Data from satellites reveal the vast extent of fighting in Ukraine
Scars of the war can be found far beyond the front lines
War-related fires
BelARUS
Russia
Feb-Jun 2022
Jul 2022-Feb 2023
Chernihiv
Other fires
Feb 2022-Feb 2023
Hostomel
Maximum extent
of Russian control
Kyiv
Maximum extent
of Russian control
Kharkiv
Severodonetsk
Severodonetsk
Lyman
Lyman
Ukraine
Bakhmut
Bakhmut
Zaporizhia
Zaporizhia
Moldova
Mykolaiv
Mykolaiv
Mariupol
Kherson
Kherson
Size=people per
square km in area
of fire
Crimea
Crimea
Black
Sea
ROMANIA
The war in Ukraine is the most documented in history. Every day, social media overflows with videos of air strikes, reports from bloggers embedded with troops and round-ups of shifting front lines.
Yet such material, despite its abundance, paints only a partial picture. Events that were not recorded, or about which no one has released information, remain invisible. And when videos or photos do get shared, interpreting them can take days of complex work.
Cameras high above the battlefields can provide an alternative, broader picture of the war. Though most publicly-available satellite programmes were not designed to track conflicts, some nevertheless are fit for the purpose. The Economist has tracked the war’s evolution using two satellite-based systems. The first is FIRMS, a NASA programme that detects fires everywhere in the world twice per day using infrared sensors. It was originally designed to track forest fires. But it does not distinguish between natural and man-made conflagrations. It can reveal the time, location, and intensity of combat.
The SAR images are from Sentinel-1, a European satellite that bounces microwaves off Earth and measures the echo when they return. When the shape of objects on the ground changes, so does the strength of the returning signal. By combining this with a map of building footprints, we can calculate the likelihood that each building has been damaged, based on how much its signal has changed compared to the pre-war average.
Both approaches have weaknesses. NASA’s FIRMS cannot see through cloud cover, a particular problem in winter. SAR can pick up damage even through clouds, but is much less sensitive to changes outside of urban areas. But by combining the two datasets, we can form a fuller picture of the war. Our study shows that rather than being limited to a few big offensives and grinding battles, the war has left a brutal mark on large swathes of Ukraine. Fighting has reached 14% of municipalities, and damaged nearly half the built-up area in the hardest-hit cities.
To identify fires of military origin, we split up Ukraine into cells and calculated an expected fire rate in each one, based on factors like historical fire counts and cloud cover. Whenever the number of fires surpassed this benchmark to a statistically significant degree, we marked the excess as caused by fighting. Of the 72,221 fires during the past year, we classified 14,068 as war-related.
The front lines that appear in the data match those in other sources. Based on maps from the Institute for the Study of War, a think-tank, 64% of military fires were in contested areas or within 25km of the edge of Russian-held land. However, the rest were far from the front, meaning that attacks were common even in areas firmly held by one side. In Donetsk, the worst-hit province, we found military fires in 80% of municipalities. Four other provinces had shares above 50%.
Fires marked as war-related, by areas of control
Russia retreats from
Northern Ukraine
Ukraine acquires
long-range rockets
Ukrainian counter-offensive
begins advancing
200
Russia-held
0
Days with over
60% cloud cover*
200
Ukraine-held or
contested
400
F
M
A
M
J
J
A
S
O
N
D
J
Change in territory controlled†, sq km, ’000
40
↑ Russia gains territory
20
0
-20
↓ Russia loses territory
-40
F
M
A
M
J
J
A
S
O
N
D
J
2022
2023
*Over Ukraine †According to ISW
On the Ukrainian side, the numbers imply that the arrival last June of HIMARS, an American rocket system, was a turning point. The share of military fires in Russian-held areas rose from 26% in the two previous months to 50% in the two subsequent ones. Many other factors also contributed to Russian losses, but Ukraine has clearly used the rockets extensively.
