How variations in Earth’s orbit are melting the ice caps

Since the dawn of time, the polar caps have evolved according to variations in the Earth’s orbit. Scientists figured this out a long time ago. But exactly how these variations influence our climate has remained mysterious. Till today.

The earth rotates around Sun. It’s well known. What is perhaps less so is that the way our planet travels in space, its position on its orbitis not quite engraved in the marble. Variations are slight. But they have effects on our climate.

And today, Cardiff University researchers (UK) confirm to us that over the last million or so years it is the combined effects of theobliquity — which corresponds to the inclination of the axis of the Earth — and precession — which describes the way the Blue Planet wobbles, much like a slightly off-center spinning top — that most influenced the state of the ice caps. In any case, of that of the northern hemisphere. The result is glacial cycles of duration about 100,000 years old. But before that, the obliquity effect tended to dominate. During the Lower Pleistocene period, instead, glacial cycles lasted almost exactly 41,000 years.

Probing the past to better understand the climate

After 12 years of work on nearly 10,000 samples, the researchers show that precession still played a role in this distant period. It could, for example, be the cause ofwarmer summers. themselves responsible for melting of the ice cap. But without going as far as his collapse complete.

“Early Pleistocene ice sheets in the Northern Hemisphere were smaller and restricted to higher latitudes where the effects of obliquity dominate over those of precession. This probably explains why it took us so long to find evidence of precessional forcing in the early Pleistocene.”explains Stephen Barker, a researcher at Cardiff University, in a communicated. What improve the understanding that scientists have of the climatic dynamics of our Earth and, in fact, better predict the future climate change.