Robot Sub Finds Surprisingly Thick Antarctic Sea Ice

[sylas]

Actually the coming 'Ice Age' is likely inevitable, but were talking maybe ~20,000 to 40.000 or more in the future.

Probably not inevitable at this point. Absent the human effect, yes; that's the likely order of time to the next ice age. (There's been a interesting set of papers with different proposals for the time scale, but it's probably academic.)

The human impact is a spanner in the works; the long range impact of an enhanced greenhouse effect is very likely to have prevented the next ice age from occurring at all, even if we manage to put strong limits on future emissions and limit the consequent extent of warming over the next century. If we overheat the planet in a big way by continuing to burn as much fossil carbon as we can, then the whole ice age cycle thing is likely to stop for quite a long time; maybe several hundred thousand years.

In brief: long range estimation of a perturbed climate indicate that the usual triggers for the next ice age won't be enough; we've ALREADY prevented the next ice age. This long range isn't a long range climate projection as such; it's a long range CO2 projection (which is on much more solid quantified grounds.) Since raised CO2 levels persist for a long time, they become a factor to compare with the orbital forcings thought to precipitate ice ages. If CO2 levels are significant raised, a glacial epoch can't get started.

Typically, discussions of global warming and human driven climate change focus on the next 100 years. The impact of a changed atmosphere lasts much much longer than this.

A good book on this is Deep Future, by Curt Stager (2011). Subtitled: "The next 100,000 years of life on Earth". Online resources include This review at Science magazine, and Stager, C. (2012) What Happens AFTER Global Warming? in Nature Education Knowledge 3(10):7

Keep in mind that the sun is actually increasing it's energy output. 20 to 40 k years may be enough to offset this inevitable ice age. Not a claim just a question.

The answer to this is the effect of increasing solar output is way way too small to offset the next ice age. The Earth has for the last 2.8 million years or so been in what it called the Quaternary period, which is marked by cycles of advance and retreat of glaciers, on cycles of about 40K or 100K years. (A roughly 40K year cycle in the early part of the Quaternary, and roughly 100K cycle in the last million years.) There have many many many such cycles, and each cycle involves an "ice age" and a short interglacial warm phase (like our current Holocene period). Absent something drastic, these cycles of glaciation and recovery can be expected to continue for a long time yet.

However, as noted, the "something drastic" has already happened, and glacial cycles have most likely had a hiccup for the next hundred thousand years, at least.

You do touch on a very interesting point, however!

Solar changes have their impact on a scale of more like 100 million years; and it has been a mystery as to why Earth's climate has been so comparatively stable on such scales with the Sun getting brighter all the time. This is called the "faint young sun paradox". Google it; it's a well known puzzle in science.

The answer turns out to be carbon dioxide again; carbon dioxide levels in the atmosphere have fallen as the Sun has got brighter, and so the two factors (roughly) cancel out. There's a fairly well supported hypothesis about this phenomenon. Specifically, that this is no accident, but is rather the consequence of a very long range "slow" negative feedback. Hotter temperatures tend to result in increased weathering, and a draw down of carbon from the atmosphere to carbonates into geological reserves. The specifics mean that there is a characteristic temperature at which the draw down matches the comparatively steady output of carbon dioxide again from geological carbonate reserves through volcanic activity; and the feedback tends to drive temperature towards that sweet point, for a whole range of very different solar inputs. The effect is really really slow however. It's enough to keep up with the slow rate of increased solar output, but not enough to be a big factor driving swings in climate as occur from time to time for many reasons.

Cheers -- sylas

[Catholicity]

I might need to read a bit more as the memory of a young child can cross a bit..... I was my daughters age and younger (sheesh time flies)

[Truthseeker]

Keep in mind that the sun is actually increasing it's energy output. 20 to 40 k years may be enough to offset this inevitable ice age. Not a claim just a question.

By then most humans might live off earth in space colonies. Earth might become largely a nature preserve. If, that is, we have not nuked or polluted ourselves into extinction by then.

[Cow Poke]

Also, please see the graph i posted on the previous page.

science.jpg

[Jedidiah]

Actually the coming 'Ice Age' is likely inevitable, but were talking maybe ~20,000 to 40.000 or more in the future.

Keep in mind that the sun is actually increasing it's energy output. 20 to 40 k years may be enough to offset this inevitable ice age. Not a claim just a question.

