.

Although focusing on dairy farming, parts of the paper are applicable to other farming activities.

Preconceived ideas as to who will have any interest in this work, I have none. Hopefully, someone will gain some ideas of the scale of these two problems and possible practical solutions, and be able to put the paper to use.

I would be glad to receive any comments.


Sustainable Dairy Farming – Eutrophication and Greenhouse Gas Mitigation


Lies, Damn Lies and Killing Sharks (Part 2)

My last post about the Commonwealth of Australia’s approval of shark cull program in the State of Western Australia focused on the use of statistics with low power, and low merit, to amplify the argument that shark attack incidents in recent years are a cause for concern. Similarly the lack of statistics and use of anecdotal evidence to hype the economic downturn alleged to be caused by the flurry of shark attacks was red-flagged as being a poor substitute for proper analysis, particularly where the proposed solution was the targeted killing of animals listed as vulnerable to extinction or near threatened.

This post will look at the remaining points I listed as being the reasons provided by Minister Hunt for granting an exception to the Environment Protection and Biodiversity Conservation Act 1999 (Cth) for the cull, being:

1. A statistically significant increase in shark attack strikes in Western Australia in the years 2010 to 2013 compared to population increase;

2. As a result of point 1, people are scared of entering the water and there is anecdotal evidence of tourist businesses suffering financially;

3. The proposed cull will reduce the incidence of shark attacks and will provide useful information to other states in dealing with the same problem;

4. The West Australian government has implemented measures to reduce the risk of death to other sea life from the exercise; and

5. It is in the national interest (due to points 1 to 3 above) for the cull to be allowed, and therefore within the class of reasons the EPBC Act gives as being the basis for an exemption to be allowed.

3. The proposed cull will reduce the incident of shark attacks and will provide useful information to other states in dealing the same problem

The most striking aspect of this section of the approval is that, when read without any insight into shark control measures already in place in our own country let alone any other country, it would seem that this was a pioneering approach that would be provide new insights in this problem.

New South Wales and Queensland have implemented and maintained shark control measures since 1937 and 1964 respectively. Queensland and KwaZulu-Natal in South Africa, which also has shark control program presently operating, utilise netting and drum-lines just like the West Australian culling program proposed to use. Programs have also been implemented in New Zealand, Brazil and Hawaii.

Although literature on the results of shark cull activities was limited from my searches, Minister Hunt could have easily obtained a detailed report on the effects, both good and bad, of such a cull. Indeed, the State of Western Australia had already engaged Associate Professor Daryl McPhee of Bond University to provide a report to the West Australian Department of Fisheries in which he explains the objectives of his report as including a literature review of studies and reports on shark exclusion programs in other jurisdictions.

The report is not long (23 pages) and easy to read. It follows from the report that perhaps the only change to result from the program will be analogous to the placebo effect; make people feel like they are safer while the treatment offered has no effectual value.

There are noted problems with using shark attack data from New South Wales and Queensland to assess the effectiveness of those programs however. Associate Professor McPhee’s report doesn’t specify how effective those programs have been and nor could he. Any assessment can’t be controlled for other variables, such as increasing efficiency and expertise in providing aid to injured victims from becoming fatal victims, that will affect the analysis. This point he makes clear. He makes further comments about the variability of the programs in those states and internationally which wreak havoc on assessing the impact of these programs.

Similar to the basis of my critique of the statistical significance of the increase in shark attacks in my last post, a statistical analysis of these existing programs will be beset by problems of low statistical power.  This was amply illustrated by Jessica Meeuwig of the Centre for Marine Futures at University of Western Australia, who was driven to write on the subject given the same pretence as I am now writing. After analysing the data on shark fatalities in Queensland she concluded:

“This highlights the problems we face when trying to understand patterns in shark attacks and the effect of mitigation programs – fatalities are such rare events that differentiating between random coincidence and underlying patterns is fraught with difficulty”.

With that limitation on her analysis put forth, she found that that data indicated declines in shark-related fatalities in areas both with and without drum lines, and that the greatest decline in fatalities was prior to the installation of drum lines.

We already have similar programs in place to look to if this solution is the fancied solution and the data obtained is likely to be no different than that obtained in West Australia; the effectiveness cannot be measured to exclude random chance or independent, uncontrolled variables from being the cause of increases or decreases in shark attack numbers.

4. The West Australian government has implemented measures to reduce the risk of death to other sea life from the exercise

If the preceeding three sections outlined the problems with evaluating the effectiveness of a cull on protecting human life, the problem with this point 4 of the basis for allowing the program is almost opposite. The problem of by-catch of shark programs is of critical concern to those who have researched the effect of netting and drum-line programs.

Associate Professor McPhee evaluates this risk as long established. Citing data from the New South Wales, Queensland and South African programs he lists non-targeted species of shark and other animals such as rays, turtles, dugongs, seals, dolphins and whales as being the worst affected. He further notes the high incidence of by-catch in the initial years of these programs, an important fact should the approval for this program not be renewed in following years but re-implemented again at a later time. These implications, coupled with the dubious evidence of effectiveness of meeting the stated aims of the proposal, led him to recommend the West Australian Department of Fisheries against initiating such a program.

