Wednesday, 12 September 2018

Seasons of the mind: how can we escape subjective thinking?

According to some people I've met, the first day of spring in the Southern Hemisphere has been and gone with the first day of September. Not incidentally, there are also some, myself included, who think that it has suddenly started to feel a bit warmer. Apparently, the official start date is at the spring equinox during the third week of September. So on the one hand, the weather has been warming since the start of the month but on the other, why should a planet followed neat calendrical conventions, i.e. the first of anything? Just how accurate is the official definition?

There are many who like to reminisce about how much better the summer weather was back in their school holidays. The rose-tinted memories of childhood can seem idyllic, although I also recall summer days of non-stop rain (I did grow up in the UK, after all). Therefore our personal experiences, particularly during our formative years, can promote an emotion-based response that is so far ingrained we fail to consider they may be inaccurate. Subjectivity and wishful thinking are key to the human experience: how often do we remember the few hits and not the far more misses? As science is practiced by humans it is subject to the same lack of objectivity as anything else; only its built-in error-checking can steer practitioners onto a more rational course than in other disciplines.

What got me to ponder the above was that on meeting someone a few months' ago for the first time, almost his opening sentence was a claim that global warming isn't occurring and that instead we are on the verge of an ice age. I didn't have time for a discussion on the subject, so I filed that one for reply at a later date. Now seems like a good time to ponder what it is that leads people to make such assertions that are seemingly contrary to the evidence.

I admit to being biased on this particular issue, having last year undertaken research for a post on whether agriculture has postponed the next glaciation (note that this woolly - but not mammoth, ho-ho - terminology is one of my bugbears: we are already in an ice age, but currently in an interglacial stage). Satellite imagery taken over the past few decades shows clear evidence of large-scale reductions in global ice sheets. For example, the northern polar ice cap has been reduced by a third since 1980, with what remains only half its previous thickness. Even so, are three decades a long enough period to make accurate predictions? Isn't using a scale that can be sympathetic with the human lifespan just as bad as relying on personal experience?

The UK's Met Office has confirmed that 2018 was that nation's hottest summer since records began - which in this instance, only goes back as far back as 1910.  In contrast, climate change sceptics use a slight growth in Antarctic sea ice (contrary to its steadily decreasing continental icesheet) as evidence of climate equilibrium. Now I would argue that this growth is just a local drop in the global ocean, but I wonder if my ice age enthusiast cherry-picked this data to formulate his ideas? Even so, does he believe that all the photographs and videos of glaciers, etc. have been faked by the twenty or so nations who have undertaken Earth observation space missions? I will find out at some point!

If we try to be as objective as possible, how can we confirm with complete certainty the difference between long term climate change and local, short term variability? In particular, where do you draw the line between the two? If we look at temporary but drastic variations over large areas during the past thousand years, there is a range of time scales to explore. The 15th to 18th centuries, predominantly the periods 1460-1550 and 1645-1715, contained climate variations now known as mini ice ages, although these may have been fairly restricted in geographic extent. Some briefer but severe, wide-scale swings can be traced to single events, such as the four years of cold summers following the Tambora eruption of 1815.

Given such variability over the past millennium, in itself a tiny fragment of geological time, how much certainty surrounds the current changes? The public have come to expect yes or no answers delivered with aplomb, yet some areas of science such as climate studies involve chaos mathematics, thus generating results based on levels of probability. What the public might consider vacillation, researchers consider the ultimate expression of scientific good practice. Could this lack of black-and-white certainty be why some media channels insist on providing a 'counterbalancing' viewpoint from non-expert sources, as ludicrous as this seems?

In-depth thinking about a subject relies upon compartmentalisation and reductionism. Otherwise, we would forever be bogged down in the details and never be able to form an overall picture. But this quantising of reality is not necessarily a good thing if it generates a false impression regarding cause and effect. By suffering from what Richard Dawkins calls the “tyranny of the discontinuous mind” we are prone to creating boundaries that just don't exist. In which case, could a line ever be found between short term local variation and global climate change? Having said that, I doubt many climate scientists would use this as an excuse to switch to weather forecasting instead. Oh dear: this is beginning to look like a 'does not compute' error!

In a sense of course we are exceptionally lucky to have developed science at all. We rely on language to define our ideas, so need a certain level of linguistic sophistication to achieve this focus; tribal cultures whose numbers consist of imprecise values beyond two are unlikely to achieve much headway in, for example, classifying the periodic table.

Unfortunately, our current obsession with generating information of every quality imaginable and then loading it to all available channels for the widest possible audience inevitably leads to a tooth-and-claw form of meme selection. The upshot of this bombardment of noise and trivia is to require an enormous amount of time just filtering it. The knock-on effect being that minimal time is left for identifying the most useful or accurate content rather than simply the most disseminated.

Extremist politicians have long been adept at exploiting this weakness to expound polarising phraseology that initially sounds good but lacks depth; they achieve cut-through with the simplest and loudest of arguments, fulfilling the desire most people have to fit into a rigid social hierarchy - as seen in many other primate species. The problem is that in a similar vein to centrist politicians who can see both sides of an argument but whose rational approach negates emotive rhetoric, scientists are often stuck with the unappealing options of either taking a stand when the outcome is not totally clear, or facing accusations of evasion. There is current trend, particularly espoused by politicians, to disparage experts, but discovering how the universe works doesn't guarantee hard-and-fast answers supplied exactly when required and which provide comfort blankets in a harsh world.

Where then does this leave critical thinking, let alone science? Another quote from Richard Dawkins is that "rigorous common sense is by no means obvious to much of the world". This pessimistic view of the human race is supported by many a news article but somewhat negated by the immense popularity of star science communicators, at least in a number of countries.

