Archive for the ‘environment’ Category
clothing: when a solution becomes a problem
Canto: So we talked previously about the horror of stilettos, which was all about the absurdity of fashion, and the sad fate of fashion victims, sigh, but fashion, and the clothing industry in general has lots of problems at the production end as well as for the end-users.
Jacinta: Yes – of course at the user end there’s the huge problem of waste. I walked past a nearby Salvos shop on the weekend, and their donation bins were overflowing to a ridiculous degree, piled up in the doorway, and neighbouring doorways, extending a long way down the street.
Canto: At least people are trying to recycle, but I wouldn’t like the job of sorting that stuff out. And of course the people who do that job are volunteers, though living in a country with a reasonable safety net and a minimum wage which is one of the highest in the world according to this Australian Industry Group website. But wages and conditions, as well as our buying habits, especially those of your fellow female primates, are what I want to focus on today.
Jacinta: So women, especially teens, buy these cheap foreign-made clothes from overseas sweat-shops, wear them once or twice and chuck them out – they call it ‘fast fashion’ – and the cycle continues. A handful at the top are making tons of money, while others are getting sick from overwork or from ingesting toxic chemicals. Petrochemical-based textiles now make up 10% of the world’s carbon emissions and rising. They also add to the biosphere’s growing microplastics problem. According to the International Union for the Conservation of Nature (IUCN), 35% of microplastics come from these textiles.
Canto: I should point out another issue with ‘fast fashion’. When the fashion changes, which it does on an almost weekly basis, the brand names, such as H&M, Topshop, PrettyLittleThing and please don’t make me name any more, they just dump them.
Jacinta: Yes, but not in recycling bins. Only about 1% of textile waste is currently recycled, for all sorts of reasons, such as the technology required to separate blended chemical textiles. They can be shipped to India or African countries, but that just delays the problem briefly.
Canto: It’s kind of fascinating how many problems we make for ourselves by becoming supposedly more sophisticated, manufacturing and then dumping all these techno-solutions. We’re the only mammals that wear clothes, and as with footwear, it’s hard to say exactly when all that began, never mind when it all morphed into competitive fashion shite.
Jacinta: Actually we can only say that we’re the only extant mammals to wear clothes. An associated question is, when did we start, and finish, losing our body hair? Here’s an interesting quote from one Charles Darwin:
No one supposes that the nakedness of the skin is any direct advantage to man; his body, therefore, cannot have been divested of hair through natural selection.
He thought it was a matter of sexual selection. Do we find hairless bodies more attractive? Maybe, but probably not universally. Today we undoubtedly find bonobo/chimp/gorilla-type hair unattractive, but that’s surely because we associate it with non-human primates. Many women I know find men with hairy legs quite the turn-on.
Canto: But not furry legs. They have to be humanly hairy. So maybe there was a natural advantage to being less hairy. The move into open, sunlit spaces seems to have been key. If you’re covered in hair, it reduces heat loss through the skin. Also, being upright exposed less of the body surface to the sun. Probably explains why we keep the hair on our heads, to protect those heads, and the ever-expanding brains inside them, from getting fried.
Jacinta: And in the cooler regions, and during cooler eras, and at night, we could supplement our hair with artificial coverings, proto-clothing. But in those regions and times, plenty of hair would be an advantage. But anyway, for some reason, our ancestors started losing their body hair. I wonder when, exactly.
Canto: There’s probably no exactly. But upright stature helped in hunting, allowing us to run long distances, in which case losing heat through sweating would’ve been advantageous. Remember, it would’ve been easier to keep warm, through covering, than to cool down, with all that hair.
Jacinta: They could stay in the shade, like bonobos do.
Canto: Big-brained humans require too much energy for their owners to spend time under yum-yum trees. We have lots of sweat glands compared to other primates. It helps us to run fast and long. Those monkeys that have more sweat glands than others are also fast movers. There are some puzzles about all this, though, about what came first and why – reduced hair, bipedalism, larger brain.
Jacinta: But getting back to modern clothing and fast fashion and the like – or maybe not modern clothing. I’m thinking, when did clothing become mandatory. Maybe it’s not manatory in all cultures, but among our European forebears, how did it manage to become grossly offensive to go about naked like our bonobo cousins? It seems to have happened very recently in paleontological terms. I mean it’s associated with civilised behaviour somehow.
Canto: Only ‘savages’ went about in the altogether. Or ancient Greek actors and athletes. Of course, clothing quickly became a hierarchical thing – the higher-ups dressed more elaborately, and the proles weren’t allowed to, and so were despised for their shabbiness. Being completely naked was real low-life stuff, and a sexual element evolved alongside all of that. And a gender element.
Jacinta: That’s going a bit fast, perhaps, but I’m sure it’s on the right track. So I’ve found various sites discussing this issue of hiding our genitals. John Romero provides a pretty comprehensive account, of clothing in general as well as our new age modesty. He reminds us, for example, that nakedness among the Greeks wasn’t confined to performers and athletes. Public baths were communal, as were Roman toilets – they didn’t blush when they flushed. Actually, they didn’t flush, at least not the way we do. Of course the creation myth of Judeo-Christianity, which had small beginnings but soon spread throughout Europe and the globe, had Adam and Eve feel ashamed when they realised they were naked, but it doesn’t explain the realisation, since they were the only humans on the planet at the time apparently. Nevertheless, this association with nakedness and shame was hammered home by church authorities, and has much to do with current attitudes.
Canto: But the association between nudity and shame was clearly felt by those early biblical writers. That dates it to around 2,600 years ago at most, though religious biblical scholars generally prefer an older date.
Jacinta: We just don’t have any way of dating the origin of nudity as shameful. Clothing is only the most obvious way of concealing nudity, but the origin of clothing surely has nothing to do with shame. And nobody really knows when clothing originated, or when we lost our body hair, which was clearly a gradual process. But to return to our arguably over-dressed, throwaway modern society – which often plays with modesty in a titillating way…
Canto: Modesty’s a tricky word though. Isn’t wearing showy expensive clothing a kind of immodesty?
Jacinta: I was thinking of the skin-tight fashion of young women – I don’t know about the price. Not that I disapprove, I’m only concerned with the waste.
Canto: Better for the environment if they go about naked, you’re right.
Jacinta: Hmmm…
References
http://www.bbc.com/earth/story/20160801-our-weird-lack-of-hair-may-be-the-key-to-our-success
https://www.quora.com/Why-did-humans-initially-start-to-hide-their-privates-from-other-humans
https://en.wikipedia.org/wiki/Clothing
the bonobo world 4: more on Rapa Nui
“These frozen faces … mark a civilization which failed to take the first step on the ascent of rational knowledge.” Bronowski said, “I am fond of these ancient, ancestral faces, but in the end, all of them are not worth one child’s dimpled face”, for one human child—any child—has the potential to achieve more than that entire civilization did. Yet “for most of history, civilizations have crudely ignored that enormous potential … children have been asked simply to conform to the image of the adult.” And thus ascent has been sabotaged or frozen.
