After September 11th and the COVID lockdowns, scientists noted an increase in global surface temperature due to the absence of contrails. So yes, this is actually something we are already doing!

Sulfur dioxide however is an even more effective reflector of sunlight compared to water vapor. And don’t forget, water vapor is itself a very greenhouse agent that contributes toward planetary heating.

Supposedly the new stringent heavy shipping emissions controls are having an impact on the greenhouse effect. Reduction of sulfur dioxide which had a reverse greenhouse effect is warming the oceans up more.

“Carbon Brief analysis shows that the likely side-effect of the 2020 regulations to cut air pollution from shipping is to increase global temperatures by around 0.05C by 2050. This is equivalent to approximately two additional years of emissions.”

https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/#%3A~%3Atext=Global+emissions+of+sulphur+dioxide%2Cwarming+coming+from+greenhouse+gases.

So this may be our first example of the threats of NOT enacting terraforming for climate change will have.