Geesthacht scientists reconstruct the climate of the past
Scientists of the Helmholtz-Zentrum Geesthacht are participating in the most comprehensive reconstruction to date of regional climatic changes over the past 2000 years. A team of 78 scientists from the international research project PAGES (Past Global Changes) has analysed climate data from seven continental regions for the study “Continental-scale temperature variability during the past two millennia”. The results of the study have recently been published in the journal “Nature Geoscience”.
The global climate is changing. However, there can be considerable regional and temporal variations. The international PAGES 2k research team has reconstructed the climate over the past 2000 years for the seven continental regions: Arctic, Antarctic, North America, South America, Europe, Asia and Australia/Southeast Asia.
Dr. Eduardo Zorita and Dr. Sebastian Wagner from the Institute of Coastal Research at the Helmholtz-Zentrum Geesthacht have been actively involved in the study. These two palaeo-climate researchers, working in cooperation with other scientists, have evaluated the climate data for Europe. The European data is based on studies of tree rings and historical documents. For other continental regions, data was gathered from studies of sediment and ice cores, stalagmites and corals.
One main result of the study: a long-term cooling trend in all continental regions, influenced by volcanic eruptions, changes in solar activity, variations in the earth’s orbit and other factors, came to an end at the close of the 19th century. Up to that point, the temperature had dropped by between 0.1 und 0.3 degrees centigrade per 1000 years, whereby considerable regional and temporal variations were evident. According to the study, the increase in temperature in most recent times has reversed the long-term cooling period.
The average warmest 30 year period of the last 1400 years occurred between the years 1971 and 2000. Only the Antarctic remained cold in this period of time.
A further result of the study: particular climate phases in the past 2000 years, such as the Medieval Climatic Anomaly and the Little Ice Age, revealed strong spatial and temporal variations. Thus, although temperatures everywhere did indeed fall to below the long-term mean value around 1500, this occurred in the Arctic, Europe and Asia decades earlier than in North America and in the Southern Hemisphere.
This study is the most comprehensive reconstruction of regional climates for the past 2000 years to date. Previous studies of global climatic change presented mean values pertaining to the Northern and Southern Hemispheres or the whole world.
To the publication of the study in Nature Geoscíence To PAGES press releases To PAGES FAQs To the Department of Paleoclimatology of the Institute of Coastal Research at the Helmholtz-Zentrum Geesthacht
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