Read here and here. A new study reconstructs 2,000 years of temperature variation from 30 datasets. The authors eliminated the discredited data and techniques utilized by Michael Mann (of Climategate fame) for multiple studies, and also used by his close paleo research comrades. For example, this study totally avoids the bristlecone pine and foxtail pine data that so miraculously produced the fake hockey-stick blades of temperatures in the 20th century.

This new study's findings demonstrate that climate change has been very active over 2,000 years, with pronounced changes in temperature being one of the results. This past climate change and temperature variation happened in a atmosphere of low CO2 levels. These results also reveal Roman and Medieval temperatures that exceed modern temperatures derived from the same 30 datasets. (click on image to enlarge)





This chart shows the modern global warming, as do so many paleo studies, but confirms that both warming and cooling are natural cyclical events.



Additional historical temperature charts. Climate history postings. Modern temperature charts.