Libertarian-socialism was the position that was taken by communists that rejected Marxism (Marx isn’t completely rejected, but read with awareness that not everything he suggests is desirable), it has nothing to do with the later capitalist forms of libertarianism. It includes anarchism, but not all lib-socs are anarchists.
Marx expelled them from the First International at the Hague Congress
When the people are being beaten with a stick, they are not much happier if it is called "the People’s Stick
We are convinced that liberty without socialism is privilege, injustice; and that socialism without liberty is slavery and brutality.
It would best be described as anti-state voluntary collectivism, which doesn’t fit on a “state to individual” axis with mixed economies in the centre.
One suggestion is a federation of communes (Think of French communes, rather than hippy communes). Problems are solved at the lowest level possible, environmental issues like the one you suggested would be high up, possibly even at the world level.
This is not the only suggestion though, r/Anarchy101 would be able to tell you some of the other options.