Recent research by the University of Arizona provides a compelling explanation for the rapid expansion of ice sheets that marked the last ice age and possibly other glacial periods in Earth’s history. Published in Nature Geoscience, the study delves into the origins of these massive ice sheets that once covered much of the Northern Hemisphere and their quick spread, a subject that has long puzzled paleo-climate experts. This investigation highlights the critical periods of Earth’s climate, swinging between extremely cold phases, with glaciers dominating vast regions, and warmer periods where glaciers retreated.
About 100,000 years ago, during a significant temperature drop in the Northern Hemisphere, mammoths roamed an earth burgeoning with massive ice sheets over regions including today’s Canada, Siberia, and northern Europe. These ice sheets emerged over about 10,000 years, defying previous understanding of their formation in areas like Scandinavia and northern Europe, known for milder temperatures due to influences like the North Atlantic Current.
The breakthrough came from the use of the Community Earth System Model, an intricate Earth-system model that replicated the starting conditions of the last glacial period. This model, extended to cover a significant part of the Northern Hemisphere in high detail, pinpointed the ocean gateways in the Canadian Arctic Archipelago as a decisive factor in ice sheet formation. The simulations showed that blocking these waterways led to cooler conditions in Scandinavia, conducive to ice growth.
This discovery not only sheds light on past climate changes but also enhances climate models for future predictions. It underscores how minor disturbances can cause significant, abrupt changes in ice sheet distribution, affecting sea levels, ocean currents, and global climate patterns. The interdisciplinary collaboration behind this research, employing advanced computational resources to simulate Earth’s atmosphere, oceans, and ice sheets, marks a significant advance in understanding Earth’s climate history and its dynamic system.