Read here. This lamebrain temperature graph was published in the 2007 IPCC report and the linked article explains its creation. The IPCC needed to convince the MSM that global temperatures were "accelerating" -- not a very difficult objective considering the low science IQ that MSM reporters and pundits represent. Needless to say, unprofessional behavior and a non-scientific, political agenda by IPCC representatives was the genesis. Surprised?
(Note: green arrow lines added by C3 to show how easy it is to cherry-pick a time period and then draw a trend line indicating a desired result.)
Other modern temperature charts. Historical charts here. Climate history postings here.