War and Refugees in the 20th Century: History of War Refugees Series (5)

The 20th century witnessed refugee movements on an unprecedented scale. While war had caused forced migrations in earlier periods, the industrialization of conflict, emergence of totalitarian ideologies, and global reach of two world wars elevated the scope and brutality of displacement. Refugees in the 20th century not only fled battlefields but also genocide, revolution, ideological purges, and partition. The collapse of empires, rise of nationalism, and the Cold War all shaped the creation, management, and international response to refugee populations. By century’s end, the modern international refugee system—codified by the 1951 Refugee Convention—was forged in response to the staggering displacement crises of this era.

World War I and the Fall of Empires

The First World War (1914–1918) marked the first global conflict of the modern age, involving over 30 nations and resulting in more than 9 million soldiers' deaths and millions more civilian casualties. Alongside this devastation, the war displaced more than 10 million people across Europe and the Middle East.

One of the largest refugee crises during this period occurred on the Eastern Front. The Russian Empire’s “scorched earth” policy led to the forced relocation of over 500,000 Jews, Poles, and ethnic Germans, accused of being security threats. Many were expelled from the Pale of Settlement and border regions into the Russian interior (Gatrell 2013). Ethnic Armenians, too, faced annihilation: the Ottoman Empire, amid wartime paranoia and nationalism, carried out the Armenian Genocide in 1915, leading to the deaths of 1.5 million and the displacement of hundreds of thousands into Syria, Lebanon, and the Caucasus (Suny 2015).

Following the war, the collapse of the Ottoman, Austro-Hungarian, Russian, and German empires created ethnic minorities trapped in new national borders, sparking fresh migrations. The Greco-Turkish War (1919–1922), in particular, culminated in the forced population exchange of over 1.5 million Greeks and 500,000 Muslims under the 1923 Lausanne Convention—a legal precedent for compulsory resettlement (Hirschon 2003).

World War II and the Largest Displacement in Human History

World War II (1939–1945) remains the most catastrophic conflict in human history, claiming over 70 million lives. It also triggered the largest refugee crisis ever recorded, displacing more than 60 million people.

The Holocaust and Stateless Refugees

Central to this catastrophe was the Holocaust—the Nazi regime’s systematic extermination of 6 million Jews, along with Roma, disabled individuals, Slavs, and others deemed “undesirable.” In the years preceding the war, thousands of Jews sought asylum from Germany, Austria, and occupied Czechoslovakia. However, most countries—including the United States and Britain—maintained restrictive immigration quotas. The infamous failure of the S.S. St. Louis in 1939, which was denied entry by multiple countries and forced to return to Europe, symbolizes the international community’s failure to protect stateless Jewish refugees (Wyman 1984).

By war’s end, over 11 million people were classified as “displaced persons” (DPs) by the Allied powers. These included Holocaust survivors, Eastern Europeans fleeing Soviet occupation, and former forced laborers brought to Germany by the Nazi regime. Many languished in DP camps well into the 1950s. The United Nations Relief and Rehabilitation Administration (UNRRA), established in 1943, became a prototype for future international humanitarian agencies (Cohen 2012).

Eastern Europe and Soviet Expulsions

The redrawing of borders after WWII also initiated mass ethnic expulsions. Between 12 and 14 million ethnic Germans were expelled from Poland, Czechoslovakia, Hungary, and other countries newly “liberated” by the Soviets. These population transfers, often sanctioned by Allied agreements such as the Potsdam Conference, resulted in hundreds of thousands of deaths and widespread suffering (Douglas 2012).

Similarly, the Baltic states, Ukraine, and parts of the Caucasus saw mass deportations under Stalin’s regime. Hundreds of thousands of Chechens, Crimean Tatars, and Volga Germans were forcibly relocated to Central Asia under accusations of collaboration with the Nazis, in an ethnic cleansing campaign masquerading as national security (Applebaum 2003).

Decolonization and Partition: Asia, Africa, and the Middle East

While the world wars triggered mass displacement in Europe, decolonization during the mid-20th century transformed refugee dynamics in Asia and Africa. As European empires crumbled, new states emerged—often amidst violence, civil war, and population dislocation.

Partition of India (1947)

The 1947 partition of British India into India and Pakistan generated one of the largest and bloodiest refugee crises in modern history. Amidst communal violence between Hindus, Muslims, and Sikhs, over 14 million people crossed borders to reach a religious “homeland,” while an estimated one million were killed (Kaur 2007). Trains of refugees were attacked, women abducted, and villages destroyed in one of the most traumatic mass migrations of the 20th century.

