Climate scientists and left-leaning politicians could vigorously claim that conservatives were right all along, everything is okay, and that the last thing church groups and conservatives need to do is worry about the environment. Yep, nothing to see here, don’t get involved.
Consider a formal statement expressly forbidding long-term geo-engineering, because long-term geo-engineering will definitely and for sure hurt “those people” (dog whistle of your choice). Really emphasize how much long-term engineering would be a significant “screw you” to “those people”. Probably destroy “their” communities, like long-term geo-engineering would literally raze “those” communities to the ground.
Finally, make the case that atheists oppose geo-engineering on the grounds that God did NOT give man dominion of the Earth, so any claim that humans have the right to engage in long-term geo-engineering is crazy and offensive. Emphasize separation of church and state in this argument, it’s like catnip.
That might work?