re: #121 Thanos

If it is a solid, even though small enough to remain airborne for a considerable amount of time, likely it is not totally transparent to visible light (i.e., that coming from the Sun).

The real issue though is perhaps not the optical nature of these mysterious aerosols so much as there evolution over time. If they are a harbinger of additional cloud development then that would be one effect. OTOH, are they the sign of a failure to form clouds?

Certainly for the atmospheric scientists aerosols are the hot research item.

WRT AGW, overall I think the big area of uncertainty (outside of the human economic response) is the biosphere and how it is responding to the forcings that human activity have wrought.

The elephant in the room remains the human response. Will we decide to leave some of the fossil fuels in the ground? And if so, what fraction?