Tuesday, February 16, 2010

IPCC Paleoclimate Reconstructions show no significant warming

Graphs from IPCC AR4 showing "overwhelming evidence" of unprecedented & anthropogenic global warming:

1. Northern Hemisphere Paleoclimate Reconstructions:
Comments: Once again, "Mike's Nature Trick" is used to graft the faulty instrumental record onto the paleoclimate reconstructions for scientifically-improper dramatic effect. In addition, the orange line with the highest anomaly in the top (instrumental only) graph is from a Phil Jones paper on the instrumental record of 4 mostly urban European sites: Central England, De Bilt, Berlin and Uppsala without any mention in the AR4 text of possible urban heat effects. Now back to the paleoclimate reconstructions alone, it appears that:
  • the error bars include the instrumental plus the paleoclimate data (should only be the latter)
  • the paleoclimate data shows the Medieval Warming Period to have statistically insignificant temperature anomaly compared to the 20th century and indeed no statistically significant warming over essentially the entire reconstruction
  • periods of warming at similar rates to the late 20th century instrumental record including the oft cited periods and a "new" one: years 900-1000
  • the paleoclimate data peaks in 1950-1960 and then declines at just the time the anthropogenic signal due to man-made greenhouse gases should be exponentially increasing
  • 3 of the tree-ring data series were truncated in 1960 to "hide the decline" despite availability of data beyond 1960
 2. Southern Hemisphere Paleoclimate Reconstructions:

  • "Mike's Nature trick" of improperly grafting the instrumental data from each region to the paleoclimate data is again employed
  • Of the 4 tree ring reconstructions, only 1 suggests higher temperatures in the 20th century (S Patagonia) and that record also takes a downward dive after ~1960
  • Three of the four tree-ring reconstructions show the same or significantly higher temperature anomalies before industrialization
Would this "overwhelming evidence" of unprecedented & anthropogenic global warming prove the hypothesis at an 8th grade science fair?

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