Alive: the human future
The slogan of your Festival this year is "Dead ... and alive". All around you are the cliffs recording the dead. Today I speak of one animal species - our own - which has sprung from the dead but which is very much alive. We may not descend from ichthyosaurs but we certainly do from one of their fishy cousins of even longer ago. To look ahead is always difficult. Could any of our ancestors have predicted us? For all of us the future is an unknown country.
But first where are we coming from?
- All living organisms are connected by common descent and mutual dependency. Over time they tend to create and maintain the environment most favourable to them. Occasionally the system tips one way or another to the detriment to this or that organism. The biosphere is itself analogous to a living organism which corrects itself in response to hazards from within and without.
- Humans are an infinitesimal part of the living world (0.00007% of estimated living species). Each of us has ten times more bacterial than body cells.
- Our species is relatively new. No-one was around to record the evolution of the first human-like creatures from ape like ancestors in Africa some four million years ago. They left the trees for the savannah, became relatively hairless, and learned to walk upright on two legs, with consequences for the physiology of their growing brains. By at least half a million years ago, they had split into a variety of related strains. One of their offshoots may still have been living on the Indonesian island of Flores as recently as 12,000 years ago (a mere blink in geological time).
So far through analysis of fossils and work on current humans, we have been able to trace our own genealogy back 150,000 years. All other branches of humans, including our cousins the Neanderthalers, are now extinct.
It seems likely that there was some sort of crisis in human history which drastically reduced numbers and eliminated some of the lines of descent. Among the possibilities are abrupt climate change following the violent eruption of Mount Toba in Indonesia some 73,000 years ago, which initiated a severe cooling of the Earth within the Pleistocene ice ages. We know from recent history what big effects volcanic eruptions can have (Mount Laki in Iceland in 1783, Tambora in 1815, Krakatoa in 1883 and now Iceland again). Toba was a real monster among them.
But there are other possibilities: some major epidemic like the Plague of Justinian in 540 AD, or the Black Death which devastated populations worldwide in the 14th century; or even a hit from space (if the object which devastated part of Siberia a hundred years ago on 30 June had hit London, there would have been nothing left within the M25 ring road).
The survivors of this major crisis, whatever and whenever it was, would have had many genes in common, and thereby influenced the character of subsequent generations. All modern humans are fairly close cousins. There are more genetic differences between Africans than there are between Africans and other humans, thereby indicating our African origins.
A question which still arouses much controversy is when and why humans developed the attributes we all now take for granted: language, music, symbolic and interconnected thought, art in its many forms, including jewellery, advanced technical skills, and certain behaviour patterns, including respect for the dead. Did this grow gradually out of development of tools for hunting, fishing and shelter, sexual competitiveness, the management of community relationships, or something else? Or was it the product of some genetic mutation which greatly advantaged some individuals and their descendants at the expense of others? Whenever the change took place, the extraordinary development of human brain power, which has produced ourselves, occupies much less than 1% of all human history.
Over the last 40,000 years the human impact on the Earth has slowly and then rapidly increased. Hunter gatherers fitted easily, although sometimes uncomfortably, into the ecosystems of cold and warm periods of the Pleistocene. People migrated in response to changing conditions. But farming with land clearance between 10,000 and 8,000 years ago changed everything. It may even have changed the climate and, by affecting emissions of carbon dioxide and methane into the atmosphere, halted a return to colder conditions. With a vast increase in human population came towns and eventually cities. Tribal communities evolved into complex hierarchical societies.
Before the industrial revolution some 250 years ago, the effects of human activity were local, or at most regional, rather than global. Now the impact is indeed global.
The idea may be hard to accept, but in its long history with all its variations the Earth has never been in this situation before. In my view there are six main factors which have driven this transformation. Of these, population issues are often ignored as somehow embarrassing or mixed up with religion and the ideology of development; most people are broadly aware of land resource and waste problems, although far from accepting the remedies necessary; water issues, both fresh and salt, have had a lot of publicity, and already affect most people on this planet; climate change with all its implications for atmospheric chemistry is also broadly understood, apart from by those who do not want to understand it; how we generate energy while fossil fuel resources diminish and demand increases is another conundrum (now at last under serious discussion); but damage to the diversity of life on which our species critically depends has somehow escaped most public attention. Here we remain ignorant of our own ignorance. Yet in this area human destructiveness has been most evident over the last 10,000 years. Current rates of extinction could in the long run be the most important of all these factors for human welfare. All are interlinked, and all represent pressure on the natural environment.
