Major Power's Military Expenditure │ 1830 - 2007

Source: OurWorldinData.

Max Roser and Mohamed Nagdy (2016) - There are two ways in which we might want to measure military spending; the first way is spending in real terms and the second is as a percentage of GDP. Military expenditure in real terms is important since the absolute level of expenditure matters for the outcome of war. The US spending 10% of its GDP fighting a war is likely to defeat a low or middle income country spending 50% or more of its GDP. Yet, military expenditure as a percentage of GDP allows us to get a handle on the priorities and ambitions of a country. The military expenditure of a country is largely determined by the whether it is at war or not. Outside of wartime, countries continue to spend substantial sums on maintaining their military capability. [Above] are two time series plots of military expenditure in real terms; the first is in thousands of 1900 UK pounds for the period 1830-1913, the second is in thousands of 2000 US dollars for the period 1914-2007. 

The UK’s military spending as a percentage of GDP in peacetime fluctuates around 2.5%, in times of war however, military spending rises dramatically. At the height of the Second World War, the UK was spending around 53% of its GDP on its military. Such a dramatic rise is consistent with the existential danger faced by the UK during the Second World War.

Demographics as Destiny

Business Insider (Nov 30, 2015) - What the size of the world's workforce will be like in a decade is well predictable, since the future workers have already been born. Demographics have long been a key determinant of potential growth rates, but the change in the global population over the next few years is unprecedented. Japan's population started to shrink in the mid-1990s and Germany's started shrinking around the year 2000, but the world's most populous country, China, is now seeing its working-age population shrink for the first time. Though the overall global population will continue to grow for some time yet, the growth of the working-age population is slowing down pretty much everywhere. That's relevant for a bundle of reasons. Around the world there will be fewer workers to support a growing number of retirees. But it also has some economists expecting significant pressure on wages.

The sea of red and pink across the advanced world means contraction, no growth,
or slow growth. Only in a belt of the developing world (in Africa particularly)
is there any substantial expansion coming by 2020. Credits: HSBC (Nov 2015)
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If employers have to fight for a group of workers that is growing more slowly, or even declining, they will need to encourage people to move, and their labour will be more valuable. Some countries, like Japan, Russia, and parts of Europe, have already entered the stage that the rest of the world is going into — and they've struggled with it. In Japan, slowing economic growth has made the county's ever-expanding pile of public debt more and more difficult to deal with, and the working-age population has already declined by 11.1% in the past 20 years. Smaller populations mean less demand and less potential output. More retirees relative to the number of working-age people means more fiscal pressure: greater expenditure on healthcare and less tax income. Globally, although working-age populations are still growing, HSBC expects global potential growth to be 0.6ppt lower per year over the next decade compared with the past decade given these demographic changes. Not great news for heavily indebted economies (see also HERE).