The above quote is taken from David Deutsch’s admiring essay on Jacob Bronowski and his seventies science series The ascent of man, and it refers to the statues found on Easter Island (known to Polynesians as Rapa Nui) and to the culture that created them. Deutsch highlights the ‘ascent’ element of Bronowski’s series, and he elaborates further on this in his book The beginning of infinity, the central thesis of which – that humans are capable of more or less infinite development and improvement – I’m quite sympathetic to. However, in dismissing ‘the customary condescending doublethink towards primitive cultures’, of many anthropologists, and supporting Bronowski’s apparently wholesale contempt for the Rapa Nui statue builders, Deutsch makes a fatal error, the same type of error, in fact that Robert O’Hara Burke made in rejecting the advice and help of ‘mere savages’ who had learned, no doubt by painful trial and error, to survive more or less comfortably for millennia on the meagre resources of the desert environment of Central Australia. This example of cultural arrogance led directly to Burke’s death.
Now, to be fair to Deutsch, he fully recognises that he himself wouldn’t survive for long in central Australia’s hostile environment, or that of Saharan Africa, Mongolia, Antarctica or any other forbidding place. But I think he fails to sufficiently recognise that particular cultures, like species, adapt to particular environments, some of which are more static than others – but none of which are entirely static. That’s why I think Bronowski’s statement, that Rapa Nui’s statues and the massive platforms created for them, ‘mark a civilisation which failed to take the first step on the ascent of rational knowledge’ is both dangerously arrogant and false.
In trying to show why this is so, I won’t be indulging in any romanticised view of indigenous cultures. I come from a diverse and dominating culture that has discovered only recently, thousands of exoplanets, gravitational waves that Einstein postulated but never thought could be discovered, and the Higgs boson, a particle that I’m excited by even without having much idea of its nature or vital role in the cosmic structure. I should also mention our ability to create entire human beings from a single somatic cell, through induced pluripotency – and it may be that these astonishing achievements may be overtaken by others more astonishing still, by the time I’ve finished writing this work. But of course when I say ‘our’ achievements, I’m well aware of my non-role in all this. I’m a mere particle caught up and swept along in the tide of momentous events. I had no choice in being a Europeanised human male. I could’ve been born as an Easter Islander, or an Aboriginal Australian. Or indeed, as a bonobo.
The Rapa Nui population, as mentioned, seems to have reduced from its height, perhaps in the 1500s, to Roggeveen’s 1722 visit. However, there’s a more or less total lack of agreement about the extent of that reduction, and therefore, whether it could be said that the population ‘collapsed’. We do, know, however, that the increasingly frequent visits of European adventurers and traders from the late eighteenth century into the nineteenth had a devastating effect on Rapa Nui’s Polynesian inhabitants.
It’s difficult to get clear data on Rapa Nui culture, clouded as it is by the ideologies of different researchers, by the myths and legends of the islanders themselves, by the lack of written records and the difficulties of interpreting and dating remains, tools, ash-heaps and other artifacts. No sooner do I read material about the hierarchical and destructively competitive nature of the population, than I find recently researched material arguing for necessary co-operation in creating and moving their statues from one part of the island to another. As to the deforestation, some have argued they destroyed their trees for canoe-building and also for the purpose of transporting their statues, using log rollers. Others have tried to show that trees were not used for moving the statues as they were created to be transported upright, using ropes to shuffle them along on rounded bases. Others have argued that plant species on the island weren’t suitable for boat-building. It’s frankly hard to believe that these islanders, so attuned to their environment, would have engaged in the thoughtless or ‘irrational’ destruction of it that Bronowski et al accuse them of. The most recent analysis, published only a few months ago, paints a different picture:
During the last decade, several continuous (gap‐free) and chronologically coherent sediment cores encompassing the last millennia have been retrieved and analysed, providing a new picture of forest removal on Easter Island. According to these analyses, deforestation was not abrupt but gradual and occurred at different times and rates, depending on the site. Regarding the causes, humans were not the only factors responsible for forest clearing, as climatic droughts as well as climate–human–landscape feedbacks and synergies also played a role. In summary, the deforestation of Easter Island was a complex process that was spatially and temporally heterogeneous and took place under the actions and interactions of both natural and anthropogenic drivers. In addition, archaeological evidence shows that the Rapanui civilization was resilient to deforestation and remained healthy until European contact, which contradicts the occurrence of a cultural collapse.
What is certain, as Diamond’s analysis has shown, is that the island was less hospitable than most for sustaining human life, and yet the Rapa Nui people endured, and, as the account left by Roggeveen and his men shows, they were hardly a starving, desperate remnant in 1722.
In the next part, I’ll look at the Ranga Nui people’s activities in providing themselves with the necessities before the eighteenth century, the tragedy of their post-European fate, David Deutsch’s treatment of the situation and … whatever.
References
http://nautil.us/issue/7/waste/not-merely-the-finest-tv-documentary-series-ever-made
The beginning of infinity, by David Deutsch, 2011
Collapse, by Jared Diamond, 2005
electric vehicles in Australia – how bad/good is it?
Following on from the interview with Prof Mark Howden that I reported on recently, I’m wondering what the situation is for anyone wanting to buy an EV in Australia today. What’s on the market, what are the prices, how is the infrastructure, and what if, like me, you might want just to hire an EV occasionally rather than own one?
Inspired by Britain’s Fully Charged show, especially the new episodes entitled Maddie Goes Electric, I’m going to do a little research on what I fully expect to be the bleak scenario of EV availability and cost in Australia. Clearly, we’re well behind the UK in terms of the advance towards EV. One of Maddie’s first steps, for example, in researching EVs was to go to a place called the Electric Vehicle Experience Centre (EVEC), for a first dip into this new world. I cheekily did a net search for Australia’s EVEC, but I didn’t come up completely empty, in that we do have an Australian Electric Vehicle Association (AEVA) and an Electric Vehicle Council (EVC), which I’ll have to investigate further. Maddie also looked up UK’s Green Car Guide, and I’ve just learned that Australia has a corresponding Green Vehicle Guide. I need to excuse my ignorance up to this point – I don’t even own a car, and haven’t for years, and I’m not in the market for one, being chronically poor, and not having space for one where I live, not even in terms of off-street parking, but I occasionally hire a car for holidays and would love to be able to do so with an EV. We shall see.
So the Green Vehicle Guide ranks the recently-released all-electric Hyundai Ioniq as the best-performing green vehicle on the Australian market (that’s performance, not sales, where it seems to be nowhere, probably because it’s so new). It’s priced at somewhere between about $35,000 and $50,000. Here’s what a car sales site has to say:
The arrival of the Hyundai IONIQ five-door hatchback signals Australia is finally setting out on its evolution to an electrified automotive society. The IONIQ is the cheapest battery-electric vehicle on sale in Australia and that’s important in itself. But it’s also significant that Australia’s third biggest vehicle retailer has committed to this course when most majors aren’t even close to signing off such a vehicle. In fact, just to underline Hyundai’s push into green motoring, the IONIQ isn’t just a car; it’s a whole range with three drivetrains – hybrid, plug-in and EV.