There is now a seventh factor recent in human experience. They arise from the introduction of new technologies. Damage to the ozone layer, which protects ecosystems from harmful ultraviolet radiation from the Sun, was the first to receive major public attention. The eventual result was to establish international agreements to ban the manufacture and use of chlorofluorocarbons.
But this may only be the beginning. In a recent book by the President of the Royal Society, Sir Martin, now Lord, Rees explored the dangers arising from human inventiveness, folly, wickedness and sheer inadvertence. The ramifications of information technology, nano-technology and nuclear experimentation and the rest have still to be understood and explored. His conclusion was to give our civilization only a 50% chance of survival beyond the end of this century.
In broad terms we suffer from creeping impoverishment of the biosphere. As E. O. Wilson said in his book The Creation:
"We have, all by our bipedal, wobbly-headed selves, altered Earth's atmosphere and climate away from the norm. We have spread thousands of toxic chemicals world wide, appropriated 40% of the solar energy available for photosynthesis, converted almost all of the easily arable land, dammed most of the rivers, raised the planet sea level, and now, in a manner likely to get everyone's attention like nothing else before it, we are close to running out of fresh water. A collateral effect of all this genetic activity is the continuing extinction of wild ecosystems, along with the species that compose them. This also happens to be the only human impact that is irreversible."
What then are we to expect? How are we to recognize that the last 200 years or so have been a bonanza of inventiveness, exploitation and consumption which may not continue? All successful species, whether bivalves, beetles or humans, multiply until they come up against the environmental stops, reach some accommodation with the rest of the environment, and willy-nilly restore some balance. Are we near to those stops?
In September 2009 the magazine Nature published an article by Johan Rockstrom and others identifying nine scientific boundaries or stops which humans would cross at their peril. Three had already been crossed: climate change: loss of biodiversity; and interference with the nitrogen and phosphorus levels. The other six were stratospheric ozone depletion; ocean acidification; use of freshwater; changes in land use; chemical pollution; and atmospheric aerosol loading.
Obviously we can all have our own lists and calculations of the dangers we face in each case. I have already suggested my own more general ones. Going back to them I have no doubt that we have to re-think some of the underlying assumptions on which we run our society. That means confronting the major issue of our own proliferation in all its aspects; looking again at a lot of economics; replacing consumerism as a goal; giving high priority to conservation of the natural world; working out new ways of generating energy; dispersing and to some extent localizing the ways by which we feed ourselves; managing and adapting to climate change, or as I prefer to call it climate destabilization; and creating the necessary institutional means of coping with global problems. In the future global village, we cannot afford to have too many village idiots.
We all suffer from the disease of what has been called conceptual sclerosis. Little is more difficult than learning to think differently, above all when problems go to the roots of conventional wisdom. Old ideas haunt us like ghosts.
It is time now to turn to the future of our species in a world which is changing under human pressure before our eyes. Bear in mind that nearly all forecasting turns out to be wrong. We do well to expect the unexpected.
In his book The Meaning of the 21st Century, James Martin laid out what he saw as the prospects.
"The 21st century is like a deep river canyon with a narrow bottle neck at its centre. Think of humanity as river rafters heading down stream. As we head into the canyon, we'll have to cope with a rate of change that becomes much more intense - a white water raft trip down an unknown river with the currents becoming much faster and rougher - a time when technology will accelerate at a phenomenal rate."
He went on to identify the main challenges facing us. Some relate to the Earth as a whole: for example the natural disruptions known throughout history, volcanic explosions, earthquakes, impacts of extra terrestrial objects, changing climates, and variations in ecosystems, including patterns of disease. Others relate to the specific problems of our society, including the widening divisions between rich and poor within and between countries, the high vulnerability of cities, the growth of terrorism, the risks of war with unimaginably horrible weapons, and the exhaustion of often irreplaceable resources. On this reckoning we will be lucky to come out the other side of the deep river canyon with anything like civilization as we know it.
