What's really behind Europe's decline: Birth rates

This decline in population and mounting out-migration of young people means Spain will experience ever-higher proportions of retired people relative to those working. This “dependency rate”, according to INE, will grow by 57 % by 2021; there will be six people either retired or in school for every person working.

If Spain, and other Mediterranean countries, cannot pay their bills now, these trends suggest that in the future they will become increasingly unable or even unwilling to do so. As Macarron notes, an aging electorate is likely to make it increasingly difficult for Spanish politicians to tamper with pensions, cut taxes and otherwise drive private sector growth. Voters over 60 are already thirty percent of the electorate up from 22 percent in 1977; in 2050, they will constitute close to a majority.

Without a major shift in policies that favor families in housing or tax policies, and an unexpected resurgence of interest in marriage and children, Spain and the rest of Mediterranean face prospects of a immediate decline every bit as profound as that experienced in the 17th and 18th Century when these great nations lost their status as global powers and instead devolved into quaintlocales for vacationers, romantic poets and history buffs.