Wed 20 Feb 2008
Ok, so Ice Ages come along every so often. With global warming and are unstable environment we are sure to eventually trigger an ice age.
When this does happen, and assuming humans are still around. Will we be able to reverse such a huge global climate trend? If an ice age were to hit us right now, could we stop it? Is that even possible? Is anyone researching the answers to these types of questions right now, or do we have our heads in the sand?
Posted by drewbody8 answers so far!
Well, an ice age would probably come on very slowly, so it would take a while for people to figure out what was going on. Scientists would call it a “cooling trend”. People would start moving to warmer climates. I don’t know if anybody would really start thinking it was something that needed to be stopped until it was too late.
And hey, so we’d all just party in the tropics and the walrusses would rule everything else. What’s the big deal?
Well, we could just dump CO2 into the atmosphere to heat the Earth up again. Since everyone says that’s what’s causing global warming. Oh but wait they also say global warming could cause an ice age.
Oh that’s right, now I remember. Global warming is a natural trend and is absolutely nothing new.
Short version: No, humans, despite THINKING we’re god-like, cannot alter the climate significantly no matter how hard we try.
Willy’s on the right track. The Earth has small cycles that we can see and understand because they occur many times during our lives: tides and seasons are relatively well understood. The cycles that take several orders of magnitude longer than our lifetimes are exponentially harder to understand. We’re only now beginning to recognise some of them, and almost certainly have yet to recognise others.
One such cycle is that of glacial minimums and maximums. They’re huge. There have been a series of glacial minimums along the way, and huge sea-level rises and falls. I’m talking in the order of hundreds of metres, although some of that data is a little shady because they may have failed to take into account tectonism and land rising independently of sea level. Either way, global warming is not new, and it’s not our fault. We’ve added to it, and we sure as shit should be more careful about what we’re doing to the world, but we’re not going to stop it. Same thing with ice ages- when the next one come, tens of thousands of years down the track, it will be incredibly gradual and we’ll just get colder. We’ll find ways to deal with it, and if people today could even imagine the way people fifty thousand years into the future will deal with it, then I’d be disappointed with the lack of technological advances in the future.
Basically, we couldn’t reverse it, we couldn’t stop it, and noone’s researching it (or at least I hope noone is) because it’d be as effective as researching ways to stop the tides or seasons. Even if it was possible, the consequences would be catastrophic beyond imagining.
Actually, the last major ice age ended in, some think, as little as three years, and certainly less than 100 years. All the ice did not disappear right away, and the presence of the ice created somewhat different conditions, of course, but the climatic shift was very abrupt. The Greenland Ice Cores and Vostok Ice Cores are quite clear on this. Following that, there were at least two backslides - the Younger Dryas event and the 8200 BP cold event - when the earth returned to near glacial conditions in very short period — a single year.
Longer term, while such astronomical-scale events as the Milankovitch cycles do influence whether the earth goes into a cold period, it appears the earth has two fairly stable states: a warm one and a cold one, and climate being a somewhat nonlinear chaotic system, it can flip from one steady state to another.
Sea level change is actually quite well understood for the last glacial maximum (climatic minimum). The global minimum sea level at last glacial maximum was about 130 metres less than today. In some places that are very tectonically active, there can be some variability in this, but the global (eustatic) figure is well established at -130. Tectonic sea level change is actually a fairly slow, gradual process in most places, barring sudden megathrust earthquake-induced uplift or collapse (parts of Alaska coast rose 15 metres in two minutes during the 1964 earthquake). A more important cause of local, relative sea level change is isostasy, or th e depression or uplift of the earth’s crust due to the pressure of the ice. This can create very local sea level change — thus one place where I have worked on this problem, in a 100 km W-E transect, we see sea levels at 12,000 years ago as, in order, simultaneously, -150 metres — +12 metres — +50 metres — +200 metres, all the difference being produced by isostatic warping of the crust.
Before the last maximum, it is indeed harder to study this problem because each glacial period tends to obliterate much of the evidence of the previous ones. Ultimately if you go back to about 700 million years, the earth was completely glaciated to the tropics - thought to be due to the particular orientation/arrangement of the continents. Google “snowball earth”
To answer the question, there is no guarantee we will enter into another ice age. Ice ages were not the norm before about 2 million years ago, and with anthropogenic change they may not occur again. I’m not an expert but I think that all else being equal, if the conditions are right for an ice age there is probably nothing we can do about it.
Ok, so Ice Ages come along every so often. With global warming and are unstable environment we are sure to eventually trigger an ice age.
Actually, it looks like greenhouse warming will overwhelm the natural cycle. Spencer Weart, The Discovery of Global Warming:
Well, I dont know much because im very young, but eyeryone should know that another ice age will occur. The main reason is because of global warming or freezing. But we can’t just take it easy and go to a place where things aren’t happining. Think about it: you would have to move all those people to a whole different place.
how long are we lookin at from an ice age
how long does it take?
im very scared for my kids
Given the chaotic aspects to any nonlinear system, the best we can say is that the earth will most likely shift into the other steady state cycle of ice and snow. Although it was accurately corrected that ice ages to come in relatively short periods of time, we are still talking 10’s if not 100’s of years. As for stopping one, I don’t see why there couldn’t be a way to understand the mechanisms of the change and try to push back a little in one or more variables. The other good point made here, is that there are alot of variables at play here, and I would not discount the remote possiblity that humanity maybe - just maybe - might be able to tweek to many variables in too many directions at once and create another order of instability. Where the ball rolls into the quilt of possibility is anyone’s best guess.