The point I get is that natural insolation will not be cancelling the impacts of man-made global warming. Another point is in the tittle: ice age, interrupted. Compare with:

Tate's "ice age" (defined by the presence of ice caps) is ending. Because of us. -- Olivier5

So your article agrees with me, or rather, my take on CC is far closer to current science than Tate's crypto-denialism. — Olivier5

No one says the insolation will cancel the man-made global warming. But neither does the man-made global warming stop everything and prevent the earth from entering the ice age period.

And no, the article does not agree with your assessment that the man-made CO2 will end the ice age. "Interruption" means there is the change in downward trajectory of the climate temperature because the CO2 produced by industrialization is increasing the temperature. But it cannot go on indefinitely so as to stop the glacial cycle.

As for metronomes... sometimes they break. Gime a sledgehammer and a metronome, and I'll show you how it might happen. The metronome is our climate, the sledgehammer is greenhouse gases. — Olivier5

It's good to insert what-if scenarios, but let's deal with what's real right now. It's not broken yet, let's deal with that.

This is a report on a computer model. — Tate

"Global Warming Good News: No More Ice Ages"

I cannot comment on the computer model, but my argument is that this is very very bad news, not good news.

If ice sheets and glaciers don't melt a bit in the summer, the ice accumulates and starts to advance—in past ice ages, sheets of ice covered all of Canada and most of the Northern United States.

I have already pointed out that Earth has been in a fluctuating ice period for 33 million years. A world without ice is going to be a totally unrecognisable place. Covering Northern Europe and Canada with ice would happen very slowly and would not disrupt the whole world to anything like the same extent.

I cannot comment on the computer model, but my argument is that this is very very bad news, not good news. — unenlightened

That title was click bait. The article was supposed support this statement:

"The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for the next 500,000 years, which otherwise would begin in around 50,000 years..."

Firstly, the Wikipedia statement doesn't even make sense. Secondly, the cited articles don't support it. That Wikipedia article is going to be edited.

but my argument is that this is very very bad news, not good news. — unenlightened

Ya think?

But it cannot go on indefinitely so as to stop the glacial cycle. — L'éléphant

I don't see why not.

I don't see why not. — Olivier5

Icebergs. That's why. Icebergs breaking away and migrating farther to other oceans and melting, causing changes in oceanic patterns which then causes the oceans to absorb excess CO2 from the atmosphere. The resulting cooling effect triggers the ice age.

Take away: when oceans temperature lowers, more CO2 are absorbed into the oceans.

scientists believe the climate is likely headed toward reglaciation, — Tate

We the planet should be so lucky to re-glaciate, preferably before the 2024 election.

Icebergs. That's why. Icebergs breaking away and migrating farther to other oceans and melting, causing changes in oceanic patterns which then causes the oceans to absorb excess CO2 from the atmosphere. The resulting cooling effect triggers the ice age. — L'éléphant

I think you are telling yourself fairy tales, perhaps because you are too afraid to face the truth. At current melt rate the northern hemisphere won't have any permanent ice by 2040, 2050 at the latest.

At current melt rate the northern hemisphere won't have any permanent ice by 2040, 2050 at the latest. — Olivier5

"Sea ice" you should say; Greenland ice will take a little longer to melt, fortunately.

Firstly, the Wikipedia statement doesn't even make sense. Secondly, the cited articles don't support it. That Wikipedia article is going to be edited. — Tate

I'm all for editing articles, and I agree the sentence is wooly and inaccurate, and at the same time too precise about the future which remains open to an extent. But wiki is better than clickbait.

"Sea ice" you should say; Greenland ice will take a little longer to melt, fortunately. — unenlightened

That's correct. Thanks for the precision.

But wiki is better than clickbait. — unenlightened

That click bait article was referred to by the Wiki article.

I'll be using a range of articles from scientific publications.

We the planet should be so lucky to re-glaciate, preferably before the 2024 election. — Bitter Crank

It's going to be a shit show. I agree.

That click bait article was referred to by the Wiki article.

I'll be using a range of articles from scientific publications. — Tate

Ah. Apologies; since you had just said that, I thought that it was one of your articles.

