I highly doubt that solarpunk is specifically depicted in these pictures, although in theory it should be exactly that. Solarpunk, atompunk, biopunk, cryopunk and even cyberpunk - recently, neural networks have lumped all this together and mixed it to such an extent that no one will separate it. It seems to me that AI simply takes advantage of the fact that no one can convict of poor quality work, and works anyhow.
Prompt: photorealistic image of a retro solarpunk, naturecore, by roger dean and by dean ellis
Sources:
I generated this set on Lexica Aperture
Artificial Intelligence Art Universe Group
Stable Diffusion Facebook Fan Group
Midjourney Official Facebook Group