Scientists have determined the rate at which global warming has delayed the onset of the next ice age

Ice age Earth

Zoonar/Alexander Savchuk/Alamy

Without human-induced climate change, the Earth could have been on track to enter another ice age within 11,000 years. This long-term prediction of the planet’s “natural” climate is based on a new analysis of how orbital shapes and the tilt of their axis combine to change the amount of solar energy reaching Earth.

For millions of years, these orbital oscillations (known as the Milankovich cycle) entered and left the planet during the Ice Age about every 41,000 years. However, in the past 800,000 years, ice age has only occurred every 100,000 years. The ambiguity of the record as the ice sheets were willingly retreated meant that it was not possible to explain how trajectory changes were involved in driving this long cycle.

If previous research attempted to link orbital changes to a specific period, such as onset of an ice age, Stephen Barker Cardiff University in England and his colleagues took a new tack. They came back fading during the “glacial age” where they saw the overall pattern of the ice age, also known as ice age. This allowed us to link changes in trajectories with changes in ice, despite the ambiguity of ice records over the past million years.

They discovered that these 100,000-year cycles appear to follow simple rules. For the last 900,000 years, following the most circular phase of the orbit, the planets also tilted towards the Sun, thus causing an all-interglacial period after the Earth’s axis wobbled at the farthest from the Sun.

This suggests that all three of these aspects of Earth’s orbit (known as precession, oblique and eccentricity) are combined to create a 100,000-year glacial cycle, Barker says. “Since 900,000 years ago, this simple rule has predicted all of these major glacial end events, which says it’s really very easy to predict,” he says.

Under that rule, the next ice age where you currently live is expected to begin approximately 66,000 years from the year, as there is no impact on greenhouse gas emissions. But that could only be started if there was an ice age before that,” says Barker.

The diagonal and gradual stages of precession that preceded the Holocene suggest that the glacier is likely to be on track between 4300 and 11 and 100 years from now. We may now live in what would have been the onset of this next ice age. “Of course, it’s just a natural scenario,” says Barker.

More than 1.5 trillion tons of carbon dioxide have been released into the atmosphere as the Industrial Revolution is expected to cause sufficient warming to disrupt this long-term glacial cycle.

“The amount we’ve already put into the atmosphere is so big that it takes hundreds to thousands of years to pull it out through natural processes,” Barker says. However, he says more research is needed to define the planet’s future natural climate in a more detailed way.

This states that this is consistent with previous modeling suggesting that increased CO2 levels due to artificial emissions would prevent the onset of the next ice age, from dozens to hundreds of thousands of years. Andrei Ganopolsky At the Potsdam Climate Impact Research Institute in Germany.

But he says even pre-industrial levels of CO2 in the atmosphere were so high that it delayed the start of the next ice age by 50,000 years. This is due to the unusually small orbital changes expected in thousands of years and the unpredictable way that Earth responds to those changes.