COSMOS MAGAZINE
Climatologists have linked small changes in Earth's orbit over millions of years to ice age cycles, but human-caused climate change may have disrupted this natural pattern.
Credit: Matt Perko, UC Santa Barbara.
Serbian scientist Milutin Milanković first proposed that variations in Earth's orbit and rotation influence the planet's climate, an idea later confirmed in the 1970s as Milanković cycles.
Three key factors —obliquity (tilt of Earth's axis), precession (wobble of the axis), and eccentricity (shape of Earth's orbit) — interact to drive a 100,000-year cycle of ice ages.
Recent research has found that precession is the primary driver of the end of ice ages, while obliquity plays the dominant role for the beginning of ice ages.
The result is that ice ages have a roughly 21,000-year cycle with their relative intensity determined by each cycle lining up. This confirms that Earth's climate cycles are largely predictable, not random.
We are now living in an interglacial period, and although the next ice age would typically be expected in about 10,000 years, ongoing human-caused carbon emissions are likely to prevent this transition.