ViewpointsOpinionFresh Water: The World’s No. 1 Environmental ChallengeSavePrintThe Carlsbad, Calif., desalination plant on Sept. 4, 2015. AP Photo/Lenny IgnelziJohn Paul Micha5/17/2022|Updated: 5/18/2022CommentaryMankind’s most useful environmental improvement would be to increase clean, fresh water supplies.We had a problem loading this article. Please enable javascript or use a different browser. If the issue persists, please visit our help center.