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Post by flearider on Sept 5, 2013 9:59:42 GMT
how would an ice age start ?? from which pole ..?? would it happen in 10-20 or 1000 yrs do we really know ? if over the last 30 yrs we have had a grand max .. could it take that long for an ice age ? i'm sure it's a question of balance but what would tip the scales ?? a grand min while entering new galactic arm ? thoughts on a post card plz ..
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Post by cuttydyer on Sept 5, 2013 10:46:55 GMT
how would an ice age start ?? With the UK Met Office predicting a long warm spell...
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zaphod
Level 3 Rank
Posts: 210
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Post by zaphod on Sept 5, 2013 11:44:31 GMT
Slowly.
May have started already. Maybe not.
Does anybody know what a reliable sign would be, before it becomes obvious?
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Post by glennkoks on Sept 5, 2013 11:57:34 GMT
Either or. A super volcanic eruption could send us into a deep freeze pretty quick or long term changes in our orbit, tilt and wobble around the sun could do it slowly over hundreds and hundreds of years.
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Post by glennkoks on Sept 5, 2013 11:57:54 GMT
Either or. A super volcanic eruption could send us into a deep freeze pretty quick or long term changes in our orbit, tilt and wobble around the sun could do it slowly over hundreds and hundreds of years.
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Post by dontgetoutmuch on Sept 5, 2013 14:04:41 GMT
In the short term, I agree with Gleenkoks, it would take a catastrophic event to begin an ice age within the lifetime of anyone currently living.
In the long term, I feel that changes in solar energy reaching the earth, followed by changes in ocean currents that transport heat to the poles better would be the most likely culprits. With orbital changes a distant third. I am in the minority on this I'm sure...
On the other hand, with the efficiency of world governments being what they are, a few years without a summer, IE. large scale crop failures, for two years back to back, would most likely begin a series of wars for global resources. This WILL be caused by natural variation at some point in the future. We have all seen how the East coast has absolutely failed to prepare the inevitable hurricane. "Superstorm" Sandy was not even a hurricane when it came ashore, nor was Diane. The blame for the damage that resulted from these two weak storms demonstrates how poorly local governments have planned for an event that will happen. I don't see that changing. Instead, damage from bureaucratic incompetence will be blamed on climate change.
There is plenty of arable land or land that could be made arable if the farmers and engineers were allowed to actually work. However between environut wackos in the West, and central planning follies in the East I don't see that happening. I do see states like China, Russia, and other bad actors moving to secure arable land in the third world, at the expense of the locals, who as Darwin would say, have failed to compete. It will be ugly in those areas. I do not see that same happening in the West. The West has the resources and the ability to adapt to any slow motion changes in climate. I do imagine that a few libtards and environut wackos will get squished along the way...
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Post by flearider on Sept 5, 2013 21:38:52 GMT
so how low would the output of the sun have to go before it did start that way ?would a drop of 4-8 deg c over 20 yrs do it ?
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Post by trbixler on Sept 5, 2013 21:51:28 GMT
Maunder minimum was a solar driven event. Cycle 25 is predicted to be low. see Henrik Svensmark link
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Post by glennkoks on Sept 5, 2013 22:50:12 GMT
My guess (and it's just a guess) is that a 4-8C drop in a twenty year period would certainly start the process. I got this from wiki: The Younger Dryas or big freeze was an abrupt climate shift. "In the UK, coleopteran fossil evidence (from beetles) suggests that mean annual temperature dropped to approximately 5 °C (41 °F)." So you could easily see what the current mean temp is in the UK and see how much it would have to drop to get down to a mean of 5C.
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Post by karlox on Sept 6, 2013 9:19:48 GMT
Let´s assume our Sun is entering a Solar Minimum, Maunder alike. Then think it doesn´t seem so unlikely that during these very low cycles and decades to come other factors -such as vulcanism- adds additional cooling... My questions are: 1- Could these two (solar Minimum and vulcanism) by themselves trigger a rapid global cooling?
2- How likely or unlikely is that scenario? (Could think in a third possibility: supernovas burst reaching us or any sustained noticeable increase in galactic rays further enhacing Low Solar activity effects... (Svenkmark´s) Opinions welcome
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Post by dontgetoutmuch on Sept 6, 2013 18:56:43 GMT
My guess (and it's just a guess) is that a 4-8C drop in a twenty year period would certainly start the process. I got this from wiki: The Younger Dryas or big freeze was an abrupt climate shift. "In the UK, coleopteran fossil evidence (from beetles) suggests that mean annual temperature dropped to approximately 5 °C (41 °F)." So you could easily see what the current mean temp is in the UK and see how much it would have to drop to get down to a mean of 5C. What apples and oranges are you talking about Glenn? I'm probably wrong about this, and willing to be educated, so don't jump down my throat, but if there was an abrupt globally average temperature drop of 5C or so, most of the drop would be focused at the mid latitudes. For the most part, the tropics will probably not be affected as much by the temp change. With this in mind, IMHO a 5C drop will kill off most of the world before the ice sheets get out of hand. A 5C drop this means that no one will be growing anything in much if not all of the best farmland in the world. There are a couple of farmer guys that hang around here, you might try asking them on the Global Crop Production thread what would happen to their crops if next year was 5C cooler.
