20th Century - Summary

Summary

The early arms races of the century escalated into a war which involved many powerful nations: World War I (1914–1918). Technological advancements changed the way war was fought, as new inventions such as machine guns, tanks, chemical weapons, grenades, and military aircraft modified tactics and strategy. After more than four years of trench warfare in western Europe, and 20 million dead, those powers who had formed the Triple Entente (France, Britain, and Russia, later replaced by the United States and joined by Italy) emerged victorious over the Central Powers (Germany, Austria-Hungary, and the Ottoman Empire). In addition to annexing much of the colonial possessions of the vanquished states, the Triple Entente exacted punitive restitution payments from their former foes, plunging Germany in particular into economic depression. The Tsarist regime of His Imperial Majesty Nicholas II was overthrown during the conflict and Russia was transitioned into the first ever communist state, and the Austro-Hungarian and Ottoman empires were dismantled at the war's conclusion.

At the beginning of the period, Britain was the world's most powerful nation; having acted as the world's policeman for the past century. Fascism, a movement which grew out of post-war angst and which accelerated during the Great Depression of the 1930s, gained momentum in Italy, Germany and Spain in the 1920s and 1930s, culminating in World War II (1939–1945), sparked by Nazi Germany's aggressive expansion at the expense of its neighbors. Meanwhile, Japan had rapidly transformed itself into a technologically advanced industrial power. Its military expansion into eastern Asia and the Pacific Ocean culminated in a surprise attack on the United States, bringing it into World War II. After having had several years of dramatic military success, Germany was defeated in 1945, having been repelled and invaded by the Soviet Union from the east and invaded from the west by the United States, the United Kingdom, Canada, and Free France. The war ended with the dropping of two atomic bombs on Japan. Japan later became a U.S. ally with a powerful economy based on consumer goods and trade. Germany was divided between the western powers and the Soviet Union; all areas recaptured by the Soviet Union (East Germany and eastward) were essentially transitioned into Soviet puppet states under communist rule. Meanwhile, western Europe was influenced by the American Marshall Plan and made a quick economic recovery, becoming major allies of the United States under capitalist economies and relatively democratic governments.

World War II left about 60 million people dead. When the conflict ended in 1945, the United States and the Soviet Union emerged as very powerful nations. Allies during the war, they soon became hostile to one other as the competing ideologies of communism and democratic capitalism occupied Europe, divided by the Iron Curtain and the Berlin Wall. The military alliances headed by these nations (NATO in North America and western Europe; the Warsaw Pact in eastern Europe) were prepared to wage total war with each other throughout the Cold War (1947–91). The period was marked by a new arms race, and nuclear weapons were produced in the tens of thousands, sufficient to end most human life on the planet had a large-scale nuclear exchange ever occurred. The very size of the nuclear arsenal on both sides is believed by many historians to have staved off an inevitable war between the two, as the consequences of any attack were too great to bear. The policy of unleashing a massive nuclear attack, knowing a massive nuclear counterattack would be forthcoming, was known as mutually assured destruction (MAD). Although the Soviet Union and the United States never directly entered military conflict with each other, several proxy wars, such as the Korean War (1950–1953) and the Vietnam War (1957–1975), were waged as the United States implemented its worldwide "containment" policy against communism.

After World War II, most of the European-colonized world in Africa and Asia gained independence in a process of decolonization. This, and the drain of the two world wars, caused Europe to lose much of its long-held power. Meanwhile, the wars empowered several nations, including the UK, U.S., Russia, China and Japan, to exert a strong influence over many world affairs. American culture spread around the world with the advent of Hollywood, Broadway, rock and roll, pop music, fast food, big-box stores, and the hip-hop lifestyle. British culture continued to influence world culture, including the "British Invasion" into American music, leading many top rock bands (such as Swedish ABBA) to sing in English. The western world and parts of Asia enjoyed a post-World War II economic boom. After the Soviet Union collapsed under internal pressure in 1991, the communist governments of the Eastern bloc were also dismantled, followed by rocky transitions into market economies.

Following World War II the United Nations was established as an international forum in which the world's nations could get together and discuss issues diplomatically. It has enacted resolutions on such topics as the conduct of warfare, environmental protection, international sovereignty, and human rights. Peacekeeping forces consisting of troops provided by various countries, in concert with various United Nations and other aid agencies, have helped to relieve famine, disease, and poverty, and to suppress some local armed conflicts. Europe slowly united, economically and, in some ways, politically, into what eventually became the European Union, which consisted of 15 European countries by the end of the century.

In approximately the last third of the century, concern about humankind's impact on the Earth's environment caused environmentalism to become a major citizen movement. In many countries, especially in Europe, the movement was channeled into politics partly through Green parties, though awareness of the problem permeated societies. By the end of the century, some progress had been made in cleaning up the environment though pollution continued apace. Increasing awareness of global warming began in the 1980s, commencing several decades of social and political debate.

Medical science and the Green Revolution in agriculture enabled the world's population to grow from about 1.6 billion to about 6.0 billion. This rapid population increase quickly became a major concern and directly caused or contributed to several global issues, including conflict, poverty, major environmental issues, and severe overcrowding in some areas.