Pre-war expectation In the inter-war years, a growing expectation developed that, on the outbreak of war, cities would be rapidly destroyed by bombing raids. The use of poison gas was expected and a high level of devastation was anticipated from high explosive bombs. This originated, in part, from the views of military experts such as
Douhet, and was taken up by politicians and journalists, with, for example,
Stanley Baldwin coining the phrase "
The bomber will always get through". The targeting of the civilian population would, some theories suggested, cause a breakdown in morale that would lead to civil unrest that would compel a government to surrender. The combatant powers could, according to Baldwin, be in a competition to break the morale of the other side's civilian population first. There were two results from this. Firstly, civil defence programs were set up, with gas masks being issued, plans for air raid shelters were set up and organizations to manage civilians before a raid and deal with damage and casualties after one were put in place. Secondly, agreements were sought to make the targeting of civilians illegal under international law. At the time that Douhet and others were publishing their ideas, no air force had planned their capabilities with the intent of making a "knockout blow" against civilian targets. The Hague Rules of Air Warfare were developed in 1922–23 to prevent deliberately attacking civilians, yet it was not ratified by any country. At the start of World War II, the Royal Air Force had an initial instruction to abide by the Hague Rules for as long as the enemy did. This restraint was followed by both Britain and Germany until 11 May 1940, when, with Winston Churchill now in the role of Prime Minister and the
war in France going badly, the RAF attacked industrial and transport infrastructure targets in
Mönchengladbach. This raid caused civilian casualties.
Bombing by Germany In the
European theatre, the first city to suffer heavily from aerial bombardment was
Warsaw, on 25 September 1939 following the start of the
German invasion of Poland. Continuing this trend in warfare, the
Rotterdam Blitz was an
aerial bombardment of
Rotterdam by 90 bombers of the
German air force on 14 May 1940, during the
German invasion of the Netherlands. The objective was to support the German assault on the city, break Dutch resistance, and force the Dutch to surrender. Despite a ceasefire, the bombing destroyed almost the entire historic city centre, killing nearly nine hundred civilians and leaving 30,000 people homeless. The destructive success of the bombing led the
Oberkommando der Luftwaffe (OKL, the Luftwaffe High Command) to threaten to destroy the city of
Utrecht if the Dutch Government did not surrender. The Dutch capitulated early the next morning. As the war progressed, the
Battle of Britain developed from a fight for air supremacy into the strategic and aerial bombing of London, Liverpool, Coventry and other British cities.
Bombing by the Western Allies At the beginning of war,
RAF Bomber Command lacked both the navigation systems for finding a target and the numbers of bombers that were needed to make attacks of any scale in Germany. As heavy bombers were brought into service and technology and tactics were improved, the selection of targets was changed. The intention of avoiding civilian casualties as collateral damage disappeared. Instead, the civilian population which worked in war-related industries—and their housing—became the target. Some of this change came from a wish to retaliate for the German attack on Coventry. It was also based on what was learnt from being the target in the Blitz. It had been found that factory buildings were more resistant to critical damage than the homes of their workers. Absenteeism of the workforce rose significantly if their housing was uninhabitable, so affecting industrial production. Whilst morale was still discussed, the meaning of the word changed from its pre-war usage. Now a reduction in morale was intended to reduce industrial production that supported the war effort. The
area bombing directive was issued to RAF Bomber Command in 1942. The
Eighth Air Force of the
USAAF arrived in Britain over the summer of 1942. Despite
Roosevelt's pleas to
Hitler to avoid bombing civilians prior to the United States joining the war, he was a supporter of bombing Germany. Both
Churchill and Roosevelt were in the position that
Stalin was pressing for the Western Allies to open a new front in Europe, something which they were not ready to do. Therefore a bombing campaign—the
Combined Bomber Offensive—following the Casablanca directive to the Allied air forces was all they could offer to support the
Soviet Union.
Operation Gomorrah, carried out by Bomber Command against
Hamburg, targeted a city with both high susceptibility to fire and a large number of factories making products for the German war effort. The raid caused substantial damage to the city, especially the housing of industrial workers. A carefully developed mix of high explosive bombs and incendiaries was used. High explosives broke windows and made fire-fighting dangerous, whilst the incendiaries set the buildings on fire. This methodology was used for further attacks on urban areas (though not with such major effect) throughout the war, with
Dresden being one of the final targets. Carpet bombing was also used as
close air support (as "flying artillery") for ground operations. The massive bombing was concentrated in a narrow and shallow area of the front (a few kilometers by a few hundred meters deep), closely coordinated with the advance of friendly troops. The first successful use of the technique was on 6 May 1943, at the
end of the Tunisia Campaign. Carried out under
Sir Arthur Tedder, it was hailed by the press as '''Tedder's bomb-carpet
(or Tedder's carpet'''). The bombing was concentrated in a four by three-mile area, preparing the way for the
First Army. This tactic was later used in many cases in the
Normandy Campaign; for example, in the
Battle for Caen.
Pacific War dropping a bomb over the
Pasig River in Manila targeting the dockyard, November 14, 1944 In the
Pacific War, carpet bombing was used extensively against Japanese cities such as Tokyo.
On the night of 9/10 March 1945, 334
B-29 Superfortress heavy bombers were directed to
attack the most heavily populated civilian sectors of Tokyo. In just one night, over 100,000 people burned to death from a heavy bombardment of incendiary bombs, These attacks were followed by similar ones against
Kobe,
Osaka and
Nagoya, as well as other sectors of Tokyo, where over 9,373 tons During the final months of the war in the Philippines, the United States military used carpet bombing against the Japanese forces in
Manila and
Baguio, reducing much of the cities to rubble. Manila became the second-most-destroyed city of World War II. ==Korean War==