I need to find out the precise difference between a hybrid and a plug-in… It’s steep learning curve time.
Anyway, some reporting suggests that Australia’s bleak EV situation is turning around. This Guardian article from August 2019 predicts that EV sales are set to rise significantly, regardless of government inaction:
Modelling suggests the electric vehicle share of new car sales in Australia will rise from about 0.34% today to 8% in 2025. It is predicted to then leap to 27% of new car sales in 2030 and 50% in 2035 as prices of electric car technology fall.
2025 isn’t far off, so I’m a bit skeptical of these figures. Nevertheless, I’ll be monitoring the Australian EV scene more closely from now on.
References
https://www.iea.org/policies/7885-a-national-strategy-for-electric-vehicles
https://www.greenvehicleguide.gov.au/
Maddie Goes Electric, Episode 1: Choosing your electric car (A beginner’s guide) | Fully Charged
climate change – we know what we should be doing
Here in Australia we have a national government that hates to mention human-induced climate change publicly, whatever their personal views are, and clearly they’re varied. I’ve long suspected that there’s a top-down policy (which long predates our current PM) of not mentioning anthropogenic global warming, lest it outrage a large part of the conservative base, while doing a few things behind the scenes to support renewables and reduce emissions. It’s a sort of half-hearted, disorganised approach to what is clearly a major problem locally and globally. And meanwhile some less disciplined or less chained members or former members of this government, such as former PM Tony Abbott and current MP for Hughes, Craig Kelly, are ignoring the party line (and science), and so revealing just how half-arsed the government’s way of dealing with the problem really is. The national opposition doesn’t seem much better on this issue, and it might well be a matter of following the money…
So I was impressed with a recent ABC interview with Australian climate scientist and leading member of the IPCC, Professor Mark Howden, also director of the Climate Change Institute at the Australian National University, who spoke a world of good sense in about ten minutes.
The interview was preceded by the statement that the government is holding to its emission reduction targets – considered to be rather minimal by climate change scientists – while possibly ‘tweaking’ broader climate change policy. This is another example of ‘don’t scare the base’, IMHO. It was also reported that the government felt it might reach its Paris agreement without using ‘carry-over credits’ from the previous Kyoto agreement.
The issue here is that our government, in its wisdom, felt that it should get credit for ‘more than meeting’ its Kyoto targets. As Howden pointed out, those Kyoto targets were easy to meet because we’d have met them even while increasing our emissions (which we in fact did). Spoken without any sense of irony by the unflappable professor.
There’s no provision in the Paris agreement for such ‘carry-over credits’ – however the government has previously relied on them as an entitlement, and in fact pushed for them in a recent meeting in Madrid. Now, it’s changing its tune, slightly. The hullabaloo over the bushfire tragedies has been an influence, as well as a growing sense that reaching the Paris targets without these credits is do-able. Interestingly, Howden suggests that the credits are important for us meeting our Paris commitments up to 2030, as they make up more than half the required emissions reductions. So, if they’re included, we’ll need a 16% reduction from here, rather than a 26 – 28% reduction. But is this cheating? Is it in the spirit of the Paris agreement? Surely not, apart from legal considerations. It certainly affects any idea that Australia might play a leadership role in emissions reductions.
So now the government is indicating that it might scrap the reliance on credits and find real reductions – which is, in fact, a fairly momentous decision for this conservative administration, because the core emissions from energy, transport, waste and other activities are all rising and would need to be turned around (I’m paraphrasing Howden here). So far no policies have been announced, or are clearly in the offing, to effect this turnaround. There’s an Emissions Reductions Fund, established in 2014-5 to support businesses, farmers, landowners in reducing emissions through a carbon credit scheme (this is news to me) but according to Howden it’s in need of more public funding, and the ‘carbon sinks’ – that’s to say the forests that have been burning horrifically in past weeks – which the government has been partly relying upon, are proving to be less stable than hoped. So there are limitations to the government’s current policies. Howden argues for a range of additional policies, but as he says, they’ve rejected (presumably permanently) so many options in the past, most notably carbon pricing, that the cupboard looks pretty bare for the future. There’s of course a speedier move towards renewables in electricity generation – which represents about 30% of emissions, the other 70% being with industry, agriculture, transport and mining (see my previous piece on fracking, for example, a practice that looks to be on the increase in Australia). Howden puts forward the case that it’s in this 70% area that policies can be most helpful, both in emissions reduction and jobs growth. For example, in transport, Australia is well behind other nations in the uptake of EVs, which our government has done nothing to support, unlike most advanced economies. Having EVs working off a renewables grid would reduce transport emissions massively. Other efficiencies which could be encouraged by government policy would be reducing livestock methane emissions through feed and husbandry reforms, such as maintaining shade and other stress-reducing conditions. This can increase productivity and reduce per-unit environmental footprint – or hoofprint.
As to the old carbon pricing argument – Howden points out that during the brief period that carbon pricing was implemented in Australia, core emissions dropped significantly, and the economy continued to grow. It was clearly successful, and its rescinding in around 2015 has proved disastrous. Howden feels that it’s hard to foresee Australia meeting its 2030 Paris targets without some sort of price on carbon – given that there won’t be any deal on carry-over credits. There’s also an expectation that targets will be ramped up, post-2030.
So, the message is that we need to sensibly revisit carbon pricing as soon as possible, and we need to look positively at abatement policies as encouraging growth and innovation – the cost of doing nothing being much greater than the costs involved in emissions reduction. And there are plenty of innovations out there – you can easily look them up on youtube, starting with the Fully Charged show out of Britain. The complacency of the current Oz government in view of the challenges before us is itself energy-draining – like watching a fat-arsed couch potato yawning his way towards an early death.
References
https://iview.abc.net.au/show/abc-news-mornings
https://www.environment.gov.au/climate-change/government/emissions-reduction-fund/about
the SUV abomination, or when will we reach peak SUV?
I was amused by a recent rant from Robert Llewellyn of the highly-recommended Fully Charged vodcasts, regarding the rise and rise of petrol and diesel-fuelled SUV sales in this period of carbon emission concern and climate change. So I have to share an anecdote.
As a young perennially poor person in the seventies I hitch-hiked quite a lot. Hitch-hiking is barely a thing nowadays, and I suspect the hitch-hiking experience I’m about to describe, sometime in the eighties, was my last. It often comes back to annoy me.
I was picked up by an overweight middle-aged woman with a blaze of dyed blond hair and a dire Aussie accent, in an SUV. Obviously, it was a kind gesture.
This was my first experience of being in an SUV, and I’ve had very few since. It felt strange to be looking down at other cars on the road. I wondered if this created psychological effects. The woman, I think, tried to elicit conversation but I’m very shy with strangers and pretty hopeless at small talk. So she made her own, which soon developed into a rant against ‘small cars’, which she seemed to regard as death traps and a form of road litter. Certainly there was a strange, disproportionate rage that got to me, as I nodded with an air of non-committal sagacity.
