War and Peace after 1945

OWID presents work from many different people and organizations. When citing this entry, please also cite the original data source. This entry can be cited as:

Max Roser (2016) – ‘War and Peace after 1945’. Published online at OurWorldInData.org. Retrieved from: https://ourworldindata.org/war-and-peace-after-1945/ [Online Resource]

I have split up the data presentation on war and peace in two sections: the very long-term perspective and wars since 1945.

There are two reasons to split the presentation this way. Firstly, the availability and quality of data for wars after World War II is much better than for the time before, and secondly, as I show below, there are good reasons to think that the observed decline in wars since 1945 is driven by a number of forces whose influence grew since 1945.

# Empirical View

# The Absolute Number of War Deaths is Declining since 1945

The absolute number of war deaths has been declining since 1946. In some years in the early post-war era, around half a million people died in wars; in contrast, in 2007 (the last year for which I have data) the number of all war deaths was down to 22.139.

The detailed numbers for 2007 also show which deaths are counted as war deaths:1

  • Number of State-Based Battle Deaths: 16773
  • Number of Non-State Battle Deaths: 1865
  • Number of One Sided Violence Deaths: 3501
  • The total sum of the above is: 22139. This is the number of all war deaths on our planet in 2007.

The decline of the absolute number of battle deaths is visualized in the following graph that shows global battle deaths per year by world region. There are three marked peaks in war deaths since then: the Korean War (early 1950s), the Vietnam War (around 1970) and the Iran-Iraq and Afghanistan wars (1980s).

# Number of annual war battle deaths by world region, 1946-2007 – Max Roser2

Click to open in Full Screen


# The Share of War Deaths is Declining even Faster

The previous graph showed absolute numbers, but as the world has seen rapid population growth (see our entry on global population growth), it is more appropriate to look at relative numbers. The following graph therefore shows the battle deaths per 100,000 people per year. The figures are shown by type of conflict.

# Rate of battle deaths in state-based armed conflicts by type of conflict, 1946-2013 – Max Roser3

Full screen view of the interactive chart Download the data visualized in the chart

# The Number of Wars Increased until the End of the Cold War

As we have seen, the number of war victims varies hugely between different wars; whereas 1,200,000 died during the the Korean War (1950–1953), other wars had ‘just’ 1,000 victims. For this reason, statistics on the number of wars should not be considered without information on the size of these conflicts.

The following figure shows that the number of wars increased until the breakdown of the Soviet Union and has been decreasing since then. Extrastate conflicts are colonial conflicts that ended with the end of colonialism. Interstate conflicts – wars fought between countries – have almost ceased to exist. As other wars are becoming rare, intrastate conflicts (civil wars) in some parts of the world remain.

# Number of state-based armed conflicts by type, 1946-2007 – Max Roser4

The increase in the number of wars shown before is predominantly an increase of smaller and smaller conflicts. This follows from the previously shown facts that the number of war victims declined while the number of conflicts increased. The decreasing deadliness of conflicts is shown in the following graph.

# Deadliness of wars – average battle deaths per conflict by decade, 1950-2007 – Max Roser5

# Ongoing Wars

Information on ongoing wars that is always up-to-date can be found at Wikipedia’s List of Ongoing Military Conflicts.

After the documented decline of war, large parts of the world have now been peaceful for an unprecedented long period. Although wars are still fought, the world is now more peaceful than ever.6

# Data Quality & Definition

Definition of War Most data are taken from the PRIO/UCDP dataset. The following definitions quoted from the website of the Human Security Report Project apply:

  • A conflict is coded as a war when the battle-death toll reaches 1,000 or more in a given calendar year.
    • An extrastate armed conflict is a conflict between a state and an armed group outside the state’s own territory. These are mostly colonial conflicts.
    • An interstate armed conflict is a conflict fought between two or more states. An intrastate armed conflict (also known as a civil conflict) is a conflict between a government and a non-state group that takes place largely within the territory of the state in question.
    • An intrastate armed conflict becomes an internationalized intrastate armed conflict when the government, or an armed group opposing it, receives support, in the form of troops, from one or more foreign states.

For more information on definitions visit the website of the Human Security Report.

# Data Sources

There are two major projects that gather on wars on a global scale for the post-war period and make their finding publicly available:

1. The Correlates of War Project

2. The PRIO, UCDP & Human Security Reports PRIO and UCDP collaborate to build the data set on wars. This data set is the base for the annual publication of the Human Security Project and for most of the data in this post.

Peace Research Institute of Oslo (PRIO)

Uppsala Conflict Data Program (UCDP)

Human Security Report Project

# Data on Civil Wars

Data on on civil conflicts for the period 1945–99 was collected by Fearon and Laitin and can be found here.