EX-GLACIER

"A record of rapid climate change from the Pyrenees, Spain"

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 Obiettivo del progetto (Objective)

'Throughout the last hundred thousand years, Europe has experienced rapid swings in climate. Some of these changes have been of the order of 5-10°C in only a few decades. The cause of these changes lies in the oceanography of the North Atlantic Ocean. The Gulf Stream transports vast amounts of heat from the Tropics and releases it into Europe, maintaining a warm climate. However, this surface current has not always done this. It is now understood that in the past this current has sometimes abruptly swung to a more southerly position off the Iberian Peninsula, robbing northern Europe of heat and moisture. In this project we will explore the effect of these changes on glacier extent in the Spanish Pyrenees. Glaciers are highly sensitive to climate change, particularly to temperature. We will use the cutting edge technique of exposure dating using cosmogenic nuclides to determine the position of glaciers in the past. We will then reconstruct the position of the glaciers through time to determine the response to climate change on this system. To implement this project we will use existing infrastructure at the University of Exeter to introduce a capability to prepare samples for Cl-36 dating. Climate change is one of the greatest challenges facing humanity today. The findings from this project will help us understand the future effects of global warming so that we are better prepared for the environmental and economic costs.'

Introduzione (Teaser)

Climate scientists are investigating the Gallego Valley in the Spanish Pyrenees to determine how ice responded to abrupt, rapid climate change during the last ice age.

Descrizione progetto (Article)

Heat is transported from the tropics to Europe by the Gulf Stream, an Atlantic Ocean surface current that allows the continent to enjoy a warm climate suitable for agriculture. However, over the millennia there have been rapid fluctuations in the position of the Gulf Stream of over 20 degrees of latitude, resulting in dramatic changes in climate. During the last ice age, the surface ocean current lay south of the Iberian Peninsula and the ice sheets reached northern Germany.

The EU-funded project 'A record of rapid climate change from the Pyrenees, Spain' (EX-GLACIER) used state-of-the-art technology to determine the timing of glacier advances in the central Pyrenees. Scientists employed exposure dating to date rock surfaces using rare radionuclides such as Chlorine-36, which is produced by exposure to cosmic radiation. The results were used to reconstruct the position of the glaciers through time in order to determine the response to climate change.

Glaciers should have been at their maximum extent when sea surface temperatures were at their minimum at the height of the last ice age. Ice sheets and glaciers are highly sensitive to climate warming and the Gallego Valley in the Spanish Pyrenees is host to a small single glacier that is rapidly receding. Climate change studies in this region have been hampered due to the lack of a complete record for the advance and retreat of ice in the valley and elsewhere in the Pyrenees.

Radiocarbon dating of samples taken from a lake in the valley indicated that glaciers were limited in the last ice age. However, this finding conflicted with the presence of young looking landforms created as the glacier advanced. Initial findings from exposure dating indicated that some features were much younger than previously believed. Samples were analysed to date the rate of retreat of ice up to the present day extent of the glacier.

Researchers used the project's results to reconstruct the glacier enabling them to estimate rates of temperature change as regional climate rapidly changed during global warming at the end of the last ice age. The findings from this project will help scientists and decision makers better understand the future effects of global warming and take mitigating actions to combat the environmental and economic costs.