Paterson’s 1990 report “Effects of Long-Term Anti-shark Measures on Target and Non-target Species in Queensland, Australia” found that these measures have continuing deleterious effects on non-target species including the ones listed above. Problematic for such mitigation strategies is that some species affected are also listed species needing protection. While Paterson indicated the program to be a success in decreasing human injuries, a conclusion to be sceptical of in light of the above, his conclusion about the effect on non-target species adds historical weight to the problem of this significant side-effect.

Further, and possibly more importantly for the effectiveness of the program compared to detrimental impacts, he found that anti-shark measures in Queensland were most successful against indigenous sharks, not migratory sharks. The Great White Shark, one of the target species of the West Australian cull and the species most commonly involved in shark attack incidents, is a migratory shark with the West Australian coastline thought to be on the shark’s migration route. Meeuwig’s article above noted that in Queensland less than one percent of the sharks caught were Great Whites, while 97% of the sharks caught were conservation listed.

Development of non-lethal methods and technology as well as the use of current methods with greater effectiveness are noted in the above reports. An example is given of surface to seafloor netting at designated beaches in Hong Kong that completely separate sharks from swimmers, unlike the nets currently used in Australia, with added design factors to limit the fatal effects of netting on sea life. The Department of Fisheries in West Australia has itself been researching the use of repulsion devices that are effective for deterring sharks but have little or no effect on non-targeted species. It also has in place a monitoring program to track shark movements around the coastline.

A study by Caldicott et al looked for consistent factors surrounding shark attacks to find correlations between environmental factors and increased incidents of shark attack; colour, sound frequencies and electrical fields were found to attract shark activity. This information can assist in the development of non-lethal shark-repulsing methods and better education of the ocean-going public to reduce the likelihood of interaction between sharks and people.

The West Australian government, with the help of the Commonwealth Government, has determined that the risk posed by the use of netting and drum-lines is a reasonable risk to take. This is despite what appears to be overwhelming data showing the significant risk posed to numerous threatened species given the indiscriminate death the results from use of this equipment.

5. It is in the national interest for the cull to be allowed given all of the above

‘National interest’ appears to be a term that, despite any attempt to pin it down to a precise definition, can float back to the surface to be used again with an alternate or expanded definition to justify its use. Its use in this scenario must be considered a case study on point.

National interest is given a non-limiting definition in subsection 5 of the EPBC Act as being cases of defence, security or national emergency. I don’t believe the sharks are mounting an offence against Commonwealth and surely, given the oft quoted comparisons of road fatalities, drug and alcohol related fatalities, bee sting fatalities, etc, to shark attack fatalities, the supposed concerning increase in the latter within one State must mean that almost any state of affairs, even if limited to small geographical area and a few adverse outcomes, could see the national interest being used to justify intervention.

It therefore must be defined in this case outside those three considerations provided for in the Act. Given the claims of economic harm the term must be defined as relating to the economic interest of the country. I could envisage a widespread plague of unrestrained creatures, freed from ecological balance by the drastic reduction in predators, resulting in people being forced to stay on dry land and thereby effecting national tourism, as being a problem deserving of attention under the National Interest. I could see destruction of pristine areas of our natural land and sea environment as being in the national interest due to effects on the fishing industry and tourism, not to mention the loss of national natural assets recognised internationally, as being considered in the National Interest. It seems a long bow to draw to mount a case that one business’ reported reduction in scuba diving pupils is the platform to argue that this action is required in the National Interest

Either the benchmark for what meets the definition of national interest has been dropped to justify any issue of limited geographical, economic or health concern falling within its purview or the issue of shark attacks in West Australia has been bloated to seem like it should fit – I would argue it is the latter.


1. Stating that the increase in shark attacks is statistically significant, while correct, fails to address the limitation of statistical analysis of the shark attack data given the low numbers being used. The uncritical adoption of these tests gives undue credence to the assertion that shark attack incidents and fatalities are increasing for any reason other than chance alone.

2. Basing a decision to take action to minimise shark attacks due to the economic effects on one-off anecdotal reports of a drop people learning to scuba dive is inadequate justification.

3. Allowing the program will not provide any extra information as suggested in the approval as the same methods are already being used elsewhere.

4. There is a significant problem non-targeted species, a large portion of which are threatened species, being detrimentally affected by the program.

5. Given all the above, the issue must fall well below the minimum criteria to be considered ‘in the National Interest’.




Ethics by P.H Nowell-Smith

This is the first of my new series of posts containing selected extracts and quotes from books I’ve been reading.

The topics will fall within the general range of subjects I cover on this blog, from science based topics to philosophy and environment.

All my posts of this nature come with the exhortation that a better understanding of the extracts and the subjects of these books can only be achieved by reading the book, not by relying solely on the parts I’ve picked out as being, in my opinion, the most notable or instructive parts.

Today’s post covers “Ethics” by P.H Nowell-Smith published in 1954.

In brackets I’ve provided the context of the quotes and extracts that follow it, but have attempted to provide extracts that explain the context within the extract itself.

