Arne Nss Jr. (1937-2019) was a Norwegian philosopher and environmentalist. He was the son of philosopher Arne Nss Sr. and the brother of philosopher and mountaineer Liv Nss. Nss Jr. is best known for his work on deep ecology, which emphasizes the intrinsic value of all living beings and the importance of preserving the natural world.
Nss Jr. was a prolific writer and lecturer, and he taught at several universities around the world. He was also a co-founder of the Deep Ecology Research Network and the Arne Nss Foundation. In 2008, he was awarded the Sophie Prize for his work on environmentalism.