Palestinian Nakba (1948)

The creation of the state of Israel in 1948 following the Arab-Israeli War led to the displacement of over 700,000 Palestinians, who fled or were expelled from their homes during and after the conflict. Known in Arabic as the Nakba (“catastrophe”), this event remains a core issue in the ongoing Israeli–Palestinian conflict. Refugees were placed in camps in Gaza, the West Bank, Lebanon, Syria, and Jordan—many of which still exist today (Khalidi 1992).

Korean War (1950–1953)

Following World War II, Korea—liberated from Japanese rule—was divided into U.S. and Soviet occupation zones, culminating in the Korean War in 1950. The war displaced more than 10 million people, with civilians fleeing bombardments, executions, and shifting frontlines. Many never returned to their homes, and family separation continues to this day. South Korea absorbed over 1.5 million North Korean refugees, and internal displacements persisted throughout the conflict (Cumings 2005).

Cold War Conflicts and Ideological Displacement

The Cold War (1947–1991) polarized the world into capitalist and communist blocs. Proxy wars, revolutions, and authoritarian crackdowns led to the displacement of millions.

Vietnam War and Southeast Asia

The Vietnam War and subsequent communist victories in Laos and Cambodia triggered a massive exodus from Indochina. After the fall of Saigon in 1975, over 1.6 million refugees fled Vietnam, Cambodia, and Laos, seeking asylum in the U.S., France, Australia, and across Asia.

The “boat people” crisis gained international attention as thousands perished at sea due to overcrowding, piracy, and dehydration. Refugee camps in Thailand, Malaysia, and Hong Kong became temporary homes before third-country resettlement under coordinated Western programs (Robinson 1998).

In Cambodia, the Khmer Rouge regime (1975–1979) under Pol Pot unleashed genocide that killed nearly two million people. Survivors fled to Thailand and Vietnam, living in squalid border camps for years (Chandler 1991).

Afghan Wars (1979–2001)

The 1979 Soviet invasion of Afghanistan inaugurated decades of war that would make Afghans one of the largest and longest-standing refugee populations. Over 6 million fled to Pakistan and Iran during the 1980s. Following the Soviet withdrawal, civil war, Taliban rule, and the post-9/11 U.S. invasion created additional waves of displacement (Edwards 2015).

Genocide and Ethnic Cleansing

The 20th century bore witness to repeated genocides and ethnic cleansings that generated enduring refugee crises.

Rwandan Genocide (1994)

In just 100 days in 1994, extremist Hutu militias in Rwanda killed over 800,000 Tutsis and moderate Hutus. The violence prompted more than 2 million refugees to flee to Zaire (now DRC), Tanzania, and Burundi. Refugee camps themselves became militarized and were later targeted by cross-border interventions, especially during the First Congo War (Prunier 1995).

Yugoslav Wars (1991–1999)

The collapse of socialist Yugoslavia in the early 1990s unleashed a series of ethnonationalist wars in Croatia, Bosnia, and Kosovo. The Bosnian War (1992–1995) was marked by ethnic cleansing, especially by Serb forces, and the siege of Sarajevo. Over 2.2 million people were displaced, and hundreds of thousands were killed or raped (Silber and Little 1996).

In Kosovo (1999), Serbian repression of Albanians triggered NATO intervention and the displacement of nearly 850,000 Kosovar Albanians. Ethnic Serbs later fled retaliatory violence, adding to the region’s cycle of displacement.

The Birth of International Refugee Law

The immense refugee movements following World War II led to the formalization of international refugee law. The 1951 Convention Relating to the Status of Refugees and its 1967 Protocol established the legal definition of a refugee and codified the principle of non-refoulement—the obligation not to return refugees to countries where they face danger.

UNHCR, the United Nations High Commissioner for Refugees, was established in 1950 to coordinate protection and assistance. Initially created for postwar Europe, its mandate quickly expanded globally as Cold War and decolonization crises unfolded.

Conclusion

The 20th century redefined the scale, causes, and international response to refugee crises. No longer a phenomenon confined to specific regions, displacement became global, shaped by ideology, ethnic nationalism, genocide, and post-colonial realignment. Refugees became central figures in international law, diplomacy, and humanitarianism.

While many of the root causes remain—ethnic tension, political violence, state collapse—the century also saw new mechanisms of protection emerge. Yet the persistence of refugee crises into the 21st century signals the enduring challenge of securing safe haven in a world where borders, politics, and fear too often prevail over compassion and justice.

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