Climate change is easy to understand — boethius

For decades now, scientists have known, just from looking at the geological record, that the reglaciation should start sometime in the next few centuries. That means glaciers come back down and cover Chicago. It means the UK is under a sheet of ice. This was disturbing news when it was first discovered, and we now know quite a bit more about how it works, what the trigger is, and so forth.

We don't presently know if increased CO2 will cause us to miss the trigger, or if reglaciation will begin anyway. There are aspects of the question that we don't even know how to model right now.

No, it's not simple.

↪boethius

With global warming

1. The greenification of Antarctica will occur.

2. The northward march of the timber line has been predicted.

Negative feedback loops, oui? — Agent Smith

These are not negative feeback loops. The greenification of the Antarctic would be a massive change the the earth-life-system.

Eventually the CO2 will come down due to mostly weathering over hundreds of thousands of years.

However, this is not a negative feedback loop changing the earth-system back to what it is now.

Mass extinction, followed by a green antarctic, followed by millions of years of biodiversity recovery and potentially returning to the glaciation that we've had recently, is not stability.

These are not negative feeback loops. — boethius

Why? A rise in CO₂ causes global warming which in turn causes greenification that then causes a fall in CO₂. That's a negative feedback loop alright!

For decades now, scientists have known, just from looking at the geological record, that the reglaciation should start sometime in the next few centuries. — Tate

You present yourself as "knowledgeable" about ice-ages ... but have not even bothered to read the second paragraph of the wikipedia entry "ice age":

In glaciology, ice age implies the presence of extensive ice sheets in both northern and southern hemispheres.[3] By this definition, Earth is currently in an interglacial period—the Holocene. 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, and likely more glacial cycles after. — Ice age

What would have been the natural pattern if we didn't dump billions of tons of carbon a year into the atmosphere ... is not of predictive value if we do dump billions of carbon a year into the atmosphere.

It's like we're discussing building a damn, and you're explaining how that's not a problem for the ecosystems because the river has been naturally flowing without a problem for the fish for thousands of years, and scientists have already said the salmon come back every year to spawn (it's their instinct).

The problem is that it's as irrelevant as stating any random fact about the climate.

The problem is that it's as irrelevant as stating any random fact about the climate. — Xtrix

For decades now, scientists have known, just from looking at the geological record, that the reglaciation should start sometime in the next few centuries. That means glaciers come back down and cover Chicago. It means the UK is under a sheet of ice. This was disturbing news when it was first discovered, and we now know quite a bit more about how it works, what the trigger is, and so forth.

We don't presently know if increased CO2 will cause us to miss the trigger, or if reglaciation will begin anyway. There are aspects of the question that we don't even know how to model right now.

No, it's not simple. — Tate

You present yourself as "knowledgeable" about ice-ages ... but have not even bothered to read the second paragraph of the wikipedia entry "ice age": — boethius

We're in an interglacial period of a large scale ice age. Specifically, we're at the end of an interglacial awaiting reglaciation.

Why? A rise in CO2 causes global warming which in turn causes greenification that counters the rise in CO2. That's a negative feedback loop alright! — Agent Smith

That's not a negative feedback loop that keeps the system stable, which is the issue: stability.

Negative feedback loop, connotes a a feedback mechanism strong enough to return a system to the same state: maintaining stability.

There is negative feedback, but it is not some sort of loop that returns the system to stability. Some carbon is absorbed by greening the antarctic, but it is a paltry amount compared to what we've emitted so far, and, in any-case, even small compared to other sources of CO2 such as permafrost and rain forests burning away.

It is not a feeback look, but better described as a buffer; absorbs some, like the oceans, slows down warming, but doesn't return the system to its former state.

A feedback loop would be that CO2 increase triggers mad greenification of deserts rapidly absorbing the excess C02 back to equilibrium baseline. This would be hypothetically possible if CO2 was the limiting factor to plant growth; however, it's not.

An example of a feedback mechanism in the earths system is ice melting:

More ice melts in the arctic ocean, more exposed water, more energy is absorbed resulting in more melting.

More ice melts in Greenland, more water absorbing more energy, but also lower the altitude of the ice surface gets, the lower the altitude the hotter, causing more melting (under a certain threshold catastrophic melting will occur).

We're in an interglacial period of a large scale ice age. Specifically, we're at the end of an interglacial awaiting reglaciation. — Tate

If we did not change the composition of the earth's atmosphere.

I literally just cited the wikipedia article on "Ice age" explaining this, that we have already delayed the next glaciation by a good 500 000 years due to the carbon we've already emitted.

If we change the earths atmosphere composition even more, we can exit an ice-age to a significant (mass-extinction scale) degree (lose all year-round ice in the arctic) or even exit an ice age completely and melt the Antarctic as well, mass-extinction even harder.

If we change the earths atmosphere composition even more, we can exit an ice-age significantly (lose all year-round ice in the arctic) or even completely. — boethius

It's possible. If we burn all the coal we can access it will become more likely. That would take around 200 years.

It's possible. If we burn all the coal we can access it will become more likely. That would take around 200 years. — Tate

So how does that square with the earth's biosphere is "self correcting"?

And, again, assuming you're aware outcomes increase in severity with the warming and have uncertainties (maybe it takes "burning all the coal", maybe it takes significantly less), how are these acceptable risks to take?

Earth Overshoot Day

Jul 28, 2022 (this year)

By the way, they do list some actions that can help.

