BANGKOK (AP) — Feeding a hungry planet is growing increasingly difficult as climate change and depletion of land and other resources undermine food systems, the U.N. Food and Agricultural Organization said Wednesday as it renewed appeals for better policies and technologies to reach "zero hunger."

Population growth requires supplies of more nutritious food at affordable prices, but increasing farm output is hard given the "fragility of the natural resource base" since humans have outstripped Earth's carrying capacity in terms of land, water and climate change, the report said.

About 820 millio...