Ethics – P.H.Nowell-Smith – Pelican, 1954

(On theoretical ethics)

“The central phenomenon of ethics is, then, the moral judgement or, as Broad also calls it, the “opinion that something is right or wrong”. It should be noticed from the start that moral judgements are said to be, not emotional reactions or attitudes or expressions of approval and disapproval, but opinions.” Pg 26

“The intuitionists are, in fact, trying to combine in one form of judgement two assets, objectivity and relative incorrigibility. But these cannot be combined since the objective-subjective contrast loses its point if objective judgements are made relatively incorrigible. They use the language of ‘really is’; but the test that they apply to discover whether something really is right or wrong is the test of immediate insight, which is analogous to the test for ‘looks’ and ‘feels’”. Pg 58

(On the logic of Sentences and Arguments)

“Phrases such as ‘speaking offhand…’, ‘I don’t really know but…’, and ‘I should be inclined to say that…’ are used by scrupulous persons to warn the hearer that the speaker has not got what seem to him good reasons for his statement. But unless one of these guarding phrases is used we are entitled to believe that the speaker believes himself to have good reasons for his statement and we soon learn to mistrust people who habitually infringe this rule”. Pg 82

(On reasons for choosing)

“There is an air of tautology about ‘I laughed because it was amusing’, ‘I ran away because it was terrifying’ and ‘I remonstrated because it was an objectionable proposal’ which is absent from explanations in terms of statements of fact. But in spite of this A-sentences do not give complete explanations. This is partly because the explanatory force is inversely proportional to the obviousness of the tautology. ‘I objected because it was objectionable’ implies that I had some reasons for objecting but does not even begin to say what they were.” Pg 119

We often explain both why we did something and why we intend to do something by saying that it is fitting or appropriate to a situation or that it is in accordance with a moral rule. But these explanations are only logically complete if they contextually imply a pro-attitude to doing what is fitting or to obeying the rule; and this, in practice, they always do. But a part of an explanation that is so obvious that it can in practice be left out must not, on that account, be assumed to be unnecessary.” Pg 121

(On egoism and hedonmism)

“To be selfish is not to do what one wants to do or enjoys doing, but to be hostile or indifferent to the welfare of others. It comes out in two ways. (a) A man whose dominant desires were for his own pleasures (in the ordinary, not the philosopher’s sense) and who seldom or never wanted to do good to others would be a selfish man. (b) A man who does what he wants to do or what he likes,, when he does it at the expense of others, is a selfish man, even if what he does is not in itself selfish.” Pg 143

(In the context of G-words – words that imply not merely that the relevant person is likely to have a certain reaction, but that he ought to have it)

“That is not to say that we do not use G-words or ‘ought’ when making up our minds what to do, but that when we so use them we are, as it were, advising, exhorting, or commanding ourselves. If a man prefers one thing to another there is no temptation to represent the situation as one in which two people participate; but we do this quite naturally when a man tells himself that he ought to do something. It is an important fact that, while the personification of Desires is always strained and artificial, it has always seemed quite natural to represent Conscience as a little voice inside me that tells me what I ought to do.” Pg 151

(On advising and exhortation)

“This brings out one general difference between A- and G-sentences. Since the latter belong par excellence to the realm of choosing, advising, and exhorting and since the logic of these activities is such that sentences used to play a part in them must have a pro- or a con-force, G-sentences are always explicitly for or against something. A-sentences, on the other hand, are neutral unless the context shows which force they have. It may not be clear, for example, whether ‘It’s a dangerous (or onerous or responsible) post’ constitutes advice or or against; but ‘it’s a post worth having’ is not so ambiguous.’ Pg 155

‘The Persuasive Theory is an incorrect account of the use of moral language; but it enshrines an important truth. Advising is something that we choose to do and we must, therefore, have some reason for doing it. This reason may be a desire to persuade someone to do something and a man who gives advice (unless he gives it ironically) must, as we have seen, hope that it will be taken. This does not mean, however, that advice can never be disinterested. A man who advises another on the choice of a career may be concerned solely for the welfare of the recipient of his advice, and the farther who gives death-bed advice to his son can hardly hope to gain by it. The Persuasive Theory, but implying that man who gives advice must have an ulterior motive, makes an unfortunate and unnecessary concession to the doctrine that all human action is necessarily selfish.” Pg 157-8

(On exhortation – rhetoric, propaganda or suggestion – technique used by evangelical preachers on emotional congregations and advertisers who instil desires into their victims by suggesting that they already have them)

“It is important to notice that this is a secondary use of language, parasitic on genuine advice; and this fact is fatal to the ‘Persuasive’ Theory of moral language. A man can only learn to seek, accept, and reject advice if, in the majority of cases, accepting the advice does in fact lead to the result he himself desires. … Unless moral words had first been used in a way which connects them with our own interests – whether these be selfish or unselfish – we could never have come to be persuaded or dissuaded by their use and they could not act, as they sometimes do, as levers with which to manipulate the conduct of others”. Pg 158-9

“To tell someone that something is the best thing for him to do is to advise him to do it, but not irresponsibly. The speaker implies that he has good reasons for his advice, that he knows what the problem is and that his advice is relevant. The same predictive and causal elements are present as in the case of A-sentences; and advice may, as before, be given disingenuously, improperly, mistakenly, or unfortunately if one or other of the contextual implications is absent.” Pg 162-3

(On appraising and what we consider good)

