A carbon tax doesn't destroy the economy per se, it changes the tilt on the game board creating new winners and losers. It only causes big problems if you insist that the old winners must continue to be winners, which isn't something that any government ought to promise.
Utterly and completely wrong. At the root of the Industrial Revolution is one simple thing: material abundance didn't happen until people found out how to replace muscle power with the stored energy in abundant fossil fuels (there isn't enough wood). A carbon tax makes that energy more expensive. When energy costs rise, everything gets more expensive -- especially food. Cheap food and cheap energy are the basis of modern civilization. Start bumping up the costs of those two things, and marginal countries won't be able to "catch up to the curve" and start improving the lot of the world's poor.
In short, don't kid yourself. Whether AGW is real or not (we don't know), whether it poses a threat or not (surely a big event like this would have SOME positive impacts as well as some negative ones), don't kid yourself. Cutting down carbon emissions will kill some people -- it just won't be people you know.