Only in the central North Atlantic and the far south Pacific in 2011 to 2030 is the mean change less than the standard deviation, in part a result of ocean model limitations there (Section 8.3.2). (ipcc.ch)
The fuzziness associated with the spread between the model results is often referred to by the catch - all phrase «uncertainty `, referring to (unpredictable) chaotic internal variations, vaguely known forcing estimates, and climate model limitation. (realclimate.org)