Japan's population falls below 100 million
For most of the 20th century, Japan experienced high population growth. The post-war "miracle" saw its booming economy catapulted into second place behind only the USA by the 1980s. This period of rapid expansion ended with the bursting of the asset price bubble in 1991 and was followed by the "Lost Decade", which persisted into the 21st century. Japan experienced stagnation both financially and demographically.
By 2010, the country's population had peaked at 128 million.* From this point onward it would undergo a long, slow decline.* This net loss was caused by falling birth rates and almost no net immigration, despite the highest life expectancy in the world at 84.6 years of age. The rising costs of childbirth and child-raising, later average age of marriage, the increasing number of unmarried people and greater numbers of women in the workforce were all contributing factors. Japan's "total fertility rate" (defined as the average number of children born to a woman over her lifetime) was now 1.43, far below the 2.07 replacement-level fertility needed to sustain a country in the long term. In some isolated rural areas, this trend was so damaging that entire communities were already disappearing.
The shrinking segment of productive workers aged 15 to 64 began to seriously impact on Japan's GDP, affecting pensions and social welfare in particular. As the overall standard of living fell, calls were made for radical policies, but the low birth rate could not be fundamentally reversed. By the 2040s the population was falling by over a million each year. By 2046, it has dropped below 100 million,* a level last seen in the 1960s. This trend will continue for the rest of the century, with Japan struggling to achieve a "managed decline" as it deals with the inevitability of its situation and its waning influence on the world stage. Among the solutions being introduced is greater use of robots to keep society running. Japan's love for and experience of robotics (perhaps more than any other country) and its already well-established industry is helpful in this regard, mitigating some of the impacts it would otherwise have felt.
The UK state pension age has risen to 70
Due to increases in life expectancy, and unsustainable levels of age-related spending, the UK's state pension age has risen from 65 in 2012, to 70 now.* This provides a net benefit to the public finances of around 0.7% of GDP.