Strategic bombing during World War II

• 1. Introduction

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  Strategic bombing during World War II began in the first minutes of the conflict. On the 1st of September 1939, the same day Germany invaded Poland, Luftwaffe bombers were already over Polish cities. The small town of Wieluń was one of the first targets struck, a place with little to no military value. That detail raises the central question of the entire six-year air war: when does a bomb dropped from altitude become a war crime, and when does it become accepted military practice?

  The answers the major powers gave to that question would reshape cities across Europe and Asia. Estimates of the death toll from strategic bombing range from hundreds of thousands to over a million. Millions more were made homeless. The debate over whether any of it was legal, effective, or morally defensible has never fully settled.

• 2. The Legal Vacuum

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  The Hague Conventions of 1899 and 1907 established the rules of war on land and at sea, but they were drafted before aircraft existed. Repeated diplomatic attempts to update international humanitarian law to cover aerial warfare all failed before 1939. Most nations refused to ratify such updates because of vague or impractical treaty language, including the 1923 Hague Rules of Air Warfare.

  The major powers also had another reason to resist. They had invested in advanced bombers that gave them a decisive military edge; accepting legal limits on that weapon was not in their interest. So when war began, both sides fell back on the 1907 Hague Conventions, signed and ratified by most major powers, and interpreted those documents to permit the bombing they intended to carry out.

  General Telford Taylor, who served as Chief Counsel for War Crimes at the Nuremberg Trials, put it plainly. He wrote that the ruins of German and Japanese cities were the result not of reprisal but of deliberate policy, and bore witness that aerial bombardment of cities and factories had become a recognized part of modern warfare as carried out by all nations. That recognition is precisely why the Allies at Nuremberg never criminalized aerial bombardment of non-combatant targets, and Axis leaders who ordered similar attacks were not prosecuted for them.

• 3. Poland: First Experiments

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  Frampol was chosen as an experimental object, a German writer later recorded, because test bombers flying at low speed were not endangered by anti-aircraft fire. The town's baroque street plan formed a perfect geometric grid for calculations and measurements, and its centrally placed town hall gave bomber crews an ideal orientation point. British historian Norman Davies, writing in his book Europe at War 1939-1945: No Simple Victory, noted that Frampol was chosen partly because it was completely defenceless.

  The Luftwaffe's campaign in Poland was not purely experimental. Its formal directives ordered it to prevent the Polish Air Force from influencing ground battles, to support German ground forces, and to destroy strategic rail routes to deny mobility for Polish reinforcements. In practice, those missions blurred into something broader. Polish reports from early September documented the strafing of civilians, the bombing of cemeteries, and the targeting of marked hospitals. According to professor Tomasz Szarota, the attacks on fleeing civilians were a direct violation of the Hague Convention.

  On the 13th of September, following orders from the Luftwaffe's Commander-in-Chief, 183 bomber sorties targeted Warsaw's Jewish Quarter with a fifty-fifty load of high explosive and incendiary bombs. The justification given was unspecified crimes against German soldiers. On the 25th of September the Luftwaffe flew 1,150 sorties and dropped 560 tonnes of high explosive and 72 tonnes of incendiaries on Warsaw in a single day.

• 4. The Blitz and Its Turning Points

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  On the 24th of August 1940, several off-course German bombers accidentally dropped ordnance on central areas of London. The RAF responded the next day by bombing Berlin for the first time, targeting Tempelhof airfield and the Siemens factories in Siemenstadt. The Germans viewed this as an indiscriminate attack, and Hitler was infuriated. In a public speech in Berlin on the 4th of September 1940, he announced that when the British dropped two, three, or four thousand kilograms of bombs, Germany would drop 150,000, 180,000, 230,000, 300,000, 400,000 kilograms on a single night, and would eradicate British cities.

  On the 7th of September, 318 bombers from the whole KG 53, supported by eight other Kampfgruppen, flew almost continuous sorties against London. By the morning of the 8th of September, 430 Londoners had been killed. Hitler himself had hoped that bombing London would terrorize the population into submission. He believed that if eight million Londoners went mad, it might turn into a catastrophe, and that even a small invasion might then go a long way.

  Operation Abigail Rachel, the bombing of Mannheim on the 16th of December 1940, marked the start of a deliberate British drift toward area bombing. The raid was declared internally to be a reprisal for Coventry and Southampton. Churchill ordered it on condition it receive no publicity and be treated as an experiment. Target marking failed and most bombs missed the city centre, but rather than abandon the approach, the British developed the bomber stream technique and continued.

