Geoscientist Online

Geoscientist Online 21 May 2007

The keys to the future of our species and our planet have always lain in the deep past. Richard Fortey FRS, in his Presidential Address to the Society 2007, wonders what the future will hold for the Earth sciences...

In this, the 200th year of the Geological Society of London, it is permissible to indulge a little reflection on the future of the geosciences. In the first years of the Society, the President was wont to review the progress of the subject in his annual address – that was a comparatively easy matter then, when it was still possible to summarise what was known of “the mineral structure of the Earth” within the covers of a few volumes.

Since those early days, the compass of geology has been transformed by its growth and fragmentation into a host of sub-disciplines: geophysics, geodesy, geochronology, geochemistry, sedimentology mineralogy, volcanology, and so on almost endlessly. No doubt the most effective science can now be performed by a researcher who concentrates intensely on a small area of his or her expertise. But perhaps the Bicentenary is one occasion when larger prospects should be reviewed. What will dominate the geological agenda in the next century? How will our scientists and intellects be deployed?

Some outcomes are certain. We can be sure that the former division between academic and ‘practising’ geologists will cease to be an issue. New technical advances in subsurface imaging that have industrial origins are being deployed by academics; while new remote sensing techniques have uses that are eminently practical - to detect changes in ‘groundswell’ prior to volcanic eruptions, for example – but are also are used by others to test geodetic theory. Ancient continental reconstructions mused over by palaeontologists impact on the hard-nosed search for minerals. There is no room now for arguments between ‘professionals’ and leisured ‘gentlemen’ that occupied our 19th Century forebears.

I make no apology for starting with climate change, since the Earth’s reaction to this phenomenon will probably drive the future funding of our science. This effect will be to ‘reverse’ geological time, restoring greenhouse conditions that have not been seen since the Palaeogene. A stratigrapher with knowledge of Tertiary sediments will suddenly find herself embarrassed by an abundance of research grants as - in an inversion of the famous dictum - the past becomes a clue to the present.

Glaciology will assume centre stage, because ice sheets are on the move. The fact that melting is occurring faster than was anticipated is related to what happens within, and particularly underneath the major ice sheets. If Greenland is our first concern (where shrinkage has been dramatic already), satellite measurements tell us that the ice sheet is actually thickening in its central region as a result of heavy precipitation– this in turn has increased the rate of flow. A predictive drainage theory will be vital. Drumlins may turn out to have a central role, if they are produced by continuous deformation of till beneath a glacier under high water pressures – they may provide the décollement surface for fast ice flow. As the effects of sea-level rise begin to bite, the remedial expertise of the engineering geologist will become more important than it has ever been: mitigation and prevention of potential catastrophes will occupy the working life of a majority of geologists.

Energy

Whatever the dreams of environmentalists, the world’s demands for energy will not go away, and geologists will continue to be on the front line. If they were among the heroes of the 19th Century industrial revolution, the effects of atmospheric change had blackened their image, almost literally, by the end of the 20th. Despite major discoveries in places like Kazakhstan, the rising demand for oil has not been matched by comparable new discoveries: opinions differ about exactly when supplies will run short, but not that it will be before our next centenary.

Blackened image or not, petroleum geologists will be there to point industry towards oil sands, and maybe back to coal. But the emphasis now will be on ‘clean technology’ – and perhaps this will also function to scrub up the image of extractive geologists. Environmentally friendly methods already exist, and companies will realise the need to buy into them to satisfy a new environmental awareness among shareholders. For example, coal-bed methane extraction uses CO2 to “push out” the combustible gas – the overall balance being carbon friendly. Techniques of CO2 sequestration will improve to the point where former mines will be viewed as major assets rather than white elephants. The nuclear future will feature geologists both as curators of safe underground storage (which will surely be the chosen option) and as key personnel for exploration. Maybe geologists will even enter politics more willingly, and place good science at the centre of policy.

Hazards

Natural hazards will not go away. Volcanologists will continue as the ‘hard men’ of field geology even as their views on magma generation become more refined. Studies in Monserrat have shown that eruptions happen in short bursts of a few thousand years alternating with longer quiescent periods – but the controls on that periodicity remain to be discovered, as does the cause of transitions between explosive activity and lava effusion. However, prediction of eruptions from geodetic and seismic data is already good and will get better, saving lives.

By contrast, the potential for mass destruction by major Earthquakes gets worse: casualties in the last few decades are up over any period in history. Population increase in vulnerable areas is the root cause, and throughout tectonically active zones towns have grown up precisely because of the geological underpinning; for example, in the Middle East vital water resources in arid areas follow the same geological prompting that might engender a major event. The recent tragic events at Bam and in Pakistan were not exactly predictable, but if relatively simple changes in building techniques had been applied to domestic dwellings it would have enormously reduced casualty lists.

James Jackson believes that Teheran is particularly vulnerable to a future event. The future lies in taking preventive action, rather than attempting to predict exactly when a fault might ‘give’. The same might be said about the development of reliable networks to warn of approaching tsunamis. That does not mean that we will not get to learn much more about the way faults work. The San Andreas Fault Observatory at Depth (SAFOD) will continue to reveal new facts about the way faults operate from direct observation, while ever more sophisticated research vessels (such as that currently under construction in Japan) will help our understanding of fault systems near subduction zones and spreading centres.

