Measuring war deaths is fraught with difficulties. Even the seemingly straightforward question of how many people were killed by armed actors can be a matter of controversy. In the case of the Iraq War, estimates of direct mortalities caused by violence (including both military and civilian deaths) range from the 110,000 reported in US military documents made public by WikiLeaks in 2010 to the more than 650,000 estimated by a 2006 Lancet survey.

Beyond deaths inflicted directly by violence, however, wars also cause many indirect deaths. Indirect deaths are a result of infrastructure damage or destruction — for instance of water treatment plants or electrical grids needed to keep food and medicine cool.

Yet it is notoriously difficult to gauge the indirect effects of war, particularly in a country with poor health-sector recordkeeping, decades of conflict, years of crippling economic sanctions, and a series of environmental disasters. Despite these many obstacles, a Boston University researcher argued, “war certainly caused extensive destruction of infrastructure in Iraq and . . . it would not be surprising if indirect death were 2 to 4 times the number of direct deaths due to violence — reaching as high as 536,000 indirect deaths.”