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From Gaza to Ukraine, experts are trying to gauge the true human cost of war – hidden death tolls including those who perish from hunger or disease, as well as those killed by bombs and bullets.
A recent report in UK medical journal The Lancet suggested Gaza's true death toll could be four times the 39,000 recorded from violence.
Conflict monitors also assess those killed directly by violence but nonetheless unaccounted for.
Many dead may be missing in the chaos of fighting or buried under rubble. This figure can be a colossal addition to recorded deaths, which can include those verified as dying from a bomb blast – perhaps recorded by journalists or a local morgue.
Data scientists and economists sift through reams of government records on mortality, including all types of deaths, and within those numbers is the true toll.
These conflicts obviously have a visible impact: entire cities in ruins and millions displaced.
But keeping track of the true scale of deaths becomes harder, as health systems come under increasing pressure.
Civilians are of course the most vulnerable, although mortality data can also be used to determine male combatant casualties, figures often hidden by the propaganda of warring sides.
Excess deaths
Human masses, huddled in tents or in the open, without access to sanitation or health care, are often vulnerable to deaths that go unregistered.
About 1.7 million people in Gaza have been displaced, many of them more than once, with an estimated 6.5 million displaced inside Ukraine.
"Excess deaths" among these populations are those over what is known as the "baseline" death rate of a population – those expected to pass away under normal conditions, before a pandemic, war or other shock, such as a sharp economic recession or natural disaster.
In some cases, the gap between baseline deaths and the excess can illustrate how many people have died from war or other disasters: the experts track unusual surges in deaths.
In such emergencies, many succumb to illness in overcrowded hospitals that lack power, or staff to keep them running. Understanding this is important to assess the needs of civilians during a crisis.
Caitlin Moe, an epidemiologist at the University of California, told The National “the occurrence of indirect deaths is generally the core impetus for conflict mitigation and humanitarian responses”.
She said the increased targeting of health facilities in Gaza and Ukraine is “particularly salient” because most indirect deaths are “healthcare-related, in terms of disease morbidity and healthcare access”.
Lancet report on Gaza
The Lancet suggested the actual death toll from disease and displacement in Gaza could be 186,000, four times those killed by violence.
“Armed conflicts have indirect health implications beyond the direct harm from violence,” its report says. "Even if the conflict ends immediately, there will continue to be many indirect deaths in the coming months and years from causes such as reproductive, communicable and non-communicable diseases.
"The total death toll is expected to be large given the intensity of this conflict; destroyed healthcare infrastructure; severe shortages of food, water and shelter; the population's inability to flee to safe places."
In some cases, indirect deaths comprise the overwhelming majority of fatalities during a war.
Hunger, not bombs and bullets, will kill most in Sudan’s civil war, former Sudanese prime minister Abdalla Hamdok recently told The National.
Tally of tragedy
In Gaza today, the toll of 39,000 people killed in just over nine months has been carefully tracked by the enclave's hospitals and health clinics, even though they are being destroyed across the strip.
How many die beyond this figure – as well as The Lancet article, a study by Johns Hopkins University put the figure up to 80,000 – is subject to some controversy.
For a sense of how colossal indirect deaths can be, in the Democratic Republic of Congo the International Rescue Committee estimated only 10 per cent of 3.9 million deaths were directly due to violence in the civil war that gripped the country between 1998 and the early 2000s.
But there are uncertainties around many of these estimates, says Michael Spagat, a professor at Royal Holloway, University of London.
One obvious reason is the quality of critical services in different settings, that keep people alive as the war begins and drags on.
Mr Spagat makes clear that while “an immediate ceasefire and sustained humanitarian aid remain essential” in Gaza, The Lancet lacks sound methodology for claiming 186,000 Gazans have died.
Mr Spagat says the authors make their estimate based on a table in another, far-reaching study, The Burden of War, that references 13 conflicts and associated indirect deaths, with an average of four to every direct war death.
"These wars are just a tiny fraction of all the wars in recent decades," he said. "Kosovo is included, for which the table says, correctly, that the ratio of indirect to direct deaths was, essentially, 0. But the others range from 2.3 to 15.7.
"If we imagine that the numbers in the table are all correct and that these 13 wars and the Gaza war were all drawn from the same urn (so to speak) with equal probabilities of selection, then it would be reasonable to say that a projection of four indirect deaths for each direct one is conservative. But there are a number of problems.”
The wars chosen, he says, are not “representative of the likely mortality outcome in Gaza. Most simply don’t resemble Gaza.”
In Gaza, he says, the Ministry of Health has been effective for much of the conflict, at least until recently amid very heavy fighting around some hospitals, in reporting deaths daily.
“Why would they regularly announce numbers that are just 20 per cent of the real death toll?”
Gaza's health ministry says Israeli attacks are indiscriminate, while Israel says that Hamas hides its fighters in civilian infrastructure and homes.
Sifting through the data
Ariel Karlinsky, an economist from the Hebrew University of Jerusalem, and creator of the World Mortality Dataset, says quality record-keeping is critical when assessing a war’s indirect impact.
He says it is extremely difficult to assess excess deaths in areas with little data, such as the Democratic Republic of Congo, or parts of occupied Ukraine.
"Ideally, excess mortality is a great measure for conflict-related deaths but conflicts tend to occur in areas with poor state capacity and sometimes regions with no or little vital registration data,” he said.
This has affected assessments of deaths in conflict in Darfur, Sudan during genocidal violence in 2004. One study said indirect deaths at the time were five times the number of violent deaths, while another said the indirect toll was 10 times higher.
Yet another study on Darfur claimed indirect deaths did not surpassed violent ones.
Other challenges include changing territorial control, Mr Karlinsky says.
“In settings with good enough state capacity (such as Ukraine or to a much lesser extent, Syria), conflict sometimes means loss of territory such that deaths that occur in areas no longer under control of the central government (Donbas in Ukraine, Aleppo in Syria) are completely unobserved. In fact, Ukraine stopped all demographic statistical reporting back in February 2022.”
If the American Civil War is a guide, the true toll of these wars will be debated for a long time.
For more than 100 years, war records from the Union and Confederate states put the four year-long war death toll at about 620,000, but data for the southern states was considered patchy, so even this was only an estimate.
In 2012, J David Hacker, a demographic historian at Binghamton University in the US, looked at census data on the conflict to find that 23 per cent of southern men between 20 and 24 may have died in the conflict. The final death toll of the war, he said, could be as high as 850,000.
