/ Ice house earth vs Greenhouse Earth

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skog on 11 Jan 2017

There's plenty of talk about climate change and global warming, but I haven't seen as much discussing the "alternatives".

The Earth is in Ice House mode at the moment - we're currently in an ice age.

Within an ice age, the climate flips back and forth between interglacial periods (the permanent ice is restricted mostly to the areas around the poles, and high altitudes - what we're experiencing just now), and glacial periods (the ice advances, covering much more of the globe - what most of us probably think of when the term "ice age" is used).

On a longer cycle, the climate flips between Ice House and Greenhouse "modes"; when it's Greenhouse, the permanent ice melts away, and sea levels rise.

There seems little doubt to me that humans are having a significant effect on the climate by increasing greenhouse emissions and modifying terrain. The Earth has a lot of mechanisms which push it back towards some sort of equilibrium, but it looks very possible that we're about to tip it from the current mode to another.

A period of rapid climate change will inevitably cause a lot of disruption, population displacement, and a host of other problems while we (and the rest of life) adapt to it - it will lead to some very difficult times, I'm not disputing that at all.

What I'm wondering here is whether tipping Earth back to Greenhouse mode might actually be preferable (in the longer term) to letting the cycles run their course, and having it tip back into a fresh glacial period within the current ice age.

Some possible advantages of each:

Ice House:
- more land available; current coastal cities may find themselves further inland, but are unlikely to end up submerged.
- less extreme weather due to lower atmosperic energy content

Greenhouse:
- no land lost to permanent ice
- more shallow ocean, possibly leading to a boom in life (this is where most life lives, I believe) and potential for food production
- more atmospheric energy available for power generation


UKC has a lot of very knowledgeable users; I'd be very interested to hear thoughts from those who know more about this sort of thing.
Post edited at 12:15
1
davidbeynon on 11 Jan 2017
In reply to skog:

An abrupt change in any direction risks breaking agriculture, which would result in all sorts of fun. It would probably only take 4 or 5 years with harvests as bad as 2012 before we would be in real trouble.
no_more_scotch_eggs - on 11 Jan 2017
In reply to skog:

risk of this happening

https://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation

that would be very bad indeed.

even without an oceanic anoxic event, acceleration of desertification is likely to cause large scale conflict and population movements which i doubt our currently configured global society could withstand.

the consensus is that global rise in temperature must be kept below 2 degrees, otherwise positive feedback mechanisms kick in and its likely to turn out very bad for future generations
skog on 11 Jan 2017
In reply to davidbeynon:

Yes, I'm pretty sure that's true, but it isn't what I was hoping to talk about here.

I'm really asking about the long term situation, once the climate settles down into a new mode.
skog on 11 Jan 2017
In reply to no_more_scotch_eggs:

Yup. But please see my reply to davidbeynon!
no_more_scotch_eggs - on 11 Jan 2017
In reply to skog:

not sure a mad max style post apocalyptic dystopia with conflict and death on an unimaginable scale is likely to be a useful starting point for building a long term future that's better than likely ones based on our current environmental configuration... an awful lot of pain for some pretty uncertain gain...!
Trevers - on 11 Jan 2017
In reply to skog:

I don't think anyone's seriously suggesting climate change will be the end of the world, extinction of all life, Earth becoming Venus type event some people imagine. Simply that life today, and human civilisation in it's current state, is not robust to rapid changes in climate.

Interestingly, primitive hunter/gatherer society was probably much better able to adapt to rapid changes than we are now.
1
skog on 11 Jan 2017
In reply to no_more_scotch_eggs:

> a mad max style post apocalyptic dystopia with conflict and death on an unimaginable scale

This is one possible result. It seems quite possible, but none of us know whether it would happen that way.

Regardless, I'm not suggesting we should deliberately cause a climate flip to happen! I do, however, think it's very likely that it's going to, anyway - people aren't good at proper long-term thinking.

Isn't it also worth considering how well we'd handle the alternative, though, with large parts of the currently temperate regions freezing over?

As I said above, change will cause disruption and lead to very hard times. However, barring massive sci-fi style advances in climate-controlling technology, change is definitely coming - the most we can hope for is to influence the timing, speed, and direction of the change.

Delaying and slowing change are pretty clearly good things. But when it comes, which direction is preferable?
davidbeynon on 11 Jan 2017
In reply to no_more_scotch_eggs:

The Mad Max approach only works until the stored food runs out. You just have to hope that not all the farmers get killed before the bandits starve.

Starting civilisation again from scratch is unlikely to be fun, and with all the cheap and easy fuel gone the survivors would have a job powering an industrial revolution.

On the other hand there will be plenty of pre refined metal lying around for a couple of hundred years so it may not be so bad if they get their act together quickly.

