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List of large-scale temperature reconstructions of the last 2,000 years


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 2000 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.

The IPCC Third Assessment Report (TAR WG1) of 2001 cited the following reconstructions supporting its conclusion that the 1990s was likely to have been the warmest Northern Hemisphere decade for 1,000 years:

North et al. 2006 highlighted six recent reconstructions, one of which was not cited in AR4:

The IPCC Fourth Assessment Report (AR4 WG1) of 2007 cited the following reconstructions in support of its conclusion that the 20th century was likely to have been the warmest in the Northern Hemisphere for at least 1,300 years:

The IPCC Fifth Assessment Report (AR5 WG1) of 2013 cited the following reconstructions in support of its conclusion that for average annual Northern Hemisphere temperatures, "the period 1983–2012 was very likely the warmest 30-year period of the last 800 years (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence)":


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