For millions of years, Earth’s climate has been driven by natural cycles linked to its orbit, shifting between ice ages and warm interglacial periods. A new study has uncovered a clear, predictable pattern in these shifts, revealing that the next ice age should naturally begin in about 10,000 years.

However, human activities — especially greenhouse gas emissions — have disrupted this cycle, making it unlikely that we’ll see another glaciation anytime soon. These findings not only help us understand past climate changes but also provide a crucial tool for predicting long-term future climate trends and assessing the real impact of human intervention.

The Ice Ages and Earth’s Climate Cycles

Around 2.5 million years ago, Earth entered a cycle of alternating ice ages and warmer interglacial periods. The most recent ice age ended about 11,700 years ago. Now, a new analysis suggests that the next ice age could naturally begin in approximately 10,000 years.

An international team of researchers, including scientists from the University of California, Santa Barbara, based their prediction on a fresh interpretation of subtle changes in Earth’s orbit around the sun. These small shifts have driven major climate changes over thousands of years. The study, which examines a million years of climate data, reveals new insights into Earth’s glacial cycles. Published in Science, the findings mark a significant advance in understanding the planet’s long-term climate patterns.

Uncovering Patterns in a Million Years of Climate Data

The team examined a million-year record of climate change, which documents changes in the size of land-based ice sheets across the Northern hemisphere together with the temperature of the deep ocean. They were able to match these changes with small cyclical variations in the shape of Earth’s orbit of the sun, its wobble and the angle on which its axis is tilted.

“We found a predictable pattern over the past million years for the timing of when Earth’s climate changes between glacial ‘ice ages’ and mild warm periods like today, called interglacials,” said co-author Lorraine Lisiecki, a professor in UCSB’s Earth Science Department. One type of change in Earth’s orbit was responsible for the end of ice ages, while another was associated with their return.

“We were amazed to find such a clear imprint of the different orbital parameters on the climate record,” added lead author Stephen Barker, a professor at Cardiff University, in the UK. “It is quite hard to believe that the pattern has not been seen before.”

Decoding the Triggers of Glacial Cycles

Predictions of a link between Earth’s orbit of the sun and fluctuations between glacial and interglacial conditions have been around for over a century but were not confirmed by real-word data until the mid-1970s. Since then, scientists have struggled to identify precisely which orbital parameter is most important for the beginning and ending of glacial cycles because of the difficulty of dating climatic changes so far back in time.

The team was able to overcome this problem by looking at the shape of the climate record through time. This allowed them to identify how the different parameters fit together to produce the climate changes observed.

Why the Next Ice Age Is Still Far Away

The authors found that each glaciation of the past 900,000 years follows a predictable pattern. This natural pattern — in the absence of human greenhouse gas emissions — suggests that we should currently be in the middle of a stable interglacial and that the next ice age would begin many millennia in the future, approximately 10,000 years from now.

“The pattern we found is so reproducible that we were able to make an accurate prediction of when each interglacial period of the past million years or so would occur and how long each would last,” Barker said. “This is important because it confirms the natural climate change cycles we observe on Earth over tens of thousands of years are largely predictable and not random or chaotic.” These findings represent a major contribution towards a unified theory of glacial cycles.

“And because we are now living in an interglacial period – called the Holocene – we are also able to provide an initial prediction of when our climate might return to a glacial state,” said co-author Chronis Tzedakis, a professor at University College London.

How Human Activity Disrupts Natural Climate Cycles

“But such a transition to a glacial state in 10,000 years’ time is very unlikely to happen because human emissions of carbon dioxide into the atmosphere have already diverted the climate from its natural course, with longer-term impacts into the future,” added co-author Gregor Knorr from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.

Using Past Climate to Predict Our Future

The team plans to build on their findings to create a baseline of the Earth’s natural climate for the next 10,000-20,000 years by calibrating past changes. Used in combination with climate model simulations, researchers hope to quantify the absolute effects of human-made climate change into the far future.

“Now we know that climate is largely predictable over these long timescales, we can actually use past changes to inform us about what could happen in the future,” Barker added. “This is something we couldn’t do before with the level of confidence that our new analysis provides.”

“This is vital for better informing decisions we make now about greenhouse gas emissions, which will determine future climate changes.”

Explore Further: Ice Ages Follow a Hidden Pattern, and Scientists Just Cracked It

Reference: “Distinct roles for precession, obliquity and eccentricity in Pleistocene 100kyr glacial cycles” 27 February 2025, Science.
DOI: 10.1126/science.adp3491