Saturday, 23 January 2021

Why the UK Variant (or Kent Variant) being More Lethal might be a Good Thing

Firstly, I must make it clear that I don’t want more people to die.  And I do realise that some people already have caught the UK variant (or Kent variant) of Covid-19, and it being more lethal is difficult to see as a good thing – for them.  However, there is a sense in which the new variant being more lethal, as well as being more transmissible, is a good thing.

 

Part of the argument is that the UK variant being more transmissible is a really bad thing.  There are reports that the UK variant is in the order of 50% more transmissible, which means that after 10 rounds (where a round is where those now infected have infected those that they are going to infect) about 40 times as many people will die (as would have with the original variant).  If it is only 30% more lethal, and not more transmissible, then it will kill 30% more people, so 1.3 as many people will die.  Combine the effects together and it’s about 50 times as many.  Which, at first blush, is not good.

 

However, the increased lethality of the disease only comes into effect once you have managed to catch the disease.  It’s entirely possible that people are going to be far more scared by the notion that they are 30% more likely to die with the new variant, and 50% more likely to get it, than they are by the notion that they will transmit it to 50% more people.

 

This might open up a channel into the mind of an otherwise unreachable and selfish individualist – especially if they can wrap their mind around the fact that it is not 50% more likely that they will get Covid-19 with the new variant.  That’s just 50% more likely to get it from each person with Covid-19 that they interact with, if they are interacting with more people (which will be the effect if infection rates are not otherwise stemmed) then there will be a compounding effect.

 

In other words, the increased lethality of the UK variant might just be the motivation that is needed for selfish people to act selfishly and, through acting selfishly, protect us all.


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On the mathematics side, if the 30% lethality was enough to scare the non-cooperative types into better behaviour such that it reduces the replication number by 10%, then this could halve the number of deaths – or more – over the long term (assuming just the increase in transmissibility).

Thursday, 21 January 2021

Atomic Tea

There is at least one complaint made by my climate denialism curious friend, JP, that is valid.  Some elements of the media are guilty of catastrophising.

 

I can understand why they do it, to a certain extent – they are selling papers, or magazines, or advertising airtime, or clicks, or eyeballs, or bums on seats etc etc.  The complete and accurate truth is, in at least one sense, not primary.  If the complete and accurate truth got them the outcome there are after, then they would be all for it, but still only as a means to an end, not as the end itself.  Even non-commercial media has to report viewer numbers, or levels of engagement, making them more and more like the commercial outlets with their click-baity headlines and sensational content.

 

The most recent example that I have read, at time of writing, is a piece by the Australian ABC, talking about how bad 2020 was.  I think we call all agree that 2020 was pretty bad but this article was focussed on something that has not been foremost in our concerns for a while – the climate.  The climate is still there, even if it’s largely outside and many of us have been locked inside more than usual.  And it’s still on a bit of a slide.

 

The article in question did highlight something of considerable concern, namely that the “world's oceans absorbed 20 sextillion joules of heat due to climate change in 2020 and warmed to record levels” (referencing a paper that has “temperature” in the title, but not so much in the text).  For context, it’s worth considering what NOAA have to report.  They talk about this in terms of a “heat content anomaly” measured against the average for the period 1955-2006 in the top 700m of (ocean) water:

Note that a sextillion (or zetta) is 1021, so don’t let the fact that this is sitting just under 20x1022 confuse you.  Things are a little more clear in another chart (lower on the same page).


It does seem like 20 zettajoules in a year is a bit of a spike, but there are ups and downs, so we really should be thinking about the trend, which is a bit over 160/27 = ~6 zettajoules per year.  Still not great.

 

The most egregious statement, in my view, is that 20 zettajoules is equivalent to the release of 10 Hiroshima grade atomic bombs each second.  That’s more than 300 million bombs, or slightly over two bombs for every square kilometre of land surface on the planet which, even if it happened only once in a year, would be enough to make that a worse year than 2020.

 

(For those keeping score, the Hiroshima bomb, “Little Boy”, is calculated to have released between 50 and 75 terajoules.  If we say it was 63 terajoules [15 kilotons], then you would indeed need very close to 10 bombs per second for a year to reach 20 zettajoules.)

 

It’s very scary to think of so many atomic bombs going off and one could well imagine that this was intention of the writer.  It’s also probably pretty scary to imagine that amount of energy being added to the oceans, since it’s the heat in oceans that cause the sort of storms that can do so much damage to coastal regions and it’s simple to imagine that more energy equals either more storms or stronger storms (or perhaps both).  Whether there is such a simple link? … perhaps, perhaps not.  Oil extraction companies have upgraded their drilling platforms, so perhaps they think there might be.

 

I wondered, however, how much energy we expend each year on hot drinks?  To make it easier, I am going to limit it to tea and assume that for tea, one boils fresh water from room temperature (293K) to boiling (373K) without markedly affecting the density of said water.  I am also going to assume one drinks from a standard cup at 0.24 litres.  So, a litre of fresh water weighs one kilogram and the heat capacity of water is 4.2kJ per kg per K.  Conveniently, this is very close to 1kJ per cup of water per K and since the temperature difference is 80K, we expend 80kJ on boiling water for each cup of tea (assuming no wastage).

 

The question then is how many cups of tea do we, as humans, drink?  World Tea News (yes, there is such a thing) has the answer, conveniently in terms of cups per second – 25,000 cups.  That means that we expend about 2 million kilojoules per second on tea.  This is somewhat short of a sextillion, but we are thinking in terms of Hiroshima grade atomic bombs, each at 63 terajoules.   A terajoule is 1012 joules, so one bomb is equivalent to 31437 seconds of tea preparation, which is one bomb every 8.7 hours, or very close to 1,000 bombs a year.

