What role did World War I play in causing the February Revolution?

The February Revolution took place in Petrograd (today's St. Petersburg), then the Russian capital, in 1917. For one week, demonstrators rioted in reaction to food shortages, and the Russian police attempted to quell their uprising. The demonstrators were joined by 90,000 striking workers. In the end, the Russian army decided to revolt against the tsar, Nicholas II, and join the rioters, leading to the abdication of the tsar and the end of the Russian monarchy. 

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The February Revolution took place in Petrograd (today's St. Petersburg), then the Russian capital, in 1917. For one week, demonstrators rioted in reaction to food shortages, and the Russian police attempted to quell their uprising. The demonstrators were joined by 90,000 striking workers. In the end, the Russian army decided to revolt against the tsar, Nicholas II, and join the rioters, leading to the abdication of the tsar and the end of the Russian monarchy. 

World War I played a large role in the uprising, as the war had long fallen out of favor. While Russians largely supported the war when it broke out in 1914, the Russian army had begun to suffer defeats and were very badly equipped. By 1917, about six million Russians casualties had resulted from the war. In addition, the Russian home front was in a disastrous state, as the railroads were being used to serve the war effort, meaning that people could not get enough food and other goods. People were facing widespread poverty and famine. In addition, the Russian economy was hobbled because Russian goods could not reach European markets. As a result of these problems, people had simply lost faith in the ability of the tsar to govern. The lower house of Parliament, the Duma, asked the tsar to establish a constitutional government, but he refused and was eventually deposed, leading to the establishment of a provisional government under Prince Georgy Lvov.