The Short Term Cause: World War 1

The First World War provided the catalyst for Russia’s revolutionary year of 1917. The war itself went badly from the start, prompting the Tsar to take personal charge in 1915, a decision which placed the full responsibility for the next years of failure on his shoulders. As demand for ever more soldiers increased, the peasant population grew angry as young men and horses, both essential for the war, were taken away, reducing the amount they could grow and damaging their standard of living.

Russia’s most successful farms suddenly found their labour and material removed for the war, and the less successful peasants became ever more concerned with self-sufficiency, and even less concerned with selling a surplus, than ever before.
Inflation occurred and prices rose, so hunger became endemic. In the cities, workers found themselves unable to afford the high prices, and any attempt to agitate for better wages, usually in the form of strikes, saw them branded as disloyal to Russia, disaffecting them further. The transport system ground to a halt due to failures and poor management, halting the movement of military supplies and food. Meanwhile soldiers on leave explained how poorly supplied the army was, and bought first hand accounts of the failure at the front. These soldiers, and the high command who had previously supported the Tsar, now believed he had failed them.
The Russian Revolution in more depth