If you think our winters are chilly, be glad you weren’t alive around 12,000 years ago, when Earth was undergoing its last Ice Age.

Our planet’s last glacial period (colloquially known as the Ice Age) began around 115,000 years ago and lasted for over 103,000 years of the Pleistocene Epoch. During this time, the Earth underwent repeated glacial (very cold) and interglacial (very warm) periods. In the interglacial periods (like the one we’re in now), ice sheets and ice caps melted, leaving rocky surfaces behind.

Even during the Ice Age though, temperatures across the planet were not as cold as you might think.

Though temperatures were cold enough to build up huge ice sheets (with lower ocean water levels as a result), the average global temperature was around 46 degrees Fahrenheit (8 degrees Celsius) according to a University of Arizona study.

To modern humans, the Ice Age sounds like a thing of the past – and given the last Ice Age happened so long ago, this much is true.

However, it’s important to note that we are currently in what is known as an interglacial period. As in, we are in a warm period between Ice Ages.

Though we won’t see it in our lifetimes, another Ice Age is coming.

And according to a statement from UC Santa Barbara, we can expect it to come in just 10,000 years’ time.

How do they know? Well, along with an international research team, UC Santa Barbara scientists explored how the Earth’s climate cycles in line with how the Earth orbits the sun.

As the orbit has changed over millions of years, our home planet’s climate has shifted, with glacial and interglacial periods a result, as Lorraine Lisiecki, from UC Santa Barbara’s Earth Science Department, explained in the statement:

“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.”

In their research – which was recently published in the journal Science – they discovered that as the Earth moved on its axis, as well as following its orbital trajectory around the sun, these micro adjustments eventually led to the end and return of Ice Ages.

As the team observed the Earth’s orbital parameters and climate records, they were able to explain how the climate experiences natural changes as millennia pass.

By doing so, they were able to clearly demonstrate how our climate does change over time due to natural causes, as Cardiff University’s Stephen Barker continued in the statement:

“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. 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.”

So the climate does undergo fluctuations of its own, due to natural changes in the Earth’s orbit and axis tilt.

With this information and millennia of data in mind, the scientists were able to predict that the next glacial state will occur in approximately 10,000 years.

However, their prediction comes with a warning.

Since the majority of the Earth’s 4.5 billion year lifespan has been spent with only natural factors affecting it, this is what the team’s data is based on. That means that all of the human factors that affect the climate cannot yet be accounted for.

Considering the significant effects that our species have had on our atmosphere – including high levels of greenhouse gas emissions – it is unlikely that the planet’s climate patterns will follow their usual patterns any longer, as Gregor Knorr from Helmholtz Centre for Polar and Marine Research warned in the statement:

“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.”

As a result, the team are currently exploring models that will take into account the effects of human-made climate change and demonstrate just how significantly we have affected the Earth’s natural rhythms, as Barker concludes:

“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.”

And that’s the thing: natural climate change is predictable, something that our planet is used to and can cope with. Human-made climate change, on the other hand, is unprecedented, its effects on our planet’s cycles unknown.

The best thing we can do is limit our effects on the environment now, before our climate spirals any further out of control.

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