At that point in my life I’d never driven a car – I didn’t get my licence until my late thirties – but I knew the kind of car I wanted to drive, and it was the precise opposite of an SUV, a ridiculous vehicle that was just starting to pollute city streets at the time of this awkward incident. Of course the environment was already a major public issue in the eighties, so I naively thought this woman was on the wrong side of history. The SUV would surely go the way of the dinosaur, in somewhat less than a couple of hundred million years.
But SUV sales are soaring worldwide, in spite of a greater recognition of climate change and anthropogenic global warming due to greenhouse gas emissions. I suppose there’s some excuse for them in Australia, this land of sweeping plains (and sleeping brains), but given our apparent indifference to the EV revolution and the phobia re climate change issues of our federal government, we’re just going to have to put up with these tanks continuing to proliferate in our suburbs. And it’s going on everywhere – there’s currently a huge spike in SUV sales worldwide. I mean, WTF?
So, instead of a pox on SUVs, how about a tax on them? It worked with cigarettes here….
Of course I’m joking. Western governments are more likely to subsidise the manufacture of SUVs than to tax them. This US business website presents in graphic detail the surge in SUV sales:
48% of car sales in the United States last year [2018]’were SUVs, which was the highest percentage worldwide, but other countries are catching up. Large cars can be seen as a status symbol, and sales are rising in countries like China and India where the middle class is growing.
The website cites a study which found that the number of SUVs on the road has increased about six-fold since 2010, and SUVs alone were the second largest contributor to the global increase in carbon emissions during that period. So, I wonder, when will we reach peak SUV?
fish deaths in the lower Darling – interim report
Jacinta: We wrote about this issue in a piece posted on February 11, so it’s time to follow up – an interim report came out on February 20, and a final report is due at the end of March, but my feeling is that the final report won’t differ much from this interim one.
Canto: Yes I get the feeling that these experts have largely known about the situation for a long time – unusual climatic conditions plus an increasing lack of water in the system, which would make the remaining water more susceptible to extremes of weather.
Jacinta: So here’s some of what they’re saying. There were three separate events; the first on December 15 involved tens of thousands of fish deaths over a 30km stretch of the Darling near Menindee, the second on Jan 6-7, over 45kms in the same area, involved hundreds of thousands of deaths, even millions according to some residents, and the third on Jan 28, with thousands of deaths. Likely effects on fish populations in the Darling will last for years.
Canto: And they warn that more deaths are likely to occur – though no major events have been reported since – due to low inflows and continued dry conditions in the catchment area. Monitoring has shown that there are problems of low dissolved oxygen and ‘high stratification’ at various points along the river. I presume ‘high stratification’ is self-explanatory, that the water isn’t mixing due to low flows?
Jacinta: Yes, but I think the issue is thermal stratification, where you have a warm surface layer sitting above a cooler, oxygen-depleted sub-surface layer. These are excellent conditions for algal blooms apparently. And the low flows are a natural feature of the Darling. It’s also very variable in flow, much more so than the Murray, due to its low relief, the more variable rainfall in the region, and the tributaries which create a large catchment area. I don’t know if that makes sense.
Canto: Neither do I. I note that they’ve been carefully critical of the NSW government’s ‘Barwon-Darling Water Sharing Plan 2012’, because between the draft and final implementation of the plan the number of high-flow Class C shares was reduced and the number of Class A (low flow) and Class B (medium flow) shares increased, which meant more extraction of water overall, and at lower flows. They recognise that there have been recent Federal moves to reverse this, but clearly they don’t consider them sufficient.
Jacinta: Yes and the problem goes back a way. They refer to an analysis from almost two decades ago:
The flow regime in the lower Darling has changed significantly since the completion of the Menindee Lakes storage scheme in 1968, and as a result of abstractions in the Barwon–Darling and its tributaries. It is estimated that the mean annual flow in the Darling River has been reduced by more than 40% as a result of abstractions in the Barwon–Darling (Gippel & Blackham, 2002).
Presumably ‘abstractions’ means what I think it means – though elsewhere they use the term ‘extractions’ which is confusing.
Canto: We should point out the immense complexity of the system we’re dealing with, which we can see from detailed maps that accompany the report, not to mention a number of barely comprehensible charts and graphs. Anyway the effect of ‘water management’ on native vegetation has been dire in some regions. For example, reduced inundation of natural floodplains has affected the health of the river red gums, while other trees have been killed off by the creation of artificial lakes.
Jacinta: And returning to fish deaths, the report states that ‘the influence of upstream extractions on inflows to the Menindee Lakes is an important consideration when assessing the causes of fish deaths downstream’. What they point out is that the proportion of extractions is higher in times of lower inflow, which is intuitively obvious I suppose. And extractions during 2017-8 were proportionally the second highest on record. That’s in the Northern Basin, well above the Menindee Lakes.
Canto: And the extractions have been mainly out of the tributaries above the Barwon-Darling, not those principal rivers. Queenslanders!
Jacinta: No mention of Queenslanders, but let’s not get bogged down..
Canto: Easily done when there’s hardly any water…
Jacinta: Let’s go to the provisional findings and recommendations. There are 18 briefly stated findings in all, and 20 more expansive recommendations. The first two findings are about extreme weather/climatic conditions amplified by climate change, with the expectation that this will be a continuing and growing problem. Findings 3 and 4 focus on the combined effects of drought and development. There’s a lack of updated data to separate out the effects, but it’s estimated that pre-development inflows into the Menindee Lakes were two or three times what they are now. Further findings are that the impact of diversions of or extractions from flows are greater during dry years, that extractions from tributaries are more impactful than extractions from the Barwon-Darling Rivers.
Canto: The findings related directly to fish deaths – principally findings 10 through 15 – are most interesting, so I’ll try to explain. The Menindee Lakes experienced high inflows in 2012 and 2016, which caused greater connection through the river system and better conditions for fish spawning and ‘recruitment’ (I don’t know what that means). So, lots of new, young fish. Then came the bad 2017-8 period, and releases from the Menindee Lakes were less than the minimum recommended under the water sharing plan, ‘with the intent to prolong stock and domestic requests to meet critical human needs’. So by the end of 2018, the high fish biomass became trapped or restricted between weirs, unable to move upstream or downstream. As the water heated up, significant algal blooms developed in the areas where fish had accumulated. Thermal stratification also occurred, with hypoxic (low oxygen) or anoxic (no oxygen) conditions in the lower waters, and algal blooms proliferating in the surface waters, where the fish were forced to hang out. Then conditions suddenly changed, with lower air temperatures and stormy conditions causing a rapid destratification. The low oxygen water – presumably more voluminous than the oxygenated water – dominated the whole water column and the fish had no way out.
Jacinta: Yes, you can’t adapt to such sudden shifts. The final findings are about existing attempts at fish translocation and aerating water which are having some success, about stratification being an ongoing issue, and about lack of knowledge at this preliminary stage of the precise extent of the fish deaths.