“But in many cases the criteria now used are connected to natural criteria only through a long process of change and have become modified to such an extent that their original connexion with natural pro-attitudes has been entirely lost. And in such cases it often happens that we do not use the criteria we do because people have the pro-attitudes they have, but we have the pro-attitudes we have because the criteria are what they are. It may be that on one can now remember exactly why certain criteria were originally chosen to be the standards of judging something to be good or bad of its kind and that people are now prepared to admire, praise, and pat highly for objects because the conform to the accepted criteria, rather than accepting the criteria as ‘proper’ ones because, under them, the things that they admire rate highly. Taste is dictated by fashion, not fashion by taste.” Pg 173

“Sentiments, as Hume noticed, seem to vary in rough proportion to the propinquity of their objects. We are not moved by the iniquity or remote historical characters as we are by those closer to us; and we feel more approval for and sympathy with those near to us than with those who are more remote. Yet our moral judgements do not vary in the same way.” Pg 176

“…moral appraisals must be universal. Anyone who makes a moral appraisal even of a remote character must be willing to apply the same criteria universally. And it follows from this that he must be willing to apply them in practical contexts. If I am not prepared to condemn anyone whose behaviour is like that of Verres in all relevant respects, then, in calling Verres a villain, I am not making a genuine moral judgement; and the relevant respects are all of an empirical, objective kind.” Pg 177

“Ethical Naturalism is the attempt to trace logical connexions between moral appraisals and the actual pro- and con-attitudes of men, their desires and aversions, hopes and fears, joys and sorrows. One-track naturalistic theories always fail to do justice to the complexity both of the facts and of the logical connexion, since they suggest that there is only one thing towards which men have a pro-attitude, pleasure, or that all pro-attitudes are desires. And these theories are both psychologically and logically misleading.” Pg 181

“There is one peculiarity which right’ shares with ‘good’ and ‘ought’ and with no other words. Except in ironical or other secondary uses it is always a pro-word. We saw that while A-words must always carry a pro-force when used in the contexts of choosing and advising, they do not always carry the same force, and we have to gather whether they are pro- or con-words from the context. This is never the case with ‘right’. Some words that are akin to ‘right’, such as ‘just’, ‘fair’, and ‘honourable’, are almost always pro-words, but they admit of exceptions. They imply a code of rules but they could be used in cases where we want to advise a man to disobey the code. We might think, for example, that this was a case in which justice should give way to mercy and we should then say: “It would be the just thing to do; but in this case I don’t think you ought to do it”. But the word ‘right’ is seldom, if ever, used in this way.” Pg 189-90

“But we use ‘you ought’ sentences precisely when we are not in apposition to issue orders; and this fact and the fact that these sentences must be backed by reasons provide an important clue to their logic. Although ‘advice’ is far too weak a word for many ‘you ought’ sentences, their logic in primary cases is always that of advising, never that of commanding. For they are addressed to a rational agent as solutions to this problem of choice and, in consequence, they imply a pro-attitude on the part of the recipient. The author of a command, on the other hand, is not logically bound to be concerned with the pro- and con-attitudes of his subordinates, though, of course, he may be.

It is for this reason also that it is a mistake to define moral ‘oughts’ in terms of God’s commands or ‘God’s will’. For the mere fact that a command has been issued by a competent authority, even by Go, is not a logically good reason for obeying it. …We do in practice often appeal to the existence of a command in backing up an ought-sentence, in the same sort of way that we appeal to the existence of a rule; but this procedure contextually implies a general pro-attitude on the part of the recipient towards obeying the commands of that authority, as such” Pg 192

(On differences of opinion about whether a course of action ought to be taken)

“It might seem that this situation is still analogous to a dispute about an empirical matter. For if Jones says “It’s a dog” and Smith say “No, it isn’t”, they can both be right in the sense that each has used the correct form of words to express what he intended to say, but they cannot both be right in the sense of saying what is true. But, as we have seen, there is in empirical matters a test of truth which is independent of the beliefs of the speaker, namely the correspondence with the facts, so that in these cases there is a point to the distinction the two senses of ‘right’. But if the dispute is a moral one there is no test of this kind.” Pg 194-5

“The theory that men can only aim at their own happiness is plausible only if ‘happiness’ is covertly used as a general word covering ‘whatever men aim at’. Since this conflicts flagrantly with its normal use it is not surprising that some teleologists have slipped into covert egoism.

Gay is not the only or the best known philosopher to have made this mistake; Mill also seems, at time, to have supposed that ‘right’ means ‘conducive  to the greatest happiness of the greatest number’ and Moore expressly says that “the assertion ‘I am morally bound to perform this action’ is identical with the assertion ‘This action will produce the greatest happiness of the greatest possible amount of good in the Universe’.”, although neither Mill nor Moor slips into egoism”. Pg 222

(On the purpose of moral rules)

“(i) Duties of beneficence. There are two reasons why beneficence should be considered a duty. In the first place benevolence is one of our natural pro-attitudes. It is one that conflicts with other pro-attitudes and it is one that tends to be stronger in our calmer and more reflective moments. If to do good to others is one of a man’s dominant aims he has a good reason for making this type of conduct a duty; for if he does so his desire to do good to others will now be backed up by his desire to do his duty, which is an exceedingly powerful motive. In this way he is more likely to try to do good to others even at moments when he does not much want to do so, and so come to fulfil his dominant aim more completely than he would if he did not adopt this rule.” Pg 231

