By Ross Pomeroy
Hundreds of millions of Americans are presently besieged by a massive arctic blast and winter storm. Luckily for them, it will only be temporary. That wasn’t the case 20,000 years ago…
Between 26,500 to around 19,000 years ago, gargantuan glaciers covered around a quarter of Earth’s land area year round. Their frigid reach extended to the areas that are now Minneapolis, Chicago, Detroit, and Boston. The average global temperature was then about 46 degrees Fahrenheit (8 degrees Celsius), 11 degrees F (6 degrees C) cooler than the global annual average today. It was a chilly time to be alive.
And make no mistake, humans were alive. Though much of our species sheltered around the equator at the time, some did live in cooler regions such as central Europe, not far from the glaciers’ icy reach. Clothing, constructed dwellings, fire, and omnivory all helped our ancestors outlast the cold.
When that great freeze ended and the ice retreated about 11,700 years ago, then humanity really started to thrive. Buoyed by the warmth of the current “interglacial” period, humans have been able to propagate pretty much everywhere on the surface of Earth.
But what if this period of relative warmth we’ve enjoyed were to come to an end? What if Earth entered another “ice age”?
First off, Earth is technically in an ice age right now, defined as a time when both of the planet’s poles are covered with ice. What people actually mean when they talk about an “ice age” is a “glacial period.” This is when the ice at the poles creeps toward the equator. These glaciers reflect the sun’s rays back into space, making the Earth colder, which allows the glaciers to spread further, which chills the Earth even more – a positive feedback loop.
Glacial periods are initially triggered by subtle changes in Earth’s orbit as well as its tilt and wobble. These factors collectively affect how much solar radiation the Earth receives. Such changes are cyclic and predictable, which means that we have the ability to gauge when another glacial period is on the way. So when will that be?
Current estimates suggest that we have at least 10,000 more years of relative warmth, and perhaps as many as 200,000. Why the wide range? Because we are ourselves drastically altering the climate by burning fossil fuels. The more we burn, the longer we delay the next glacial period.
In a study published in December, a team of researchers estimated that under current conditions, the next ice age is expected 50,000 years into the future. If we emit twice as much carbon as we have so far, which we’re on pace to do in the next five decades, the next ice age will begin in 100,000 years. The researchers say we could delay glaciation by up to 200,000 years from present, but by then an ice age is likely unavoidable.
Professor Andreas Born at the University of Bergen’s Department of Earth Science isn’t so sure.
“If a new ice age were to come, cities like Oslo, Stockholm, and Chicago would be covered by several thousand metres of ice. In that case, it’s probably highly unlikely that humans would allow this to happen again, as long as there’s a society,” he told ScienceNorway. “That could mean that the last ice age was actually the last ice age.”
Over the next tens of thousands of years, it’s reasonable to assume that humanity will have pioneered numerous ways to geoengineer the planet’s climate on rapid timescales, so another ice age could very well be preventable. But if not, humans will likely have hundreds or even thousands of years to adapt as polar ice returns to claim the land at lower latitudes. It won’t appear as suddenly as America’s current cold snap.
This article was originally published by RealClearScience and made available via RealClearWire.
Earth remains glaciated. Antarctica and Greenland are still ice blocks.
The bulk of the NH is in an interglacial that is coming to its natural end. And burning carbon will not delay that unless the air quality is constantly degraded to lower the albedo of the ice.
Warming oceans in the NH means more snow. This year already above trend snow extent. Eventually the snow does not melt from year-to-year and accumulates as already being observed on Greenland plateau.
In contrast to this clear statement on incipient re-glaciation the timescale of centuries (sub-millennial), the Norwegian simulations (the subject of Pomeroy’s post) indicate no appreciable glaciation over the next 50,000 years (that’s 50 millennia), even for the reference case wherein atmospheric CO2 never topped 300 ppm!
In light of historical evidence — the 2,7-Myr of the Pleistocene’s ‘true Ice Age’ shows not one Interglacial duration briefer than ~ 20-kyr — this looks like gross malpractice.
Yet ‘Hans Erren’ (commenting above) writes that such predictions (for ~ 50 millennia of continued mild climate) are nothing new!
Meanwhile back to reality. Earth has experienced a glaciation with TEN TIMES today’s atmospheric CO2 levels. CO2 “drives” NOTHING.
what’s the definition of “ice age” again?
We’re in one now. The definition being the presence of permanent ice sheets in both hemispheres.
Either stupidity or a linear combination of ignorance and hubris. Difficult to determine which.
No, ice ages are cyclical and unstoppable. The next one is overdue.
As for CO2, we were at very dangerous low levels. Even with the slight modern increase, levels are way lower than in the past, when life flourished on Earth.