Canto: So now to the 20 recommendations. They’re grouped under 3 headings; preventive and restorative measures (1-9), management arrangements (10-13), and knowledge and monitoring (14-20). The report noted a lack of recent systematic risk assessment for low oxygen, stratification and blackwater (semi-stagnant, vegetation-rich water that looks like black tea) in the areas where the fish deaths occurred. There was insufficient or zero monitoring of high-risk areas for stratification, etc, and insufficient planning to treat problems as they arose. Flow management strategies (really involving reduced extraction) need to be better applied to reduce problems in the lower Darling. Reducing barriers to fish movement should be considered, though this is functionally difficult. Apparently there’s a global movement in this direction to improve freshwater fish stocks. Short term measures such as aeration and translocation are also beneficial. Funding should be set aside for research on and implementation of ecosystem recovery – it’s not just the fish that are affected. Long-term resilience requires an understanding of interactions and movement throughout the entire basin. Fish are highly mobile and restriction is a major problem. A whole-of system approach is strongly recommended. This includes a dynamic ‘active event-based management’ approach, especially in the upper reaches and tributaries of the Barwon-Darling, where extraction has been governed by passive, long-term rules. Such reforms are in the pipeline but now need to be fast-tracked. For example, ‘quantifying the volumes of environmental water crossing the border from Queensland to NSW…. would increase transparency and would help the CEWH [Commonwealth Environmental Water Holdings] with their planning, as well as clear the path to move to active management in Queensland’.
Jacinta: Right, you’ve covered most of the issues, so I’ll finish up with monitoring, measuring and reporting. The report argues that reliable, up-to-date accounting of flows, volumes in storage, extractions and losses due to seepage and evaporation are essential to create and maintain public confidence in system management, and this is currently a problem. Of course this requires funding, and apparently the funding levels have dropped substantially over the past decade. The report cites former funding and investment through the Co-operative Research Centre, Land and Water Australia and the National Water Commission, but ‘by the early 2010s, all of these sources of funding had terminated and today aggregate levels of funding have reduced to early 1980s levels, at a time when water was far less of a public policy challenge than it is today’.
Canto: We await the government’s response to that one.
Jacinta: And on fisheries research in particular, it has been largely piecemeal except when their was a concerted co-ordinated effort under the Native Fish Strategy, but the issue right now is to know how many fish (and other organisms) of the various affected species survived the event, which involves multi-level analyses, combined with management of Basin water balances, taking into account the ongoing effects of weather events due to climate change, in order to foster and improve the growth and well-being of fish stocks and freshwater habitats in general. Connectivity of the system in particular is a major concern of the report.
Canto: Right, so this has been a bit of a journey into the unknown for us, but a worthwhile one. It suggests that governments have been a bit dozey at the wheel in recent years, that extractions, especially in the upper reaches and tributaries, haven’t been well monitored or policed, and the connectivity of the system has suffered due to extractions, droughts and climate change. Funding seems to have dried up as much as some of the rivers have, and we’ll have to wait and see if this becomes an election issue. I suspect it’ll only be a minor one.
kin selection – some fascinating stuff
Canto: So we’ve done four blogs on Palestine and we’ve barely scratched the surface, but we’re having trouble going forward with that project because, frankly, it’s so depressing and anger-inducing that it’s affecting our well-being.
Jacinta: Yes, an undoubtedly selfish excuse, but we do plan to go on with that project – we’re definitely not abandoning it, and meanwhile we should recommend such books as Tears for Tarshiha by the Palestinian peace activist Olfat Mahmoud, and Goliath by the Jewish American journalist Max Blumenthal, which highlight the sufferings of Palestinian people in diaspora, and the major stresses of trying to exist under zionist monoculturalism. But for now, something completely different, we’re going to delve into the fascinating facts around kin selection, with thanks to Robert Sapolski’s landmark book Behave.
Canto: The term ‘kin selection’ was first used by John Maynard Smith in the early sixties but it was first mooted by Darwin (who got it right about honey bees), and its mathematics were worked out back in the 1930s.
Jacinta: What’s immediately interesting to me is that we humans tend to think we alone know who our kin are, especially our extended or most distant kin, because only we know about aunties, uncles and second and third cousins. We have language and writing and record-keeping, so we can keep track of those things as no other creatures can. But it’s our genes that are the key to kin selection, not our brains.
Canto: Yes, and let’s start with distinguishing between kin selection and group selection, which Sapolsky deals with well. Group selection, popularised in the sixties by the evolutionary biologist V C Wynne-Edwards and by the US TV program Wild Kingdom, which I remember well, was the view that individuals behaved, sometimes or often, for the good of the species rather than for themselves as individuals of that species. However, every case that seemed to illustrate group selection behaviour could easily be interpreted otherwise. Take the case of ‘eusocial’ insects such as ants and bees, where most individuals don’t reproduce. This was seen as a prime case of group selection, where individuals sacrifice themselves for the sake of the highly reproductive queen. However, as evolutionary biologists George Williams and W D Hamilton later showed, eusocial insects have a unique genetic system in which they are all more or less equally ‘kin’, so it’s really another form of kin selection. This eusociality exists in some mammals too, such as mole rats.
Jacinta: The famous primatologist Sarah Hrdy dealt something of a death-blow to group selection in the seventies by observing that male langur monkeys in India commit infanticide with some regularity, and, more importantly, she worked out why. Langurs live in groups with one resident male to a bunch of females, with whom he makes babies. Meanwhile the other males tend to hang around in groups brooding instead of breeding, and infighting. Eventually, one of this male gang feels powerful enough to challenge the resident male. If he wins, he takes over the female group, and their babies. He knows they’re not his, and his time is short before he gets booted out by the next tough guy. Further, the females aren’t ovulating because they’re nursing their kids. The whole aim is to pass on his genes (this is individual rather than kin selection), so his best course of action is to kill the babs, get the females ovulating as quickly as possible, and impregnate them himself.
Canto: Yes, but it gets more complicated, because the females have just as much interest in passing on their genes as the male, and a bird in the hand is worth two in the bush…
Jacinta: Let me see, a babe in your arms is worth a thousand erections?
Canto: More or less precisely. So they fight the male to protect their infants, and can even go into ‘fake’ estrus, and mate with the male, fooling the dumb cluck into thinking he’s a daddy.
Jacinta: And since Hrdy’s work, infanticide of this kind has been documented in well over 100 species, even though it can sometimes threaten the species’ survival, as in the case of mountain gorillas. So much for group selection.
Canto: So now to kin selection. Here are some facts. If you have an identical twin your genome is identical with hers. If you have a full sibling you’re sharing 50% and with a half-sibling 25%. As you can see, the mathematics of genes and relatedness can be widened out to great degrees of complexity. And since this is all about passing on all, or most, or some of your genes, it means that ‘in countless species, whom you co-operate with, compete with, or mate with depends on their degree of relatedness to you’, to quote Sapolsky.
