The West Point War Museum, right across the Hudson River from my home, offers a brisk tour of the history of weaponry, from Paleolithic stone axes to Fat Man, the atomic bomb dropped on Nagasaki in 1945. A sign at the museum's entrance states, "Unquestionably, war-making is an aspect of human nature which will continue as nations attempt to impose their will upon each other." Actually, this assertion is quite questionable. A recent decline in war casualties—especially compared to historical and even prehistorical rates—has some scholars wondering whether the era of international war may be ending.
Counting casualties is fraught with uncertainty; scholars' estimates vary according to how they define war and what sources they accept as reliable, among other factors. Nevertheless, a clear trend emerges from recent studies. Last year, 25,600 combatants and civilians were killed as a direct result of armed conflicts, according to the 2009 Yearbook of SIPRI, the Stockholm International Peace Research Institute, to be released Aug. 17. Two thirds of these deaths took place in just three trouble spots: Sri Lanka (8,400), Afghanistan (4,600), and Iraq (4,000). In contrast, almost 500,000 people are killed each year in violent crimes and well over 1 million die in automobile accidents.
SIPRI's figure excludes deaths from "one-sided conflict," in which combatants deliberately kill unarmed civilians, and "indirect" deaths from war-related disease and famine. If these casualties are included, annual war-related deaths from 2004 to 2007 rise tenfold to 250,000 per year, according to "The Global Burden of Armed Violence," a 2008 report published by an international organization set up in the aftermath of the Geneva Declaration. Even this much higher number, the report states, is "remarkably low in comparison to historical figures."
For example, Milton Leitenberg of the University of Maryland's School for International and Security Studies has estimated that war and state-sponsored genocide in the first half of the 20th century killed as many as 190 million people, both directly and indirectly. That comes to an average of 3.8 million deaths per year. His analysis found that wars killed fewer than one-quarter of that total in the second half of the 20th century—40 million altogether, or 800,000 per year.
Even these staggering figures are low in comparison with prehistoric ones, if considered as a percentage of population. All the horrific wars and genocides of the 20th century accounted for less than 3 percent of all deaths worldwide, according to one estimate. That is much less than the probable rate of violent death among our early ancestors.
The economist Samuel Bowles of the Santa Fe Institute recently analyzed dozens of archaeological and ethnographic studies of hunter-gatherer societies like the ones our ancestors are thought to have lived in for most of our prehistory. Warfare and other forms of violence led to 14 percent of the deaths in these simple societies, Bowles concludes.
In his influential book War Before Civilization, the anthropologist Lawrence Keeley of the University of Illinois estimates that violence accounted for as many as 25 percent of all deaths among early societies. Keeley includes not only hunter-gatherers but also tribal societies such as the Yanomamo in Amazonia and the Enga in New Guinea, which practice simple horticulture as well as hunting. These early people racked up such murderous totals with clubs, spears, and arrows rather than machine guns and bombs—and Keeley's stats don't even include indirect deaths from famine and disease.