When thinking about stopping another ice age, most folks just say yeah or nay without much thought. My own view is based on assuming there are critical points that when passed (aka tipping point) lead to increases in glacial advances. Hence, if you can stop the first one, you can stop the entire glaciation.
Keep in mind the Earth is still getting the same amount of solar energy, so the key to prevent the first occurrences of increased albedo.
My opinion is this first tipping point is Hudson Bay. If it does not melt out in the summer, then it allows snowfall around it to remain and that is the beginning stage. From there glacial advancement in the western hemisphere starts the cooling trend.
If true, this provides a rather simple solution. Keep Hudson Bay at current temperatures. Probably the least invasive way would be to place lots of geothermal based heating elements across the southern edge of the Bay to make sure it stays warm enough to produce open water every year.
A lot of non-scientist read WUWT; this is for them from Gemini…
If you want to find the real culprit behind Earth’s dramatic climate swings, you might need to stop looking at tailpipes and start looking at Mars.
It sounds like science fiction, but the geological record tells a different story. We are currently living in the Quaternary Ice Age, and the “extreme” weather we see today might be nothing more than the natural, violent heartbeat of a planet being tugged at by its neighbors.
The 100,000-Year Mystery: For decades, geologists were stumped. Every 100,000 years, like clockwork, Earth’s ice sheets undergo a massive “Termination”—a rapid, violent thaw followed by a brief warm spell.
The problem? Earth’s own “wobble” isn’t strong enough to cause that much change on its own.
Enter the Red Planet. Recent studies in orbital mechanics have confirmed that we are part of a celestial tug-of-war. The gravitational pull of Mars (and the heavy-hitting Jupiter) actually stretches Earth’s orbit.
The Stretch: Every 100,000 years, Earth’s orbit becomes more elliptical (squashed).The Heat: This change in shape dictates how much solar fire we catch from the sun.The Result: Without Mars, that 100,000-year cycle likely disappears, and our climate stays “stuck.”Nature Doesn’t Do “Gradual: “We’re often told that climate change is supposed to be slow and that “fast” change is a modern anomaly. The rocks say otherwise.
About 1 million years ago (the Mid-Pleistocene Transition), Earth’s climate gears shifted. We went from a relatively mild 41,000-year cycle to the “extreme” 100,000-year cycle we have now. This shift was entirely natural—driven by orbital resonance and internal Earth feedbacks.
Still in the Deep Freeze: It’s easy to forget because we’re currently in a “warm” patch called the Holocene, but we are technically still in an ice age.
An ice age is defined by the presence of permanent ice at the poles. Since Antarctica and Greenland are still frozen, we are living through a 2.5-million-year-long cold snap (which actually started 34 million years ago when Antarctica first froze over).
From this perspective:
Extreme Weather is the Baseline: In an ice age, the climate “flickers” constantly.“Normal” is a Myth: The only “normal” for Earth over the last 500 million years is a “Greenhouse” state with no ice at all.Orbital Drivers: We are passengers on a planet whose climate is dictated by its orbit, its tilt, and the gravitational nudges of its planetary neighbors.The Bottom Line: Is the climate changing? Absolutely. But is that change “unprecedented”? Not even close.
When you factor in the “Mars Effect” and the violent history of our current ice age, it becomes clear that Earth is a highly sensitive, nonlinear system. It doesn’t need a reason to be extreme—extreme is just what it does.
There is no 100,000 year glacial periodicity, interglacial periods of the last 800kyr are close to the peaks in obliquity, but not all of the peaks. The most common interval is about 84,600 years, but the interval since the Eemian is longer than any previous interval.
Oh this is so frustrating. I said this before, and I a going to repeat myself. Carbon is a solid therefore it can not be emitted! The other thing I object is the assertion, that we are postponing an ice age by burning fossil fuels. This is patently wrong. Not only we, humans, contribute less than 4% to all the CO2 in the atmosphere, but nearly 160 scientific papers were published in recent years finding CO2 to be totally irrelevant when it comes to warming the planet: https://notrickszone.com/2024/01/18/nearly-160-scientific-papers-detail-the-minuscule-effect-co2-has-on-earths-temperature/ The other proof, that CO2 is not preventing ice ages, is found in reconstruction of CO2 concentrations and temperatures for the last 600 million years: https://geocraft.com/WVFossils/Carboniferous_climate.html This requires to scroll down a page or two, until a graph with the heading “Global Temperature and Atmospheric CO2 over Geologic Time” is seen. This graph shows at 450 million years ago long lasting ice age, while CO2 was at 4000ppm. So if ice age can exist at this high CO2 levels, how is burning of fossil fuels going to postpone or even prevent an ice age!?
I have referred to this “inconvenient history” frequently.
It is interesting that no “explanation” (indeed no response whatsoever) ever comes from the usual suspects who endlessly defend the junk science of human induced warming.