Jacinta: Yes, so here’s a term to introduce and then fairly promptly forget about: allomothering. This is when a mother of a newborn enlists the assistance of another female in the process of child-rearing. It’s a commonplace among primate species, but also occurs in many bird species. The mother herself benefits from an occasional rest, and the allomother, more often than not a younger relation such as the mother’s kid sister, gets to practice mothering.
Canto: So this is part of what is called ‘inclusive fitness’, where, in this case, the kid gets all-day mothering (if of varying quality) the kid sister gets to learn about mothering, thereby increasing her fitness when the time comes, and the mother gets a rest to recharge her batteries for future mothering. It’s hopefully win-win-win.
Jacinta: Yes, there are negatives and positives to altruistic behaviour, but according to Hamilton’s Rule, r.B > C, kin selection favours altruism when the reproductive success of relatives is greater than the cost to the altruistic individual.
Canto: To explain that rule, r equals degree of relatedness between the altruist and the beneficiary (aka coefficient of relatedness), B is the benefit (measured in offspring) to the recipient, and C is the cost to the altruist. What interests me most, though, about this kin stuff, is how other, dumb primates know who is their kin. Sapolsky describes experiments with wild vervet monkeys by Dorothy Cheney and Robert Seyfarth which show that if monkey A behaves badly to monkey B, this will adversely affect B’s behaviour towards A’s relatives, as well as B’s relatives’ behaviour to A, as well as B’s relatives’ behaviour to A’s relatives. How do they all know who those relatives are? Good question. The same researchers proved this recognition by playing a recording of a juvenile distress call to a group of monkeys hanging around. The female monkeys all looked at the mother of the owner of that distress call to see what she would do. And there were other experiments of the sort.
Jacinta: And even when we can’t prove knowledge of kin relations (kin recognition) among the studied animals, we find their actual behaviour tends always to conform to Hamilton’s Rule. Or almost always… In any case there are probably other cues, including odours, which may be unconsciously sensed, which might aid in inclusive fitness and also avoiding inbreeding.
Canto: Yes and It’s interesting how this closeness, this familiarity, breeds contempt in some ways. Among humans too. Well, maybe not contempt but we tend not to be sexually attracted to those we grow up with and, for example, take baths with as kids, whether or not they’re related to us. But I suppose that has nothing to do with kin selection. And yet…
Jacinta: And yet it’s more often than not siblings or kin that we have baths with. As kids. But getting back to odours, we have more detail about that, as described in Sapolski. Place a mouse in an enclosed space, then introduce two other mice, one unrelated to her, another a full sister from another litter, never encountered before. The mouse will hang out with the sister. This is called innate recognition, and it’s due to olfactory signatures. Pheromones. From proteins which come from genes in the major histocompatibility complex (MHC).
Canto: Histowhat?
Jacinta: Okay, you know histology is the study of bodily tissues, so think of the compatibility or otherwise of tissues that come into contact. Immunology. Recognising friend or foe, at the cellular, subcellular level. The MHC, this cluster of genes, kicks off the production of proteins which produce pheromones with a unique odour, and because your relatives have similar MHC genes, they’re treated as friends because they have a similar olfactory signature. Which doesn’t mean the other mouse in the enclosure is treated as a foe. It’s a mouse, after all. But other animals have their own olfactory signatures, and that’s another story.
Canto: And there are other forms of kin recognition. Get this – birds recognise their parents from the songs sung to them before they were hatched. Birds have distinctive songs, passed down from father to son, since its mostly the males that do the singing. And as you get to more complex species, such as primates – though maybe they’re not all as complex as some bird species – there might even be a bit of reasoning involved, or at least consciousness of what’s going on.
Jacinta: So that’s kin selection, but can’t we superior humans rise above that sort of thing? Australians marry Japanese, or have close friendships with Nigerians, at least sometimes.
Canto: Sometimes, and this is the point. Kinship selection is an important factor in shaping behaviour and relations, but it’s one of a multiple of factors, and they all have differential influences in different individuals. It’s just that such influences may go below the level of awareness, and being aware of the factors shaping our behaviour is always the key, if we want to understand ourselves and everyone else, human or non-human.
Jacinta: Good to stop there. As we’ve said, much of our understanding has come from reading Sapolsky’s Behave, because we’re old-fashioned types who still read books, but I’ve just discovered that there’s a whole series of lectures by Sapolsky, about 25, on human behaviour, which employs the same structure as the book (which is clearly based on the lectures), and is available on youtube here. So all that’s highly recommended, and we’ll be watching them.
References
R Sapolski, Behave: the biology of humans at our best and worst. Bodley Head, 2017
https://www.britannica.com/science/animal-behavior/Function#ref1043131
https://en.wikipedia.org/wiki/Kin_selection
https://en.wikipedia.org/wiki/Eusociality
on luck, and improving environments
I’m in the process of reading Behave, by Robert Sapolsky, a professor of neurology and biology at Stanford University, who has tried in his book to summarise, via the research literature, the seconds, then minutes, then hours, then days, then lifetimes and more, that precede any particular piece of behaviour. It’s a dense but fascinating book, which aligns with, and provides mountains of evidence for, my view that we’re far less in control of ourselves than we think.
It seems we think this because of what might be called conscious awareness of our behaviours and our decisions. This consciousness is something we sometimes mistake for control. It’s interesting that we consider it obvious that we have no control over the size of our nose or the colour of our eyes, but we have more or less complete control of our temper, appetites, desires and ambitions.
Humanistically speaking, this understanding about very limited control needs to have massive implications for our understanding of others. We don’t get to choose our parents, our native country or the immediate environment that most profoundly affects our early life and much of our subsequent behaviour. The flow of hormones and neurotransmitters and their regulation via genetic and epigenetic factors proceed daily, hourly, moment by moment, and all we’re aware of, essentially, is outcomes.
A lot of people, I note, are very uncomfortable about this kind of talk. For example, many of us want to treat each other as ‘equal before the law’. But is one person ever ‘equal’ with another? We know – it’s obvious – that we’re all different. That’s how we distinguish people, by their smiles, their voices, their fingerprints, their DNA. So how can we be different and equal at the same time? Or, to turn things around, how can a legal system operate if everyone is treated as different, unique, a special case?
Well, in a sense, we already do this, with respect to the law. No two bank robberies, or rapes, or murders are the same, and the judiciary must be highly attuned to the differences when applying punishments. Nowadays, and increasingly, the mental state of the offender – particularly at the time of the offence, if that can be ascertained – is considered when sentencing. And this is surely a good thing.
The question here is, considering the exponential growth of our neurophysiological knowledge in the 21st century, and its bearing on our understanding of every kind of negative or positive behaviour we engage in, how can we harness that knowledge to improve outcomes and move from a punitive approach to bad behaviours to something more constructive?
Of course, it’s one thing to identify the release or suppression of glucocorticoids, for example, and its effect on person x’s cognitive faculties, it’s entirely another thing to effect a remedy. And to what effect? To make everyone docile, ‘happy’ and law-abiding? To have another go at eugenics, this time involving far more than just genes?
