He was a professor at Oregon State University. In the 1965 paper The Role of the Oceans in Climatic Change: a Theory of the Ice Ages, he became the first to propose that excess fresh water released by melting Artic ice could disrupt the Thermohaline circulation (and thereby wreak havoc).
1. According to Spencer Weart in his book The Discovery of Global Warming:
"As scientists came to see that the ocean circulation might be crucial for climate change, not just over geological time but more immediately, more of them paid attention to the problem. A particularly stimulating idea came from Peter Weyl of Oregon State University in the mid 1960s. He noticed that the moist trade winds that cross the Isthmus of Panama and drop rain into the Pacific Ocean carry fresh water out of the Atlantic, leaving behind saltier water.
Weyl built on this to develop a theory of the ice ages, involving the way changes of saltiness might affect the formation of sea ice. He did not publish his model until 1968, but he presented the rudiments at the 1965 Boulder conference. The theory would scarcely have been noticed among the many other speculative and idiosyncratic models for climate change, except for a novel insight. Weyl pointed out that if the North Atlantic around Iceland should become less salty — as might happen if melting ice sheets diluted the upper ocean layer with fresh water — the entire circulation could lurch to a halt. Without the vast drift of tropical waters northward, he suggested, a new glacial period could begin."