This has been brought up before
...and several people pointed out "What if the cure is worse than the disease?".
I hope they've made some arrangements to recover these "tonnes of particles" just in case they get it wrong.
Then again, maybe this is just a way of saying "We don't have to worry about global warming because there is a quick technological fix we can always implement if it gets out of hand."
Did you accidently drink some HCl? Quick, take an NaOH chaser!