Ice Ages are triggered by Earth's orbit, and 2 physics concepts prove it

A new simple yet comprehensive model depicts how the planet's orbit affects climate cycles.
Sade Agard
Woolly mammoth
Woolly mammoth

Daniel Eskridge/iStock 

A century ago, Milutin Milankovitch, a Serbian scientist, proposed that the long-term, cumulative effects of changes in Earth's location concerning the Sun are a significant driver of the planet's long-term climate and the onset and termination of glaciation periods.

Still, while numerous models prove that Milankovitch is correct, these techniques are frequently complicated and study-specific.

One scientist has proposed a new paradigm to simplify the verification of the Milankovitch hypothesis, according to a study published in the journal Chaos by AIP Publishing on March 7. 

How do Milankovitch cycles affect glacial transitions?

Significant variations in the amount of ice on Earth, sea level, carbon dioxide levels, and surface temperatures point to cycles of a lengthy, gradual transition into a glacial period and an abrupt change to a warm, brief interglacial phase.

According to Milutin Milankovitch's theory, the Earth's orbital parameters, such as the shape of its journey around the Sun and the planet's tilt, determine when such cycles occur.

For instance, a slightly closer orbit or a more tilted planet may result in a slight increase in solar radiation. Still, this change would be enough to trigger a feedback loop that causes significant climatic changes. Fundamentally, this theory implies that the climate, a notoriously complex system, may be somewhat predictable.

"The main motivation behind this study was to characterize and illustrate the Milankovitch hypothesis in a simple, elegant, and intuitive way," Pierini said in a press release

Pierini's "deterministic excitation paradigm" approach establishes a more general connection between Earth's orbital parameters and glacial cycle by combining the physics concepts of relaxation oscillation and excitability.

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In his "threshold crossing" criteria, he considers climate feedback loops, such as the one in which an increase in ice cover reflects more radiation into space, which causes more cooling and an increase in ice cover. This implies that climate change only happens suddenly when a parameter hits a particular tipping point.

The relaxation oscillation component explains how, following a disturbance, the climate gradually returns to its glacier-like initial state. The excitability component of the model then detects the external orbital shifts and starts the next glacial cycle.

Predicting Ice Ages

Pierini achieved the correct and consistent timing of the most recent glacial cycles by employing his threshold-crossing methods and adopting a classical energy-balance model.

"The application of the deterministic excitation paradigm in the present basic formulation can explain the timing of the last four glacial terminations," he stated. "Extending the same analysis to the whole Pleistocene will be the subject of a future investigation."

In Pierini's opinion, similar techniques could be applied to other nonlinear scientific disciplines and climate-related events.

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