Based on studies of tree rings, a team of international scientists from the Johannes Gutenberg University in Mainz published climate model of northern Europe over the past 2000 years. To reproduce the climate period from 138 BC to the present day, the team of Professor Jan Esper used the data on the density of the Rings subfossil pines from Finnish Lapland.
These results demonstrate a clear trend to a cooling of the climate. "We found that there is an attempt to reflect the climate of the Roman period and the Middle Ages distorted data to lower temperatures. Such studies provide a good contrast in the context of the warmer periods in history, "- said Esper.
Was the climate in the Roman period and the Middle Ages actually warmer than the modern? And why did the early periods of warming is so important in the assessment of the current state of climate change? Paleoclimatology attempts to answer these questions. Scientists analyze these indirect indicators of climate variability, as turbid core in a block of ice, ocean deposits to reconstruct the climate of the past. Annual increase of the Rings is an important sign of climate warming and cooling over the past 1000 and 2000 years.
Scientists from Germany, Finland, Scotland and Switzerland have investigated the density of tree rings in Finnish Lapland. In this region, there are cases when a tree falls in one of the many lakes, where they can save warriors properties for thousands of years. The density of tree rings subfossil pine correlated with summer temperatures in the region, the transition zone Nordic taiga. Model with high-resolution temperature allowed to reproduce the period of the Roman period and the Middle Ages. Have been isolated not only periods of warming, but also small ice ages.
In addition, for the first time on the basis of data obtained from the annual circles, the researchers were able to track the longer a cooling trend over the last 2000 years: each new millennium accompanied by cooling at 0.3 degrees Celsius. This process is the gradual change in the position of the sun and the distance between the Earth and the Sun.
"These results may seem insignificant, but in terms of global warming, which now has the performance is less than 1 degree Celsius, not negligible. New data show the need to re-evaluate the longer the general trend to cooling. "