An international team that includes scientists from Johannes Gutenberg
University Mainz (JGU) has published a reconstruction of the climate in
northern Europe over the last 2,000 years based on the information
provided by tree-rings. Professor Dr. Jan Esper's group at the Institute
of Geography at JGU used tree-ring density measurements from sub-fossil
pine trees originating from Finnish Lapland to produce a reconstruction
reaching back to 138 BC. In so doing, the researchers have been able
for the first time to precisely demonstrate that the long-term trend
over the past two millennia has been towards climatic cooling.
"We found that previous estimates of historical temperatures during
the Roman era and the Middle Ages were too low," says Esper. "Such
findings are also significant with regard to climate policy, as they
will influence the way today's climate changes are seen in context of
historical warm periods." The new study has been published in the
journal Nature Climate Change.