The Bombing War: Europe 1939–1945

by Richard Overy

  Part Three

  ‘THE GREATEST MISCALCULATION’?

  10

  The Balance Sheet of Bombing

  Reflecting on his time as an economist mobilized to help prepare the United States Strategic Bombing Survey in 1945, J. K. Galbraith explained how shocked he and his colleagues were to discover that the German economy had not suffered the severe damage the whole world had been led to expect. Instead, the raw German statistics showed that war output grew dramatically under the pressure of Germany’s many military commitments, even while the bombing became heavier and more damaging. The economists were forced to conclude, as Galbraith later wrote, that ‘strategic bombing had not won the war’. On the most favourable account it had simply eased the path of the ground troops who did. ‘We were beginning to see that we were encountering,’ he wrote in his memoirs, ‘one of the greatest, perhaps the greatest miscalculation of the war.’1

  Whatever the merits of Galbraith’s judgement, the bombing offensives in the Second World War were all relative failures in their own terms. Before 1939, bombing wars were popularly expected to be short and sharp and probably decisive. The major offensives conducted by Germany, Britain and the United States were instead long drawn-out affairs, wars of attrition with high losses of men and machines, with no clear-cut end and a wide gap between ambition and outcome, a Western Front of the air. The more minor operations conducted by the German Air Force in the Soviet Union or the Italian Air Force in the Mediterranean were poorly resourced and ineffective. Little of this had been predicted. The bomber offensives were regarded as unique expressions of the changing form of war, thought to be more appropriate for an age of mass politics and scientific modernity, in which whole societies were mobilized to fight each other using cutting-edge technology to do so. ‘The advent of air power,’ wrote one American airman after the war, ‘created total war. Prior to air power, opportunities for destruction of another nation’s total strength were limited almost entirely to the destruction of the armed forces.’2 That is why the history of the bombing war is not only about the strategic planning and operational reality of the campaigns, but also about the response of the societies subjected to attack, whose resilience helped to prolong and intensify the campaigns and fostered the cruel materialization of the ‘total war’ metaphors of the interwar years.

  All of the bombing offensives share some generic characteristics. In the first place, despite all the thinking that had gone into the air war of the future, they were all ‘accidental’ campaigns. None of the three major offensives had been fully anticipated or prepared for. The German bombing of Britain came about by chance after the German victory over the Western Allies in summer 1940 and the failure to stifle RAF defensive power in the Battle of Britain. The British bombing of Germany had been thought about more carefully before 1939, but little hard preparation had gone with the thinking either in terms of the necessary technical and scientific support needed or the strategic aims worth pursuing when an offensive was unexpectedly permitted in May 1940 during the Battle of France. At the end of the war, in an atmosphere of greater critical awareness of the drawbacks of the bombing campaign, John Slessor defended the record of Bomber Command with the argument that no one before the war knew what a bomber offensive really entailed:

  We certainly grossly underestimated the time it would take to build up our air power. But … in 1939 we embarked on the first Air War. The only previous war of any size in which aircraft played any part provided us with no previous experience worth having at all and we had no opportunity even of full-scale trials in peace time. Looking back now on our abysmal ignorance in 1939 of the potentialities of air warfare, what amazes me is, not that we made a lot of mistakes, but that we didn’t make far more.3

  The United States air campaign in Europe was also quite unanticipated, even if air force leaders had spent time in the 1930s thinking about what a future air war might entail. No American in 1939 had expected to be dropping bombs on Germany and Italy in four years’ time. When war suddenly became a probability, plans were hastily drawn up in late summer 1941, but the reality of forging an air weapon from the ground up meant that the American bombing campaign took frustrating years to realize its potential. This was very different from preparation for war in the Cold War era, with defined enemies and a technology that could be mobilized and lethally deployed in a matter of minutes.

  The accidental nature of the campaigns explains much about their limited achievements. Each of the major offensives had muddled strategies precisely because so little was known about what effect large-scale bombing was really having on an enemy economy or on enemy war-willingness. Bombing results, wrote the British scientist Patrick Blackett in 1942, were largely ‘a matter of speculation’.4 Hard information for either side was generally lacking. This made it difficult in all cases properly to relate means and ends. The German offensive hovered between trying to gain air superiority against the RAF, preparation for invasion, contributing to the blockade by sea of British trade, degrading Britain’s industrial war potential and vague expectations of a crisis afflicting the enemy’s morale. In an interrogation at Nuremberg in 1946, while his post-war trial was in progress, Göring told his interviewer that thanks to Hitler’s style of decision-making he never knew ‘what would be undertaken, or what would be left alone’. As a result, he continued, ‘I could never concentrate my energy on any one particular plan, and that was a decided disadvantage.’5 The last German Air Force chief of staff, Karl Koller, who had been Sperrle’s operations chief throughout the Blitz, blamed the failure of the campaign on the fact that ‘the actual pattern of attacks on British targets was never consistent and fluctuated from one system to another’.6 The British offensive also suffered from a failure to define its purpose clearly and from the multitude of different tasks expected of it. The many directives issued during the war show the extent to which Bomber Command was treated as a kind of fire service, summoned for every emergency. In the same post-war evaluation, Slessor confessed that thanks to ‘every sort and kind of inroad’ on bombing resources, ‘we never had a consistent policy of how we [the air force] proposed to win the war’.7 The American bombing effort was similarly divided between different theatres and different strategic objectives. Only in 1944, with the focus on establishing and retaining air superiority, was a strategy found that finally promised decisive results.