A lot of that metal is tied up in coastal infrastructure so it's probably easier to reach and less likely to corrode if it isn't under water.
no_more_scotch_eggs - on 11 Jan 2017
In reply to skog:

as i understand it- not being a climatologist- once we're past 2 degrees, the predictive value of the models drops off rapidly- there are lots of potential events such as the thermohaline collapse which may or may not happen- if it did, for example, the earth may get hotter overall, but western europe would end up with a severe drop in temperature, rendering it effectively uninhabitable, along with large parts of the tropics also being lost to cultivation. a new equilibrium will possibly take millennia to arrive at. if we're poor at changing behaviour with a known target and risks, over an understandable timescale, we're likely to be really rubbish at adapting society to meet an unknown end point 30-50 generations hence, with the probability that we would go through complete collapse of society to get there. i think preventing this is the only game in town, the alternatives are too grim to seriously consider

and- by then, we'll have used up all the resources that got us to the current state of advancement- good luck trying to rebuild society without access to hydrocarbons and coal. i think this is our only shot we get on this planet, its really important we don't blow it...
no_more_scotch_eggs - on 11 Jan 2017
In reply to davidbeynon:

i should have read your reply before making mine- same points made really!
skog on 11 Jan 2017
In reply to no_more_scotch_eggs:

OK, this isn't what I was hoping to talk about at all (having fully accepted that the period of rapid change in either direction will be awful, and having said so in my first post). But either I didn't phrase my question well, or people just aren't interested; fair enough!
Mike Stretford - on 11 Jan 2017
In reply to skog:

> Delaying and slowing change are pretty clearly good things. But when it comes, which direction is preferable?

Early humans seems to have coped with recent ice ages, but we were not around the earths 'hot' periods.
no_more_scotch_eggs - on 11 Jan 2017
In reply to skog:
i think you overestimate the knowledge of ukc users ... i'm not sure we have the knowledge to comment usefully on whether a world at a warmer equilibrium would be 'better' than our current one. there are too many unknown variables.

but you appeared to be asking more than that-

Isn't it also worth considering how well we'd handle the alternative

the sample of two of us that have replied think, very badly indeed- a potentially irretrievable collapse of civilization seems very likely indeed. i don't think trying to plan a managed change is an option, as you also wondered about; if we can't plan to reduce carbon emissions, we dont have a cats chance in hell of managing an orderly loss of entire subcontinents to habitation with the displacement of hundreds of millions of people...


so your initial question: i dont think anyone is able to usefully comment

and your implication of trying to 'ride the tiger' of change successfully- i'm not betting on that one working...

its limit rise in temperature to 2 degrees, or 'start genning up on survival tactics from the mad max franchise' time...


Post edited at 13:26
Mike Stretford - on 11 Jan 2017
In reply to skog:

> But either I didn't phrase my question well, or people just aren't interested; fair enough!

It isn't that we are not interested, you question prompted 15 minutes of online reading on my part. It's just too uncertain for us laymen to discuss in any meaningful way, hence my short reply.
skog on 11 Jan 2017
In reply to Mike Stretford:

> Early humans seems to have coped with recent ice ages, but we were not around the earths 'hot' periods.

This is what I was hoping for, thanks! Are you able to expand, or point me at some reading?
skog on 11 Jan 2017
In reply to no_more_scotch_eggs:

> whether a world at a warmer equilibrium would be 'better' than our current one.

Ah, I see - no, that wasn't really it.

As I understand it, the climate will change to a different mode in the next few thousand years, and possibly a lot sooner than that - there are natural cycles of change in addition to the change humanity is causing.

I was interested in whether a world at warmer equilibrium would be better than a world at colder equilibrium, which is the realistic alternative unless humanity can invent something which can stabilise the climate as it currently is (which might happen, but is science fiction for now).
Mike Stretford - on 11 Jan 2017
In reply to skog:
> This is what I was hoping for, thanks! Are you able to expand, or point me at some reading?

I just cross referenced this

https://en.wikipedia.org/wiki/Timeline_of_human_evolution

with this

https://en.wikipedia.org/wiki/Geologic_temperature_record#Overall_view

At first impression I would say some sort of civilisation could survive the highs of the Miocene period (up to 6 degrees), but not those of the Eocene (+12 degrees).

What we can say is humans have survived the coldest periods.
Post edited at 14:16
no_more_scotch_eggs - on 11 Jan 2017
In reply to Mike Stretford:

wow. +12 degrees. that would have been interesting to see!
skog on 11 Jan 2017
In reply to Mike Stretford:

I'm not sure how much can really be gleaned from that - humans have only been around for a few million years (evolving at the end of the Miocene), modern humans only for a couple of hundred thousand years, and large scale societies only for tens of thousands of years at most.

> What we can say is humans have survived the coldest periods.

