April 4, 2020

Some things that are not obvious about The Curve, and the numbers in New Zealand

Posted in Science, Uncategorized tagged at 9:48 pm by Chris

The curve, in all its varying degrees of flatness, has been getting so much attention lately, that I’ll admit to being slightly embarassed about how long it took me to realise its implications (despite being not only numerate, but supposedly numerate in this exact type of thing). If you’ve been living under some sort of magically-hygienic rock for the last six weeks, let me give you a precis, with help from the excellent work of Siouxsie Willis and Toby Morris, below. As the number of people infected with The Virus That Sounds Like A Mexican Beer increases in the population, the relatively small percentage of people who require hospitalisation will at some point overwhelm the capacity of even the most amazing healthcare system. At this point, people will start dying all over the place, not just of the disease itself but of all the other things you’d normally need a hospital for: because the hospitals will be not just full, but totally overloaded. Ghastly death-toll aside, at some point the virus will run its course through the population, peak, and start to decline. The idea of “flattening the curve” is to delay this whole process, so that although people will still get sick, there will never be so many sick at once that hospitals can’t cope.


The tools to flatten the curve are clear, in public health terms: reduce the rate of spread by reducing the amount of contact between infected and non-infected people. Social distancing, closing schools, reducing the movement of people within and between urban centres. Etc. Currently in force to varying degrees of enthusiasm pretty much everywhere in the world.

The implications of pursuing “flatten the curve” as a model are also clear, just less immediately obvious. Look at that lovely illustration again. The total number of people dying over the course of the epidemic is defined, to a first approximation, by the area under the curve, not the shape or maximum height of the curve itself (and leaving aside the significant collateral effect of overwhelming the healthcare system). A curve that doesn’t get as high goes on for longer, because you’re assuming that the disease will still spread through the population, and a percentage of that population will die once they get infected. In other words, the flattened curve is a “best of a bad situation” strategy, and assumes that you can’t really contain the disease. It also assumes that once a certain number of people have had the disease, it will go away. That is… optimistic… at best.

It seems that someone in New Zealand’s response team looked at the numbers for these scenarios and came to the same conclusion. Our current aggressive lockdown, pursued very early by the standards of other Western democracies, is a sign that we’re at least attempting to follow another strategy: kill the fucker. Speaking as a high-risk person for said disease (hello, dysfunctional bone marrow), I am totally on board with that idea. New Zealand is in an unusually good position to pursue this. We’ve got an excellent natural barrier to infected people arriving under their own steam, our current number of cases is small, and we have a modern hospital system and the resources to get our population locked down and take care of them (yes, really). In invasive species ecology, a field in which I can lay claim to some expertise, this is the “nuke it ’til it glows” school of incursion response. It works, provided you’re prepared to go in early, very aggressively, and accept a certain amount of collateral damage on the assumption that the long-term alternative is much worse.

So what about those New Zealand numbers? Well, to my eyes they’re showing some very interesting things. Here they are, hot off the press for the 3rd of April (with thanks to The Spinoff):


Straight away, that looks imposing: numbers are soaring. But stop: wait a minute. Everyone pause. There’s something very important that those numbers aren’t doing: they’re NOT increasing exponentially. If they were, we’d have not 868 cases, but several thousand. In fact, between the 23rd of March and now (so nearly two weeks), the line is basically straight. That’s really good. It means that in actual fact, the rate of increase per infected person is dropping. With 800 confirmed cases, we were only seeing new cases at the same rate (less than 100 per day) as when we had 200 cases.

Obviously, the majority of our virus cases are still in people who came home from overseas already infected. In which case, we shouldn’t expect the population curve to grow exponentially, because it’s not being fueled by its own inherent rate of increase. The real test of our lockdown, our contact tracing, and all the other precautions, will come when those overseas arrivals have recovered from their own infections, hopefully without infecting anyone else. Roughly speaking, that should come some time in the next week or two, say week two or three of the lockdown. At that point, we should really see the rate of new cases start to flatten off. If it doesn’t, we’re doing something wrong. If we were seeing exponential growth, this would actually be easier to predict because the curve would tip down. We call that an inflection point. But straight lines don’t have an inflection point, so we’ll just have to wait.

