If you haven't yet, I encourage you to download or stream my fourth (and so far, I think, best) Point of Inquiry program--with Eli Kintisch on the subject of geoengineering. All this week on the blog, I'm going to be discussing issues raised on the show--so having heard it will be kind of an essential baseline. This post is to raise the first issue, which has to do with Eli's response to my question around minute 6, where I ask about the geoengineering techniques that scientists consider to have the most promise. In response, Eli provided a fairly encyclopedic answer that essentially broke geoengineering schemes into two categories: 1) carbon capture/removal techniques to get the stuff out of the air, by sucking it into machines, into the ocean, into trees and plants, etc; and 2) sunlight blocking techniques, which essentially reduce the total solar radiation being absorbed by the planet. My problem is that the carbon removal techniques (with perhaps the exception of iron fertilization) are relatively uncontroversial. Whereas the sunblocking techniques--and especially what Kintisch calls the "Pinatubo option"--are wildly so. So is it really wise to group them both together under the rubric of "geoengineering"? Don't we have a pretty big category issue here? It would be interesting to hear Eli's--and anyone else's--response.