In many sustainability circles, "bioengineering" = "bad and scary," while "biomimcry" = "cool and useful." Biomimicry usually doesn't involve bioengineering, and in fact often relies upon completely non-biological processes to mimic biological effects. And it is, in fact, pretty cool and useful.
I wonder if some of the negative reaction to "geoengineering" comes from its linguistic parallel to bioengineering. Such a parallel seems to suggest that there's a connection; I have attended more than one event where the two were lumped together, even though there's almost no material or process relationship. And since "bioengineering," by definition, involves the engineering and manipulation of biological systems, the immediate conclusion is that geoengineering must be operating with the same level of invasiveness, with similar risks.
There's no doubt that some forms of geoengineering involves the direct manipulation of geophysical systems, and (in general) the term remains the most appropriate one. But there's a very wide variety of approaches and ideas that fall under the geoengineering umbrella. Some -- but not all -- of them actually intentionally mimic existing geophysical processes, with the intent of producing similar geophysical effects.
A proposal, then: it might make sense to start referring to the forms of geoengineering that intentionally attempt to reproduce known geophysical processes as geomimetic technologies, or more generally, geomimicry.
This idea has a couple of benefits. The first is a bit of reframing: talking about "geomimetic" proposals can counter some of the subtle negative connotations of "geoengineering." This isn't an attempt to make geoengineering seem benign, but an attempt to balance the discussion a bit more, so that we can make smarter decisions.
The second is that it's actually a useful category. Right now, discussions of geoengineering are typically divided into discussions of "Solar Radiation Modification" (i.e., blocking a bit of incoming sunlight to hold temperatures down) and "Carbon Dioxide Removal" (i.e., directly taking CO2 out of the atmosphere). This is a pretty useful split, but still leaves us lumping together ideas like orbiting mirrors and cloud brightening above the oceans, or carbon capture at factories and attempts to boost mid-ocean algae blooms.
Geomimetic technologies would be those that seek to replicate known geophysical processes, so stratospheric sulfate injection (which attempts to reproduce the high-atmosphere effects of a large volcanic eruption) is geomimetic SRM, while white-rooftop programs (which attempt to increase urban/suburban albedo by literally painting rooftops white) would be, um, let's call it infrastructure SRM. Similarly, large-scale tree-planting projects could be called geomimetic CDR, while CO2 scrubber towers would be infrastructure CDR.
Language matters, and the terms we use to describe or categorize things can greatly shape how we react to them. I'm a strong advocate for research into all forms of geoengineering, not with the goal of immediate deployment, but to see which ones might have dangerous (and unexpected) side-effects that should bar deployment, no matter how bad things get. Having clearer labels on the processes, and using terms that are less likely to provoke an emotional reaction, will help us take a more thoughtful look at our options.