I often hear that we are in an interglacial period, which is like a break in an ice age. Will global warming prevent this, or will the ice age come back at some point?
Summary: (pdf) some scientists expect this interglacial may last 50,000 years.
Ignoring anthropogenic warming, the temperature cycling during the Pleistocene has been erratic. Here’s an article that summarizes reasons for the cycling: forcing by “astronomical conditions” (Earth’s orbit configuration), amplified by positive feedbacks (mainly greenhouse gases but also ice albedo). The article is a reasonable summary, but I linked to it primarily because the diagram at the top, when enlarged, shows temperature estimates going back 650,000 years. There are better graphs to show the Milankovitch cycles, whose aperiodic behavior directs the “forcings,” but in the 2nd part of the 3-part graph just mentioned you can see Green (CO2, a proxy for temperature) not reaching 260 ppm for 200,000 years but then, starting 440,000 BP, remaining above 260 for about 40,000 years. This illustrates the irregularity of the Milankovitch cycles. The present state of those cycles is similar to that 430,0000 years ago, suggesting that the present interglacial is due to be long even without anthropogenic forcing.
Factoring in human’s CO2 contributions, it’s easy to accept the premise of the pdf above. Moreover, the Earth has entered and exited from Glaciation Epochs before the Pleistocene for largely unknown reasons. AFAIK, few scientists speculate when the 2-plus million year-old Pleistocene glaciation epoch itself will end, or if man’s activities could end it “prematurely.”
Mods - this is hardly a question with an actual answer. Predicting the future isn’t one of the forums here, now, is it? What’s this question doing here?
A recent similar thread.
I guess the answer is, “it’s complicated.” But, it’s reasonable to assume we’ll eventually get our CO2 emissions under control and a long time after that we could enter another ice age, unless we decide to actively prevent it.
Yes, just like “when will Pluto next reach the pericenter of its orbit” is not a question with an actual answer. Just because we can’t say something with 100% certainty does not prevent us from giving solid, well-justified answers. We have a pretty decent idea of what turns the knobs of long-term climate, and can make solid inferences based on that (as was done upthread).
Related question, if I may: what precisely would living through an ice age be like? I’m not a scientist. However, I’ve read/heard/been told (by unscholarly sources) that, while it would be cooler on average, the whole planet would not turn into a ball of ice or become largely uninhabitable (for humans, anyway).
Or, that may never happen. If we manage to push the Earth into one of its warm periods, it’s unlikely humans will be still around when another ice age occurs; Earth spends 80% of its time not in an ice age, and so it might be hundreds of millions of years before the next one comes, if one ever does.
Humans are highly unlikely to be around that long, one way or another.
Glacial periods can get bad enough that humanity would be unlikely to survive; there may even have been a “Snowball Earth” during one of the earlier ice ages. Fortunately that’s unlikely to happen again; as the Sun has grown warmer over time, such catastrophic freezing has become more unlikely than it once was. The biggest problem would probably be the changeover to the new climate; apparently the transition to a cold, glacial period can happen over less than a decade or two, which wouldn’t be long for humanity to adjust to such a radical change.
There’s another problem besides ice though; climate instability. For the last few tens of thousands of years our climate has been largely stable, but that may have been a historical oddity; if that’s true then a climate shift (warmer or colder) could be disastrous for agriculture if the local climate is no longer predictable.
Well, first of all it’s not going to happen all that fast, so we’d have plenty of time to adapt. Second of all, it would depend on how big an ice age it was. At one point not long ago, Manhattan was under a mile thick glacier, so Wall Street would be a bit chilly. 
The more hospitable climates are just further south in the northern hemisphere and further north in the southern one. But it also gets a lot drier in most places, because much of the moisture is locked up in Ice. However, it’s often thought that we (our intelligence, that is) is the product of an ice age, so how knows-- we might come out the other end smarter!
An ice age is coming back. Is a matter of when, not if. Now this could be in 10 years, 100 years, 1000 or 10,000 years. That is the issue no one knows.
We do not understand enough of the cycles of nature. Atmosphere cycles, ocean current cycles, ocean temperature cycles, the orbital cycles of the earth, the sun cycles. I left a couple out, and I am sure there are cycles we not even know about. Then there is the interaction between them, in which one will affect others etc. It is the interaction of all of these that determine the climate.
Will global warming stop the coming of the next ice age? Highly doubt it IMHO.
