About "volcano storms:" they are real. And they show up in the tree-ring record, right here in Oklahoma. The largest known storm was probably Fimbul Winter (535-537 AD), apparently the result of an eruption of a South American volcano. The storm of 1886 produced the strongest tree-ring storm signal since 1650 - and devastated the livestock industry; it was a delayed effect of the eruption of Krakatoa.
One can imagine some effects like a few earthquakes being set off as a result of the shifting of water masses (Those already occur during the filling of large reservoirs.), but whole countries disappearing is a little hard to believe.
Climate change deniers would do better if they actually read the books and articles and then tried to refute them, instead of making up things the articles never said.