  The air force view during the conflict was, of course, more positive, prompted as it was by service self-interest. All the air commanders in Europe wanted to be able to demonstrate that air power from its inception possessed unique qualities that needed to be exploited for their own sake, not at the behest of armies or navies. Since air forces consumed around 40 per cent of the direct budget for the armed forces, and recruited highly trained and expensive personnel, they were under considerable pressure to demonstrate that they were value for money. Portal was delighted to learn in 1944 that a single Lancaster allegedly eliminated more German man-hours on its first sortie than the number of British man-hours needed to build it (‘the results of all subsequent sorties,’ ran the report, ‘will be clear profit’).8 Bomber offensives were certainly sustained, despite the absence of clear evidence of their effect, because air force leaders wanted air power to rival or even to supersede the achievements of armies and navies. Hence the claim made by Harris in March 1945 that it was Bomber Command that had won the ‘Battle of the Ruhr’ long before the arrival of Montgomery’s 21st Army Group. Karl Koller, asked to reflect in captivity on the achievements of air power, gave an airman’s answer: ‘If someone denies today that even in spite of the heroic efforts of the Armies and Navies the wars in Europe and the Pacific were decided only by the Air Force, then he is either malevolent or stupid.’9 Most airmen who favoured independent bombing as a strategy assumed that much more would be achieved if only the army or the navy would let them get on with the job. Air Vice Marshal Saundby, Harris’s deputy at Bomber Command, called D-Day ‘an unnecessary “boating expedition�
� ’, and thought the war would be won more quickly by the strategic bombing of towns than by supporting invasion.10 The strategic confusion surrounding bombing campaigns owed a great deal to the fact that armies and navies (and a substantial number of air force commanders) looked at air force support for surface operations as a key element in the conduct of the war, whereas other air force leaders believed their identity and future military-political influence depended on the pursuit of a clearly defined independent air strategy. The extent of enthusiasm for bombing strategy reflected these different service cultures as well as the political balance between the three services.

  Air forces hoped to dress up their wartime credentials by exploiting vanguard technologies that made air power distinct from land power and made heavy demands of industrial and scientific resources which it would be difficult to reverse. Bombing aircraft were large and complex pieces of engineering, requiring an extensive technical commitment and a large servicing apparatus once in combat. The development of the American B-29 ‘Superfortress’ cost more than the Manhattan Project for the development of the atomic bomb. The navigation and aiming technologies demanded sophisticated scientific support and a burgeoning scientific intelligence establishment. Operational research became increasingly complex and science-based in the effort to find optimum ways of getting the bomber’s payload onto a precise target or a defined area. A report produced in February 1945 by the British Air Warfare Analysis Section, ‘On a Problem in Maximising the Expectation of Damage to a Target’, showed that with ‘N’ bombs dropped with modulus ‘h’ the outcome would be ‘H = (1−qn)ραρ’.11 Harris suggested that the reports distributed to him and others by the operational research agencies ought if possible to be expressed in a language they could all understand, though even he came to appreciate the extent to which the bomber offensive relied on scientific input.12

  Yet for all the scientific sophistication, long-range bombing in the Second World War was a crude strategy. It was designed to carry large quantities of explosive and incendiary chemical weapons from point A to point B and to drop them, usually from a considerable height and without much accuracy, on the ground below. Artillery remained far more accurate and more destructive, as was short-range dive-bombing. (The exception here was anti-aircraft artillery, which expended millions of shells over the course of the war, most of which, even with improved radar guidance, failed to disable an aircraft.) Without so-called ‘smart’ weapons, strategic bombing was a wasteful use of resources, since most bombs did not hit the intended target, even when that target was the size of a city centre. The sheer weight of bombs or acres burnt out became by default the only practical ways to measure what was being achieved. The obsession with the quantity of ‘bomb-lift’ displayed by Allied air forces was a reflection of the extent to which weight or scale was the driving force of the campaign, when the key variable was evidently accurate and effective destruction of a particular target. The German development of guided bombs and ground-to-air missiles, incomplete though it was, would prove to be the way forward.13 By contrast the American Air Force boasted by autumn 1944, after the one-millionth ton had been dropped, that three tons of bombs were falling every minute on Axis targets.14 As late as April 1945, when it was possible to bomb by day as well, the British Air Ministry argued that because accuracy was still compromised by the weather and uncertain navigation, area attacks had to be maintained with ‘maximum continuity and weight of attack’ on the implausible claim that even heavier raids might still shorten the war.15 Instead of smarter weapons, the Western Allies focused vanguard research on nuclear development, which promised nothing but infinitely larger areas of destruction and levels of casualty. This paradox of a strategy that required advanced technology to achieve a blunt end was epitomized by the firebombing of Japanese cities begun in March 1945 and the dropping of the two atomic bombs, on Hiroshima and Nagasaki, in August.

