|No! No Dangerous Rise!|
by Des Moore
Figures 5 to 7 show that the 0.6 increase occurred about the same time as breaks in the time series showing CO2 concentrations. This suggests that there is a strong interaction between the ocean and the atmosphere, that is, when there is a significant (natural) change in the behaviour of the oceans that may in turn cause a significant change in increases in CO2 concentrations.
As to likely temperatures before 1850 when fossil fuel usage and CO2 concentrations were small, the IPCC’s 1990 report included a graph showing estimated temperatures for the Medieval Warming Period (800 -1,100) higher than for the 20th century. Although the IPCC did not repeat that graph in subsequent reports, and did not explain why, it is now widely accepted that there is strong evidence that temperatures were higher then and also in the Greco-Roman warm period (600 BC - 200 AD). A report commissioned by US Congress from an expert statistician concluded that there were fundamental flaws in an analysis purporting to show, from tree rings, little or no increase in temperatures prior to the industrial revolution – the so-called hockey stick presentation. More generally, it is not surprising that some warming from natural causes has been experienced since the end of the Little Ice Age, which occurred around 1800 well before CO2 emissions became significant.