(On conscientiousness)

“Aristotle held that a man was not really good unless he enjoyed doing what is good, and I am inclined to agree. The sense of duty is a useful device for helping men to do what a really good man would do without a sense of duty; and since none of us belongs to the class of ‘really good men’ in this sense, it is a motive that should be fostered in all of us. But it plays little part in the lives of the best men and could play none at all in the lives of saints. They act on good moral principles, but not from the sense of duty; for they do what they do for its own sake and not for the sake of duty.” Pg 259

(On the paradox of representing all motives other than the sense of duty as ‘forces’ which oblige me to act as I do, since this entails that I do not act freely when I do what I want to do)

“There can be no such thing as intentional or even voluntary wrong-doing, and therefore no such thing as just blame or punishment. In the mouth of a Socrates or a Spinoza there would be nothing strange about this conclusion; for Socrates though no wrong-doing could be voluntary and was puzzled to know how any man could deserve blame, and Spinoza was prepared to push the theory to its inevitable conclusion and say that blame is never justified.. A wise man tries to understand why men behave as they do; only a fool blames.

But the theory of the self-propelling conscience is often found in conjunction with the view that conscientiousness is the only virtue and acting against one’s conscience the only vice. And it is this combination that is paradoxical, since on this theory a conscientious action is the only type of free action, all actions prompted by desire being unfree.” Pg 264

(On freedom and Responsibility)

“For in the great majority of cases of moral difficulty what is difficult  is not to decide to do what one knows one ought to do, but to decide what one ought to do. This sort of difficulty arises in three main types of case. (I) A humble and unimaginative person who accepts a customary code of morals without much question may find that two rules conflict; the voice of conscience is in this case ambiguous. (ii) A more self-confident, imaginative, and reflective person may wonder whether he ought, in the case before him, to do what the customary rule enjoins. He knows very well what the rule enjoins; but what prompts him to depart from it is no “part of his desiring nature”, but a suspician that the rule is one that, in this particular case, he ought not to follow. (iii) A man of fixed moral principles (whether or not they are those customarily adopted) may find himself in a radically new situation that is not catered for in his code. What is he to do? It is here, if anywhere, that the idea of an unpredictable ‘creative’ choice seems to make sense. He takes a leap in the dark, but just because it is a leap in the dark I doubt if we should be inclined to blame him if he leapt in what turned out to be the wrong direction.

Men who belong to a generation for whom the questioning of accepted principles has been no mere academic exercise and who have found themselves faced with momentous choices in situation not covered by their traditional rules will be less likely than their father perhaps were to suppose that the only sort of moral difficulty is that of resisting temptation.” Pg 288-9

“And if, as some suggest, desires are internal forces which operate on the will, do they exculpate in the way in which external forces do? The problem of free will is puzzling just because it seems impossible, without indulging in sheer dogmatism, to know just where to stop treating desires as ‘compelling forces’.” Pg 291

“If I regard something as immoral, then, however trivial it may be and however great may be the non-moral advantages of doing it, I cannot debate with myself whether I ought to do it; and we discover what our own moral principles are very often by putting this sort of question to ourselves.” Pg 308

“A principle is not usually called a moral one unless the person who adopts it is prepared to apply it universally. If a man says that he does something as a matter of principle, he cannot (logically) make exceptions unless another moral principle is involved. However narrow in scope it may be, a moral principle must be applied to all cases that are alike in all relevant respects.” Pg 309

“What sort of principles a man adopts will, in the end, depend on his vision of the Good Life, his conception of the sort of world that he desires, so far as it rests with him, to create. Indeed his moral principles just are this conception. The conception can be altered; perhaps he meets someone whose character, conduct, or arguments reveal to him new virtues that he had never even contemplated; or he may do something uncharacteristic and against his principles without choosing to do it and, in doing it, discover how good it is. Moral values, like other values, are sometime discovered accidentally. But the one thing he cannot do is to try to alter his conception of the Good Life; for it is ultimately by reference to this conception that all his choices are made. And the fact that he cannot choose to alter this conception neither shields him from blame nor disqualifies him from admiration.” Pg 313-4

Lies, Damn Lies and Killing Sharks (Part 1)

On 15 January 2014 Greg Hunt, the Commonwealth Environment minister, approved a request by the Western Australian Government to be exempted from the Environment Protection and Biodiversity Act 1999 (Cth) so that it could proceed with plans to set up 72 baited drum lines in order to cull white sharks, tiger sharks and bull sharks greater than 3 metres long. The exemption is required due to the listing of those species being listed as threatened species.

The predominant reasons for granting the exemption were:

1. A statistically significant increase in shark attack strikes in Western Australia in the years 2010 to 2013 compared to population increase;

2. As a result of point 1, people are scared of entering the water and there is anecdotal evidence of tourist businesses suffering financially;

3. The proposed cull will reduce the incidence of shark attacks and will provide useful information to other states in dealing with the same problem;

4. The Western Australian government have implemented measures to reduce the risk of death to other sea life from the exercise; and

5. It is in the national interest (due to points 1 to 3 above) for the cull to be allowed, and therefore within the class of reasons the EPBC Act gives as being the basis for an exemption to be allowed.

