Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum Global Warming

ok one of the things i see from this is that we are in agreement on many points, but are disagreement on several.

1) all models i have ever seen say that once all land masses were part of a super continent, and have seperated.

2) the pacific ocean is the reminatate of the single ocean that existed then. the atlantic has the atlantic rif where new plate is being created meaning that the atlantic is growing a few inches every year, and the pacific is getting smaller by most of that. so the size of the pacific has really not been any factor at all.

3) my comment about the polar bears having non polar forefathers and the ice not existing was concerning a period beyound that which your refering to, ie, the million years plus of the current ice age. i was refering to the time 2.2 million years ago when there was no ice cap, and the tempature was 8 to 15 degrees warmer than current. there is indication that we will return to that at some point.

4) in the previous thread of yours you mention and then refered to about 7 out of 10 of the expansions (glaciation period) being linked to volcano's, but not the others. considering that we have no idea where many of the super valcanos are, how can you claim that they did not have effect on the others.

5) i dont believe the current of the oceans really play that much in extending or creating a peroid of glaciation

you claim that the volcano activity has not been that great lately, but have you check out the warning signs of impending eruptions and compaired them to the activities of several of the supervolcano (the proper term really is caldera volcano not super, the term was coin, i learned recently, but tv producers for the effect the word has). we could very easily be looking at two eruptions within the next century, one of them being in the top three size wise.

as i said there are many points that we do agree.

1) mankind really cant influence the mixture of gasses in the air that much. super volcanos on the other hands, can, drastically, over a short time, effect the tempature down wards.

2) we really dont have enough info on the suns activity to really argue the point of weither or not it can cause long term ice ages.

3) like you i hope we have had some effect on warming the earth, because from where i sit, it appears that we are in for some cold days, when the two supers erupt. fortuantely, one of them erupted only 74000 years ago, so if it does erupt soon, it will not have that much of an effect. the other unfortunately has been waiting some 722000 years to release its gass pressure.

There are no ice covered mountains in North America year-round? I guess you've never seen Glacier National Park, have you? I can assure you the glaciers are there year-round. I guess I've seen something that isn't there. It was sure impressive.

Hi dehammer and anyone else interested,

This is LONG. Most won?t be interested unless you are interested in what Volcanos can do to climate but it certainly is relevant to global climate discussions so here goes.

Dehammer, I?m responding in turn even if the items are not really relevant to global warming.

1. Super continent. Yes, there were super continents from time to time (Columbia maybe 1.5 billion BC: Rodinia about 750 m BC; Pangea 300 m BC; etc). The major continents were connected but still separate plates. Even in geological terms the last one was a very long time ago. Since then there have been many different patterns of continents.

2. Pacific Ocean. This is not a remnant of the single ocean because there have been several intermediate steps to its formation.

3. Ice Caps and Average Temperatures. There weren?t any thermometers around 2 million years ago however I do not believe that there is evidence to suggest a period in earth's history during the time of land animals that was 15 or even 7 degrees warmer for the global average. The upper end is more than double the current average temperature. The best estimates based on ice cores that go back around 800,000 years in the Antarctic (tending to indicate that the Antarctic has had an ice cap for at least 800,000 years continuously but the Antarctic actually started to form an ice cap around 40 million years ago and has had one pretty much throughout that period) is that the maximum fluctuation is around three degrees. After that world temperatures have to be guessed at through sediment cores and it is much easier to dispute the figures. The difference between the last glaciation and the peak of this interglacial period is said to be only 2 degrees.

4. Volcanos. This is very relevant to global warming. Around 70% of the interglacial periods in this ice age ended in the same period as heightened volcanic activity. With the exception of a couple of specific eruptions, it is quite possible that some of these volcanic activities cannot be easily traced to a specific volcano or group of volcanos or even region. The evidence of volcanic eruptions is in the ash left behind (the Antarctic ice cores are good for this). These thin layers of ash can be found in many places around the world for the 70% of the end of interglacial periods.

I think you are confusing the massive eruptions of volcanos that occur far less frequently than the periods were are discussing. Vulcanologists use a scale to describe these ?super volcanos?. The ones that change world climate are called VEI-8 volcanic events. The last one was 75,000 years ago in Sumatra. Depending on which expert you talk to, this caused from a low of 60% of the world?s humans to die, all the way to all but 2,000 surviving in one small part of Africa (this estimate is from DNA studies). Now that is really frightening. A few hundred breeding humans were all that stood in the way to our not having this global warming argument at all (and they were black if you are a white supremisct and think you are somehow superior).

There have been VEI-6 or 7s more recently but they do not correspond with interglacial transitions. Once again, this is not particularly my field of expertise but I did have to study eruptions around the time of interglacial/glaciation transitions because the cause and effects were and still is what interests me. In this interglacial period there has been a VEI-7. This was 6,300 years ago in Japan. It was fairly sizeable, spewing out a little less than 200 cubic kilometres of gunk. Interglacial periods have ended with volcanic activities around the same time of considerably less than this (and still get counted in the 70%). Once again, there is a problem with the bald statistic. You need to know at what altitude various percentages of the stuff actually made it to. But that is a pretty good argument that a super volcanic eruption does not necessarily result in the end of an interglacial period. Surprisingly, more than once massive eruptions have occurred around the time of a transition to an interglacial period.

