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Comment by Padding | Hacker News Reader

> global warming is just as bad as a new ice age, which, extrapolating from the past, would be about due by now, if not for mankinds influence

So global warming bought us all a huge chunk of (comfortable) time? Why is it a bad thing then?

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Desertification, increased sea levels causing flooding, higher atmospheric CO2 causing ocean acidification that will kill nearly all life in coral reefs sans jellies, etc etc.

Global warming probably isn't inherently bad if spread out over enough time, but large temperature fluctuations within a few centuries doesn't leave time for non-human species to adapt.

> Desertification, increased sea levels causing flooding, higher atmospheric CO2 causing ocean acidification that will kill nearly all life in coral reefs sans jellies, etc etc.

Yes .. or Maybe .. but that all still sounds preferable to an ice age, if kaybe is right, right?

> Global warming probably isn't inherently bad if spread out over enough time, but large temperature fluctuations within a few centuries doesn't leave time for non-human species to adapt.

Eh, I don't know about that - you're not wrong but I don't think this is a relevant/useful consideration given that

(1) given that reasoning "spread out over enough time" everything and anything will work out fine

(2) in the long run (or rather the "even longer run", considering the first point) we're all dead anyways

Is there actual clear evidence that global warming has truly prevented an ice age? It's certainly the first time I've seen that assertion put forth and I'd need some actual scientific evidence that's the case.

I do agree though, an actual ice age would probably have a much more severe impact that global warming...but I'd definitely prefer that neither occur.

No, there is no clear evidence for that, unless you count models. It is all extrapolation founded in data - we have the temperature curve for the last few hundred thousand years (basically this: [1]), as well as information about the composition of the atmosphere. It is not even clear why and how ice ages happen exactly [2].

I'd not even be sure how to show evidence for that unless we waited a few hundred thousand years to make sure the temperature curve does not behave as before. I can, however, give some links to the discussions (e.g.[3][4]). The people in [4] ran a model, here's the paper: [5], and found a small effect (contact me if you can't access it). It's hard to say how good model evidence is, however. A lot of influences are missing, and we'd need to validate the model with more data, which isn't there. (So yeah, I wouldn't count that as evidence, just a hint.)

At this point, this is just an idea discussed by people with domain knowledge and experience, nothing more. It doesn't change the fact that we have a problem, it just influences how people look at details of climate models, and which questions to ask the models.

[1] https://en.wikipedia.org/wiki/Temperature_record#mediaviewer...

or even longer for all of the planet's existence:

https://en.wikipedia.org/wiki/File:Five_Myr_Climate_Change.s...

[2] https://en.wikipedia.org/wiki/Ice_age#Causes_of_ice_ages

[3]http://www.technologyreview.com/article/416786/global-warmin...

[4]http://www.news.wisc.edu/16083

[5] http://www.sciencedirect.com/science/article/pii/S0277379104...

This is a great comment and I really appreciate you putting it together for me. I've read through all the links but can only read the abstract of the paper linked at:

http://www.sciencedirect.com/science/article/pii/S0277379104...

You mentioned that you could likely get that to me- it would be very appreciated. I'll send you a quick email as well. Thanks again!

Earth's surface is already 70% water, so lowering the sea level is better than raising it (coasts are productive, so 50% would probably be ideal); high temperatures also have implications for e.g. parasites (one possible explanation for why countries in cooler latitudes have been generally more successful than those closer to the equator).

You're right that cooling would be bad, and maybe a certain amount of controlled geoengineering through CO2 emissions would have been in order by now. But the level we currently have is past that, to the point where we're going to get far too hot, which is worse than being a bit too cold. If you're about to drive into a ditch then turning left a bit is good, but driving into oncoming traffic is worse than doing nothing.

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