1. Statistically significant rise in shark attacks

At the outset, I am not formally trained in statistics and have only learned small sections of statistical analysis in passing. I would be grateful for any comments from those with greater knowledge about my analysis and conclusions.

The assertion made is that, when adjusted for population increase over time, the number of shark attacks has risen by a statistically significant degree. The paper this is based on (here) doesn’t provide the population or shark attack numbers used. However, a comparison between graphs on pages 10 and 11 of that paper (showing frequency of attacks per year and frequency of attacks per year per 100,000 people respectively) don’t show any major distortion. On the basis of this lack of distortion, my analysis will use the non adjusted figure of shark attacks per year, which I have obtained from the Shark Attack File.

However, before doing so, one variable not taken taken into account for which it could be argued must be accounted for in order to properly analyse the data, is any increase in average time spent per person in the ocean. Such a variable could result in an increased number of attack incidents due to the same number of people entering the water, the same number of sharks in the water, but an increase in the chance the two will interact.

Below is my tabling of shark attack data over the past 30 years extracted from the Shark Attack File. The data represents number of people injured per attack. Therefore, there may be incidents where one incident injures two people. Further, I’ve attempted to remove all reports listed as a hoax or reports where a shark has been caught in Australian waters with human parts found in their stomach contents (therefore not necessarily an incident which has occurred in Western Australia), but I cant guarantee that all instances of such data points have been completely removed.

One other point to note is the greater number of reports of minor incidents in the later years of the data. Data in the earlier years appears to be limited to incidents with either very serious or fatal outcomes, while there are greater reports of minor incidents or incidents where no injury is reported in the last decade or so. This may be a common finding in databases reliant on the reporting of events which are gaining increased importance or scrutiny for some particular reason. This skewing of the data can lead to false trends being extracted from it.

Incidents Fatalities Incidents Fatalities
2013 18 3 7 2
2012 22 3 7 2
2011 18 5 6 3
2010 16 2 5 2
2009 30 0 5 0
2008 18 2 3 1
2007 18 2 2 0
2006 12 1 2 0
2005 17 2 2 1
2004 16 4 6 1
2003 9 1 3 0
2002 12 3 1 0
2001 13 1 3 0
2000 18 5 2 1
1999 2 1 0 0
1998 4 2 0 0
1997 10 2 3 1
1996 15 1 2 0
1995 7 1 2 1
1994 3 1 1 0
1993 7 3 1 0
1992 6 1 0 0
1991 7 1 2 0
1990 8 1 0 0
1989 12 2 1 0
1988 7 3 1 0
1987 4 2 1 0
1986 5 0 2 0
1985 2 1 0 0
1984 3 1 1 0

Given the assertion about shark attacks being significant above the average in the years 2010 to 2013, I’ve decided to use the chi-squared test to assess the statistical significance of the number of attacks over those 4 years compared to the average of the proceeding 26 years (1.77 incidents per year):

Year Expected Average ( E ) Observed Number ( O ) O – E = D D²/E
2010 1.77 5 3.23 10.4329 5.8942937853
2011 1.77 6 4.23 17.8929 10.1089830508
2012 1.77 7 5.23 27.3529 15.4536158192
2013 1.77 7 5.23 27.3529 15.4536158192
      Sum D²/E   46.9105084746
      Degrees of freedom = 3    

A chi-squared value of 46.91 with three degrees of freedom gives an absurdly high, statistically significant p value of much less than 0.05, meaning that the likelihood of the increased number of shark incidents in those years could occur by chance alone is less than 5% (this is the level considered to give high enough confidence for the null hypothesis, such as “shark attack incidents per year remain static, to be rejected). This does not mean that shark incidents are definitely increasing, or that there is some underlying cause for an increase in shark incidents (such as a greater number of sharks in the ocean).

There may well be a better way of analysing this data than the chi-squared test given we are using a yearly data set and the chi-squared value I got being extremely high (and I’m open to suggestions in the comments).

There is a further assertion in the exemption statement that the increase in average attacks from 1995 on-wards is also made. Whether this is correct or not is not my main concern.

My concern with basing public policy on statistical analysis of this data is that the low number of attacks per year means any analysis will be of low statistical power. With such a low average number of attacks per year figure and a sampling of a small number of years to compare to the long term average, small deviations above or below the average can result in a statistically significant, but none-the-less erroneous, conclusion. Similar problems arise in medical trials when small sample sizes can lead to either significant improvements in effectiveness of, say, a specific treatment, not being found to be statistically significant, or, as in this case, statistical significance is found in a sample set which, after a few more years worth of data is collected, could yet be seen to be no more than a ‘blip’ in the data based on chance alone (see here, which I found to be useful in explaining the difficulties in making positive assertions about statistical significance test in large sample sizes and small sample sizes equally, and about drawing conclusions for analysis of single data sets by themselves).

Further, debate continues about the ability reliably draw conclusions based on a statistically significant finding from a single or small number of experiments or trials – how reproducible the result is is a greater determinant of whether the statistics are describing an event or occurrence that is really occurring, as does the debate about whether some tests are actually useful in drawing meaningful conclusions from otherwise good data. See here, here, here for example.

