Time for Another World War?

Since 1945, the world has been – comparatively – peaceful.

Some believe this ‘long peace’ is the start of a new, conflict-free era. However, a recent analysis suggests it is just a blip, and a major war could be around the corner.

The long peace began after the second world war. In his 2011 book The Better Angels of our Nature, Harvard psychologist Steven Pinker argued that if we make good choices now, it could well become permanent.

To see if we truly have turned a corner, Aaron Clauset at the University of Colorado in Boulder studied wars that took place between 1823 and 2003.

He used data from the Correlates of War project, which gathers data on conflicts. Over the 181-year period, there were 95 wars: one every 1.91 years on average.

Clauset measured the size of each by comparing the number of soldiers killed. The second world war was the worst, killing 16.6 million.

He defined a large war as one in the top quarter by military casualties.

Clauset split his study period into three.

  • In the first period, prior to the first world war, there were 19 large wars, one every 6.2 years.
  • During the middle period, the ‘great violence’ encompassing both world wars, there were 10 large wars, or one every 2.7 years.
  • But the long peace since the second world war only saw five, one every 12.8 years.

This may seem to support the idea that the long peace is a period of unusually low conflict.

However, statistically, the great violence and long peace cancel out, so the rate of wars over the last 100 years is roughly  what it was in the 1800s (Clauset, 2018).

Therefore, the long peace may not be special. It could be a “statistical fluke”, says Clauset.

Clauset also estimates that wars as large as the second world war occur on average every 205 years. That implies we need at least another century of peace to be confident the long peace is a genuine departure.

With global warming and water shortages, I think we can see the cause of the next one.


Clauset, A. (2018) Trends and fluctuations in the severity of interstate wars. Science Advances. 4(2), pp.. eaao3580. DOI: 10.1126/sciadv.aao3580.

Coghlan, A. (2018) Another World War Could Still Be on the Cards. New Scientist. 03 March 2018, pp.15.


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