How many have died in Sudan’s civil war? Satellite images and models offer clues
Barred from the country, researchers try to monitor death and destruction from afar
At Yale University’s Humanitarian Research Lab, researchers are poring over satellite images and thermal sensing data captured over the Darfur region of Sudan over the past few weeks, looking for telltale signs of recent violence. Where a hospital stood just a few weeks ago, there may only be scarred ruins today. A graveyard on the edge of a town has undergone a sudden expansion. Entire villages have been torched.
The lab, part of Yale’s School of Public Health, is one of several groups gauging the devastation caused by the brutal civil war in Sudan. The conflict, drowned out in the media by other wars and political upheaval, has resulted in the worst famine in 40 years, disease outbreaks, and the destruction of vital infrastructure, and has driven more than 14 million people from their homes. The recent U.S. freeze on foreign aid, which has provided billions of dollars to Sudan since the conflict began, has deepened the crisis. But assessing the toll, which can guide humanitarian responses and help investigate war crimes, can only be done from afar.
One reason is the intense fighting, which has made large parts of the country inaccessible. But the warring factions are also blocking access. The Sudanese government is “very hostile to data gathering and to having a major humanitarian presence,” says Alex de Waal, an expert on food security and Sudan at the World Peace Foundation at Tufts University.
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As a result, estimates of how many people have died from fighting and related causes have varied from 20,000 up to 150,000. “We can’t responsibly give a number,” says Nathaniel Raymond, executive director of the Humanitarian Research Lab. “Many who would do the counting are dead or displaced.” But the few data available show that “absolutely more people are dying of starvation and disease than bullets and bombs,” says Maha Sulieman, a doctor and director of outreach for the nonprofit Sudanese American Physicians Association (SAPA).
Since April 2023, the government’s Sudanese Armed Forces (SAF) have been battling the paramilitary Rapid Support Forces (RSF), an outgrowth of the Janjaweed militia that slaughtered at least 200,000 people in Darfur at the turn of the century. A U.N. fact-finding mission in September 2024 concluded both sides have committed an “appalling range of harrowing human rights violations and international crimes,” including mass rape, arbitrary arrests, and torture. They have also destroyed hospitals, schools, communication networks, and water and electricity supplies. The U.S. Department of State has charged the RSF with genocide against non-Arab ethnic minority groups. The SAF and RSF are both using starvation as a weapon, blocking food, medical supplies, and other aid from reaching many of the estimated 30 million people who desperately need them.
The situation is especially dire in the state of North Darfur, where aid groups are largely unable to go, says Leni Kinzli of the United Nations’s World Food Programme. In Zamzam camp, home to half a million internally displaced people and under attack from both sides, a child was dying every 2 hours a year ago, Doctors Without Borders (MSF) estimated. In Tawila, elsewhere in North Darfur, a “staggering” 35% of children were suffering from acute malnutrition, MSF reported in December 2024.
A widely recognized international body that uses scientific criteria to evaluate food security, the Integrated Food Security Phase Classification (IPC), has confirmed that Sudan is starving. In December 2024, its Famine Review Committee, a panel of independent experts, said famine had spread to at least five areas, and five more would face the same fate by May. There was a risk of famine in 17 additional areas—“an unprecedented, deepening, and widening of the food and nutrition crisis,” the committee wrote. But the Sudanese government has dismissed the findings and has withdrawn from the IPC process, says a humanitarian worker who asked not to be named. “A famine declaration shows they are no longer in charge and can’t take care of their people,” she says.
Outbreaks of infectious diseases, which are especially deadly in malnourished children, have compounded the disaster. A cholera outbreak in 10 states has killed 546 people and is expected to resurge with the coming rainy season. MSF is seeing more cases of malaria, dengue, measles, acute respiratory infection, and diarrhea, says Melat Haile, the group’s medical advisor in Sudan. People with HIV and tuberculosis can’t get their drugs, and some with cancer and diabetes are dying for lack of care, says Frank Ross Katambula, MSF’s medical coordinator in eastern Sudan.
To assess the toll, the Yale lab collects satellite images and relies on SAPA, which provides humanitarian aid in Sudan, for “ground-truthing”—checking whether hospitals are still functioning, for example. “We are able to get in where the U.N. can’t,” Sulieman says. “Our work is only possible because we are Sudanese.”
In December, the Yale lab reported that nearly half of hospitals in Khartoum state were damaged. On 5 February, it said the RSF had attacked Zamzam and other camps in January and razed dozens of communities around El-Fasher, the capital of North Darfur, often setting them ablaze. It found many newly dug mounds highly consistent with graves near Zamzam and in Abu Shouk, another camp for the internally displaced. Satellite imagery has also shown the warring factions are burning fields and corrals and attacking water boreholes and reservoirs. “If you want to kill people, deny them the ability to water and graze their animals. We see both,” Raymond says.
The Yale researchers don’t produce death estimates, but other groups do. The Armed Conflict Location and Event Data (ACLED), an independent nonprofit that monitors conflicts around the world, relies on death estimates from international nongovernmental organizations and other partners, traditional media, and verified Telegram and WhatsApp accounts. In December, it estimated that since the start of the conflict, at least 28,700 Sudanese had died from “intentional injuries,” including 7500 civilians. That conservative number does not include those who died from war-related malnutrition and disease.
Maysoon Dahab at the London School of Hygiene & Tropical Medicine and colleagues think the toll is far higher. Death estimates often rely on hospital or morgue records, she explains. “But what about people never buried or who never made it to the hospital?” Her team used a modeling technique that compares data from multiple sources, including surveys and obituaries posted by first responders, to estimate that Khartoum state alone—where the best data were available—had more than 26,000 deaths from intentional injury between April 2023 and June 2024—higher than ACLED’s estimate for the entire country during the same period—and more than 61,000 deaths from all causes combined, a 50% increase over the prewar death rate.
Sarah Elizabeth Scales of the University of Nebraska Medical Center and colleagues have adopted another way to estimate the total number of deaths: multiplying the number of direct deaths from violence by a factor based on past experience. In 2008, for example, the secretariat of the Geneva Declaration on Armed Violence and Development estimated, based on 24 small-scale surveys, that there were 2.3 indirect deaths for every direct death from violence during the earlier Darfur genocide. Using that multiplier, Scales and colleagues conservatively estimated the total deaths since the start of the current war until October 2024 at 62,000. But calculating these ratios is hard, de Waal says. Based on other armed conflicts around the world, the secretariat has reported that the multiplier ranged from three to 15. Other estimates are lower.
Raymond says such estimates are no substitute for attempting to collect mortality data directly while the war continues. “Since September 2023 we have been screaming at the top of our lungs that international health care organizations and funders should prioritize mortality data collection,” he says. But, “They want to wait to do a body count until the conflict is over.” He worries things in Sudan will only get worse: “We haven’t hit bottom yet.”
A version of this story appeared in Science, Vol 387, Issue 6737. Download PDF
Images: Satellite images captured on 3 February (left) and 10 February (right) reveal that the main market in Zamzam camp in North Darfur in Sudan was attacked, 2025. Source: Maxar Technologies Via Getty Images.
