World War 1 was one of the largest and deadliest wars in human history, lasting from 1914 to 1918 and directly killing an estimated 22 million people. But which year was the bloodiest?
It is difficult to definitively say which year was the bloodiest in World War 1 as it depends on whether one considers direct casualties only or indirect casualties too. 1916 was an extremely violent year, but 1918 was more deadly when considering the Spanish flu.
Read on to find out more about the deadliest years of World War 1 and the reasons why.
Starting in 1914, the first two years of World War 1 were marked by a stalemate on the Western Front, the use of new weapons like poison gas, desperate fighting, and offensives in the Balkans and along the Eastern Front.
It also notably featured the search for a break in Gallipoli to assist the Russians in 1915, rapid Japanese advances against German possessions in East Asia, and conflict between the European colonies in Africa.
As technology developed and warfare changed, the war became deadlier and more desperate as the powers sought an overwhelming victory to overcome the stalemate and put an end to the war. The war had turned into one of attrition, where the Central Powers and Triple Entente fought against each other to slowly sap the other’s forces.
This is best evidenced by the German offensive at the Battle of Verdun, where the German high command had decided their best chance of winning the war was to bleed France dry by forcing it to use as many soldiers as possible to defend a tactically and culturally important location. The battle lasted from February 21 to December 18, 1916, and resulted in around 750,000 casualties and 300,000 deaths.
The pressure on the French at Verdun prompted both the Russians and the British to launch major offensives on German positions to try to relieve their allies. On June 4, 1916, the Russians launched one of their largest offensives in the war and one of the deadliest in history: the Brusilov Offensive.
In this offensive, the Russians launched a colossal assault on the Austro-Hungarian Empire, from which the Austro-Hungarians never recovered, and German troops had to be pulled away from the Western Front to provide support. By September 1916, it had resulted in some 2.5 million casualties.
Meanwhile, on the Western Front, the British and the French launched the Battle of the Somme on July 1, 1916, with the aim of taking pressure off the French at Verdun and breaking through the German lines. Despite the colossal British artillery barrage, German defenses were largely unaffected and able to repel the British attack on the first day, leading to the deadliest day in British military history with around 60,000 casualties.
By the end of the battle on November 18, 1916, there had been around 1 million casualties with limited Allied advances.
Also in 1916, Romania entered the war to fight against the Central Powers, British assaults against the Ottoman Empire in the Middle East continued, the Easter Rising took place in Ireland, fighting between the Italians and Austro-Hungarians intensified during the Trentino Offensive, the British won the naval Battle of Jutland, and Ottoman genocide continued against the Armenians, Assyrians, and Greeks.
1917 saw the United States and Greece enter the war, as well as the Russian Revolution, continued fighting on the Western Front, the Austro-Hungarian victory against the Italians at the Battle of Caporetto, and British and Arabic advances against the Ottoman Empire.
In 1918, with German and Austro-Hungarian troops freed up on the Eastern Front and American soldiers joining the Western Front, the war looked to escalate and the Germans launched their Spring Offensive on March 21, 1918, to try to defeat the Allies before the full mobilization of the Americans. This led to around 1.5 million casualties by the time it ended on July 18, 1918.
On August 8, 1918, the Allies launched their counter-offensive against the Germans during the Hundred Days Offensive, which led to an Allied breakthrough and the official end of World War 1 on November 11, 1918, resulting in around 2 million casualties.
Following the end of World War 1, the drawing of new boundaries and the rise of a communist power led to further conflicts in much of Europe and Asia.
Meanwhile, the Spanish flu began to spread around the world in 1918, killing around 50 million to 100 million people or 5% of the global population. The rise of this pandemic made 1918 the deadliest year of the war by far, although 1916 still had major conflicts and it is difficult to know the deadliest due to controversy over records.