But this is not the whole story. Nor does it cover changes in the balance of power between East and West, and North and South. That is a huge subject in itself - political, economic and technological. For the moment I want to jump a hundred years, and from this vantage look backwards. In doing so, I shall assume (I hope correctly), that humans will have faced up to and coped with at least some of these problems. People are not stupid. So what will the world look like?
First they are likely to be living in a more globalized world of rapid communication. Ideas, units of information - or memes - will pass almost instantaneously between countries, communities and individuals. The wiring of the planet with fibre optics, cellular wireless, satellites and digital television is already transforming human relationships. For the first time there will be something like a single human civilization. More than ever humans can be regarded like certain species of ants, as a super-organism.
Human numbers in cities or elsewhere will almost certainly be reduced, but some people will live much longer, bringing its own train of problems. Their distribution will be different. It has been suggested that an optimum population for the Earth in terms of its resources would be nearer to 2.5 billion rather than - as now - over 6 and a half billion, or even 9 billion later this century.
Communities are likely to be more dispersed without the daily tides of people flowing in and out of cities for work. Agriculture will be more local and specialized with more reliance on hydroponics. Energy and transport systems will be decentralized. Archaeologists of the future may even wonder what all those roads were for.
Then there are other developments in information technology. They raise the question of evolution itself. At present we can alter isolated genes while disregarding the complexity - and totality - of what genes can do. Here the law of unintended consequences is important. Already chips have been inserted into humans for a variety of purposes. We can even insert extra chromosomes in the knowledge that they would not be heritable.
On the one hand humans may thereby be liberated from many current drudgeries. Soon houses may be able to clean themselves, robots may produce meals on demand, cars may drive under remote instruction, and evolution of desirable characteristics could even be automated. All this seems unimaginable when so many still have to trudge miles to collect fuel wood and water.
On the other hand humans could well become dangerously vulnerable to technological breakdown, and thereby lose an essential measure of self-sufficiency. Already dependence on computers to run our complex systems, and reliance on electronic information transfer, are having alarming effects. Here industrial countries are far more vulnerable than others. Just look at the effects of single and temporary power cuts. More than ever individuals feel out of control of even the most elementary aspects of their lives.
The implications for governance reach equally wide. In some areas good regulation will be more important than ever. In the words of a recent book, we have to recognize that most things fail, whether they be organisms or human institutions. Already there is a movement of power away from the nation state: upwards to global institutions and corporations to deal with global issues; downwards to communities of human dimension; and sideways by electronic means between citizens everywhere.
Let us hope without total confidence that by 2100 humans will have worked out, and will practice an ethical system in which the natural world has value not only for human welfare but also for and in itself. The human super organism must take its place along side other super organisms
For the long term I hesitate to speculate. Tectonic plate movement will shift the relationship between land and sea. Changes in oxygen levels in the atmosphere may affect the viability of life itself. The human species may even change its shape, assuming some are still alive to tell the tale. For example, given the evolutionary significance of our brains and the current hazards of childbirth, we might imagine a sort of human marsupial in which women gave birth earlier in the reproductive process, and developed a kind of pouch.
I sometimes wonder how long would it take for the Earth to recover from the human impact. Future visitors from outer space might well be puzzled by the fossil remains of ourselves and the agglomerations we call cities. They might also wonder at the fossils of the other animals and plants we have so abruptly adapted for our own purposes: rats as big as dogs, water hyacinths blocking lakes, micro organisms gone macro. But they should know, as should we, that life itself, from the bottom of the seas, to the top of the atmosphere, is so robust that the dominance any one species could be no more than a relatively short episode in the history of life on Earth. Ours is certainly a peculiar species, and its impact on the Earth has been marked by many geologists as the Anthropocene epoch. Let us enjoy it while we can.
My message to you today, among the many eloquent reminders of the long past around us, is to recognise how small and vulnerable we are as creatures of a particular environment at a particular moment in time. We are like microbes on the surface of an apple, on an insignificant tree, in an insignificant orchard, among billions of other insignificant orchards stretching over horizons beyond our sight or even our imagining.