These researchers haven’t seen Highlander 2 and it’s a problem.
No one has seen Highlander 2 There can be only 1!
“You have to go measure things in the real world, because nature surprises you,” Keith said at that conference in 2017.
He has continually stressed that the amount of material involved would represent a small fraction of the particulate pollution already emitted by planes, and that doing the same experiment for any other scientific purpose wouldn’t have raised an eyebrow.
I agree with that. It seems overblown that some folks were opposed to spreading two kilograms of limestone dust and measuring the result.
A single aerobatic flight of an ultralight aircraft with a smoke trail probably requires more pyrotechnical material, not to speak of fuel. Not to speak of a proper passenger or cargo flight. Not to speak of a satellite launch.
People already do the things anyway, only without properly understanding the results.
As for the argument that “then everyone will start experimenting” - well, that depends on the result of the previous expriment, does it not? And some do it anyway. China has a weather modification bureau, Saudi Arabia practises cloud seeding to increase chances of rainfall, etc.