Tate

Ah. Apologies; since you had just said that, I thought that it was one of your articles. — unenlightened

No. I was just killing two birds with one stone: contributing to this topic and preparing to edit a poorly written Wikipedia page. That page used sources that misquoted other sources. Not good.

If you want, we could talk a little bit about the present major ice age, sometimes called the Quaternary. We can discuss theories about why it happened. The Wikipedia articles for that are pretty good, so I'll reference them.

To review:
Major ice ages, as we discussed, happen for a variety of reasons.

In the case of the Quaternary, for some time now the leading theory has been about a change in ocean currents which happened about two and a half million years ago. It is true that atmospheric CO2 is down about 90% from what it was before the Quaternary, but that may be a positive reinforcing side effect as opposed to a cause. Cold water holds more CO2 than warm water, so as the ocean currents changed to cool the surface, the oceans started pulling in CO2, cooling the world further.

From here:

An important component in the development of long-term ice ages is the positions of the continents.[16] These can control the circulation of the oceans and the atmosphere, affecting how ocean currents carry heat to high latitudes. Throughout most of geologic time, the North Pole appears to have been in a broad, open ocean that allowed major ocean currents to move unabated. Equatorial waters flowed into the polar regions, warming them. This produced mild, uniform climates that persisted throughout most of geologic time.

"But during the Cenozoic Era, the large North American and South American continental plates drifted westward from the Eurasian plate. This interlocked with the development of the Atlantic Ocean, running north–south, with the North Pole in the small, nearly landlocked basin of the Arctic Ocean. The Drake passage opened 33.9 million years ago (the Eocene-Oligocene transition), severing Antarctica from South America. The Antarctic Circumpolar Current could then flow through it, isolating Antarctica from warm waters and triggering the formation of its huge ice sheets. The Isthmus of Panama developed at a convergent plate margin about 2.6 million years ago, and further separated oceanic circulation, closing the last strait, outside the polar regions, that had connected the Pacific and Atlantic Oceans.[17] This increased poleward salt and heat transport, strengthening the North Atlantic thermohaline circulation, which supplied enough moisture to arctic latitudes to create the northern glaciation.[18]"

At current melt rate the northern hemisphere won't have any permanent ice by 2040, 2050 at the latest. — Olivier5

I'm not gonna ask for source on this. I'm not concerned about sources. I'm more concerned about the logic of what you're saying. If icebergs are breaking away from the ice sheet, then they are mobile. If they're mobile, they're drifting to the other oceans. And if they're going to those oceans, then they are cooling those oceans, like the Atlantic. Which is what we need to happen so the oceans can absorb CO2. The ice need to migrate to faraway oceans, and not just stay in the antarctic. The arctic apparently is enclosed, trapping its ice.

So then, the absorption of excess CO2 will allow the natural processes of insolation changes, which would trigger the start of glacial event or the ice age.

I apologize in advance to the families of polar bears. They will adapt, I'm sure.

The gist of the OP seems to be that global warming maybe just what the doctor ordered for the coming ice age. Hot + Cold = Just right (re Goldilocks & the 3 bears).

Of course this makes sense only if the rising CO₂ levels don't cause a paradoxical reaction and hasten/sustain/intensify/prolong an ice age.

The gist of the OP seems to be that global warming maybe just what the doctor ordered for the coming ice age. Hot + Cold = Just right (re Goldilocks & the 3 bears). — Agent Smith

Actually the OP doesn't say that at all.

Actually the OP doesn't say that at all. — Tate

I read between the lines! Perhaps an overactive imagination. Apologies, I'm into conspiracy theories! :blush:

I read between the lines! Perhaps an overactive imagination. Apologies, I'm into conspiracy theories! :blush: — Agent Smith

Let's not do that, ok?

Let's not do that, ok? — Tate

Roger!

Let's not do that, ok? — Tate

I don't know, this thread has not gone anywhere in millions of years of discussion. Maybe a good conspiracy theory could liven it up a bit.

I don't know, this thread has not gone anywhere in millions of years of discussion. Maybe a good conspiracy theory could liven it up a bit. — Metaphysician Undercover

This is a weekend project for me.

