The United States Strategic Bombing Survey was a written report created by a board of experts assembled to produce an impartial assessment of the effects of Anglo-American strategic bombing of Nazi Germany during the European theatre of World War II. After publishing its report, the Survey members then turned their attention to the efforts against Imperial Japan during the Pacific War, including a separate section on the recent use of the atomic bombs.
In total, the reports contained 208 volumes for Europe and another 108 for the Pacific, comprising thousands of pages. The reports' conclusions were generally favourable about the contributions of Allied strategic bombing towards victory, calling it "decisive".
A majority of the Survey's members were civilians in positions of influence on the various committees of the survey. Only one position of some influence was given to a prominent USAAF General Orvil A. Anderson, and that too in an advisory capacity. Anderson was the only one on the survey board who knew about procedures of strategic bombing as Jimmy Doolittle's former deputy commander of operations. While the Board was not associated with any branch of the military, it was established by General Hap Arnold along with Carl A. Spaatz. Failing to obtain the prominent public figure he had hoped for, Arnold settled for Franklin D'Olier.
The Survey team was formed on 3 November 1944 by Secretary of War Henry Stimson in response to a directive by President Roosevelt. The headquarters was in Teddington, England. The sociologist, Charles Fritz was part of the survey team before going on to become a significant theorist in disaster research. The Survey was tasked with producing an impartial report on the effects of the bombing against Nazi Germany, in order to:
The Report, along with some 200 supporting documents, was released on 30 September 1945. The major conclusion of the report was that strategic bombing, particularly the destruction of the oil industry and truck manufacturing had greatly contributed to the success of the Allies in World War II. However, despite the overall contribution of the bombing, the survey concluded that the impact of strategic bombing could not be separated from the general collapse of Germany in 1945.
The Survey noted several successes against crucial industrial areas:
The Survey also noted a number of failed or outcomes of limited success:
The Survey concluded that one reason German production rose in so many areas was in part that the German economy did not go on a complete war footing until late 1942 and 1943. Up until then, factories had been on a single shift in many industries and the German economy was generally inefficient and not operating at full capacity. They also noted that women's participation in the manufacturing field remained low, lower than during World War I. The sections of the Survey regarding the German production system remain one of the best resources on the topic.
After the European report was completed, the Survey turned its attention to the Pacific campaign. The report opens with a discussion of the Japanese strategic plans, which were based on an initial victory against the U.S. Navy which would upset any U.S. plans in the Pacific for an estimated 18 months to 2 years. During this time, they planned to "speedily extract bauxite, oil, rubber and metals from Malaya, Burma, the Philippines and the Dutch East Indies, and ship these materials to Japan for processing". They also noted the belief that high casualties would not be accepted by the U.S. democracy, and that if the initial campaigns were successful, a negotiated peace was possible.
The Survey received sufficient information to detail every ship used by the Japanese during the war. They noted that the Imperial Japanese Navy began the war with 381 warships of approximately 1,271,000 tons, and completed another 816 ships of 1,048,000 tons during the war. Of these, 1,744,000 tons were sunk; "625,000 tons were sunk by Navy and Marine aircraft, 375,000 tons by submarines, 183,000 tons by surface vessels, 55,000 tons by Army aircraft, and 65,000 tons by various agents".
The Japanese merchant fleet was likewise destroyed. They started the war with 6,000,000 tons of merchant ships over 500 tons gross weight, which was alone not sufficient to provide for the wartime economy. Another 4,100,000 tons were constructed, captured or requisitioned. However, 8,900,000 tons were sunk, the vast majority of their fleet. Of this, "54.7 percent of this total was attributable to submarines, 16.3 percent to carrier based planes, 10.2 percent to Army land-based planes and 4.3 percent to Navy and Marine land-based planes, 9.3 percent to mines (largely dropped by B-29s), less than 1 percent to surface gunfire, and the balance of 4 percent to marine accidents." The Allied submarine campaign played the largest role, while naval mining by air in Operation Starvation also played a significant role, sinking or damaging more than 1,250,000 tons.
In total, Allied aircraft dropped 656,400 tons of bombs on Japanese targets, 160,800 tons on the home islands. This was much smaller than the 2,700,000 tons dropped over Europe, or even the 1,360,000 tons on Germany.
After initial attacks from high-altitude precision bombing in which less than 10% of the bombs fell near their targets, Allied air forces switched to low-level night-time incendiary attacks against Japanese cities. On the night of 9–10 March 1945, 16 square miles of downtown Tokyo were burned out and tens of thousands were killed by U.S. Army Air Forces B-29s. (The Survey estimated that 88,000 died, while the Tokyo Fire Department estimated 97,000. Historian Richard Rhodes estimated more than 100,000, though journalist Mark Selden considered even this figure to be too low.) In the following 10 days, a total of 31 square miles were destroyed. The Survey notes that these attacks had little direct effect on manufacturing, with factories that were hit by bombs having less drop off in production than those that did not. However, they also noted that production dropped by 54% during this period due to the effects of bombing: the killing, injuring and dehousing of the workers as well as the destruction of the transportation network. They noted a precipitous reduction in food availability as well, dropping from about 2,000 calories per day at the start of the war, to 1,680 for industrial workers at the height of the campaign, and less for non-essential workers.
They noted that although the blast wave was of about the same pressure as that of a high-explosive bomb, the duration of the effect was longer and that brick buildings were collapsed as far as 7,300 feet at Hiroshima and 8,500 feet at Nagasaki, while traditional wood houses were about the same, while reinforced-concrete structures suffered structural damage or collapse up to 700 feet at Hiroshima and 2,000 feet at Nagasaki.
In Hiroshima, approximately 60,000 to 70,000 people were killed, and 50,000 were injured. This is out of a pre-war population of about 340,000 that had been reduced to 245,000 through evacuations. Of approximately 90,000 buildings in the city, 65,000 were rendered unusable and almost all the remainder received at least light superficial damage.
In Nagasaki, approximately 40,000 persons were killed or missing and a like number injured. This was from a population of about 285,000, which had been reduced to around 230,000 by August 1945. Of the 52,000 residential buildings in Nagasaki, 14,000 were totally destroyed and a further 5,400 badly damaged. The vast majority of Nagasaki's industrial output was from the Mitsubishi factories and steel plant, which was 58 and 78 percent destroyed, respectively.
Unlike Hiroshima, Nagasaki featured extensive bomb shelters in the form of tunnels cut into the sides of hills. "...all the occupants back from the entrances survived, even in those tunnels almost directly under the explosion. Those not in a direct line with the entrance were uninjured. The tunnels had a capacity of roughly 100,000 persons. Had the proper alarm been sounded, and these tunnel shelters been filled to capacity, the loss of life in Nagasaki would have been substantially lower."
The report also concluded that: "Based on a detailed investigation of all the facts, and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated."