Abdoulaye is a lost child of the post-9/11 world – one among millions. Born into a village community displaced by Islamist violence, he and his family found refuge in an abandoned school near Ouagadougou, capital of Burkina Faso. Weakened by malnutrition and anaemia, Abdoulaye, 3, contracted malaria. Despite frantic efforts to save him, he died, unremarked and unknown to the world at large.

“Abdoulaye is doubly uncounted: as a displaced person and as a war death,” writes Stephanie Savell, a cultural anthropologist, recalling his brief life in a disturbing new report that reveals the vast, unacknowledged human costs of contemporary global warfare. “Though he is mourned by his family and his community, officially, he never existed. His story is emblematic of how this kind of death, and its omission in counts of the dead, happens in any number of conflicts.”

Savell’s report, How Death Outlives War: The Reverberating Impact of the Post-9/11 Wars on Human Health, published by the Costs of War project at Brown University’s Watson Institute, focuses on what she terms “indirect deaths” – caused not by outright violence but by consequent, ensuing economic collapse, loss of livelihoods, food insecurity, destruction of public health services, environmental contamination and continuing trauma, including mental health problems, domestic and sexual abuse and displacement.

Calculated this way, the total number of deaths that occurred as a result of post-9/11 warfare in Afghanistan, Pakistan, Iraq, Syria, Yemen, Libya and Somalia rises dramatically from an upper estimate of 937,000 to at least 4.5 million, of which up to 3.6 million were “indirect deaths”. Such deaths grow in scale over time. In Afghanistan, where the war ignited by the 2001 US-led invasion ended in 2021, the indirect death toll and related health problems are still rising.

Experts suggest “a reasonable, conservative average estimate for any contemporary conflict is a ratio of four indirect deaths for every one direct death”, Savell says. The poorer the population, the higher the resulting indirect mortality when conflict erupts. “Indirect deaths are devastating, not least because so many of them could be prevented, were it not for war,” she writes. Generally speaking, men are more likely to die in combat. Women and children are disproportionately affected indirectly.

Savell does not attempt to apportion blame between various actors, although the US, which launched the “global war on terror” in 2001, bears heavy responsibility. She concedes that establishing definitive figures for war deaths of any kind is problematic and politically contested. Using the best available sources and data, her aim, she says, is to expand awareness of the fuller human costs of these wars and support calls for governments to alleviate continuing harms.

“The mental health effects of war reverberate through generations, impacting parents and children, and then their children after that. Estimates [suggest] … anxiety and depression are two to four times greater among conflict-affected populations than the global average,” she writes. “Women tend to suffer [these effects] more acutely due to gender-based violence, which is heightened in wartime. In Iraq, rape and sexual violence increased sharply after 2003 [when the US and UK invaded] … Children are also particularly vulnerable. [Those] who experience high levels of collective violence are twice as likely to develop chronic diseases.”

Levels of child malnutrition are indicators of the scale of war-related damage. “More than 7.6 million children under five are suffering from acute malnutrition, or wasting, in Afghanistan, Iraq, Syria, Yemen, and Somalia,” the report estimates. “‘Wasting’ means not getting enough food, literally wasting to skin and bones, putting these children at greater risk of death, including from … weakened immune systems.”

In Afghanistan specifically, where the economy has collapsed after the Taliban takeover, more than half the population now lives in extreme poverty. Tens of thousands of children under five are dying of preventable diseases such as cholera and measles, of acute malnutrition and neonatal complications. “As much as anyone killed by an airstrike or a gunshot wound, their deaths must be counted among the costs of war,” the report says.

This scrupulously compiled examination of war’s unconsidered, long-term lethal impacts has great power to shock. In Pakistan, for example, between 2004 and 2010, the US conducted “double-tap” drone strikes, mostly on Pashtun villages in Waziristan, along the Afghan border, in which a second strike targeted people rushing to help victims of an initial bombing.

“Reports document that residents of these regions suffered from PTSD, chronic anxiety and constant fear,” Savell writes. “A local resident explained: ‘God knows whether they’ll strike us again or not. But they’re always surveying us, they’re always over us, and you never know when they’re going to strike.’” Untreated, such trauma is debilitating and unceasing.

In many conflict zones, deliberate attacks on healthcare facilities are a favoured tactic. Both direct and indirect deaths result. At one point in Syria’s civil war, according to a 2019 study quoted in the report, “each attack on a healthcare facility corresponded to an estimated 260 reported civilian casualties in the same month”, because of the resulting non-availability of medical assistance.

Displacement is another big driver of indirect deaths, caused by physical insecurity, heightened mental stress, and abuse, exploitation and indifference suffered during attempted flights to safety. An estimated 38 million people have been displaced since 2001. Britain fought in many of these wars. As it debates tougher anti-migrant regulations, the UK must acknowledge its part in causing this crisis.

The report details many additional, lingering deathtraps, including environmental contamination, unexploded ordnance, landmines, and damage to water, sanitation and aid and food distribution systems. More research data is badly needed, Savell writes, but it’s already evident governments must do more to mend what they broke – and that “reparations … are imperative”.

Those who have died are beyond help. But for millions of adults and children still suffering the consequences of the post-9/11 conflicts, the need is urgent. They are condemned to war without end.