Small fluctuation in the size of ice sheets during the last ice age may have caused extreme climate changes.
A Cardiff University team compared simulated model data with that retrieved from ice cores and marine sediments in hope of gaining insight into temperature jumps up to 10 degrees that took place in the far north during the last ice age.
The researchers confirmed thicker ice sheets increased the ocean circulation, transferring more heat north through a reduction in prevailing winds. As the north grew warmer the glaciers retreated and the winds returned to normal conditions, this cooled down the north once again and completed the climate cycle.
"Using the simulations performed with our climate model, we were able to demonstrate that the climate system can respond to small changes with abrupt climate swings. Our study suggests that at medium sea levels, powerful forces, such as the dramatic acceleration of polar ice cap melting, are not necessary to create abrupt climate shifts and temperature changes," said Conor Purcell from Cardiff University's School of Earth and Ocean Sciences.
The extent of the Arctic sea is much smaller than it was during the last glacial period. The Laurentide Ice Sheet, which was a major factor in ocean circulation during the glacials, has completely disappeared. These factors suggest the same patterns will not repeat themselves during the next ice age.
"In terms of the Earth's history, we are currently in one of the climate system's more stable phases. The preconditions which gave rise to rapid temperature changes during the last ice age do not exist today, but sudden climate changes cannot be excluded in future," said Professor Gerrit Lohmann, leader of the Paleoclimate Dynamics group at the AWI.
The findings were published Aug. 21, 2014 in the scientific journal Nature.
