Reality Check: Local Warmers Please Provide Explanation
07/14/2012 7 Comments
Scientist have two long temperature records that go beyond the 300 year of temperatures using the mercury thermometer. One is the ice cores from the arctic and antarctic glaciers, the other is tree rings from fossilized trees. Assuming that the tree ring analysis is consistent with good scientific practice. Long time readers of my blogs, Watts Up With That and Climate Audit know about the “hockey stick” tree ring fraud.
Two studies, one tree ring and the other ice core have come to may attention. Both signal a long term cooling, with past warm periods much warmer than we experienced in the 1980s and 1890s during a warm phase PDO and a very active sun. As you look at the following graphs you can see the warm periods and the following cold periods. The planet warms and then it cools, on a regular cycle. We just completed a warm cycle and are now we are on the cusp of a long down slope cooling cycle. But, I digress.
Here are the two graphic I mentioned above. The first by Grootes, P.M. (et al), “Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores,” Nature, 366, 1993, pp. 552-4
The second is a more recent study of tree-ring which concludes that not only has our climate often been noticeably hotter than today, temperatures have actually been on a falling trend for the past 2,000 years.
Orbital forcing of tree-ring data Jan Esper, (et al) Nature Climate Change (2012) Published online 08 July 2012
Now, I would like to hear from our local warmers who are claiming that humans are responsible for the unprecedented global warming. When is fact the earth has warmed and cooled many times in the past without any human intervention. So, why is the current warming human caused? How do you know? What evidence do you have that refutes the two graphics above? Please post your results in the comments.