JEFF VANDERMEER replies in interview:
It’s important to recognize that bits of contemporary mainstream literary novels like Tom McCarthy’s Satin Island are doing more interesting things with regard to environmental extrapolation than the entirety of whole science fiction novels.
Because we’re now fairly deep into the middle of this slow apocalypse, writers of fiction set in the here-and-now can speculate quite effectively without recourse to the science-fictional. My next novel is science fiction and deals with issues of biotech, scarcity, and survival. But the one after that is set in the present-day and has no speculative elements. That happened naturally, but I think it also happened because we are, as they say, already living in the SFnal future. I also think Aase Berg and other poets are demonstrating that poetry is quite a powerful form when it comes to interesting exploration of environmental issues.
So, the short answer is: Any writer can now write “environmental science fiction.”