The research draws parallels between Earth's ancient ice ages and its eccentric orbital patterns. These findings suggest that when Earth's orbit becomes more elongated, variations in the planet's distance from the Sun lead to increased melting of the Antarctic ice sheet. Conversely, a more circular orbit stabilizes the ice sheet.
Dr. Tim van Peer, lead author from the University of Leicester, commented, "From our research, we can see that the Antarctic ice sheet is more unstable than previously thought. We demonstrate how sensitive the geologically early Antarctic ice sheet was to changes in Earth's orbit and axis."
The study analyzed geological cores retrieved during a 2012 expedition by the Integrated Ocean Drilling Program (IODP). These cores contained microorganism fossils whose oxygen isotope ratios helped the team reconstruct the growth and shrinkage of the ice sheet over millions of years.
Professor Paul Wilson from the University of Southampton explained, "It may be a surprising thing to learn that we take the pulse of the Antarctic ice sheet by doing some simple chemistry on pinhead-sized fossil shells from the deep sea floor on the other side of the world. But the really beautiful thing is that we can do it back through the geological record over tens of millions of years."
The research reveals that during warmer periods, such as 28 to 20 million years ago when only the Antarctic ice sheet existed, shifts in Earth's orbit caused dramatic changes in ice volume. These insights not only enhance our understanding of ancient climate systems but also offer critical lessons about the potential impact of current ice sheet melting.
Dr. van Peer added, "We cannot assume that the modern-day Antarctic ice sheet is stable. If climate emissions continue unabated, we are on course to melt a large amount of the Antarctic ice sheet. We need to mitigate climate change by reducing our emissions. This is the only way to not cross tipping points in the stability of the Antarctic ice sheet."
The study was funded by UK Research and Innovation/Natural Environment Research Council and the German Science Foundation (DFG).
Research Report:Eccentricity pacing and rapid termination of the early Antarctic ice ages
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University of Leicester
Beyond the Ice Age
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