Scientists have discovered how the tilting and rocking of the Earth affected the fate of ancient ice sheets

Researchers have finally answered a long-standing question about the role of the Earth’s orbit in managing global ice age cycles.

Scientists have succeeded in deciphering the precise role in controlling the cycles of the global ice ages, which play the tilting and swaying of the Earth as it orbits the Sun. Their new light illuminates the influence of the slope and precession on the melting of the ice sheets in the northern hemisphere since the early Pleistocene.

In a new study published on May 26, 2022 in a journal ScienceA team of researchers at Cardiff University has been able to determine exactly how the Earth’s tilting and fluctuations around the Sun have affected the melting of ice sheets in the Northern Hemisphere for about 2 million years.

Scientists have long recognized that the increase and decrease in the massive ice sheets of the northern hemisphere is due to changes in the geometry of the Earth’s orbit around the Sun.

There are two aspects of the Earth’s geometry that can affect the melting of ice sheets: slope and precession.

Obliquita is the angle of inclination of the Earth as it moves around the Sun, and is why we have different seasons.

The precession is the way the Earth sways as it spins, much like a slightly misaligned spinning top. The angle of this fluctuation means that sometimes the northern hemisphere is closest to the Sun and other times it is closest to the southern hemisphere, which means that about every 10,000 years, one hemisphere will have warmer sums compared to another before switching.

Researchers have found that over the last million years or so, the combined effects of sloping and precession on the rise and fall of the northern hemisphere’s ice sheets have led to ice age cycles lasting approximately 100,000 years through complicated interactions within the climate system.

However, 1 million years ago, in the period known as the Early Pleistocene, the duration of ice age cycles was controlled only by skew, and these ice age cycles were almost exactly 41,000 years long.

For decades, scientists have wondered why precession did not play a more important role in managing ice age cycles during this period.

In their new study, the University of Cardiff team uncovered new evidence suggesting that precession did play a role during the early Pleistocene.

Their results show that more intense years driven by precession have always caused melting glaciers in the northern hemisphere, but 1 million years ago these events were less devastating and did not lead to the complete collapse of ice sheets.

The study’s lead author, Professor Stephen Barker of Cardiff University’s School of Earth and Environmental Sciences, said: precession. This probably explains why it took us so long to find evidence of precession during the Early Pleistocene.

“These findings are the culmination of a major effort that includes more than 12 years of careful laboratory work to process nearly 10,000 samples and develop a range of new analytical approaches. Thanks to this, we can finally calm the long-term problem in paleoclimatology and ultimately contribute to a better understanding of the Earth’s climate system.

“Improving our understanding of Earth’s climate dynamics, even in the distant past, is crucial if we hope to predict change over the next century and beyond. Ongoing change can be man-made, but there is only one climate system and we need to understand it. ”

Reference: “The Lasting Influence of the Precession on the Variability of the Arctic War from the Early Pleistocene” by Stephen Barker, Aidan Starr, Jeroen van der Lubbe, Alice Doughty, Gregor Knorr, Stephen Conn, Sian Lordsmith, Lindsey Owen, Alexandra Nederbragt, Sidney Hemming, Ian Hall , Leah Levay, IODP Exp 361 Shipboard Scientific Party, MA Berke, L. Brentegani, T. Caley, A. Cartagena-Sierra, CD Charles, JJ Coenen, JG Crespin, AM Franzese, J. Gruetzner, X. Han, SKV Hines , J. Jimenez Espejo, J. Just, A. Koutsodendris, K. Kubota, N. Lathika, RD Norris, T. Periera dos Santos, R. Robinson, JM Rolison, MH Simon, D. Tangunan, M. Yamane and H. Zhang, May 26, 2022, Science.
DOI: 10.1126 / science.abm4033