• 5. The British Area Bombing Campaign

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  A British Air Staff paper dated the 23rd of September 1941 stated the purpose directly. The ultimate aim of an attack on a town area was to break the morale of the population which occupied it. To ensure this, two things were required: the town had to be made physically uninhabitable, and the people had to be made conscious of constant personal danger. On the 14th of February 1942, the area bombing directive was issued to Bomber Command, authorizing forces to be used without restriction.

  Professor Frederick Lindemann, the British government's leading scientific adviser and a confidant of Winston Churchill, had presented a paper to the Cabinet showing that intensive bombing of German cities could dehouse the workforce and reduce their ability to work. Working-class homes were to be targeted because they had a higher density and firestorms were more likely. His calculations were questioned at the time by Professor P. M. S. Blackett of the Admiralty operations research department, but the Cabinet accepted Lindemann's conclusions.

  On the 30th of May 1942, between 0047 and 0225 hours, 1,046 bombers dropped over 2,000 tons of high explosive and incendiaries on Cologne in Operation Millennium. Some 3,300 houses were destroyed and 10,000 were damaged. Twelve thousand separate fires raged, destroying 36 factories and damaging 270 more. The fires could be seen 600 miles away at an altitude of 20,000 feet. By October 1943, Air Marshal Harris was urging the government to publicly state that the aim of the Combined Bomber Offensive was the destruction of German cities, the killing of German workers, and the disruption of civilized life throughout Germany. The most lethal of the firestorm raids was Operation Gomorrah against Hamburg, which killed roughly 45,000 people.

• 6. American Precision and Its Limits

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  The United States Army Air Forces arrived in the UK in mid-1942 committed to a different doctrine. Their commanders claimed that using the B-17 Flying Fortress and the Norden bombsight, the USAAF could carry out precision bombing of factories, naval bases, shipyards, and power plants rather than bombing cities indiscriminately. The B-17 carried ten to twelve machine guns, eventually up to thirteen Browning M2 guns per bomber, giving it heavy defensive armament. In return, it carried smaller bomb loads than British aircraft.

  The gap between doctrine and reality was revealed by the United States Strategic Bombing Survey. Only about 20 percent of bombs aimed at precision targets fell within a 1,000-foot radius of the aiming point. In the fall of 1944, only seven percent of all bombs dropped by the Eighth Air Force hit within 1,000 feet of their aim point. The American Eighth Air Force received its first H2X radar sets in December 1943, and within two weeks of their arrival, the command gave permission for area bombing of a city using radar. On average, roughly one such attack was authorized per week until the end of the war in Europe.

  Formations of unescorted bombers proved no match for German fighters. In late 1943 the Eighth halted air operations over Germany entirely until a long-range fighter could be found. The solution arrived in 1944 in the form of the North American P-51 Mustang, which had the range to fly to Berlin and back. The operation known as Big Week, from 20 to the 25th of February 1944, targeted the Luftwaffe's day fighter forces and inflicted losses so heavy that Germany's air defense over its own territory was severely degraded through most of 1944.

• 7. Civilian Cost and Contested Legacy

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  The record attack on a single target in the entire war took place on the 12th of March 1945 at Dortmund. A force of 1,108 aircraft, including 748 Lancasters, 292 Halifaxes, and 68 de Havilland Mosquitos, dropped more than 4,800 tons of bombs and destroyed 98 percent of the buildings across the city centre and the south of the city. On the 3rd of March 1945, RAF bombers carrying out a mission against V-2 launching facilities in The Hague's Haagse Bos district were issued the wrong coordinates. The bombs fell instead on the densely populated Bezuidenhout neighbourhood. The area was more crowded than usual with evacuees; 532 residents were killed and approximately 30,000 were left homeless.

  The effectiveness of the campaigns remains genuinely contested. According to economic historian Adam Tooze, in The Wages of Destruction, the Battle of the Ruhr in 1943 saw 34,000 tons of bombs dropped over five months, after which steel production fell by 200,000 tons, creating a shortfall of 400,000 tons. Albert Speer acknowledged that the RAF was hitting the right targets. The United States Strategic Bombing Survey found that attacks on waterways beginning the 23rd of September, particularly against the Dortmund-Ems Canal and Mittelland Canal, produced severe traffic problems and cut rail shipments by more than half by February 1945.

  British historian Frederick Taylor observed that roughly half a million Soviet citizens died from German bombing during the invasion and occupation of Russia, a figure roughly equivalent to the number of German citizens who died from Allied raids. Air Marshal Sir Robert Saundby, closing his analysis of the ethics of bombing, wrote that a study of the ethics of bombing cannot fail to remind one that man is an illogical creature, still far more swayed by emotion than by calm reason, and that there are none so blind as will not see, or so deaf as will not hear. The question of whether this scale of death against civilian populations was ever legally prohibited remained, in the end, unanswered at Nuremberg.