The United Nations warns that the civilian casualty statistics it publishes daily don't capture the full impact of the war in Ukraine — while military experts say the number of Ukrainian civilians killed by Russian forces likely won't be known until years after the conflict ends.
Experts say the Office of the UN High Commissioner for Human Rights (OHCHR) is providing the most accurate daily statistics on Ukraine's civilian casualties. But the OHCHR itself says it may be greatly underestimating the real casualty rate.
"OHCHR believes that the actual figures are considerably higher, as the receipt of information from some locations where intense hostilities have been going on has been delayed and many reports are still pending corroboration," it said.
Since the invasion on Feb. 24, the OHCHR has confirmed that 1,232 Ukrainian civilians have been killed and 1,935 have been injured. Of the civilians killed, the UN said it has confirmed that 250 were men, 176 were women, 18 were girls and 36 were boys. Another 58 children and 694 adults have also been confirmed dead by the UN, but the agency has been unable to determine their sex.
Experts say that civilian authorities in wartime — unlike militaries — typically lack the resources and time to count civilian casualties accurately.
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Howard Coombs, an assistant professor at the Royal Military College of Canada, said that modern militaries need detailed battle damage assessments to shape targeting plans, evaluate ongoing operations and provide direction to troops.
"You have systems and calculations that are standardized and can be used to get the most accuracy, because if you don't have accurate information you can't shape your operations properly and you don't know if you're having success," Coombs told CBC News.
"It's a very different thing on the civilian side. There is no calculating, in a systemic fashion, like there is when counting military damage."
Complete count of civilian dead unlikely, says UN
Coombs said that coming up with an accurate count of Ukrainian civilian deaths could "take years." He pointed out that no one knows for sure how many Russian civilians were killed during the Second World War.
A OHCHR official told CBC news that while a complete count of every civilian death may never happen, the agency should be able to account for about 90 per cent of civilian deaths within a few months of the war ending.
"An accurate picture of how many civilians had actually been killed could be achieved relatively quickly, while the process of recovery and identification of all mortal remains would probably never reach the stage when one could claim that every civilian death is accounted for," the official said.
The official said the UN is aware of many "improvised grave sites" and "Individually marked graves" that could be verified once the OHCHR can get in there — but that would depend on the level of devastation UN workers find on the ground.
"There may be a considerable number of bodies whose identification would remain problematic for years, as well as those who are missing and likely deceased," they said.
Refugees and the fog of war
Experts say that if a mass casualty event, such as a gas explosion, took place in an urban setting in a western democracy, it would take days to determine how many people died. When the authorities who do such work — police and paramedics — are no longer functioning, that work doesn't happen.
Walter Dorn, a professor of defence studies at the Royal Military College, said that cities experiencing intense bombing lack functioning local services and can't expect outside help.
"In the case of Mariupol, their ambulances cannot function anymore," Dorn said. "They've run out of fuel and they can't get to the sites. So there are people dying in their apartments of starvation that the UN and the local authorities don't even know about.
"In these severe conditions of war, it's impossible to actually know the condition of all the citizens. And even local authorities don't have the capacity to check up on people."
The UN says that more than four million Ukrainians have fled the country and countless others have been driven from their towns and villages to other parts of Ukraine.
"When you have a mass casualty-type incident in numerous areas, it would be incredibly difficult for authorities in a stable region to deal with that and report accurately," said Coombs.
"You throw on top of that the migration, displaced people, disrupted governance, disrupted security and safety, emergency services, and it is almost impossible to figure out what is happening."
Experts say that if a tank with a crew of three is hit with a rocket while it's moving, it's safe to assume the entire crew has been killed. But without knowing where people are — how many have fled, how many remain — officials can't estimate casualties from a missile attack on a civilian target.
UN only releasing confirmed death totals
Military experts told CBC News that the attack on the World Trade Center offered a good example of the difficulty involved in tracking civilian deaths. According to the 9/11 Memorial Museum, anywhere from 30,000 to 50,000 people could be found working in the twin towers on any given day in 2001 — but the official death toll from the attack was only 10 per cent of the low number in that range.
Another reason for the lower-than-expected estimates of civilian deaths in Ukraine is the cautious approach being taken by the UN and the 37 staff members in the human rights monitoring mission who are collecting and verifying the information.
"Neutrality is a key element in all UN type operations, military or otherwise. Without neutrality they cannot operate with all sides in the conflict," Coombs said. "So if the UN is not very judicious on how it is counting civilian casualties figures, it plays into the information war that's actually going on."
Ukraine's prosecutor general publishes a list of war crimes committed against Ukraine by Russia but only offers precise civilian death tolls for children. Ukraine says 148 children have been killed in Russia's war to date, while the OHCHR's estimate is 112.
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Dorn said Ukrainian authorities are trying to develop a reputation for accuracy and have avoided announcing unconfirmed civilian deaths.
An official from the OHCHR told CBC News in an email that it only reports civilian deaths "based on our independent verification of incidents and casualties involved," and that the agency does not provide "sum totals provided by others, including Government bodies."
The UN official said thaxjmtzywt, because its officials can't travel to much of Ukraine, "it has been very difficult to get information from some locations where there have been or are intense hostilities, and so many reports still need to be verified."