Modern day technology is offering insight into the ocean tides and currents during the glacial ice age that occurred over 21,000 years ago. © Andrew Ryzhkov

A joint research study between the Complutense University of Madrid (UCM) Spain, and the Potsdam-Institute for Climate Impact Research in Germany has been singled out for received special mention from the American Geophysical Union. Their research has been published in the prestigious journal Geophysical Research Letters.

The researchers found that small alterations in sea winds were critical factors in the abrupt change in climate that occurred during the last glacial period. The root cause for the last glacial period has yet to be determined or completely understood.

The authors of the study, Dr Marisa Montoya and Professor Anders Levermann, concluded that there is a precise point at which a small variation in the speed of sea winds corresponds to a dramatic change in circulation intensity. 'If the glacial climate had been in the vicinity of that point, small wind changes could have caused sudden and significant climatic changes during that period,' said Dr Montoya.

The researchers based their study on climatic simulations of the Last Glacial Maximum (LGM). This refers to the period of time when the ice sheets reached their maximum extent — en event that occurred over 21,000 years ago. This period lasted for several thousand years and affected the whole of Iceland, and with the exception of the southernmost tip, the whole of the United Kingdom and all of Northern Europe.

Climatic simulations positively demonstrated the existence of a tipping point where even the smallest changes in wind speed cause disproportionately large changes in the speed of sea currents. Thus, changes in wind speed may well have played an important role in the abrupt climatic change of the last ice age.

Creating climate simulations of the Last Glacial Maximum is one of the most important challenges for experts in this area. Now these simulations are able to be cross-referenced with climatic reconstructions based on data gathered from natural elements, such as sea sediments or the oldest ice samples. Thanks to these simulations, all climatic models previous made can be evaluated in a method that does not include the same parameters and conditions used in their design.

The results achieved by the model also confirm the relevance of small variations and help further substantiate the hypothesis regarding the physical mechanisms responsible for the climatic changes as observed in the reconstructions.

Now scientists have both the climatic simulations as well as the reconstructions at their disposal, both of which indicate that variations in the Atlantic Ocean circulation could have been the key mechanism responsible for the abrupt climatic change that took place over the ice age.