Mediterranean climate during the last ice age (8/7/2008)

Understanding past climate is essential for predicting future climate change. A new study published in the scientific journal Science reveals the circulation of the atmosphere over the Mediterranean during the last ice age, 23,000 to 19,000 years ago, and how this affected the local climate.

This innovative study paves the way for future interdisciplinary efforts to understand and predict regional climate change, and is co-authored by Professor Eelco Rohling of the University of Southampton School of Ocean and Earth Science, based at the National Oceanography Centre, Southampton.

The Intergovernmental Panel on Climate Change has identified the Mediterranean as a "future climate hot spot" likely to suffer increasingly from severe droughts, heat waves and wildfires, due to global climate change. This is potentially bad news for the many people who now live in the region.

The new work gives important clues about regional rainfall patterns in the past. This will help scientists check computer simulations of the Mediterranean climate, which is essential for predicting and planning for future climate in the region.

The team led by geologist Joachim Kuhlemann involves scientists from the University of Tübingen, the National Oceanography Centre, Southampton (University of Southampton School of Ocean and Earth Science), and the Institute of Particle Physics in Zürich. The scientists have assembled information on the altitudes of glaciers in mountains around the Mediterranean during the last ice age so as to help reconstruct climate.

The first surprise is that the Mediterranean climate at that time was similar to that seen during cold spells in the region today and - particularly - during the Little Ice Age (15th to 19th century), but more extreme. The new evidence suggests that the Mediterranean climate depends strongly on the shape of surrounding mountain chains.

A second finding is that cold polar air often invaded the Mediterranean region during the last ice age, causing more rain and snow to fall on Mediterranean mountains. This precipitation would have been an important source of water during the dry Mediterranean summer.

Computer models will need to account fully for these key observations, before they may be confidently applied to the forecasting of future change, say the scientists.

Note: This story has been adapted from a news release issued by the University of Southampton

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