 | This article needs to be updated. (January 2017) |
This list of large-scale temperature reconstructions of the last 2,000 years includes climate reconstructions which have contributed significantly to the modern consensus on the temperature record of the past 2,000 years.
The instrumental temperature record only covers the last 150 years at a hemispheric or global scale, and reconstructions of earlier periods are based on climate proxies. In an early attempt to show that climate had changed, Hubert Lamb's 1965 paper generalised from temperature records of central England together with historical, botanical, and archeological evidence to produce a qualitative estimate of temperatures in the North Atlantic region. Subsequent quantitative reconstructions used statistical techniques with various climate proxies to produce larger-scale reconstructions. Tree ring proxies can give an annual resolution of extratropical regions of the northern hemisphere and can be statistically combined with other sparser proxies to produce multiproxy hemispherical or global reconstructions.
Quantitative reconstructions have consistently shown earlier temperatures below the temperature levels reached in the late 20th century. This pattern as seen in Mann, Bradley & Hughes 1999 was dubbed the hockey stick graph, and as of 2010 this broad conclusion was supported by more than two dozen reconstructions, using various statistical methods and combinations of proxy records, with variations in how flat the pre-20th century "shaft" appears.[1]