Why did World War I make warfare more deadly than earlier wars?

World War I became significantly more deadly than earlier conflicts due to the convergence of rapid technological advancement and the emergence of "total war."

Technological Advancements

The Industrial Revolution transformed weaponry, leading to unprecedented lethality. The widespread use of machine guns turned open terrain into "killing zones," while improvements in artillery—including recoil mechanisms and high-explosive shells—allowed for massive, sustained bombardments that caused the majority of casualties. Combatants also introduced chemical weapons, tanks, and military aircraft, further increasing the destructive capacity of modern armies.1234

The Nature of Total War

World War I was a "total war," meaning entire societies were mobilized to sustain the conflict. Because nations utilized their full industrial and bureaucratic resources, they could maintain continuous, large-scale trench warfare for years rather than days. This stalemate, combined with the belief that only total victory could justify the immense suffering, led to a war of attrition where millions of soldiers were fed into a cycle of indiscriminate slaughter, resulting in over 8.5 million military deaths.523