Origins of ice age climate changes may lie in the Southern Hemisphere, where interactions among the westerly wind system, the Southern Ocean and the tropical Pacific can trigger rapid, global changes in atmospheric temperature, according to an international research team led by the University of Maine.
The mechanism, dubbed the Zealandia Switch, relates to the general position of the Southern Hemisphere westerly wind belt — the strongest wind system on Earth — and the continental platforms of the southwest Pacific Ocean, and their control on ocean currents. Shifts in the latitude of the westerly winds affect the strength of the subtropical oceanic gyres and, in turn, influence the release of energy from the tropical ocean waters, the planet’s “heat engine.” Tropical heat spreads rapidly through the atmosphere and ocean to the polar regions of both hemispheres, acting as the planet’s thermostat.
The Southern Hemisphere climate dynamics may be the missing link in understanding longstanding questions about ice ages, based on the findings of the research team from UMaine, Columbia University’s Lamont-Doherty Earth Observatory, the University of Arizona, and GNS Science in New Zealand, published in Quaternary Science Reviews.
For more than a quarter-century, George Denton, UMaine Libra Professor of Geological Sciences, the journal article’s first author, has led research reconstructing the history of mountain glaciers in the Southern Hemisphere. In the late 1980s, he and Wallace Broecker, a geochemist at Columbia University, noted that a key question about ice ages remained unresolved — the link between ice age climate and the orbital cycles in the length and strength of the Earth’s season. Evidence showed that ice age climate changes were synchronous in both polar hemispheres, with rapid transitions from glacial to interglacial global climate conditions. They concluded that existing theories could not adequately account for changes in seasonality, ice sheet size and regional climate.
The University of Maine’s Forest Bioproducts Research Institute (FBRI) is collaborating with Poland Spring Brand 100% Natural Spring Water to evaluate and develop bio-based solutions that could serve as alternative packaging for Poland Spring products. As part of the collaboration, UMaine will explore new possible uses of materials derived from sustainably harvested Maine wood.
FBRI represents an interdisciplinary group of researchers and scientists dedicated to advancing understanding and development of forest-based bioproducts. The institute is directed by Hemant Pendse, professor and chair of the Department of Chemical and Biomedical Engineering. FBRI has brought the Maine forest industry and public and private technology innovators together to explore emerging bio-based solutions, from materials to chemicals to fuels, demonstrating the exciting possibilities available through advancement of the circular economy.
“UMaine is grateful for Poland Spring’s support of our world-leading research, development and commercialization in this area,” says UMaine President Joan Ferrini-Mundy. “Forestry is a cornerstone of Maine’s economy, and the Forest Bioproducts Research Institute was created to provide and promote technology validation and partnerships that will meet societal needs for materials, chemicals and fuels in an economically and ecologically sustainable manner.
“This collaboration serves that important mission,” says Ferrini-Mundy, “leveraging the expertise of our faculty and staff, and facilitating the engagement of our students in cutting-edge research with important implications for our state and the wider world.”
The initiative aligns with the University of Maine System Research and Development Plan.