Life history

The marriage of molecular techniques and palaeontology will yield new progeny, everything from testing the ‘gaps’ in the fossil record, to a better understanding of the tempo of evolution in relation to world events. One hopes there will still be a place for serendipity – who would have dreamed in the middle of the last century that feathered dinosaurs would turn up? Maybe we will discover more about elusive Precambrian fossils. But we can probably be certain that more hominid fossils will be found in Africa and beyond to flesh out the story of the evolution of our own species. One can guess that this story will link into new discoveries about how genes function, to help us understand the order of acquisition of the characteristics that make us human. Meanwhile the study of very small fossils will intensify because they are carriers of information about climate change – not just from the changes in their species but also in the isotopic information entombed in their shells. Ever more precise methods of isotopic measurements will focus on a fuller range of climate-change proxy elements, such as boron. This will secondarily contribute to a new level of refinement in biostratigraphy.

Scientific advance will depend on a fruitful interplay between new thoughts and new, improved ‘kit’. Geochemists will explore a range of different isotopes of hitherto un-analysable elements to discover stories about the origins of everything from planets to magmas. Geochemistry will continue to focus to an ever finer scale, using such instruments as the Diamond light accelerator at Oxford for producing ultra high-energy analytic beams at 3GeV. However, geochemistry will also link more creatively with the life sciences. Molecular geomicrobiology will expand the study of the interactions between organisms and Earth processes at a molecular level – bacterial metabolism is now understood to drive geochemical cycles. And as the structure of the genes which specify proteins are other interactive biomolecules in these organisms are better understood, a prospect of the biochemical evolution of the Earth will open up; its traces will be interrogated from an ever greater range of degradation signatures preserved as chemical fossils in ancient rocks.

Deep issues

We will understand more about the lithosphere and what lies beneath it. McKenzie and Priestley have recently used calculations based on surface waves to provide maps of continental lithosphere variations in thickness. They ingeniously tested their calculations against the occurrence of diamond bearing kimberlites which indicate the P-T conditions of the diamond stability field. We have all become accustomed to another set of maps portraying palaeogeography in deep time – but many questions about how the world looked in the Precambrian remain. One limitation has always been that palaeomagnetics does not provide a fix for longitude, only latitude. Even this may change if it is true that the deep “plumbing” for Large Igneous Provinces (like Deccan) has been constant over geological time – at last this will provide a fixed point for reconstructions. We can look forward to new worlds: and also to answers to questions like whether, and by how much the Wilson cycle has slowed down through geological time.

Deeper still into the Earth’s interior: the D'' (“D double prime”) zone has been recognised as a layer of the Earth about 200km thick lying at the base of the mantle. A new high pressure phase – the post-perovskite polymorph of MgSiO₃ – has been made in the laboratory, and has properties consistent with making up the mysterious layer. For example, it is highly anisotropic - which can explain some of the odd seismic characteristics of D''. The presence of a deep-seated phase change may produce an extra thermal boundary layer – and this may mean that the core loses heat more slowly than previously thought. This in turn would have implications for models of the geodynamo and the origins of the Earth’s magnetic field. And we still don’t know some important things about the inner core – such as the crystal structure of the iron there. Useful though diamond anvil experiments are, pressures of over three million atmospheres at temperatures of >5000K make experiments technically very difficult. The way forward may lie with quantum mechanical modelling to anticipate the properties of such high P/T phases: recent work suggests that the inner core should be partially (c. 8%) molten to account for its seismic properties. We will know more in the coming decades.

Other planets

Surely we will advance from surface geography to understanding about planetary interiors, especially those of Mars and Venus. Mars (and its life, or not) will reappear in the news headlines regularly. Experimental geology will continue to attempt to simulate the nature of fractures, and the generation of magma in the lab.

However, I hope that geologists will still take off into the field to study rocks close-to – the hammer should not rust away through lack of use. After all, the generation of magma can also be studied in Ladakh where evidence of partial melting lies now at the surface. The field remains the best place to learn the geological trade, and to test speculations against the truth on the ground. Our future has always lain in the past.

It has become a cliché of our times to refer to every needful action as a ‘challenge’ - as if pursuing science were somehow like a medieval joust. My experience suggests that most geologists do what they do for pleasure, to satisfy their curiosity (and just a little bit for money). There is much that needs to be discovered, and I hope that success gives joy as much as a kind of grim satisfaction in rising to a ‘challenge’. No doubt, the world will face real problems over the next century. The real challenge will be to discover wise solutions.

Thanks should go to those who helped me with this review – especially: Geoffrey Boulton, Tony Doré, Mike Hambrey, Richard Hardman, Herbert Huppert, Dan McKenzie, David Price, Ernie Rutter, Steve Sparks, Alex Halliday, James Jackson, Peter Styles, Claudio Vita-Finzi, Trond Torsvik and Jan Zalasciewicz.