Manpower
Over 140 million men and women were mobilized to fight in the Second World War. The Soviet Union was the power that mobilized the largest number of soldiers and was able to draw upon its massive population to defend against the German invasion in 1941. However, it was the Axis powers who mobilized the largest share of their populations, with Germany and Italy mobilizing over 40 percent of their male populations. The major powers used various conscription systems to draft men into their armies, on top of the already-high volunteer rates. Colonial powers were also able to draft men from overseas to bolster their armed forces - the British Empire made particular use of its Commonwealth forces in the Mediterranean theater while its domestic forces dealt with German aggression in Europe, and pulled from its Asian territories to defend against Japan after 1941.The Axis powers were able to offset the loss of men in their workforce using forced labor or by drafting workers from other countries. The Allied powers did, however, have higher participation rates for women in the workforce, in order to meet the production demands of the war effort - Axis leadership was reluctant to make this change until later in the war. Women also made up a large part of military personnel serving in medical, logistical, and administrative roles, while others, depending on the country, even served on the frontlines. In the Soviet army alone, up to 800,000 women served in a military capacity, with those serving in combat disproportionately employed as snipers and artillery operators.
Natural resources
To feed and supply their vast armies, the major powers of the Second World War often had to look beyond their own borders for resources. This was not only because domestic output could not meet the demands of the war effort, but also because some fuels or metals were not available at home. Major economies prioritized military manufacturing, and therefore depended on agricultural imports to maintain industrial output. For example, German demands for agricultural imports from Eastern Europe’s Axis powers were so high that it delayed their industrial development, and allowed German manufacturing to proceed. More severe examples include the British Army’s diversion of manpower and food supplies from the Indian subcontinent to the frontlines, which exacerbated food shortages and contributed to the two million deaths during the Bengali famine of 1943. The destruction of food sources could also be used tactically as a weapon against invading forces, such as the scorched earth policies used by retreating Soviet forces, or the flooding of the Yellow River by Chinese defenders.Gaining or preventing access to these materials was often the driving factor behind political alliances throughout the war, as well as dictating which regions would be invaded or targeted. At this point in history, three of the most important resources for waging war were coal, to fuel production; iron, for making steel and manufacturing; and petroleum, to fuel transport and combat vehicles, ships, or aircraft. Even before the war, both Japan and Germany had militarily seized control of the coal- and iron-rich regions of Manchuria (China) and the Rhineland Palatinate (League of Nations mandate) respectively, and the German invasions of territories in Poland, Czechoslovakia, France, and the low countries at the onset of WWII granted further access to these resources. Sweden’s rich iron ore deposits in the north allowed it to maintain neutrality throughout the war, and the German war effort relied heavily on Swedish iron, however, this did have repercussions for Sweden’s neighbors, as Germany’s invasions of both Denmark and Norway were largely in order to protect this supply and facilitate its transport.
Access to oil, however, was more difficult. In the late 1930s, Japan was dependent on the U.S. to meet roughly 80 percent of its oil demands, and when the U.S ceased these exports in 1941, Japan launched its invasion of Southeast Asia (including the attack on Pearl Harbor) in an attempt to secure the oil-rich region of the Dutch East Indies (Indonesia). Japan then had to create a shipbuilding program to transport this oil to both the home front and various frontlines, but U.S. submarine attacks meant that Japanese tankers were sunk at a faster pace than they could be produced, ultimately stalling Japan’s war effort. The pursuit of oil also became a key objective for the European Axis powers. As Operation Barbarossa stalled and became a war of attrition, Germany pushed south to the Caucus oil fields to replenish its dwindling petroleum supplies – the operation was initially a success, although it was broadened to include the city of Stalingrad, the battle for which was the bloodiest in human history and would ultimately become the turning point in the European theater.
Production
While the Axis powers may have made some intermittent gains after the Allies began their counteroffensives in 1942, they could not reinforce these positions or sustain military offensives as their production lines had fallen so far behind the Allies, particularly the United States. The U.S. had emerged as the world’s foremost economic power after the Great Depression, and became the world leader in weapons, ammunition, and vehicle production as the war progressed. Alongside imported food and metals from its partners in the Americas, the U.S. was also able to utilize its vast natural resources to supply equipment to its own army, as well as other Allied armies, with Britain and the Soviet Union receiving the largest share of U.S. Lend-Lease exports. The difference in production grew starker as the war progressed, and the Allied offensive capabilities grew as the Axis defensive capabilities weakened. Strategic air raids against the major industrial centers in Germany and Japan intensified in the war’s latter stages, contributing to the Axis defeat. By the war's end, U.S. gross domestic product was larger than those of the UK, USSR, Japan, Germany, France, and Italy combined, and the United States continued to supply its Allies (including the defeated Axis powers) with material and financial aid, which would eventually contribute to the post-WWII economic boom.
