May I point you to doi 10.1002/2017JD027331 that concluded "This analysis demonstrates that while modest, statistically significant differences occur during the first few years, longer‐term impacts are unlikely, regional in scope, and limited in scale. None of the simulations produced a nuclear winter effect."?
I guess that is good and bad news. Hopefully India and Pakistan don't try and refute the findings.
Since you are now my Oracle, how large of a cold spot can we create using a space based sun shade? What would it take to keep arctic methane in the ground?