Russian artillery probably accounts for most war-related fires in Ukrainian-held territory. Additional explosions resulted from attacks on Ukraine’s power grid, and occasional strikes on distant targets using missiles or drone barrages. The data suggest that Russia has exacted revenge on civilians for the Ukrainian army’s successes. When Russia has lost territory, military fires in the following month outside areas it controls have been unusually concentrated in cities.
To assess how much damage Russian strikes have done, Ollie Ballinger of University College London has used SAR to categorise every building in Ukraine as probably damaged or not. Sentinel-1 passes over Ukraine at least twice every 12 days. To make these classifications more reliable, he grouped images of each location taken during periods of a few months, and compared them with a year’s worth of data from before the war.
Mariupol
May 2022
On May 20th Russia took control of the city of Mariupol, following a three-month-long siege. The fighting left the city in ruins. By the time Ukrainian troops surrendered nearly half of the city's built-up area had been damaged. Our estimates from that time found that 90% of the damaged buildings were residential. Russian shells hit numerous civilian sites like hospitals and universities—most prominently the Donetsk Theatre in the centre of town, whose basement was being used as a shelter. The strike is thought to have killed more than 600 people, and Amnesty International has declared it a war crime. Mariupol suffered particularly heavy destruction in part because Russia was able to fly heavy bombers over the city.
Severodonetsk & Lysychansk
July 2022
Perhaps the most gruelling battle of Russia’s offensive in the Donbas region played out on the streets of Severodonetsk and Lysychansk. Throughout May and June Russian forces progressively took control of the cities. Comparing SAR images from before the war with those taken between June and September reveals that more than a quarter of the buildings in Severodonetsk and 30% of the built-up area have been damaged. In Lysychansk the figure was around 10%.
Homes, shopping centres, government buildings and a gold-domed Orthodox church were wrecked. For the 200,000 residents of the two towns, these scenes may be reminiscent of Russia's last invasion in 2014, where many buildings were also destroyed.
Kharkiv
October 2022
As Russia’s offensive efforts petered out, they left Kharkiv—a city that Russia was never able to capture, despite an early raid at the war’s outset—pockmarked with scars. SAR images captured between September and December reveal that around 5% of the city’s building area had been damaged. Much of the destruction is centred around the university district. Missiles struck the city’s Rare Book Library, home to 60,000 books and manuscripts, and destroyed the university’s economics department. Many students and staff have been forced to flee. The strikes on Kharkiv continue; four missile strikes hit the city on February 22nd.
Lyman
October 2022
Lyman, a small city in the north of the Donetsk region, was captured by Russia on May 27th after a five-day battle. SAR images from before this time show the city intact, but by the time this round of fighting ended 20% of buildings had been damaged.
In mid-September Ukraine launched an attack to take back Lyman, and regained control on October 1st. This second wave of fighting was markedly less destructive. Of previously unharmed buildings around 7% suffered damage in the counter-offensive. Russia now has its sights on Lyman again, attacking from forests to the east.
Bakhmut
February 2023
A year on from the invasion, fighting in urban areas still rages. Russia began shelling Bakhmut in May, and has tried to besiege it ever since. Some sources estimate that around 97% of the population has fled. Damage to the city, detected using SAR, has slowly accumulated since the war began. Our most recent estimate is that around 20% of the city’s built-up area has been damaged. However, since our method uses an average of images taken between December and February, this figure probably leaves out some of the most recent destruction.
Share of building area damaged, 2022-23, %
Kyiv
Kharkiv
Izium
Hostomel
20
0
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Bakhmut
Severodonetsk
& Lysychansk
Lyman
Mariupol
40
20
0
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Since the beginning of February the Russian attack on Bakhmut has only intensified. Ukrainian officials increasingly acknowledge that the city will fall soon. “It is not a particularly big town,” noted Volodymyr Zelensky, Ukraine’s president, on February 19th. “It is important for us to defend it, but not at any price and not for everyone to die.” ■
Sources: DMSP Nighttime Lights; ESA; Google Earth Engine; Institute for the Study of War; Microsoft Open Buildings; NASA; Ollie Ballinger; WorldPop; The Economist
Note: To see the code and data behind the model used in this story, or run it yourself, see our GitHub repository.
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