Northern Hemisphere Annual Temperatures from High-Resolution Proxy Data, AD 200-1995

P.D. Jones and M.E. Mann Complete Scientific Reference This collection of Northern Hemisphere temperature reconstructions is from a variety of studies, all based on high-resolution proxy data. The reconstructions are derived from different but in some cases, not entirely independent data sets. Some are based solely on extra-tropical continental data from tree rings, while others are based on multiple proxies, including tree rings, ice cores, corals, historical documents, and long instrumental records. Several are reconstructions of warm season temperatures and others are of annual temperatures. However, trends in low-frequency warm season temperatures have been shown to be very comparable to those in annual temperature. The reconstructions have been generated using a variety of statistical methods for treating the biological growth trends (standardization) in the tree-ring data to preserve the low-frequency variance, and calibrating proxy data with instrumental data to generate reconstruction models. All five series are annually-resolved reconstructions of temperature change. They have been scaled against the smoothed instrumental records based on the period 1856-1980, except Briffa et al. 2001 (scaled to 1856-1940), and smoothed with a 40-year low pass filter (Jones and Mann 2004). While there are differences between the reconstructions due to the factors mentioned above, all, even the least similar, are in agreement in showing the strong increase in temperatures since early 19th century, with the highest temperatures in the past 1000 years occurring at the end of the 20th century. The robustness of this result is clearly supported by the range of data and methods used to generate these reconstructions. Since only one of these reconstructions extends back to the early part of the previous millennia, results are more tentative, but suggest the recent warming could be unprecedented in nearly 2000 years.

Jones and Mann 2004 data and Information

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