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Post by woodstove on Sept 6, 2013 20:37:56 GMT
I've thought a lot about this. If the Maunder Minimum were duplicated in the next 60 years (and I don't believe the coming grand minimum will be quite that deep), but let's say it were duplicated, the look and feel of the changes in climate would depend significantly on where one was positioned on this actually rather large globe of ours. For instance, for the huge numbers of people living between 30S and 30N, an Eddy Minimum (as many of us would like it to be called) might not change the sensible weather all that much. The essential character of the local environment -- hot (nearly everywhere) and humid (as much of that latitude band is) -- would remain. So, when you say Ice Age, I presume you mean Little Ice Age, but at these latitudes, not all that much would change. Bear in mind that the planet enjoys more or less incredible homeostasis even taking into consideration the fluctuations during the whole of the Holocene. Northern Hemisphere sea ice, on the other hand, would likely become FAR MORE EXTENSIVE. Shipping could become very difficult, or impossible, in a lot of places where it is routine today: Iceland, Murmansk, Barrow, etc. Crop production in the temperate latitudes of both the Northern Hemisphere and the Southern Hemisphere would likely be seriously impacted. And, as it has before, that would likely lead to conflict and, quite possibly, military conflict. There are a lot of mouths to feed these days. That said, I believe in human ingenuity and foresee such changes as inexpensive widespread nuclear energy being used to desalinate water and turn much of desert Africa into a larger version of my home state's Central Valley. How long it takes to summon the will to achieve such changes is a good question. Evidently there were plenty of quite hot summers during the Little Ice Age, and so the warmists would likely be pointing to such counter-evidence all the way through the course of their own final irrelevancy. That'll be satisfying, perhaps, but I have stopped expecting to see the likes of socold, Joe Romm, and James Hansen throwing around a bunch of mea culpas. They'll be explaining why the cold is your fault before you can say "But ..."
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Post by flearider on Sept 7, 2013 0:32:08 GMT
i'm thinking it's started and will come from the south pole area .. we will see if and to what size the temp difference is to there summer is this year .. maybe a 2-3 deg drop my thinking .. with a growing Antarctic your going to have more cold pushed up into 3 oceans ,south indian well not to bad there .. but south pacific and atlantic could be a problem if it gets pushed past the south equator I think we are already starting to se this by the cold weather hitting south America .. but I have to do a little more reading ..lol well a lot ..
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Post by nautonnier on Sept 7, 2013 1:58:31 GMT
The evidence from various places is that some ice ages can occur extremely rapidly. There was a case of a glacier in South America where as the melt occurred in the late 90's plants were found in flower that had been caught in the snow that had then not melted. There are many estimates on the rate that the Earth could cool but some evidence that significant >5C changes can occur inside a decade. The problem is that the granularity of the metrics being used is too coarse to precisely define the time taken.
Everyone accepts that the climate system is chaotic. The system as a whole seems to have two attractors (look up 'strange attractors') the most powerful of these is for glacial conditions, the other for interglacial. The global climate state 'orbits' one of these attractors in a pattern called a Poincare Section (looks like the patterns drawn by a disturbed pendulum. As the chaotic subsystems within the climate themselves orbiting their own attractors vary the global climate is perturbed away from the current attractor. If this perturbation is the right size, vector, and time and perhaps associated with others, then there is a possibility that the global climate may switch to the other attractor.
In weather words. We have multiple chaotic subsystems with 'emergent' cycles and oscillations that have different lengths and impacts, PDO, AO, AMO, SOI etc etc. The Sun similarly has cycles that seem to be more chaotic and unforecastable than solar physicists admit to. Many of these cycles interactions with each other, if those interactions occur 'at the right time' and 'in the right sense' with the 'right forcing' then they may change their behavior. IF the Earth climate has moved closer to the glacial attractor due to the weather cycles and the Sun happens to move to a series of weak cycles at the right time to match the Earth climate changes and reinforce them that might be sufficient to make the climate switch to the glacial attractor. With climate cycles in their warm phase a weakness in the Sun may just cause a Dalton minimum, but if the Earth is already in a cooling phase then the Sun going cold could 'tip the balance'.
The normal claim is that a year where snow cover is retained over the summer is a sign of problems. But there are ocean current changes that could have effects, such as the Antarctic peninsula sea ice closing the gap at Tierra del Fuego. During the little ice age the Arctic ice linked Greenland to Iceland and to the North of Scotland. Inuit kayaks traveled to Scotland following the ice boundary. This would block some ocean currents. Dependent on the depth of the ice the currents could be completely blocked.
I don't think volcanoes are required - just a series of chaotic inputs at just the 'wrong' time.
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Post by numerouno on Sept 7, 2013 8:42:59 GMT
First signs would be that glaciers would be start expanding in Norway.
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