Get back to work then! It's not the weekend yet.

Get back to work then! It's not the weekend yet. — Metaphysician Undercover

:grin:

The Drake passage opened 33.9 million years ago (the Eocene-Oligocene transition), severing Antarctica from South America. The Antarctic Circumpolar Current could then flow through it, isolating Antarctica from warm waters and triggering the formation of its huge ice sheets. — Tate

This seems to me to be fundamental to the relative coolness of our climate ever since. In the North, the ice sheets come and go, but the Antarctic has been much more stable. But things are changing.

Whichever model winds up being most accurate, Dutton says it’s important to understand that the Antarctic ice sheet has an intrinsic tipping point.

“And there’s a real possibility we’re very close to it,” she says. “And we need to do everything in our power to prevent that from happening.”

https://www.nationalgeographic.com/environment/article/antarcticas-ice-could-cross-this-scary-threshold-within-40-years

Here are links from that article to a couple of papers available to the public.
https://www.nature.com/articles/s41586-021-03427-0.epdf?sharing_token=twBZA98km78OTx6AMy9W3dRgN0jAjWel9jnR3ZoTv0O1wLV2jblnuB2ZPB-nrPqiYIGrpSsWrxM6Zs9mXF_ynlXr1wSaMYX_yu3g0MtdOLlXhPdfZT7AIzZxxZPZi3eUhpkHsGguFotFouKQ8B8w2uIC2vXVZ2u18y_S1IFK1j1eEHc3lS8clGR4m-3cQS-WfAfUH5RhB-WU5xv6HTwn7ITa6h-rNuY7QaoyU5Ywu48%3D&tracking_referrer=www.nationalgeographic.com

https://www.nature.com/articles/s41586-021-03302-y.epdf?sharing_token=U2E-t2XStTtmBYyTQ7DPQdRgN0jAjWel9jnR3ZoTv0NBHKcAC_lrDjYnFOA0lhyL19H0suFTY3jD1u_wNHSNLuEPeFiQcKfrHUjiWydOqBabgwjyVi_e3JBCqopJDL-a4vTPRx8BISM-mI4eZrD-0dOT6mF18jZFK6RISo8M7dkEgurfH5a6tZ2nrBje9JYKnkjGDKrByRsfxgfGndjjnH1Jgqhn5nmt93q5gR3_Hgw%3D&tracking_referrer=www.nationalgeographic.com

I wonder if the tipping point they're talking about is where the loss of Antarctica's albedo effect causes positive feedback on warming. Once that starts, there's no easy way to go backward. It would cause a gigantic global refugee crisis and crop failures at the same time.

I'll dig into it. Thank you!

I wonder if the tipping point they're talking about is where the loss of Antarctica's albedo effect causes positive feedback on warming. — Tate

I think they are not sure. There are several positive feedback mechanisms, and some negative ones. The albedo is one, and the loss of sea ice can also speed up glacier flow rate. But also, warming seas increase snowfall. The one they are least sure about is what happens as the ice edge moves back and the exposed edge gets thicker.

The nature of tipping points is that the only way to find them in practice is to tip them. That would not be a great policy, though, however interesting.

This is from the first paper:
"These results demonstrate the possibility that rapid and unstoppable sea-level rise from Antarctica will be triggered if Paris Agreement targets are exceeded."

This is fascinating. They aren't saying Antarctica will give up all its ice, it will just be smaller by 2300. There's little reason to doubt that by 2300, a lot of presently inhabited coastline will be abandoned (unless there's a significant policy change). This was just looking at a 3 degree rise in mean temperature. A high projection is 8 degrees (assuming all available fuel is burned.)

I've been reading about climate models. There are hundreds of short term models. This is the basis of IPCC statements.

Long range models are problematic because of the proportionally larger amount of data and the challenges of testing them.

Since the 1990s, long range modeling has progressed by an accumulation of contributions by scientists. The size of ice sheets is considered to be one of the most important factors, if not the most important.

When reglaciation starts, the first step is an increase in northern ice accumulation. Likewise, deglaciation starts with a decrease in their size.

I've been surprised that it's hard to find good books on long range modeling.