Their god. Just as there has been disputation around here as to whether Allah is God. Well, the Arabic word "Allah" means "God" for sure, and Arabic speaking Christians say "Allah", and did long before there were Muslims.
The Mohammedan "Allah" is still a false concept.
By the same token, the enviro-whacks are not old-fashioned Marxist atheists. They worship an Earth god (or goddess), who is hostile to human existence.
No room for humans. Think of original sin without redemption.