Analyzing the sediment cores from the bed of the oldest lake in Europe, an international team of scientists has created a detailed climate history of the north-central Mediterranean that dates back to 1,36 millions of years ago and revealed the climate mechanism that drove the rains winter in the region.
The results of the climate analysis were published in the prestigious scientific journal Nature.
Scientists have pierced the bed of Lake Ohrid, which is located on the border between Albania and northern Macedonia, and is thought to be the oldest lake in Europe.
The drilling took place in 245 meters deep water and reached a maximum depth of 568 meters in the sediment. The progressive analysis of sediments has led to exceptional results.
Geochemical data and documentation on pollen recovered from the lake bottom show variations on the typically winter rainfall in the central-northern Mediterranean region.
Simulations of the climate model indicate an increase in cyclogenesis (the development and strengthening of low-pressure areas in the atmosphere) on the Mediterranean Sea during the summer and late autumn, leading to markedly higher winter precipitation.
The Mediterranean climate is characterized by dry summers and wet winters, therefore winter rains are fundamental for the region's population and agriculture.
The analysis of the lake bottoms has allowed to highlight an anomalous warming of the Mediterranean waters and the intensification of monsoon-type phenomena, with an increase in rainfall during the winter season.
Basically, the Ohrid seabeds bear witness to how the climate of the Mediterranean area has become more tropical. A phenomenon that seems to have been constant over the last 1, 36 million years.
The intensification of the monsoon phenomena, such as cyclones, in the western Mediterranean, causes the instability of low-pressure systems (those that bring cold air) while they move eastwards, towards the Balkan area, causing the intensification of rains in the cold season.
The data collected by Lake Ohrid will allow a better understanding of how climate change will affect the Mediterranean region. However, the data is not absolutist. Some climate models provide wetter winters, others even drier.
On a given they all agree, however. The projections must necessarily take into account the fact that now the climatic variations do not depend exclusively on the cycles of nature, but rather they are mostly caused by the hand of man.
If nothing else, scholars will be able, with the data now available to them, to create increasingly accurate climate modellers for the future.
"Some climate models predict more winter precipitation, but others predict drier winters. However, climate modellers will now be able to use the data collected by Lake Ohrid to improve their models and develop more accurate predictions of what will happen in the future. "
Curiosity: from 5 July 2019, thewhole Lake Ohrid (Liqeni i Ohrit) located on the border between Albania and Northern Macedonia has become a UNESCO World Heritage Site. (read the news )