It is not a hoax. There is a physical science basis to it. All else being equal, adding more CO₂ to the air should cause slight warming of the lower atmosphere. But, the claims that we are experiencing an “existential crisis” because of it are scientifically unsupportable and most of the proposed “solutions” are a scam. The issue has been hijacked by power-hungry politicians who want to use science as a segway to implement their authoritarian policies.