Humans have postponed the ice age on Earth, which was expected to occur in 11,000 years.

For the last 800,000 years, changes in the tilt of the Earth have driven the movement of massive ice sheets on the planet, triggering the beginning and end of all eight glacial periods, reports LiveScience.

A new study has clearly demonstrated the relationship between Earth's tilt and the formation of ice sheets, says lead author Stephen Barker. Based on the results obtained, scientists stated that the next glacial period on Earth should begin in about 11,000 years if it weren't for global warming.

"The forecast is that the next glacial period could begin within the next 10,000 years. However, this model does not take into account the increasing greenhouse gas emissions that are warming the planet to such an extent that they prevent glacial periods," Barker explains.

Glacial periods are extremely cold intervals that previously occurred on Earth every 100,000 years. During these times, much of the planet was covered by enormous ice sheets that remained in place for thousands of years. Currently, Earth is in a warm interglacial period, and the last glacial period peaked about 20,000 years ago.

Previously, scientists believed that the position and angle of the Earth relative to the Sun influence the formation of ice sheets. In the early 1920s, Serbian scientist Milutin Milankovitch proposed that slight changes in the tilt of the Earth's axis and the shape of Earth's orbit could trigger large-scale glacial phenomena.

Researchers have been testing Milankovitch's theory for the past 100 years. Notably, a 1976 study found geological evidence that two parameters of the Earth—tilt and precession, or the changes in the tilt of the Earth's axis and how the axis wobbles around itself—play a role in the growth and retreat of ice sheets. However, the exact role of each parameter remained unclear.

Now, Barker and his colleagues say they have finally unraveled the effects of these parameters.

Currently, the Earth's axis is tilted at 23.5 degrees from vertical as it orbits around the Sun, affecting how much solar energy reaches each pole, in particular. However, the tilt of the Earth's axis naturally increases and decreases in a cycle that lasts about 41,000 years. The axis also wobbles, like an off-center spinning top, influencing how much solar energy reaches equatorial regions during summer over periods of about 21,000 years.

"We found an astonishing relationship indicating that there is a direct connection between the phases of tilt and precession, which affects how long it takes for ice sheets to decay," the scientist adds.

In simpler terms, the expansion of ice sheets from the poles to the equator appears to be directly regulated by tilt. Conversely, the retreat of ice sheets from the equator back to the poles is more dependent on precession.

The graphs were so precise that scientists extrapolated the data and estimated when the next glacial period would occur if the climate were to change solely according to natural cycles. Further research is needed to accurately determine the timing, but ice sheets are likely to start expanding in about 10,000 to 11,000 years and reach their maximum size within the next 80,000 to 90,000 years. They would then require another 10,000 years to retreat to the poles.

There is much debate about the timing of the next glaciation, but most experts agree that human activities are disrupting these cycles through global warming.

"If CO2 levels remain high, there will be no new glaciation," Barker concluded.

As a reminder, scientists have determined how far the ice sheets advanced during the largest glacial period on Earth.