Table 4.8Causes of War by Polarity Models, 1816–2016Type of Polarity
Number of WarsFrequency of WarsAverage
Length of WarsSeverity of
the WarsThe three Polarity Models, 1816–2016Central WarsMajor WarsMinor WarsLength of the System in YearsWar Years1% of Years in which a War Was FoughtAverage
Length in Days2Total Killed in Combat OnlyMultipolarity,
1849–1870, 1910–19452
7
9
58
26.1
45%
9,542/18=530
27,178,565
Bipolarity,1816–1848,
1871–1909, 1946–1991
0
0
5
118
12.8
10.8%
4,642/5=928
2,105,418
Unipolarity, 1992–2016(^32)
24
3.1
13%
1,125/2=562.5
39,092
1 The total number of years in which there was a war in any of the three polarity models was calculated by dividing the total number of days of warin them by 365 (the length of one year). Multipolar systems: 1854–1870 and 1909–1945: a total of 9,522 days of war, or 26.1 years of war; bipolar systems: 1816–1853, 1871–1909, and 1946–1991: a total of 4,922 days of war, or 12.8 years of war; unipolar systems: 1992–2016: a total of 1,125 days of war, or 3.1 years of war.
2 The average length of the wars in days was calculated by dividing the total number of days of war by the number of wars fought in each of the threepolarity models. Multipolar systems: 1854–1870 and 1909–1945: a total of 18 wars lasting 9,522 days of fighting—average length of 529 days per war; bipolar systems: 1816–1853, 1871–1909, and 1946–1991: a total of six wars lasting 4,655 days of fighting—average length of 931 days per war; unipolar systems: 1992–2016: a total of two wars lasting 1,125 days of fighting—average length of 562.5 days per war.
3 In unipolar systems, every war involving the polar power, or the sole hyperpower constituting the system, may be included in the three categoriesof war: central war, major war, or minor war. Therefore, the three cells relating to the two wars in which the sole hyperpower, the United States, in the unipolar system of 1992–2016, were merged.