I've known this for close to 20-25 years.
With the fall of the USSR, and the Chicoms foray into captialism, the most extreme of the socialist, needed another activist vehicle to latch on, and enviro-whacko socialism was born. When I had to deal with activist back in the '90's like with NRDC, and PIRG, I happened to find out that many of these had socialist and communist ties.
Got to hand it to them..... They pulled off the biggest scam in history by convincing the majority of the population their intentions were honorable.