Neil Howe published a new book last year.

The Graying of the Great Powers offers the first comprehensive assessment of the geopolitical implications of "global aging"--the dramatic transformation in population age structures and growth rates being brought about by falling fertility and rising longevity worldwide. It describes how demographic trends in the developed world will constrain the ability of the United States and its traditional allies to maintain national and global security in the decades ahead. It also explains how dramatic demographic change in the developing world--from resurgent youth bulges in the Islamic world to premature aging in China and population implosion in Russia--will give rise to serious new security threats. While some argue that global aging is pushing the world toward greater peace and prosperity, The Graying of the Great Powers warns that a period of great geopolitical danger looms just over the horizon. Neither the triumph of multilateralism nor democratic capitalism is assured. The demographic trends of the twenty-first century will challenge the geopolitical assumptions of both the left and the right.

From the Major Findings:

The world is entering a demographic transformation of unprecedented dimensions.

The coming transformation is both certain and lasting. There is almost no chance that it will not happen—or that it will be reversed in our lifetime.

The transformation will affect different groups of countries at different times. The regions of the world will become more unalike before they become more alike.

In the developed world, the transformation will have sweeping economic, social, and political consequences that could undermine the ability of the United States and its traditional allies to maintain security.

In the developing world, the transformation will have more varied consequences—propelling some countries toward greater prosperity and stability, while giving rise to dangerous new security threats in others.

Throughout the world, the 2020s will likely emerge as a decade of maximum geopolitical danger.

The aging developed countries will face chronic shortages of young-adult manpower—posing challenges both for their economies and their security forces.

An aging developed world may struggle to remain culturally attractive and politically relevant to younger societies.