A new study confirms that changes in Earth’s tilt relative to the Sun have influenced the growth and retreat of ice sheets over the past 800,000 years, driving the onset and end of eight ice ages.
Researchers estimate that, under natural conditions, the next ice age would begin in around 10,000 to 11,000 years, with ice sheets reaching their maximum extent over the following 80,000–90,000 years before retreating.
The study builds on the century-old Milankovitch theory, which links ice age cycles to shifts in Earth’s axial tilt (obliquity) and its wobble (precession), both of which influence solar energy distribution.
Researchers found a strong correlation between Earth’s obliquity, which governs ice sheet expansion, and precession, which affects their retreat. These factors determine how long it takes for ice sheets to grow and decay.
Scientists agree that rising greenhouse gas emissions are preventing ice sheets from expanding, disrupting the natural glacial cycle that has shaped Earth’s climate for hundreds of thousands of years.
While preventing an ice age may seem beneficial, researchers warn that unchecked carbon emissions could lead to severe climate instability rather than a controlled long-term balance.
The study aims to provide a clearer picture of how Earth’s climate would evolve over the next 10,000–20,000 years without human interference, helping researchers assess the extent of anthropogenic impact.