The wait could be a bit of rub. Everyone seems to be counting down four weeks. I’d like to remind you that our inestimable Prime Minister said “four weeks to begin with”. Personally, I’d expect at least six. In fact, don’t get your hopes up until we’re getting no new cases at all, at which point we should probably be looking at another two weeks of lockdown if we really want to squash it. The alternative to squashing it is to keep going back into lockdown every time the number of cases starts to increase, maybe for the rest of the year. That’s exactly what South Korea are doing. This is an infectious disease: it doesn’t just go away, not unless you expect that a) once infected and recovered, you’re immune and b) almost everyone in the population will get it. That last point comes with tens of thousands of deaths and we’re back to the total area under the curve again. We don’t want to be under the damn curve. We want the curve gone.

I’m not offering public health advice here, but I will say that the more seriously we take this, the faster it will work. If you’re sneaking out of Auckland in the middle of the night to spend four weeks “in isolation” at your bach in the Coromandel, you’re not fooling anyone. We need zero transmission, and that means everyone acting as if they’re infected and everyone else acting as if they’re they’re not. If you know what I mean. So go home, wash your hands, and wait to hear that there were no new cases today. Then wait some more. I hear Netflix is good.


July 5, 2019

Farewell to Roger Grace

Posted in Uncategorized at 11:26 am by Chris

Below is the text of a tribute to my friend and mentor Roger Grace that I wrote for the EcoQuest Facebook page. Roger was one of a generation of marine pioneers, most of whom are now in their seventies: the issues about which he was so passionate are only going to become more important in the future. It’s lovely to see a new generation (people like EMR and Fish Forever) taking up the torch, but just as important to remember those who got us started, and how hard they had to fight to even establish marine conservation as a valid idea. 

Dear friends, we’re very sad to relate the passing of Dr Roger Grace on Friday morning.

Roger was a writer, a superb photographer, a passionate diver, and a lifelong advocate for conservation. His greatest passion was marine conservation, a field in which he worked tirelessly, both on his own and through his involvement with groups like Greenpeace, Forest and Bird, Whangateau Harbourcare and Experiencing Marine Reserves. To give just one example of his important advocacy work, Roger’s underwater photos help to document the wanton destruction caused by “wall of death” drift nets, as part of a wider Greenpeace campaign that eventual led to that fishing technique being banned. He was a continual thorn in the side of those who would have exploited New Zealand’s marine environment for short-term gain, and a tireless campaigner for marine reserves and the protection of the wider marine environment. In recent years he lent his expertise to the SeaChange consultation process, and pushed hard for an increased coverage of marine protected areas in the Hauraki Gulf.

Never one to blow his own trumpet, Roger often insisted that his QSM stood for “Quite Silly Man”. The QSM was one of many accolades from both society at large and professional bodies, including a Forest and Bird “Old Blue” award for a lifetime’s service to conservation, and in 2018 the New Zealand Marine Sciences Society’s John Morton Medal for an outstanding contribution to the advancement of marine conservation and sustainability in New Zealand. Awards and medals notwithstanding, Roger was always willing to talk to any group who wanted to hear from him, and was a regular feature of EcoQuest’s trips to both Goat Island and the Poor Knights (for which service he often “forgot” to invoice us).

Roger was also a very dear friend to many of us at EcoQuest. He was a lifelong friend and diving buddy of Sally-Jane and Susi, and a friend and mentor to Chris and Rebekah. When we ran a snapper DRP in 2012 and 2013, Roger was an enthusiastic supporter of the project and took photos of the fieldwork which continue to grace our brochure to this day. He was humble, charming, hugely knowledgeable and passionate to the very end. We will miss him tremendously.

A mighty tōtara has fallen in the forest.

August 28, 2018

“The massive transformation required in diets and production”

Posted in Uncategorized at 3:08 pm by Chris

This is more than just cutting back on beef: if I read this correctly, the 60% of human calories that come from just three cereal crops are in the firing line too:

Rod Oram: Time to transform our global food systems

August 23, 2018

“Optimism is a political act”

Posted in Uncategorized at 5:45 pm by Chris

Interview with Alex Steffen, he of the late lamented Worldchanging. It’s old (Worldchanging era) but still extremely fresh and relevant. I’m particularly fond of the quote that I’ve excerpted for the post title…

November 21, 2017

A video worth watching about Transhumanism and the modern world

Posted in Uncategorized at 9:42 pm by Chris

I’ve never come across this guy before, but he’s an interesting speaker. It’s a shame he does that humanities thing of reading off a prepared script. I knew that the Transhumanists were wankers, but not that they were also arseholes. He makes a thoughtful analysis of nature and the natural (or rather, the idea of the natural) which is also relevant to my own field of environmental science.