Both the methods and results of science need to find a space amongst the humorous kitten videos, conspiracy theorists and those who yearn for humanity to be the pinnacle and purpose of creation. If we can comprehend that our primary mode of thinking includes a subconscious baggage train of hopes, fears and distorted memories, we stand a better chance of seeing the world for how it really is and not how we wish it to be. Whether enough of us can dissipate that fog remains to be seen. Meanwhile, the ice keeps melting and the temperature rising, regardless of what you might hear...

Monday, 27 August 2018

Hammer and chisel: the top ten reasons why fossil hunting is so important

At a time when the constantly evolving world of consumer digital technology seems to echo the mega-budget, cutting-edge experiments of the LHC and LIGO, is there still room for such an old-fashioned, low-tech science as paleontology?

The answer is of course yes, and while non-experts might see little difference between its practice today and that of its Eighteenth and Nineteenth Century pioneers, contemporary paleontology does on occasion utilise MRI scanners among other sophisticated equipment. I've previously discussed the delights of fossil hunting as an easy way to involve children in science, yet the apparent simplicity of its core techniques mask the key role that paleontology still plays in evolutionary biology.

Since the days of Watson and Crick molecular biology has progressed in leaps and bounds, yet the contemporary proliferation of cheap DNA-testing kits and television shows devoted to gene-derived genealogy obscure just how tentatively some of their results should be accepted. The levels of accuracy quoted in non-specialist media is often far greater than what can actually be attained. For example, the data on British populations has so far failed to separate those with Danish Viking ancestry from descendants of earlier Anglo-Saxon immigration, leading to population estimates at odds with the archaeological evidence.

Here then is a list of ten reasons why fossil hunting will always be a relevant branch of science, able to supply information that cannot be supplied by other scientific disciplines:
  1. Locations. Although genetic evidence can show the broad sweeps connecting extant (and occasionally, recently-extinct) species, the details of where animals, plants or fungi evolved, migrated to - and when - relies on fossil evidence.
  2. Absolute dating. While gene analysis can be used to obtain the dates of a last common ancestor shared by contemporary species, the results are provisional at best for when certain key groups or features evolved. Thanks to radiometric dating from some fossiliferous locales, paleontologists are able to fill in the gaps in fossil-filled strata that don't have radioactive mineralogy.
  3. Initial versus canonical. Today we think of land-living tetrapods (i.e. amphibians, reptiles, mammals and birds) as having a maximum of five digits per limb. Although these are reduced in many species – as per horse's hooves – five is considered canonical. However, fossil evidence shows that early terrestrial vertebrates had up to eight digits on some or all of their limbs. We know genetic mutation adds extra digits, but this doesn't help reconstruct the polydactyly of ancestral species; only fossils provide confirmation.
  4. Extinct life. Without finding their fossils, we wouldn't know of even such long-lasting and multifarious groups as the dinosaurs: how could we guess about the existence of a parasaurolophus from looking at its closest extant cousins, such as penguins, pelicans or parrots? There are also many broken branches in the tree of life, with such large-scale dead-ends as the pre-Cambrian Ediacaran biota. These lost lifeforms teach us something about the nature of evolution yet leave no genetic evidence.
  5. Individual history. Genomes show the cellular state of an organism, but thanks to fossilised tooth wear, body wounds and stomach contents (including gastroliths) we have important insights into day-to-day events in the life of ancient animals. This has led to fairly detailed biographies of some creatures, prominent examples being Sue the T-Rex and Al the Allosaurus, their remains being comprehensive enough to identify various pathologies.
  6. Paleoecology. Coprolites (fossilised faeces), along with the casts of burrows, help build a detailed enviromental picture that zoology and molecular biology cannot provide. Sometimes the best source of vegetation data comes from coprolites containing plant matter, due to the differing circumstances of decomposition and mineralisation.
  7. External appearance. Thanks to likes of scanning electron microscopes, fossils of naturally mummified organisms or mineralised skin can offer details that are unlikely to be discovered by any other method. A good example that has emerged in the past two decades is the colour of feathered dinosaurs obtained from the shape of their melanosomes.
  8. Climate analysis. Geological investigation can provide ancient climate data but fossil evidence, such as the giant insects of the Carboniferous period, confirm the hypothesis. After all, dragonflies with seventy centimetre wingspans couldn't survive with today's level of atmospheric oxygen.
  9. Stratigraphy. Paleontology can help geologists trying to sequence an isolated section of folded stratigraphy that doesn't have radioactive mineralogy. By assessing the relative order of known fossil species, the laying down of the strata can be placed in the correct sequence.
  10. Evidence of evolution. Unlike the theories and complex equipment used in molecular biology, anyone without expert knowledge can visit fossils in museums or in situ. They offer a prominent resource as defence against religious fundamentalism, as their ubiquity makes them difficult to explain by alternative theories. The fact that species are never found in strata outside their era supports the scientific view of life's development rather than those found in religious texts (the Old Testament, for example, erroneously states that birds were created prior to all other land animals).
To date, no DNA has been found over about 800,000 years old. This means that many of the details of the history of life rely primarily on fossil evidence. It's therefore good to note that even in an age of high-tech science, the painstaking techniques of paleontology can shed light on biology in a way unobtainable by more recent examples of the scientific toolkit. Of course, the study is far from fool-proof: it is thought that only about ten percent of all species have ever come to light in fossil form, with the found examples heavily skewed in favour of shallow marine environments.

Nevertheless, paleontology is a discipline that constantly proves its immense value in expanding our knowledge of the past in a way no religious text could ever do. It may be easy to understand what fossils are, but they are assuredly worth their weight in gold: precious windows onto an unrecoverable past.