Humans have, but modern societies only really started emerging (and technological development only really picked up) after things started getting warmer. Nothing resembling modern society has been tested by global temperatures either much above, or much below, what they are just now (though there may be some interesting evidence dealing with -localised- climate changes, which can be much more extreme).

I suspect humans and society can handle things very much warmer or very much colder, as long as the change happens slowly enough to allow technological and societal adaptation - I see no obvious reason why people couldn't live just fine on a much warmer or much colder planet, as people already live in places which are almost constantly frozen or almost always very warm.

I think it would be easier overall on a warmer planet - there should be more life and more land and other resources accessible, so it should be possible to support a larger population.
Mike Stretford - on 11 Jan 2017
In reply to skog:
> I think it would be easier overall on a warmer planet - there should be more life and more land and other resources accessible, so it should be possible to support a larger population.

My suspicion that you are coming at this with an agenda has just increased..... yes there may be more arable land available nearer the poles, but what about land lost to rising sea levels, desertification or frequent flooding? Neither you or I know enough to 'think' what 'should' happen.
Post edited at 15:28
Escher - on 11 Jan 2017
In reply to skog:

I listened to a podcast recently where your question was discussed. Randall Carlson is a scientist who is investigating cataclysmic impacts (comets etc) through our history by investigating geological evidence in various places. He speaks at length about his views on when global cooling has had a much larger impact on human civilisation than warming. He perhaps has less than main stream views of current climate change, the IPCC and the scientific consensus but he believes that most of the big impacts on human civilisation we've had have been down to global cooling.

Our current impending situation may be quite different to previous warming events, who knows, but certainly, in his opinion, cooling would be worse based on historical events. He claims that warming actually encourages population growth, can grow crops further north, longer seasons etc, whereas cooling has the opposite effect. Whether that wisdom can be applied to what's coming I am not so sure about.

https://www.youtube.com/watch?v=R31SXuFeX0A
skog on 11 Jan 2017
In reply to Mike Stretford:

> My suspicion that you are coming at this with an agenda has just increased

Haha, rumbled - yes, I have perfected my anti-aging serum, so the period of turmoil as the climate flips is a price worth paying for my gain centuries or millenia from now. ;-)

Seriously, everyone I've ever known will be long dead before the climate can stabilise at a new equilibrium. I don't have an agenda on this!

> .... yes there may be more arable land available nearer the poles, but what about land lost to rising sea levels, desertification or frequent flooding? Neither you or I know enough to 'think' what 'should' happen.

I studied geology, so I know how to be wrong in a marginally more informed manner than many; I was hoping to spark a discussion between people who could speculate wildly in a slightly more informed manner than me. (OK, so I did have an agenda after all!)

But I do know that the Earth has supported the most life at times when there are more shallow oceans (higher sea levels). And sea level rise from total ice melt and the associated thermal expansion would still leave most of the land (though it could cover a lot of the best arable land); glacial advance might not leave much unfrozen.
SenzuBean - on 11 Jan 2017
In reply to skog:

Here's my crazy idea, since we're bringing out crazy ideas - how about a technocratic dictatorship as an interim solution to protecting life as we know it and minimizing suffering, before we can return to our usual experimentation with democracy.
skog on 11 Jan 2017
In reply to Escher:

Thanks, I'll have a listen.

My first impression is that he's a bit insane... (quite entertaining to listen to, though!)
SenzuBean - on 11 Jan 2017
In reply to Escher:

> Our current impending situation may be quite different to previous warming events, who knows

One variable that we are having trouble taking into account is the health and extent of the biosphere. The biosphere responds to increased levels of CO2 by growing faster - thus taking more CO2 out of the system. If CO2 levels drop too low - the biosphere grows more slowly, thus taking less CO2 and helping it to stabilize as it is matched by increases. It can be seen that the biosphere works to keep the CO2 levels at some equilibrium.
What if we had a biosphere half as good as we do now? Well what would happen if we dumped a lot of CO2 into the atmosphere, it would take a lot longer for all of it to be sequestered - close to twice as long - the system can be said to react more slowly to changes.

So with that said, what have we done to our biosphere, and its ability to react to changes in atmospheric CO2? Even more importantly - what else are we injecting into the system that the biosphere is not effective at dismantling?

So with that said, there are profound changes going on to the biosphere, and we don't really know how that will affect our ability to react to changing CO2 levels. Then of course you have other greenhouse gases that the biosphere has little to no effect on - which is vastly more reckless. It's like the difference between roped climbing and soloing.
Mike Stretford - on 11 Jan 2017
In reply to skog:

> Haha, rumbled - yes, I have perfected my anti-aging serum, so the period of turmoil as the climate flips is a price worth paying for my gain centuries or millenia from now. ;-)

> Seriously, everyone I've ever known will be long dead before the climate can stabilise at a new equilibrium. I don't have an agenda on this!

