How did the world agree to stop commercial whaling in 1986?

The world agreed because the whales were running out. After centuries of hunting, by the late 1930s more than 50,000 whales were killed every year, and the International Whaling Commission (IWC) decided in 1982 that commercial whaling should pause from 1986 because of the extreme depletion of most whale stocks. On 23 July 1982, its members voted by the needed three-quarters majority to set commercial catch limits to zero.

The vote did not come out of nowhere. Demand for whale oil spurred the hunt in the 19th century, margarine and meat in the 20th, and factory ships and explosive harpoons made it far more efficient. The IWC itself dates from the 1946 convention. Blue whales were hunted almost to extinction until the IWC banned hunting them in 1966, and in 1972 a UN conference in Stockholm recommended a ten-year moratorium on commercial whaling.

When the vote came, it passed by 25 votes to seven, with five abstentions. Japan, Norway, Peru and the Soviet Union lodged formal objections, since the moratorium was not based on advice from the Scientific Committee.

It was meant as a five-year pause, but it has been indefinitely extended. It applies only to commercial whaling, so whaling under scientific-research and aboriginal-subsistence provisions is still allowed, and the dispute is still alive.