  The strategic bombing offensives were expected to yield three kinds of dividend: dislocation and destruction of the enemy war economy; progressive demoralization of the enemy population subjected to bombing; and specific political ends related to the current war situation. The first of these strategic objectives was shared by all three major bombing offensives, and it lay behind the plans of the German Air Force in Russia in 1943 to bomb Soviet industry in order to try to reduce the pressure on the embattled ground forces. Nothing of the previous experience of bombing suggested that an economy was a potentially fruitful target. Modern industrial economies were indeed large and inert objectives, with substantial flexibility and a large cushion of industrial capacity and labour to absorb temporary damage, even of a severe nature, as was evident in both the British and German case, and would almost certainly have been the result in the Soviet Union if the German Air Force had been able to carry out a serious campaign against Soviet industry. The answer, it was generally recognized, was to try to isolate some particular element vulnerable to destruction and likely to have a multiplier effect in undermining the rest of the structure. In October 1939 the British economist John Jewkes wrote a paper for the Ministry of Economic Warfare exploring the possibility of doing just that. ‘Every economic system,’ he wrote, ‘has a series of “weak links” or “bottle necks”. If they can be identified and destroyed,’ he wrote, ‘the whole system may be thrown out of proportion and a partial collapse induced.’ He identified power supply, transport, chemicals and synthetic materials as the principal targets, because in this case bomb destruction would cause ‘the greatest disproportionality in the enemy’s industrial system’.16

  All three air forces tried to work out just what would cause this level of disruption, yet evaluation depended not only on what was operationally possible (which limited the choice substantially for much of the war), but on selecting target systems that were likely to have a severe impact on an integrated economic structure, and to try to hit them repeatedly. The German Air Force chose trade and food blockade and the British aero-engine industry. The latter represented a classic example of an industry with substantial ‘cushion’, while trade was an amorphous target. The German view, which Koller explained after the war, had been to attack London heavily because it was thought to handle a high proportion of British seaborne traffic: ‘the destruction of its dock areas would place an insuperable burden on other ports’.17 The bombing of British ports certainly had the effect of causing high levels of casualty, but it had a very limited effect on trade and stocks, which could be shifted to other coastal towns, or unloaded and stored in more improvised ways in the bombed docks. The submarine campaign and long-range air attacks at sea promised more. The British offensive focused first on the ‘Ruhr’, another amorphous target, then oil and communications, but it finally abandoned the limited effort given the problems of range and accuracy and opted for destroying working-class homes, services and lives on the assumption that at a certain but unspecified level of death and destruction an industrial economy would cease to function effectively. In November 1942 Lord Cherwell informed Churchill that by the end of 1944 he thought one-third of Germany’s urban population would be homeless and every house in the main cities damaged or destroyed, but little effort was made to relate these grim statistics to the capacity of the German war economy to continue to function or to assess the actual effect on the German armed forces, and indeed no attempt was made during the war to estimate either.18 Both the German and the British offensives were persisted with because over-optimistic intelligence suggested that much more damage was being done to the enemy economy than was in fact the case. Accurate assessments of economic loss were almost impossible to construct.

  The American approach to bombing as economic warfare was the only one to take seriously the idea of describing and quantifying the likely bottleneck sectors of the German war economy, and to bring in qualified economists and businessmen to contribute to the planning. But even here it took time before it was realized that industries with substantial ‘cushion’ were much less vulnerable than they seemed.
The aircraft industry, which was the primary economic target, adjusted in weeks to the threat and increased output by 50 per cent in the months that followed.19 The danger here, as one economist pointed out in 1945, was that the concentration on vulnerable points ‘renders the success of the air offensive as a whole more hazardous – in much the same way as the gambler assumes a great risk of failure by playing for high stakes’. If the calculation on vulnerability proves to be inadequate, ‘the results of the attacks may turn out not to be disproportionally high, but disproportionally low’.20 This was true for much of the American air effort against Germany and Italy, until two target systems were selected that met the economic criteria. Oil was a concentrated product, for which it was difficult to find compensatory production or ‘cushion’, while transport was a general target system that promised immediate and direct effects on a wide variety of military and economic operations. For the last nine months of the war, targets for daylight bombing were chosen which had an immediate and obvious impact on the German war effort. Even then they had to be attacked heavily and often, since the natural response to any crisis induced by bombing was to find ways to reduce its critical impact. When Field Marshal Kesselring was interviewed after the war by Solly Zuckerman about the Transportation Plan for Italy that Zuckerman had helped to draft, Kesselring claimed that the effectiveness of the attack on communications, thanks to countermeasures, ‘had not been the success the Allies had thought it to be’.21 Zuckerman was so keen to prove the value of transport as a target that in 1974 he went to visit Albert Speer after he had been released from prison to get further corroboration, but Speer too proved unhelpful, critical instead of the Allied failure to attack chemicals or the aero-engine industry.22