A new reconstruction of temperature variability in the extra-tropical Northern Hemisphere during the last two millennia

• A new temperature reconstruction with decadal resolution, covering the last two millennia, is presented for the extra-tropical Northern Hemisphere (90–30°N), utilizing many palaeotemperature proxy records never previously included in any large-scale temperature reconstruction. The amplitude of the reconstructed temperature variability on centennial time-scales exceeds 0.6°C. This reconstruction is the first to show a distinct Roman Warm Period c. AD 1–300, reaching up to the 1961–1990 mean temperature level, followed by the Dark Age Cold Period c. AD 300–800. The Medieval Warm Period is seen c. AD 800–1300 and the Little Ice Age is clearly visible c. AD 1300–1900, followed by a rapid temperature increase in the twentieth century. The highest average temperatures in the reconstruction are encountered in the mid to late tenth century and the lowest in the late seventeenth century. Decadal mean temperatures seem to have reached or exceeded the 1961–1990 mean temperature level during substantial parts of the Roman Warm Period and the Medieval Warm Period. The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia, although this is only seen in the instrumental temperature data and not in the multi-proxy reconstruction itself. Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. AD 300–800, despite significant differences in both data coverage and methodology.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Klimatforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Climate Research (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Meteorologi och atmosfärforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Meteorology and Atmospheric Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)

HUMANIORA  -- Historia och arkeologi -- Historia (hsv//swe)

HUMANITIES  -- History and Archaeology -- History (hsv//eng)

Keyword

Temperature reconstructions

temperature variability

Medieval Warm Period

Little Ice Age

Roman Warm Period

Dark Age Cold Period

global warming

climate change

Climatology

Klimatologi

Meteorology

Meteorologi

Physical geography

Naturgeografi

History

Historia

Physical Geography

naturgeografi

meteorologi

Meteorology

History

historia

Publication and Content Type

ref (subject category)

art (subject category)