Because they have dedicated their lives to understanding the physical world and do understand it far better than most. “Dr. David W. Fahey is the Director of the Chemical Sciences Laboratory in the National Oceanic and Atmospheric Administration in Boulder, Colorado, USA. He joined the Laboratory after receiving advanced degrees in physics.”
Utterly irrelevant. That they or anyone should have any more of a say at planetary geo engineering over the one habitable planet our species reside on. Unless you believe in some sort of intellectual tyranny. What if the “smart” credentialed people were ones you didn’t agree with and proposed eugenics as a viable solution to over coming climate change would you be so quick then. I doubt it. Not trying to call you out here but this line of reasoning that they are an expert so get to do this is bonkers. Sure propose all you like but my lord no action.
https://csl.noaa.gov/staff/david.w.fahey/