This chart is of many different scientific papers, which adds a hell of a lot of support to it. Based on the graph that shows the warmest part of the Mid-evil warm period being near .3c above "0" or avg to todays global .8c above normal. So we're half a agree oC above the med-evil warm period. Also I was reading that we're very close to the Holocene climatic optimum of 5,000-7,000 years ago->"The Holocene Climate Optimum warm event consisted of increases of up to 4 °C near the North Pole (in one study, winter warming of 3 to 9 °C and summer of 2 to 6 °C in northern central Siberia). Northwestern Europe experienced warming, while there was cooling in the south. The average temperature change appears to have declined rapidly with latitude so that essentially no change in mean temperature is reported at low and mid latitudes. Tropical reefs tend to show temperature increases of less than 1 °C; the tropical ocean surface at the Great Barrier Reef ~5350 years ago was 1°C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. In terms of the global average, temperatures were probably colder than present day (depending on estimates of latitude dependence and seasonality in response patterns). While temperatures in the Northern Hemisphere were warmer than average during the summers, the tropics and areas of the Southern Hemisphere were colder than average which comprised an average global temperature still overall lower than present day temperatures.[4" If we're now warmer then the mid-evil warm period and possibly the climatic optimum then we have to go back to at least 115 thousand years to find possibly warmer temperatures then today. 3-4c would put us back to where we where 5+ million years ago? When looking at this graph; remember that 0c is the same 0 point that we have grown to love and we're about .5-.6c above it today. As far as I'm concerned the earth with a helping hand by humanity is just heading back towards normal.