One of the points constantly hammered home in Sapolsky’s book is the effect of environment on everything that goes on inside us, so that, for example, genes aren’t quite as determinative as we once thought. Here are some key points from his chapter on genes (with apologies about unexplained terms such as epigenetic, transcription and transposons):
a. Genes are not autonomous agents commanding biological events.
b. Instead genes are regulated by the environment, with environment consisting of everything from events inside the cell to the universe.
c. Much of your DNA turns environmental influences into gene transcription, rather than coding for genes themselves; moreover, evolution is heavily about changing regulation of gene transcription, rather than genes themselves.
d. Epigenetics can allow environmental effects to be lifelong, or even multigenerational.
e. And thanks to transposons, neurons contain a mosaic of different genomes.
And genes are only one component of the array of forces that influence or control our behaviour. We know, or course, about how Phineas Gage-type accidents and brain tumours can alter behaviour, but many other effects on the brain can alter our behaviour without us and others knowing too much about it. These include stress, malnutrition, and long-term cultural and religious influences which permanently affect our attitudes to, for example, women, other species and the food we eat. Domestic violence, drug use, political affiliations, educational outcomes and sexual affinities are all more inter-generational than we’re generally prepared to admit.
The first thing we need to do is be aware of all this in our judgment of others, and even of ourselves. There’s just so much luck involved in being who we are. We could’ve been more or less ‘good-looking’ than we are -according to the standards of the culture around us – and this would’ve affected the way we’ve been treated throughout our whole lives. We could’ve been born richer or poorer, with more or less dysfunctional parents, taller or shorter, more or less mentally agile, more or less immune to the pathogens that surround us. On and on and on we could go, even to an extreme degree. We could’ve been born in Algeria, Argentina or Azerbaijan. We could’ve been born in 1912, 1412 or 512, or 150,000 years ago. We could’ve been born a mongoose, a mouse or a mosquito. It’s all luck, whether good or bad is up to us to decide, but probably not worth speculating about as we have no choice but to make the best of what we are.
What we do have is consciousness or awareness of what we are. And with that consciousness we can speculate, as we as a species always have, on how to make the best of ourselves, given that we’re the most socially constructed mammalian species on the planet, and for that reason the most successful, measured by population, spread across the globe, and what we’ve done for ourselves in terms of social evolution – our science, our technology, our laws and our politics.
That’s where humanism comes in, for me. Since we know that ‘there but for the randomness of luck go I’, it surely follows that we should sympathise with those whose luck hasn’t been as lucky as our own, and strive to improve the lot of those less fortunate. Safe havens, educational opportunities, decent wages, human rights, clean environments, social networks – we know what’s required for people to thrive. Yet we focus, I think, too much on punishment. We punish people for trying to improve their family’s situation – or to avoid obliteration – by seeking refuge in safer, richer, healthier places. We punish them for seeking solace in drugs because their circumstances are too overwhelming to deal with. We punish them for momentary and one-off lapses of concentration that have had dire consequences. Of course it has always been thus, and I think we’re improving, though very unevenly across the globe. And the best way to improve is by more knowing. And more understanding of the consequences of that knowledge.
Currently, it seems to me, we’re punishing people too much for doing what impoverished, damaged, desperate people do to survive. It’s understandable, perhaps, in our increasingly individualist world. How dare someone bother me for handouts. It’s not my fault that x has fucked up his life. Bring back capital punishment for paedophiles. People smugglers are the lowest form of human life. Etc etc – mostly from people who don’t have a clue what it’s like to be those people. Because their life is so different, through no fault, or cause, of their own.
So to me the message is clear. Out lives would be better if others’ lives were better – if we could give others the opportunities, the health, the security and the smarts that we have, and if we could have all of those advantages that they have. I suppose that’s kind of impossible, but it’s better than blaming and punishing, and feeling superior. We’re not, we’re just lucky. Ot not.
more about ozone, and the earth’s greatest extinction event
Ozone, or trioxygen (O3), an unstable molecule which is regularly produced and destroyed by the action of sunlight on O2, is a vital feature in our atmosphere. It protects life on earth from the harmful effects of too much UV radiation, which can contribute to skin cancers in humans, and genetic abnormalities in plant life. In a previous post I wrote about the discovery of the ozone shield, and the hole above Antarctica, which we seem to be reducing – a credit to human global co-operation. In this post I’m going to try and get my head around whether or not ozone depletion played a role in the so-called end-Permian extinction of some 250 mya.
I first read of this theory in David Beerling’s 2009 book The emerald planet, but recent research appears to have backed up Beerling’s scientific speculations – though speculation is too weak a word. Beerling is a world-renowned geobiologist and expert on historical global climate change. He’s also a historian of science, and in ‘An ancient ozone catastrophe?’, chapter 4 of The emerald planet, he describes the discovery and understanding of ozone through the research of Robert Strutt, Christian Schönbein, Marie Alfred Cornu, Walter Hartley, George Dobson, Sidney Chapman and Paul Crutzen, among others. He goes on to describe the ozone hole discovery in the 70s and 80s, before focusing on research into the possible effects of previous events – the Tunguska asteroid strike of 1908, the Mount Pinatubo eruption of 1991 and others – on atmospheric ozone levels, and then homes in on the greatest extinction event in the history of our planet – the end-Permian mass extinction, ‘the Great Dying’, which wiped out some 95% of all species then existing.
According to Beerling, it was an international team of palaeontologists led by Henk Visscher at the University of Utrecht who first made the claim that stratospheric ozone had substantially reduced in the end-Permian. They hypothesised that, due to the greatest volcanic eruptions in Earth history, which created the Siberian Traps (layers of solidified basalt covering a huge area of northern Russia), huge deposits of coal and salt, the largest on Earth, were disrupted:
The widespread heating of these sediments and the action of hot groundwater dissolving the ancient salts, was a subterranean pressure cooker synthesising a class of halogenated compounds called organohalogens, reactive chemicals that can participate in ozone destruction. And in less than half a million years, this chemical reactor is envisaged to have synthesised and churned out sufficiently large amounts of organohalogens to damage the ozone layer worldwide to create an intense increased flux of UV radiation.
However, Beerling questions this hypothesis and considers that it may have been the eruptions themselves, which lasted 2 million years and occurred at the Permian-Triassic boundary 250-252 mya, rather than their impact on salt deposits, that did the damage. There’s evidence that many of the eruptions originated from as deep as 10 kilometres below the surface, injected explosively enough to reach the stratosphere, and that these plumes contained substantial amounts of chlorine.
More recent research, published this year, has further substantiated Visscher’s team’s finding regarding genetic mutations in ancient conifers and lycopsids, and their probable connection with UV radiation enabled by ozone destruction. The mutations were global and dated to the same period. Laboratory experiments exposing related modern plants to bursts of UV radiation have produced more or less identical spore mutations.
