Jonathan Weiner surveys the advances today's thinkers anticipate by 2099
Tibetan diviners emptied their minds and stared into lakes, mirrors, the flaming wicks of lamps, or the balls of their thumbs. Chinese diviners inscribed questions on tortoise-shells, roasted the shells and interpreted the cracks.
Today, these ancient methods of predicting the future look like confessions of impossibility. Centuries of experimental science have taught us to distinguish between the predictable and the unpredictable. We have learned that there are questions we can answer, and others that can be answered only by the events themselves. Drop a bottle off the edge of a table and you know where it will land. Drop a bottle off a ship's railing and you cannot predict just where it will wash ashore or whose hands will pick it up.
This year, leaning on the railings, nearing the most celebrated invisible line that any of us will sail across, we know that we cannot know all that we would like to know about the shape of things to come. For us, schooled and chastened by the scientific process, the best way to think about the future is not in terms of the magic sudden knowledge of the deviner, but in terms of the hard-won knowledge of the experiment: to try to pick out a few of the future's greatest experiments - experiments already in progress. We might try to talk about the next century as a set of five experiments that will assuredly have interesting results.
The most fundamental experiment in our century and the next is the human population explosion. Our numbers have quadrupled since the beginning of the century to reach six billion at its close -six billion human beings is a global experiment.
A second experiment, coupled to the first, is global warming. Each year as the planet's temperature inches upward, the experiment is getting more interesting and absorbing.
A third experiment, entwined with both the first and second, is the progress of technology, which promises and threatens so much. A fourth experiment, again involving all the others, is the progress of evolution. Our species now has the power to shape the evolution of many others around us, and perhaps our own evolutionary future, too.
A fifth experiment is the one that evolutionist E. O. Wilson recently called consilience. This is the dream that everything we are learning about ourselves and our universe will fit together someday in one overarching vision, comprehending all our philosophies, arts and sciences, experiments and inmost feelings.
Some of the world's most distinguished academics have devoted their careers to these global experiments. Carl Djerassi, professor of chemistry at Stanford University, may have altered the course of the population explosion, at least slightly, by inventing the oral contraceptive. The Pill changed the social climate of the 1960s and helped to ensure that what is known in the United States as the baby boom was not followed by a second boom a generation later. Most population experts now believe that the growth in human numbers will level off in the mid-21st century, for the same poorly understood reasons that growth is levelling off in many technologically advanced countries.
This decline will cause its own problems. In his prediction in these pages, Francis Fukuyama, famous for stating that democracy has now come to seem the normal state of government, warns Europe that the continent's fall in fertility will necessitate importing workers from the Third World. Some countries will find it easier to manage the resulting ethnic tensions than others.
The atmospheric chemist F. Sherwood Rowland deserves the whole world's gratitude for helping to save the ozone layer and, in the process, slowing global warming. In the early 1970s, he and a colleague realised that a single chlorine atom released into the stratosphere can destroy as many as 100,000 ozone atoms. This multiplier effect meant that aerosol cans using chlorofluorocarbons as propellants could seriously damage the ozone layer. When a huge ozone hole was discovered above the South Pole in the mid-1980s, the discovery - and Rowland's campaigning - helped lead to a world ban on CFCs, which are also greenhouse gases.
Rowland predicts that some time in the next century, when the load of carbon dioxide begins to produce global changes as shocking as the ozone hole, we will begin to sequester our carbon dioxide, muzzling smokestacks and exhaust pipes and burying the carbon - trying to put it back where we found it.
As Rowland points out, we get 85 per cent of our industrial energy by burning fossil fuels. In the days when labour was limited to what each human being could do with two hands, and maybe two oxen, a single worker could do very little to change the planet. With fossil-fuel-driven machinery, each person can do much more work. So the global experiment in the air is driven both by our numbers and by the increasing power of our technology - another multiplier effect, and the outcome of the first and second experiments depends in part on the outcome of the third. One of the best places to glimpse that is Massachusetts Institute of Technology, where a team of computer engineers and consultants is building one of the world's most sophisticated robots: Cog, six feet tall and designed to learn like a baby. If we are lucky, electronics itself will turn out to be in its infancy and our engineers' explosive experiment in miniaturisation will help reduce technology's impact on the planet.
That is, if we are lucky. Before it saves the global ecosystem, electronics may swamp the human nervous system. The computer scientist Kevin Warwick foresees a future in which ergonomics will be extended and turned inside out. Call this organomics.
Instead of designing machines to fit the human body, the next generation will design machines to fit inside the body, redefining human anatomy and what it can do. In 1998, Warwick had a silicon chip implanted in his arm so that as he approached doors they would open and buildings would say, "Hello, Kevin." He hopes to link his wife's brain and his own by computer chips so they can read each other's thoughts. As I pondered the organomic future, my brain remembered and sang to itself (with no help from chips) the refrain of a Loudon Wainwright song, I'd rather be lonely.
Our fourth experiment, which has been called volitional evolution, will be accelerated by the mapping of the human genome. That map will be one of the great scientific achievements that inaugurate the new century. It is already leading to new dreams for medicine. W. French Anderson, director of gene therapy at the University of Southern California, is leading an effort to treat ADA deficiency in the womb. He predicts that gene therapy will have revolutionised medicine by 2030: by then there will be an identified gene for every disease that flesh is heir to.
Anderson believes that eventually we should begin adding and rewriting genes in sperm and eggs, making changes not just for one child, as he acknowledges, "but for grandchildren, great-grandchildren and so on", which would take us well beyond the 21st century. He is probably right that we will do this. We will do it as soon as doctors feel that they can inject genes into sperm and eggs while honouring their professional code, "First of all, do no harm."
"When the time comes, then we must do it," Anderson says, "because it is just plain human nature." We will be changing human nature, too, bit by bit.
For our self-absorbed species, this may become the most alarming experiment: the conscious and deliberate revision of human evolution. How well it goes will determine how the people who brought it to us will be remembered. No other experiment pits so many academics against each other. Anderson notes that the palaeontologist Stephen Jay Gould, "whom I have known for years," is on the board of a US organisation, the Council for Responsible Genetics, which put out a broadside against Anderson's ADA proposal under the headline "Say No to Designer Children!!!" Many academics hope that the study of the mind in the next few decades will help to unite biology and culture and the natural and the human sciences. "A fundamental division between the humanities and sciences may become as obsolete as the division between the celestial and terrestrial spheres," the cognitive scientist Steven Pinker wrote in The THES a few weeks ago.
This fifth experiment, the experiment of consilience, is in a sense an optimistic assessment that all the other experiments on the planet will add up. We may hope that the biotechnologic and electronic revolutions we are witnessing today will fit together, but it is also possible that they will continue flying apart. For guessing the fates of any one of these predictions is like guessing the path of the bottle in the ocean.
Pulitzer prizewinner Jonathan Weiner is a visiting lecturer at Princeton University. His latest book is Time, Love, Money. This and the forecasts (right) are edited extracts from Predictions: Thirty Great Minds on the Future (Oxford University Press/The THES), published on November 4.