So how does that square with the earth's biosphere is "self correcting"? — boethius

I don't even know what that means.

how are these acceptable risks to take? — boethius

It would probably be prudent to put the brakes on CO2 emissions, like completely.

I don't even know what that means. — Tate

You're the one arguing we'll stay in an ice-age ... because we're in an ice-age.

That natural cycles, like the next glaciation, will happen for some reason despite our modifications to the atmosphere.

It would probably be prudent to put the brakes on CO2 emissions, like completely. — Tate

So what are you even arguing?

Completely irrelevant, as was the initial comment.

The fact remains: climate change is caused by greenhouse gas emissions, and is happening at a rapid rate. Very simple indeed.

If you want to discuss ice ages, and how climate change may impact the next ice age, fine -- that's a different topic.

You've been making statements like:

For decades now, scientists have known, just from looking at the geological record, that the reglaciation should start sometime in the next few centuries. — Tate

Climatologists are observing glaciers melting and predicting more melting, where are the climatologists predicting reglaciation starting sometime in the next few centuries?

And if reglaciation is going to happen in the next few centuries, why worry about warming or stop CO2 emissions?

It's not a different topic if it's happening in the next few centuries and there's nothing to worry about ... except starting to move our Northern most populations south so they don't get buried in kilometres of ice.

If you want to discuss ice ages, and how climate change may impact the next ice age, fine -- that's a different topic. — Xtrix

I think it's very much on topic.

where are the climatologists predicting reglaciation starting something in the next few centuries? — boethius

As I said, we've known about this since the 1980s. It just doesn't come up much because it's centuries away.

And if reglaciation is going to happen in the next few centuries, why worry about warming or stop CO2 emissions? — boethius

I would say because of the unknown, something unforeseen. Suppose some super disease appears because of climate change,and we don't survive it?

If down the road we want to stop reglaciation, let tomorrow's scientists figure out how to do that safely.

Thanks for being so friendly, and not at all unnecessarily aggressive.

Some possibly VERY good news:

https://www.huffpost.com/entry/manchin-schumer-climate-deal_n_62e1a677e4b07f83766bafbb

A complete reversal.

If you want to discuss ice ages, and how climate change may impact the next ice age, fine -- that's a different topic.
— Xtrix

I think it's very much on topic. — Tate

Randomly stating facts about ice ages in a climate change thread is irrelevant. Stay on topic or start another thread about ice ages.

As I said, we've known about this since the 1980s. It just doesn't come up much because it's centuries away. — Tate

Can you cite one climate model predicting an ice age in a few centuries?

I would say because of the unknown, something unforeseen. Suppose some super disease appears because of climate change,and we don't survive it?

If down the road we want to stop reglaciation, let tomorrow's scientists figure out how to do that safely.

Thanks for being so friendly, and not at all unnecessarily aggressive. — Tate

Did you even bothering reading the second paragraph of wikipedia entry on "ice age"?

I'll site it again:

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, and likely more glacial cycles after.[4][5][6] — Ice age-Wikipedia

Wikipedia can certainly be wrong, but claiming it is wrong should have more support than simply vaguely referencing something scientists knew in the 80s; and at least one reference to compete with Wikipedia's 3 references for this point.

And neither 50 000 years nor 500 000 years sounds like a few centuries to me.

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, — Ice age-Wikipedia

Wow. This is wrong. Wikipedia lets us down

Didn't know that. Reference? — Tate

Apologies, can't seem to find one. However, in my defense, since climatologists claim global warming is a fact, they should be able to confirm/counter my claim; after all science is all about making accurate quantifiable predictions.

Apologies, can't seem to find one. However, in my defense, since climatologists claim global warming is a fact, they should be able to confirm/counter my claim; after all science is all about making accurate quantifiable predictions.
nowReplyOptions — Agent Smith

There is a delay from CO2 emission to associated temperature increase. Maybe that's what you were thinking about?

Wow. This is wrong. Wikipedia lets us down — Tate

I've explained at some length the idea of "supporting your conclusions".

Like, how is Wikipedia wrong on this point, what's the errors in the analysis of the cited sources? ... where are the climatologists with models demonstrating the ice age coming in a few centuries?

Like, how is Wikipedia wrong on this point, — boethius

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, — Ice age-Wikipedia

Models show that at present levels of CO2, reglaciation will begin somewhere between 500 and 3000 years. If we burn all the available coal, it becomes a near miss. In other words, we don't know for sure, but it looks like we would miss this trigger, and it would be around 40,000 years before another trigger arrives.

I'll have to look at what research they based that comment on.

There is a delay from CO2 emission to associated temperature increase. Maybe that's what you were thinking about? — Tate

Aye!

@Tate

If an ice age is in the offing, the greenhouse effect could be just what the doctor ordered. The two could cancel each other out and we would've averted a global catastrophe. If the road to hell is paved with good intentions, the road to heaven could be paved with bad ones! :snicker:

God moves in a mysterious way. — William Cowper

If an ice age is in the offing, the grenhouse effect could be just what the doctor ordered. — Agent Smith

It means change is ahead no matter what we do. Civilization emerged during a relatively serene period. It's first big test will be whatever happens in the next few centuries.

Models show that at present levels of CO2, reglaciation will begin somewhere between 500 and 3000 years. If we burn all the available coal, it becomes a near miss. In other words, we don't know for sure, but it looks like we would miss this trigger, and it would be around 40,000 years before another trigger arrives. — Tate

I’ll say it once more: not only is this inaccurate, it’s also completely irrelevant and off topic.