Statistical analysis is an extremely useful tool to study a given hypothesis and be able to draw conclusions as to the probably that an effect shown in the data gathered is due due to chance alone. But these tools are subject to limitations. The presentation of statements about statistical significance give undue legitimacy to policy decisions where the limitations to the analysis are not provided or explained.

2. Effect on people entering the water and on tourism businesses

Statistics are given of the number of holiday makers to Western Australia, how many intend to enter the water and what percentage of the State’s economy comes from tourism. A further generalised assertion that “There is substantial public concern about the safety of water based activities in Western Australia, and anecdotal evidence that the frequency of shark strikes is impacting on businesses in Western Australia”, and this is followed by a report of report of dive business saying that it had had a 90% drop in people wanting to learn to dive.

If the improper use of data and statistics is the failing in attempting to give legitimacy to the assertion that there is problem with shark attack frequency, then the lack of legitimate, grounded, provable evidence of these asserted problems is the failing with this trumping up of the effects of the ‘problem’.

One would be excused for thinking that the application for exemption has been put forward by people have done no more than read the newspapers and searched holiday stats from their own tourism department website to create a narrative it could use to promote the plan.

The real difficulty with realistic concern about increasing shark safety is the ‘zero infinity problem‘ – the chance of it happening to any particular person is so low that it barely warrants concern, but the effect on the victim if it does occur are infinite (in a non-mathematical sense of that term). To, at least in part, base policy decisions with likely deleterious effects on a population of any living thing by playing on heightened concern of something so unlikely to happen, and then in turn superimpose that on financial reasons, must be considered poor leadership.


Reliance on these two factors to support such a move as actively killing threatened species is significantly flawed. Statements about the statistical significance of a problem on minimal data points, followed by generalised statements of the effect of the problem with no proper basis in evidence, cannot pass as being reasonable premises to infer that action must be taken, let alone the mode of action to be taken.

A long time ago….

….I posted my last article on this blog. Over a year has passed since I argued about climate change denial and logical fallacies, John Spooner and Craig Kelly in the cross-hairs of my directed rage.

I can’t pinpoint the precise reason for my inaction. Work, study and family have played their role in keeping me busy, but there was also some dilemma in my mind as to the direction of this blog. To date, it has jumped from veggie gardening, to short-story telling, commentary on anti-vaccination attitudes, various ‘green living’ adaptations in different aspects of the home and climate change.

Admittedly, my interests change with some regularity. I discover or re-discover some topic that I become consumed by, shortly to be replaced by the next topic (currently, my passion is statistics, demonstrated by the current audiobook “Naked Statistics” playing on my way to and from work, the book “How to lie with statistics” eagerly waiting to be read in my study and repeated trips to Tamino’s “Open Mind” blog). This interest replaced the previous interest in feminism and prior to that was ethics and morality. Usually there is some link from one interest to another, sometimes it is finding a book at a second-hand shop on a topic that I’ve wanted to learn more about.

I have somewhat become like a deer in headlights as a result, not knowing what topics to write about in order to attract and keep the interest of people wanting to read more about a specific topic.

My answer to the dilemma in fact came from a section of the book on feminism I’ve nearly finished reading. In providing a history of the women’s liberation movement, the writer draws comparisons between the numerous political movements in recent history, such as the African-American movement towards equality and the workers movements. The book discusses that even within these progressive movements, proponents of the movements can still hold regressive attitudes towards other issues of equality, in this case towards the feminist movement.

The point made by the author is that to be properly progressive, to seek fairness throughout all aspects of society, limiting yourself to just one cause or topic without seeking to enlighten yourself with or help rectify the problems in other areas fails to recognise the connections between various forms of repression and destruction, let alone rectify forms of repression within an otherwise progressive movement.

The issues of sexism within the atheist movement provides but one example.

In what most likely is a case of deluding myself into justifying the maintenance of the status quo, I’ve therefore decided to continuing blogging about whatever I so choose, if it can reasonably be considered that someone reading my articles will be assisted in bettering themselves or the people and/or environment around them. Whether it be describing how to make a greenhouse, why vaccination is important or what to look for when considering the statistics behind reports of some new breakthrough medical treatment or behind an argument as to why global warming is a hoax/myth/evil communist plot, I will do my best to understand the content of the topic completely and write on it.

To this end, I’ve also decided to add articles posting assignments I’ve completed that address a topic that I consider important or helpful (I believe P.Z Myers gets his students to blog about their studies which inspired the idea, and is an approach that will help me with content) and posts that contain quotes from books that I’ve read (in part to help me remember more of those books in future).

I don’t intend on publicising this post through twitter as I normally do, given the navel-gazing nature of it. This is more to keep me honest in maintaining the pledge to put up a new post at least once a month whilst I’m studying, and more often when I’ve taken a study period off.


John Spooner – A cartoonist’s view of climate change

I read this commentary piece by John Spooner in the Age on 29 December 2012 with utter bemusement at the logic used.

Somewhat hastily, I wrote a letter to the editor that day as follows:

“John Spooner’s opinion piece “Sceptics weather the storm to put their case on climate” employs all the same logical fallacies and misstatements of fact that look and feel like scientific scepticism as the heroes he portrays throughout his piece do.

Beginning the article with the unfulfilled Mayan end of the world prophecy adhered to by only the ardent of true believers of such pseudo science to introduce his readers to his list unfulfilled prophecies of climate scientists will surely only lure in the most gullible readers.

