• John Maynard Keynes gave an address in Madrid in 1930 called on the Economic Possibilities of Our Grandchildren and set a century in the future. The year 2030 is still 16 years away, but the world is almost there. Anticipating its arrival, a Spanish economist asked 10 prominent economists, among them three winners of the Nobel prize, to reflect on what the next century might bring in the way of economic and other developments, recently published as In 100 Years.

    Although in 1930 the world was already sliding into the Great Depression, Keynes was relatively optimistic in his long-term outlook, suggesting that per capita incomes in his part of the world (Britain, and probably including Western Europe and North America – he wasn't specific) would rise by a factor of eight and that the workweek would have fallen to 15 hours, suggesting that people would have a lot more leisure. At least since 1950 the world as a whole is on track to achieve the first result, equivalent to 2.1 percent a year on average. The working week has fallen substantially, albeit not nearly to 15 hours, although paid vacations have increased substantially, especially in Western Europe, providing greater leisure in a different form.

    There are a number of common themes in the new book, projecting out to 2113: technological progress will continue, bringing many new and some unsuspected developments; as a result per capita income will continue to grow, perhaps even at the rate of recent decades, although partly in areas where measurement is more problematic; population growth will continue to decline, perhaps even leading to a decline in world population 100 years hence; poverty will continue to decline, and by current World Bank measurements will probably disappear altogether, although of course relative poverty will be present perpetually; longevity will continue to increase, mainly as a result of continued advances in pharmaceuticals and medical science.

    On the negative side, climate change will provide a challenge of unknown magnitude, but not on a scale to overturn the positive developments; and epidemics will continue to threaten, partly as germs and viruses evolve to resist our current methods for controlling them. It is noteworthy that most foresee no major war, the nightmare of some political scientists, nor a repeat of the Great Depression. All, in different ways, emphasize the importance of good governance for good outcomes.

    The authors also bring distinctive individual assessments to the assignment. Daron Acemoglu of the Massachusetts Institute of Technology argues that the great pace of innovation of the past two centuries is closely related to the emergence of political rights and individual freedoms, and that this linkage will continue into the future. As freedom is extended to more people, as he expects over the century, albeit with occasional setbacks, innovation will also accelerate and take place in more countries.

    In contrast, Edward Glaeser of Harvard worries that as society gets wealthier it will engage in greater self-protection, both at the family level, such as living in gated communities, and at the national level, e.g., through expenditures on national defense, and that this preoccupation with protecting what one already has will lead to resistance to further change, including disruptive innovation.

    Andreu Mas-Colell of Pompeu Fabra University in Barcelona projects substantial changes in the nature of work, with greater flexibility in terms of time both during the year and over lifetimes, and significant alterations in employer-employee relationships, toward more contract work.

    Alvin Roth of Stanford foresees the rise in acceptability of performance-enhancing drugs, not only for muscles but even more for brain-power, the modification and commodification of new human organs, and even changes in the nature of marriage and its relation to reproduction.

    Robert Shiller of Yale foresees, over a long period of time, a considerable improvement in contracts to ensure against a wider range of risks, including even major war and terrorist acts.

    Martin Weitzman of Harvard fears the urgent introduction, perhaps unilaterally by a single large nation, of "geo-engineering," in effect a giant sun-shade for the earth, to avoid the worst effects from climate change that has not been successfully mitigated through cooperative action early in the 21st century.

    One hundred years is a long time, and in a dynamic world much can happen, much of it unexpected. If one thinks back to 1913, electricity was in use, the automobile was progressing, vaccines had been discovered against a few diseases and primitive airplanes had been invented.

    But there has been no 20-year period since then in which big surprises, some pleasant, some unpleasant, did not occur. The unpleasant ones included a Great Depression and two world wars. But thanks to antibiotics, integrated circuits and the jet engine the world is radically different today – and better – than it was then. Infant and maternal mortality is way down, and healthy longevity has increased significantly. Real per capita incomes are much higher in all but a few parts of the world. If the conjectures in the book are correct, these processes will continue. But there will undoubtedly also be some complete surprises, some pleasant, some unpleasant.