[TheLurch]

CFC's were taken out in the 80's for fear of Global cooling,the now rebuilt hole in the ozone then in the late 90's early 2000's it was global warming now its climate change......

Also, please see the graph i posted on the previous page.

[phank]

in the late 90's early 2000's it was global warming now its climate change......

I think you are trying to imply that scientists are moving the goalposts here. This is not the case, as far as I can tell. Global warming has certain predicted effects, and the actual heating of the planet is perhaps the least visible, since we're only talking about a degree or two worldwide over a century. But even very slight overall warming causes side-effects of a wide variety - changes in ocean and air currents, for example, which bring unusually cold weather to nearly as many places as they bring unusually warm weather. Such things as floods and droughts aren't obviously connected to global temperature changes of fractions of a degree.

[shunyadragon]

Meh.... I heard a lot more about "Global Warming" before I ever heard of "Climate Change". I guess the reason that stuck with me was because, when I was grown up, it was "the coming Ice Age".

Actually the coming 'Ice Age' is likely inevitable, but were talking maybe ~20,000 to 40.000 or more in the future.

[sylas]

CFC's were taken out in the 80's for fear of Global cooling,

No; they were taken out because of fears that they were damaging the ozone layer. Nothing to do with temperature at all.

It's aerosols, not CFCs which have a cooling effect. CFCs actually contribute to warming, though that was NOT the reason for regulation. As for fears of global cooling: there were a few papers in the 1970s (not the 80s) which warned of possible gobal cooling from aerosols, although even then, the majority of research anticipated warming from CO2 and other greenhouse gases. There has never been a consensus on global cooling as there is with warming. Regulation generally needs a much more solid scientific case -- such as the thoroughly solid case that CFCs impact ozone. Cooling predictions, even in the 1970s when it got a bit of coverage in popular press, has only ever been a speculative notion supported by a minority of the research.... and it most definitely had nothing whatever to do with the regulation of CFCs.

With respect to CFCs, the issue with ozone was not cooling OR warming, but the vital role of the ozne layer for blocking of dangerous UV light. The regulation effort was successful, and subsequent research on the matter of CFCs seems to indicate that the ban helped us avoid a global disaster, of a global loss of most of the ozone layer by the middle of the 21st century. The world we avoided is one in which five minutes out in the Sun would result in severe sunburn.

There's a good feature article on this at NASA. See The World We Avoided by Protecting the Ozone Layer at NASA Earth Observatory.

Cheers -- sylas

[Catholicity]

CFC's were taken out in the 80's for fear of Global cooling,the now rebuilt hole in the ozone then in the late 90's early 2000's it was global warming now its climate change......

[Cow Poke]

Yeah, i'm old enough to remember that too. And an ice age most likely would have occurred in a few thousand years - they're the product of orbital changes that we can predict pretty thoroughly. But my memory makes it seem like the press hyped it as if it were something we needed to worry about now. Can't tell if that's my (limited) memory or what.

Yeah, from what I understand, it wasn't so much the scientific community making the claim, but it was "the hype", along with overpopulation. As if we didn't have enough to worry about with the Russians putting missiles in Cuba.

[TheLurch]

Meh.... I heard a lot more about "Global Warming" before I ever heard of "Climate Change". I guess the reason that stuck with me was because, when I was grown up, it was "the coming Ice Age".

Yeah, i'm old enough to remember that too. And an ice age most likely would have occurred in a few thousand years - they're the product of orbital changes that we can predict pretty thoroughly. But my memory makes it seem like the press hyped it as if it were something we needed to worry about now. Can't tell if that's my (limited) memory or what.

[rwatts]

The broader issue is both natural and human influence on climate change, and global warming from human influence. The issue is complicated yes, but picking on terminology does not face up to the problems.

I think another example here is that of the ozone hole, the cause of which was most likely, human induced. While that can never be proved with certainty, in the end people did wake up to the evidence, overcome fears of economic chaos if fixes were attempted, decide on a joint course action, and now there is hope that the hole might be closing.

[Cow Poke]

...when I was grown up...

Like THAT ever happened!

[Cow Poke]

Actually, they've both been used pretty extensively from the start.

Meh.... I heard a lot more about "Global Warming" before I ever heard of "Climate Change". I guess the reason that stuck with me was because, when I was grown up, it was "the coming Ice Age".