Operation Popeye

Operation Popeye was a secret U.S. military project during the Vietnam War aimed at manipulating weather to gain a strategic advantage. By cloud seeding, the U.S. attempted to extend the monsoon season to hinder North Vietnamese forces. The operation ran from 1967 to 1972, involving over 2000 missions. It was exposed by journalist Seymour M Hirsch, leading to public outrage and the eventual signing of the Environmental Modification Treaty in 1977, which banned weather manipulation for military purposes. The operation's true environmental impact remains unknown.

What treaty did the US sign as a result of Operation Popeye, and what did it pledge?

What lessons can be learned from Operation Popeye regarding environmental manipulation for military purposes?