The exact chain of events linking the eruptions to the ozone destruction have yet to be worked out, and naturally there’s a lot of scientific argy-bargy going on, but the whole story, even considering that it occurred so far in the past is a reminder of the fragility of that part of our planet that most concerns us – the biosphere. The eruptions clearly altered atmospheric chemistry and temperature. Isotopic measurements of oxygen in sea water suggest that equatorial waters reached more than 40°C. As can be imagined, this had killer effects on multiple species.
So, we’re continuing to gain knowledge on the ozone shield and its importance, and fragility. I don’t know that there are too many ozone hole skeptics around (I don’t want to look too hard), but if we could only get the same kind of apparent near-unanimity with regard to anthropogenic global warming, that would be great progress.
about ozone, its production and depletion
People will remember the ‘hole in the ozone’ issue that came up in the eighties I think, and investigators found that it was all down to CFCs, which were quite quickly banned, and then everything was hunky dory….
Or that’s how I vaguely recall it. Time to take a much closer look.
I take my cue from ‘An ancient ozone catastrophe?’, chapter 4 of David Beerling’s The emerald planet, in which he looks at the evidence for a previous ozone disaster and its possible relation to the great Permian extinction of 252 millions years ago. I’ll probe into that matter in another post. In this post I’ll try to answer some more basic questions – what is ozone, where is the ozone layer and why does it have a hole in it?
Ozone is also known as trioxygen, which gives a handy clue to its structure. Oxygen can exist in different allotropes or molecular structures which are more or less stable. O3, ozone, is much less stable than O2 and has a very pungent chlorine-like odour and a pale blue colour. It’s present in minute quantities throughout the atmosphere but is most concentrated in the lower part of the stratosphere, 20 to 30 kilometres above the Earth’s surface. This region is called the ozone layer, or ozone shield, though it’s still not particularly dense with ozone, and that density varies geographically and seasonally. Ozone’s instability means that it doesn’t last long, and has to be replenished continually.
In 1928 chlorofluorocarbons (CFCs) were developed as a seemingly safe form of refrigerant, which, under patent as Freon, came to be used in air-conditioners, fridges, hair-sprays and a variety of other products. As it turned out, these CFCs aren’t so harmless when they reach the upper atmosphere, where the chlorine reacts with ozone to form chlorine monoxide (ClO), and regular O2. This reaction is activated by ultraviolet radiation, which then breaks up the unstable ClO, leaving the chlorine to react with more ozone in a continuing cycle.
By the eighties, it had become clear that something was going wrong with the ozone layer. Studies revealed that a gigantic hole in the layer had opened up over Antarctica, and without going into detail, CFCs were found to be largely responsible. There was the usual fight with vested business interests, but in 1987 the Montreal protocol against the use of ozone-depleting substances (ODS) was drawn up, a landmark agreement which has been successful in starting off the long and far from completed process of repair of the ozone shield.
As a very effective oxidant, ozone has many commercial applications, but the same oxidising property makes it a danger to plant and animal tissue. Much better for us to keep most of it up above the troposphere, where its ability to absorb UV radiation has made it virtually essential for maintaining healthy life on Earth’s surface.
So here are some questions. Why does ozone proliferate particularly at the top of the troposphere, in the lower stratosphere? If it’s so reactive, how does it maintain itself at a particular rate? Has the thinning or reduction of that layer seriously influenced life on Earth in the past? From my reading, mainly of Beerling, I think I can answer the first two questions. The third question, which Beerling explores in the above-mentioned chapter of his book, is more speculative, and more interesting.
Sidney Chapman, a brilliant geophysicist and mathematician of the early twentieth century, essentially answered the first question. He realised that ozone was both formed and destroyed by the action of sunlight, specifically UV radiation, on atmospheric oxygen. He calculated that this action would reduce and finally stop at a point approximately 15 km above sea level, because the reactions which had produced the ozone higher up had absorbed the UV radiation in the process. No activation energy to produce any more ozone. That explained the lower limit of ozone. The upper limit was explained by the lack of oxygen in the upper stratosphere to produce a stable layer – for production to exceed destruction. This was interesting confirmation of observations made earlier by the meteorologist and balloonist Léon-Phillippe Teisserenc de Bort, who noted that, contrary to his expectations, the air temperature didn’t fall gradually with altitude but reached a point of stabilisation where the air even seemed to become warmer. He named this upper layer of air the stratosphere, and the cooler more turbulent layer below he called the troposphere. It’s now known that this upper-air warming is caused by the absorption of UV radiation by ozone.
Our picture of ozone still had some holes in it, however, as it seemed there was a lot less of it around than the calculations of Chapman suggested. To quote from Beerling’s book:
… there had to be some as-yet unappreciated means by which ozone was being destroyed. The fundamental leap required to solve the problem was taken comparatively recently, in 1970, by a then young scientist called Paul Crutzen. Crutzen showed that, remarkably, the oxides of nitrogen, produced by soil microbes, catalysed the destruction of ozone many kilometres up in the stratosphere. Few people appreciate the marvellous fact that the cycling of nitrogen by the biosphere exerts an influence on the global ozone layer: life on Earth reaches out to the chemistry of the stratosphere.
Now to explain why the hole in the ozone shield occurred above the Antarctic. My understanding and explanation starts with reading Beerling and ends with this post from the USA’s National Oceanic and Atmospheric Administration’s Earth System Research Laboratory (NOAA/ESRL).
The ozone hole over Antarctica varies in size, and is largest in the months of winter and early spring. During these months, due to the large and mountainous land mass there, average minimum temperatures can reach as low as −90°C, which is on average 10°C lower than Arctic winter minimums (Arctic temperatures are generally more variable than in the Antarctic). When winter minimums fall below around −78°C at the poles, polar stratospheric clouds are formed, and this happens far more often in the Antarctic – for about five months in the year. Chemical reactions between halogen gases and these clouds produce the highly reactive gases chlorine monoxide (ClO) and bromine monoxide (BrO), which are destructive to ozone.
Most ozone is produced in the tropical stratosphere, in reactions driven by sunlight, but a slow movement of stratospheric air, known as the Brewer-Dobson circulation, transports it over time to the poles, so that ozone ends up being more sparse in the tropics. Interestingly, although most ozone-depleting substances – mainly halogen gases – are produced in the more humanly-populated northern hemisphere, complex tropospheric convection patterns distribute the gases more or less evenly throughout the lower atmosphere. Once in the stratosphere and distributed to the poles, the air carrying the halogen-gas products becomes isolated due to strong circumpolar winds, which are at their height during winter and early spring. This isolation preserves ozone depletion reactions for many weeks or months. The polar vortex at the Antarctic, being stronger than in the Arctic, is more effective in reducing the flow of ozone from tropical regions.
So – I’ve looked here briefly at what ozone is, where it is, and how it’s produced and destroyed, but I haven’t really touched on its importance for protecting life here on Earth. So that, and whether its depletion may have had catastrophic consequences 250 million years ago, will be the focus of my next post.
References
The Emerald Planet, by David Beerling, Oxford Landmark Science, 2009