## Wednesday, February 01, 2012

### Email 4578, July 2005, Phil Jones: "it is possible to get a trend of nearer 0.75 if the trend starts around 1920 (especially if the cold year of 1917 is at the start)"

Email 4578

date: Mon Jul 18 14:25:52 2005 from: Phil Jones
subject: Re: Text and CQ stuff to: "Parker, David (Met Office)" , Kevin Trenberth

Kevin, Even without smoothing it is possible to get a trend of nearer 0.75 if the trend starts around 1920 (especially if the cold year of 1917 is at the start). The periods chosen for Table 3.2.2 had some justification, so we need to be a little careful. As a schematic for CQ2 though, it will be a different way of showing the same data. I'll talk it over with David. Cheers Phil

But remember since "...the first half of the 20th century warmed up naturally", we can't blame human CO2 emissions for any pre-1950 warming