Sidesplitting sarcasm aside, I think it would change the nature of the debate if there was a credible claim that human activity is preventing a devastating ice age, and instead ushering in a period of tolerable warmer earth for our descendent.

> I studied geology

That wasn't apparent.

> But I do know that the Earth has supported the most life at times when there are more shallow oceans (higher sea levels).

That's interesting, can you link to a scholarly article on that?

Overall the picture for marine life is mixed

http://wwf.panda.org/about_our_earth/blue_planet/problems/climate_change/

I suggested you had an agenda and didn't seem studied as you don't seem to be taking all the factors into account.

skog on 11 Jan 2017
In reply to Mike Stretford:

>I think it would change the nature of the debate if there was a credible claim that human activity is preventing a devastating ice age, and instead ushering in a period of tolerable warmer earth for our descendent.

Which debate? You seem to think I'm some sort of climate-change denier or similar, or that I'm suggesting we encourage the climate to warm. I'm not (though I do think it's almost inevitable that is humanity will keep pumping out vast amounts of greenhouse gasses until we either run out of fossil fuels or develop a cheap, clean alternative which can meet our ever-increasing energy needs).

> I suggested you had an agenda and didn't seem studied as you don't seem to be taking all the factors into account.

You're right - I'm not taking all the factors into account. I don't know anything like all of the factors. Perhaps I should start a thread asking people for their thoughts and knowledge on this subject? :-/


One last try - the climate changes naturally, flipping between different temporarily stable states. You linked to some information about this on wiki above; you might want to look up Milankovich cycles, too. Barring fantastical technological intervention, the current state of the global climate - an interglacial period in an ice age - will end and the climate will shift to a glacial period, or the ice age will end and we'll switch to a warmer mode. This is what happens, over and over. It may be thousands of years away, it may come much sooner.

Human activity is almost certainly causing the climate to warm. There's a real chance this will lead to a major change in the climate sooner than would otherwise happen; at face value it seems more likely to end the current ice age, but it's complicated and other possibilities exist such as the ocean circulation being shut down, leading to a larger Northern ice sheet forming, possibly leading to runaway global cooling (see above link from no_more_scotch_eggs). No, I don't know what will happen.

Rapid change will be harder to deal with than gradual change. Humanity is probably making rapid change more likely, and is probably going to make it happen sooner. This is probably going to be worse than if it had been left to change naturally, yes (though an entirely natural shift would also lead to very hard times, for much the same reasons).

I am wondering whether, once the change has completed, it would be better for humanity to find itself living in a glacial period, or in a greenhouse period. The limited amount I know suggests to me that the warm scenario would be better - and a quick look at the current land-based life, and human populations, of the Antarctic land mass in comparison to, say, the Australian one, appears to support this - but, no, I don't know. That's why I'm asking!
Mike Stretford - on 12 Jan 2017
In reply to skog:



> Which debate?

I think it is safe to say it is one of the issues of our time.

> The limited amount I know suggests to me that the warm scenario would be better - and a quick look at the current land-based life, and human populations, of the Antarctic land mass in comparison to, say, the Australian one, appears to support this - but, no, I don't know. That's why I'm asking!

Well, more people live in Siberia than Australia, both are sparsely populated.

In both scenarios land may become available that wasn't before, on a basic level that's swings and roundabouts. A fundamental requirement for us is potable water, do some research on that and we have a starting point for a discussion.

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stp - on 15 Jan 2017
In reply to skog:

I think there are some major variables that are so big to make the dichotomy between hot and cold scenarios almost meaningless. The rapidity of change is a massive factor. Also the amount of temperature change. A change of plus 3 degrees is going to be a very different scenario to plus 10.

Also are you thinking about the likelihood of civilization surviving or just the human species? The former seems unlikely to survive but I think some remnants of our species will probably survive in some areas whether it's hot or cold. But what's significant is the complete annihilation of culture. The final scene in the film 'Threads' illustrated this point pretty well. Our species stripped of it's culture is really not much more than just another species of ape.
wurzelinzummerset on 15 Jan 2017
In reply to Mike Stretford:
> ... A fundamental requirement for us is potable water...

Glacial periods are very dry, so that does lend weight to skog's argument. Furthermore, large areas of northern Europe and America would become glaciated and so uninhabitable. Contrast that to, say, the early Eocene when atmospheric carbon dioxide levels and global temperatures are believed to have been significantly higher than today allowing forests to spread to the polar regions and you can see that he does have a point. As it stands now, the glaciated scenario is where we're most likely heading (the mechanism has already been explained by skog). Evidence is that these changes can occur very rapidly (decades).
Post edited at 15:50

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