An independent global surface (GST) temperature record was recently compiled from several geological and historical sources. David Anderson, of the National Ocean and Atmospheric Administration’s National Climate Data Center, USA, and several colleagues constructed a Paleo Index which is based upon 173 temperature-sensitive proxy time series. As noted by Anderson and others in their paper in press, Global Warming in an Independent Record of the Last 130 Years (to be published in the journal Geophysical Research Letters):
“The thermometer-based global surface temperature time series (GST) commands a prominent role in the evidence for global warming, yet this record has considerable uncertainty. An independent record with better geographic coverage would be valuable in understanding recent change in the context of natural variability. We compiled the Paleo Index (PI) from 173 temperature-sensitive proxy time series (corals, ice cores, speleothems, lake and ocean sediments, historical documents).”
The PI extends back to 1730 and documents a significant increase in warmth from 1880 to 1995, much like the thermometer-based GST. The results of the PI, which are taken from numerous globally distributed proxies, well corroborates the thermometer data. This independent check on the thermometer-based GST helps to bolster assurance in its accuracy.