September 22, 2017

The day before the day after

Posted in Uncategorized at 1:58 pm by Chris

I’ve just read this, and I’m reminded about how angry I am at the incompetents currently playing at running our country. Please get out and vote tomorrow, New Zealand, and lets get rid of these no-hopers. Normally I’d say “vote, no matter how you vote for”, but on this occasion if you want to support the incumbents I think you should stay in bed. They’re a bunch of self-serving incompetents who aren’t even good at the things they claim to stand for, and are actively hostile to attempts to do well in other areas. And to top it all off, their election campaign in recent weeks has consisted of telling a series of blatant bare-faced lies, and then refusing to retract them when publicly confronted with the fact they are lies. Enough. Be off with them. My cat could do a better job of governing the country, and he sleeps for 18 hours of the day.

September 15, 2017

New Zealand’s one-child policy

Posted in Cancer at 10:03 pm by Chris

I had cause this week to be reminded of New Zealand’s one-child policy. What’s that you say, we don’t have a one-child policy? Oh, but we do. Here’s how it works. If you’re a cancer patient, hypothetically speaking about to have such intensive chemo that your ability to produce gametes will be permanently destroyed (or your existing gametes rendered inviable), you can opt to have sperm or eggs frozen in the event that you wish to pursue IVF or some such reproductive technology in the future. The public health system will pay the costs of all this — and for the uninitiated, those costs include not just initial consultations, but the ongoing costs of keeping things in cryogenic storage — but only if you don’t already have children. If you already have one child, you’re paying the bills yourself. In other words, in New Zealand, the government has chosen to pay the medical costs of you having just one child.

Note that we’re not talking about whether or not the public system should bear the cost of assisted reproductive technology for couples in some circumstances. I think that’s a reasonable discussion to have, actually, given the expense that can be involved. No, that decision has already been made, and the answer is yes, it will. But not if you already have children, even one. In a country with an average birthrate over 2, the government will only sanction you having one, unless you pay for it yourself.

Practically, this was just an inconvenience for me, and cost me money at a time two years ago when I didn’t have any money to spare. Ethically, it’s extremely bothersome: ethically, I see no difference between deciding not to pay for a second child before birth, and a second child after birth. No, we won’t cover the expenses of your second child because you’re already receiving a benefit for the first. No, your baby can’t have any expensive medical procedures because you’ve already got a child. The difference is that those types of decisions are made at high levels by ministers, or senior staff in government departments who are accountable to same. The decision not to fund reproductive technologies for cancer patients who already have one child was presumably made by a bureaucrat in an anonymous office somewhere. But that bureaucrat was no doubt looking at the bottom line in a budget they’d been told to balance. They’d been given directions from on high that their budget mattered more than people’s lives, and been given a mandate to make arbitrary decisions based on someone’s personal circumstances. The effect is that same. The moral process is the same.

I’m not aware that “existing reproductive status” is covered in the Bill of Rights Act. It really should be, and it’s consistent with the moral stance behind not discriminating on the basis of age or gender. I’m pretty sure (not a lawyer, but I know some) that it is explicitly covered in employment legislation: employers aren’t allowed to ask you if you plan to have another child, no matter how many you already have. Nor does the number of children you already have affect your entitlement to paid parental leave, or your eligibility for any number of mechanisms of state support, up to and including education and healthcare for those children. Nor should it. The fact that it’s allowed to affect this one small corner of an entitlement to state support (and again: the government has already decided that it will fund this service) suggests that these other inclusions might just be conventions, rather than something we can rely on. I don’t think that’s good enough.

March 30, 2017

Britain triggers article 50

Posted in Uncategorized at 7:33 am by Chris

Why did it seem like such a big deal when Greece wanted the drachma back?

February 16, 2017

Combustion engines continue to suck

Posted in Uncategorized at 4:46 pm by Chris

‘Filthy glamour’: could polluted Marylebone Road help fix London’s air?

More on this later, I think…

October 26, 2016

The rules according to a toddler, part 2

Posted in Uncategorized at 8:03 pm by Chris

“No” is not the answer to your question, “no” is just the first word that came into my head when you asked the question.

Even if “no” was the answer to your question, it was really just a suggestion. Think of it as a starting point for negotiation. Are we not reasonable people? What might you offer me, if perhaps “no” were not in fact the answer to your question?

“No” is most definitely the answer to your question, how dare you even think of suggesting otherwise? Aren’t you the one who keeps saying that no means no? Does that not apply to me as well as you? I have said “no”, I meant “no”, and the wold may very well come to an end right now if you question my assessment of the situation at all.


“Yes” is not the answer to your question either.

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