cc: "Michael E. Mann" , "Phil Jones" , "Keith Briffa" , , , , date: Fri Oct 3 10:59:16 2003 from: Tim Osborn subject: Re: Mann and Jones, climate of the last two millennia to: "Robert Matthews" At 10:35 03/10/2003, you wrote: Many thanks for this; it's much appreciated. Could you comment on why only the NH temperature graph shows that the current warming is unprecedented ? thanks Robert The number (and possibly the quality of some) of proxy records is lower in the SH than the NH. Thus there is greater uncertainty when using those records to reconstruct past SH temperature. Also, warming during recent decades has been greater in the NH than the SH (e.g. 1976-2000 trends quoted by the latest IPCC report are 0.6 degrees C for the NH, and 0.3 degrees C for the SH). Combining weaker recent warming with greater uncertainty in previous temperatures means that the SH warming cannot be concluded to be unprecedented compared with the last 2000 years or so. Regards Tim