By 1916 the Great War was being waged by the most advanced industrial nations on the planet—who were becoming increasingly desperate as their casualties soared. Research and production resources were hijacked by the urgent need to provide better weapons and more ammunition, and all of the other military supplies needed by the vast armies.
Some numbers tell the tale of how economies and societies were shifted over to a war footing: German production of explosives rose from 14,400 tons to 518,400 tons between 1914 and 1918. Manufacture of machine guns in the five original major belligerants rose from 4,307 a year to 649,216 a year during the war. In France between 1915 and 1918 the munitions workforce increased from 50,000 to 1,700,000—420,000 of whom were women, as 44 percent of the male population had been called for military service.
The United States was technically neutral, but was deeply involved in the world economy, supplying the belligerent nations themselves (mostly on the Allied side) with weapons, food and supplies. Even activities that do not seem at first glance to be military in nature were tied to war work: The U.S. Bureau of Mines leased uranium oxide mines in Colorado to produce radioactive sources for x-ray machines—very useful for finding bullets and shell fragments in the bodies of wounded soldiers.
Here is a brief tour through the year 1916. There are many more images in the Scientific American Archive at ScientificAmerican.com/magazine/sa
[Sources for statistics: Ioannis-Dionysios Salavrakos in International Journal of History and Philosophical Research, Vol.2, No. 1., March 2014 (explosives); “Race to the Front,” by Kevin D. Stubbs (machine guns); encyclopedia.1914-1918-online.net/article/france (munitions workforce).]