The transition to notably cooler weather might occur that quickly. That doesn’t mean that over a decade mile-deep glaciers would invade all of Europe & most of North America. That glaciation would still take centuries to millennia to grow.
To be sure we could start having marginal crop failures all up & down the latitude scale over a decadal span. The interplay between the *overreacting panickers *and the *change denialists *would be / will be fun to watch.
The systems are very complex, but much better understood than this implies. With CO2 at high levels, ice receding, and astronomical cycles neutral, the chance of an ice age in the near future is essentially ZERO.
If OP or others are serious about the question, I refer them to the links I posted above.
IMHO, I’m not well informed enough to have a useful opinion on this question.
The opinions of André Léon Georges Chevalier Berger (a Belgian professor and climatologist … best known for his significant contribution to the renaissance and further development of the astronomical theory of paleoclimates and as a cited pioneer of the interdisciplinary study of climate dynamics and history) and M.F. Loutre can be read in the final few paragraphs of the paper linked above by me.
As things are nowadays, the answer is that it is not likely to come soon. And it is really missing a lot of information when one thinks that scientists that deal with the issue have not looked at the interactions and forcings.
Lets go to the [del]thought bubble[/del] Bad Astronomer:
http://blogs.discovermagazine.com/badastronomy/2011/06/17/are-we-headed-for-a-new-ice-age/
According to the article, the Earth has spent 80% of the last 500 million years in a greenhouse state. But, the Earth is currently in an Icehouse state, and we spend only 20% of that in a temporarily warmer interglacial period, where we are now. Without human-caused warming, we’re expected to enter a new glacial period within 50,000 years. I think within the next 100-300 years we’ll get CO2 under control, one way or the other. “Other” could be extinction of course. Or, we’ll wean ourselves off fossil fuels and the Earth could fall back into it’s “normal” rhythm. But, the Earth is aging, the solar system is aging, and the galaxy at large is aging and changing, so who knows what Earth’s normal climate rhythm is going to be.
The short story is that the present ice age (all information via Wiki articles on “Paleoclimatology” and “Timeline of glaciation”):
(1) Began about 2.58 million years ago,
(2) Has exhibited glacial maxima about every 100-150k years.
(3) Has exhibited glacial minima about every 100-150k years, in cycle with the maxima.
(4) And is probably not close to ending. (There have been four other known ice ages, the shortest of which lasted about 30 million years. The other three lasted about 100, 175, and 200 million years).
For years now I have been wondering why no one has considered the fact that the anthropogenic causes of the present warm period need to be disentangled from the warming trend that began after the the end of the last glacial maximum of 20000k years ago.
I have also wondered why no one has considered that AGW may be bringing with it a silver lining by preventing occurrence of another glacial maximum.
500 thousand years ago the sun was supposedly around 4% weaker than it is now, meaning that there had to be much more CO2 in the atmosphere to keep the earf from freezing over into a solid ball of ice. However, even though the CO2 level was high, much higher than it is today, there were still significant ice age/s.
This is because all other reasons (forcings) do not explain the current warming as well as the increase in global warming gases released by humans does.
Because the timing is still way off, as the IPCC reported:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-1.html
Not clear where the source of that is, when looking at other times when the CO2 was higher, the research points to the CO2 dropping to low levels first so then glacials begin to grow. When the solar output was around 4% weaker it was during the Cambrian-Ordovician, and that was approximately 488 million years ago
Modern civilization is more advance now so I think they would do well.It not like you are trying to live out on the streets.
We have people living in the Antarctica now. But I don’t think a new ice age will get that cold like the Antarctica or Northern Canada or the North east part of Russia.
With modern homes,electricity, heating and better clothes that we have today I think people will do okay.
It appears not everyone agrees with this. The last sentence of the third paragraph of the Wiki article on “Orbital forcing” states:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-1.html
I do not see where this quotation contradicts what I have written (or what Archer and Ganopolski have written).
With more context added, the point was that an increase of ice to the levels like the ones seen in the last glacial period will not likely be seen again until 50,000 years. More than what the IPCC reported, but it seems that the difference is between the time it will be likely to begin and the time we will be fully into it.
The last part there actually says that if the ice age was coming then the CO2 emissions will suppress that, but the point is that that ice age is not likely to be here soon anyhow.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-1.html
The point stands, there is no ice age that was coming soon to make the point that the current global warming was going to ‘prevent the occurrence of another glacial maximum.’ Instead of a “silver lining” it was only a wish that the increase in warming that is currently happening with the release of CO2 thanks to human activities was going to be taken care of by nature.