To then provide his list of evidence to his readers, the “jurors” of his trial of climate change science, so that a verdict may be handed down in the same way as the judicial process does, is nothing but a false analogy. He presents his expert witnesses on the question to sway the jurors. Unfortunately for him, if this were a real trial, his experts would be ruled inadmissible for lack of expertise on the question being tried. He has effectively brought a psychic to present expert opinion on DNA evidence.

For instance, apparently “everybody agrees that the warming trend paused 16 years ago”. Assuming the MET office data and the original journalism on this issue has not been read by Mr Spooner, I can only suggest he and others look at the data properly, and take a truly scientific (read “truly sceptical”) view of how it can be concluded that warming has stopped from it. Cherry picking data so that it appears how you want it to appear is not scepticism, it is to hold onto a belief or point of view – something not at all scientific or sceptical.

As for the failings of the scientists themselves in the so-called “climate gate” scandal, these “god is in the gaps” arguments only serve as a straw man and deflect attention from the real data, and fail to report the outcomes of every investigation, either of the scientists themselves or the data and conclusions that they have contributed to this issue.

For anyone willing to truly make a decision on where the weight of evidence lies, well over 30 years of predictions and massive amounts of data can be found online in trusted journals by proper climate scientists. Make a decision from the data and the science itself, not from unscientific viewpoints on either side of the belief scale, and not from a cartoonist and his merry band of non-climate scientists.

Cameron Tout”

The letter didn’t get published (it may have been over the 200 word limit and was definitely not as eloquent as other letters with the same view that were published), but a great response was published on 7 January 2013 by Roy Robbins-Browne of Melbourne Uni, which is definitely worth reading in detail.

Although it delves into ulterior motives of Mr Spooner and using minority opinion to inform public policy, it also comments on the often used “16 years of no warming” argument (usually used by Andrew Bolt and like-minded commentators) that Spooner used, and Craig Kelly used in his article I commented on earlier, and how such tactics of cherry picking data is used by those attempting to frame the evidence to their own belief.

Robbins-Browne also explains in the limited space he had the complicated process that is the scientific method and how it is used to advance what we understand about the world around us. It is this process that anyone wanting to investigate the basis of human knowledge in any area of science must be aware of and understand, and it is the avoidance of participating in this process, and instead using the media or other outlet to publish an opinion, that must set the context for any such piece that proposes an alternative to scientific consensus.

What’s up with Craig Kelly (MLA) and his understanding of climate science?!?!?!

I was alerted to the above article written by Craig Kelly, Liberal Member for Hughes, New South Wales, by Tamino on his Open Mind blog –

I do not feel the need to rehash the absence of logic or science in Mr Kelly’s article as the web contains all the information (from reliable sources) you need to understand what climate change is, why trained scientists conclude that it is happening, why it is that human sources of carbon dioxide and other Green House Gases are the cause and why this type of argument does nothing to detract from the enormous amount of raw data and analysis that has come before it..

However, that such an inadequately researched article showing a complete misinterpretation of climate science, physics and statistical analysis of data (whether accidental or not) is authored by an elected politician is particularly concerning, particularly so if the decisions he makes on behalf of his electorate are informed by such a deluded sense of knowledge on such a subject.

By the logic of this man, if a person returns their house after a bush fire has swept through the area, and finds that his or her house remains in tact, they should conclude that no bush fire existed at all, despite the destruction surrounding them. Climate analysis works on averages, particularly averages over long periods of time and large areas of the earth’s surface, not attempting to use narrow, localised temperatures at one point in time compared to the localised temperature at another narrow point in time to prove a proposition about the climate generally.

I’m sure I speak for most of the true, science-based skeptics, that it would be wonderful for any person armed with such global warming busting evidence that Mr Kelly believes he holds, actually attempted to verify the conclusions they reach by publishing their evidence and conclusions for review by those who actually understand climate science in the same way that has led to most of the scientific and technological advances that humans have managed throughout history – if it were verifiable and a scientific reality, it would be amazing science that would shift the course of research in the area.

Unfortunately, as with all the commentary in all the media claiming legitimate advances in human knowledge about the state of climate, those claimed advances are nothing but posturing and pandering by and for those who refuse to attempt obtaining an understanding of why the consensus of climate scientists is that the planet is warming, why the laws of physics, chemistry and biology in conjunction with the raw data collected lead us to this conclusion, and most particularly what evidence would actually result in the course of human knowledge in this area to change direction towards the opinion they hold.

Until then, that same group of people as above will move from one reason to the next as to why anthropogenic climate change isn’t real (the MET data says it isn’t warming if you look only at the past x number of years, it’s warming because of the approach of the solar maximum, it is warming but it’s because of CO2 from volcanoes, my grandfather says it was hotter when he was a kid) without any real attempt to assist our knowledge or direct our efforts to appropriate action.

I fear that by posting this I may be causing something of a Streisand effect with this article, or that a non-scientist defending the scientific process in a blog post detracts from the ability of science to speak for itself. But simply allowing this post by someone in a position of power to sail by without critique or without alerting other, more scientifically knowledgeable people to opinions of Mr Kelly, would be unacceptable.