Unless they DYI a very powerful biological or chemical weapon, it would be highly unlikely IMHO.
For me it's kind of a we don't know what we don't know thing. What if it's possible for one person to engineer something similar to a Hiroshima or Nagasaki type event? You don't think that's possible given the trajectory of technology and the fact that our wisdom might be outpaced by it?
Nope. The problem with that is the knowledge already is out there, but it is impossible to get access to the explosives that are needed to initiate a nuclear chain reaction. Even the US government has had trouble getting the stuff.
If you can account for "unknowns", I can not account for them. Can't have it both ways. Clearly your OP questions weren't real questions. You have already decided that someone is going to DIY themselves a planet-destroying weapon using accessible materials. I do not.
It was just a thought and I was defending it with reason trying to have a discussion. I am saying technology will continue to advance and how can we be sure what that will or won't make an individual person capable of?
