International climate change deliberations might blast-off into the military domain. Pointing to this possibility, here's the opening paragraph from a full article in the Guardian:- "The US government wants the world's scientists to develop technology to block sunlight as a last-ditch way to halt global warming, the Guardian has learned. It says research into techniques such as giant mirrors in space or reflective dust pumped into the atmosphere would be "important insurance" against rising emissions, and has lobbied for such a strategy to be recommended by a major UN report on climate change, the first part of which will be published on Friday". TreeHugger has posted extensively on planetary engineering options, including sun-blocking, C02 "sequestration," and iron seeding to boost marine plankton productivity. The sunlight interruption schemes touched on by the Guardian article would presumably be reliant on space program and military-style weapon delivery mechanisms (symbolized by the photo), geopolitical aspects of which need to be considered as much or more than do sun-block efficacy, reliability, and secondary biological impact. If world governments agreed to focus on sun-blocking technology as the only form of climate "insurance" to be actively pursued, the US and Russia, nations with atmospheric delivery capabilities, would have strategic primacy over the principal backup response to climate crisis. This strategic demension would most certainly reshape climate change treaty expectations and might throw existing "Cap and Trade" investments askew. These geopolitical prospects are dizzying enough, regardless of the extent to which the world's climate may benefit from a single planetary engineering approach (sun-blocking). Is there a technical reason why the open-source planetary engineering approaches did not get equal mention? We can't think of one. Guess we'll have to wait for the second IPCC report segment to find out.