2) Rapid warming over next decade, as recent Nature and Science
article suggests is quite possible (posts here and here) 3) Continued (unexpected) surge in
methane 4) A megadrought hitting the SW comparable to what has hit southern Australia.
They are referring to a 1971
article written by climatologist Stephen Schneider, in which he did, indeed, make that prediction; however, as he himself now acknowledges, new evidence soon followed its publication that
suggested that 1) the cooling impact of aerosols was not nearly as high as originally estimated and 2) there were many other gases in the atmosphere, including
methane, CFCs and ozone, that had the same warming effect as carbon dioxide.