 

I am reasonably certain that the average English person would be willing to accept 1,000 bombs a year in order to have a good cup of tea.  What, on the other hand, would be patently ridiculous is to express the energy used to prepare tea in terms of atomic bombs.  I have a nagging feeling that the same applies to the amount of energy absorbed by the oceans.

 

Perhaps the author of the article (and the original paper) could have assisted by expressing the temperature change that would be caused by the 20 zettajoules being absorbed by the oceans.  If we make some assumptions, we can get a rough idea.  The ocean surface is about 360 million square kilometres.  The paper was referring to a depth of water of 2,000 metres, but not all the ocean is that deep, and beyond a certain depth (the epipelagic zone) there really isn’t much variation in the temperature, so we could make a rough calculation using an average of 600 metres depth, which is in the middle of the mesopelagic zone, so we have an ocean volume of 2.17x1017 m3 and given that there are 1000 litres in a cubic metre and it takes 3850J to raise a litre of seawater by 1K, that’s about 0.024K a year or 0.24 degrees per decade.  Note that this is very rough calculation, but it’s in the same order as what NOAA are reporting (at climate.gov) where they say that temperatures have been rising at 0.18 degrees per decade since 1981.  If we use 800m, which is towards the bottom of the mesopelagic zone, the result is very close to 0.18K per decade.  I doubt that that figure is right though, since that’s the average since 1981, and today’s figure is likely to be higher (although maybe not as much as a full third higher).

 

If anyone knows what the actual average temperature increase of the ocean was, please let me know.  Looking at the heat content chart (1955 through to 2020) overlaid on the temperature chart (1880 through to 2016), it looks like it’s probably gone up:

Monday, 18 January 2021

NEWS FLASH: Tigers Not Part of Early Human Development

 I’ve being going through the back-catalogue of Tales from the Rabbit Hole, an interesting approach to conspiracy theories and conspiracy theorists.  In the most recent that I’ve listened to, Episode 32, Mick West spoke with the Skeptic of (should be “in”) the North.

 

During their discussion, at about 24:45, there was mention of Michael Shermer talking about the evolutionary benefit of making a Type 1 error (or a false positive) when the data is ambiguous and the example given was of one of our ancestors hearing a rustle in the grass.  The cost of making a Type 1 error and assuming a tiger (when there isn’t one) is minimal, but the cost of making a Type 2 error and assuming there is no tiger (when there is one) could easily be massive.

 

Michael Shermer did in fact raise this as an example, in a blog post called Patternicity: “Better to flee a thousand imagined tigers than be taken unawares by one real one”.  What Shermer isn’t suggesting, however, is that there was an evolutionary pressure placed, by tigers, on humans to make Type 1 errors in response to ambiguous data.

 

Peter Watts did though:

 

Fifty thousand years ago there were these three guys spread out across the plain and they each heard something rustling in the grass. The first one thought it was a tiger, and he ran like hell, and it was a tiger but the guy got away. The second one thought the rustling was a tiger and he ran like hell, but it was only the wind and his friends all laughed at him for being such a chickenshit. But the third guy thought it was only the wind, so he shrugged it off and the tiger had him for dinner. And the same thing happened a million times across ten thousand generations - and after a while everyone was seeing tigers in the grass even when there weren’t any tigers, because even chickenshits have more kids than corpses do.

 

It’s bad enough when apologists use tigers attacking our ancestors as an example when trying to prove that evolution doesn’t exist, but when atheists and skeptics start talking about our ancestors on the African plain being attacked by tigers, it’s a problem.

 

There are two problems really.  First and foremost, tigers have never lived in the wild in Africa (although there might now be feral tigers, that is tigers who have escaped from zoos after being transported to Africa by humans).  If we want to pretend that humans have been shaped into regular Type 1 error makers, by tigers, then we have two options.  First, this applies solely to people with ancestors who lived in the natural range of tigers – with the rest of us not being so inclined. Or, second, our understanding of where we evolved is wrong and we somehow evolved within the natural range of tigers despite the evidence that we evolved into hominid form on the African savannah.

 

The other problem is that if we, as evolving hominids, had not already developed the handy skill of overestimating the level of risk to our lives, we would not have been in the position to evolve into Homo sapiens.  Not that tigers would have eaten us, but lions or wild dogs would have, or any number of dangerous African creatures would have killed us without even bothering to eat us.

 

Making Type 1 errors and treating something benign as a possible threat is not unique to humans: 



I am quite confident that this cat is not going through a calm assessment of the potential for risk associated with the cucumber.  It’s just an instinct to run away from something that looks vaguely like it could be a snake.  Horses are similar, with them freaking out if they see a hose (where they aren’t expecting to see one).  Admittedly horses freak out about a lot of things: plastic bags, people wearing hats, trees, the wind, sand and so on.  Even fish seem to be in the Type 1 error club.  And coral.

 

The point is that this characteristic of being overly cautious about ambiguous data is not a human thing, it’s a characteristic of all higher order animals.  Maybe, it could be argued, even lower order animals are willing (on a metaphorical level) to make the occasional error in order to increase their chance of survival.  We as humans have not developed it, we have just retained it.

 

The idiocy that is involved in thinking that humans cleverly developed this overweening caution due to their interaction with tigers on the African plain and the arrogance to think that it was only humans who did so … both are, sadly, entirely human.