Since it is the particulates that volcanos spew out that cause global cooling events, even if only for very short periods, if there is no evidence of ash at the interglacial boundary then you can be pretty sure there was no unusual volcanic activity. And I do believe that the sites of the massive eruptions are known to those that study such things, at least the last few millions years of them are.

A Caldera volcano actually doesn't necessarily change climate all that much. All a caldera is is a volcano which has blown its top, forming a depression, often becoming a lake. The eruption can cause enormous damage without changing the world's climate. Tambora went up in 1815 (a VEI-6 although it is also referred to as a VEI-7) yet it did not have any long term effect on climate, despite 1816 being known as the year without a summer (and that is throughout the world not just in the Asia/Oceanic region). Tambora is in Indonesia. The pyroclastic flows etc killed around 100,000 people and the whole world knew of the event. It was actually four times the size of Krakatoa, although Krakatoa is often remembered because it was the first world event that ?modern? communications was able to transmit around the world.

I think you are confusing major volcanic eruptions with periods of intense volcanic activities, where several volcanos become active for significant periods or the really enormous eruptions which occur much more rarely. There are several volcanos around the world that are worrying to vulcanologists. Vesuvius is one that is showing signs of being a disaster in the short term. That one volcano is capable of killing around half a million Italians without having much effect on climate at all. There is a volcano in the Canary Island that could let go at any minute, killing pretty much everyone on the US Eastern Seaboard, as well as a few French, a great many Africans but if it does happen, the effect on climate will be tiny because it will not involve prolonged high altitude particulate dispersion. There is a big difference between volcanic eruptions that are disasters and an eruption that basically blocks out the sun. And the size of the eruption or even what is chucked out of the volcano is not particularly important. What is important is how the stuff is chucked out. Spread as pyroclastic flows and you get little change. Chuck it straight up and particles will darken the world as they go around the earth for many years. Climate changing eruptions do happen and they certainly could happen tomorrow but they don't seem to be the major cause of transitions to glaciations. I don't know why. It does seem logical but the evidence does not bear it out.

As you indicated, transitions to glaciations are more often than not accompanied by periods of heightened volcanic activity but there is a chicken/egg problem with this that has not really been answered.

5. Ocean Currents. Now I might disagree with the methodology of many global warming studies and am happy to argue about whether there is any global warming, man made or not, other than a 30 year period that is clearly able to be accurately determined because of satellites, permanent buoys etc. However, I think you will find that pretty much any climatologist that has anything to do with global climate change will disagree with your statement concerning currents. Ocean currents are a real biggy in just what climate the world has. Shut down the Atlantic tractor type current today and within six weeks you will be extremely cold if you live in the US, Britain or Western Europe. You will be dead within two or three years.

El Nino turns up and Australia goes into drought. Al Nina turns up and Chile goes into drought. Now you could argue these are not exactly currents but they are heat exchange mechanisms by movement of energy within oceans.

Change a few factors such as salinity especially for the Atlantic currents by a fairly small amount and the world becomes a very different place.

There is actually a theory that the flip to glaciations could actually occur for no better reason than calving of ice sheets in the Antarctic happens to slice off too big a chunk. This theory does not argue that warming triggers the massive calving, only that calving occasionally (every several thousand years) manages to slice off a massive (we are talking something the size approaching that of Texas). It could be that the ice has built up to the extent that the piece that eventually breaks off is huge or it could be that there is a warming fluctuation. The theory suggests it can be pretty much arbitrary reasons unconnected to the actual world average temperature at the time.


My point has always been that the world is an extremely complicated place. So complicated that any attempt to model world climate is not even remotely possible with current knowledge. A vulcanologist cannot tell you the mechanisms for periods of heightened activities. A meteorologist cannot tell you where a hurricane will be two days into the future or where a tornado will touch down. A palaeobiologist cannot tell you with any certainty why pretty much all creatures that have gone extinct actually did so. They are still arguing about why dinosaurs went extinct and this was one of THE major events in this planet's history. The complexities that govern the earth to the extent that it remains inhabitable by vertebrate creatures are staggeringly immense.

Richard

Actually Rose there are a lot of mountains in the US that are snow-covered year round. A quick look out my office window to the South shows Mount Ranier. 14,100 feet of year-round snow cover. To the North ... Mount Baker ... 10,000+ feet and also covered with snow year round.

Unfortunately ... the snow level is retreating rapidly. I'm not sure I will be able to make the same statement 20 years from now.

I've been told even the Columbia Glacier in Banff National Park (Alberta Canada) will be gone in 60 years. And with it a substantial amount of the fresh water in the province.

that is because we are in an ice age. in case you could not tell from my post (appearantly) i was saying that when we are outside of an ice age, there are no glacers or year round ice capped mountains.

is that clear enough for you.

actually i believe that they do in that i dont believe the global warming trend has much of a chance of lasting more than a decade.

ok, it would appear that you missed part of what i was saying but thats ok. perhaps it has nothing to do with this conversation but i was attempting to point out that the continents were moving from a central location (as of the last one) and the atlantic is the point that they are moving away from

k, as far as the 800,000 years, we are in agreement. part of what im refering to is much longer period, for which no ice record exist. the thing is why would their be no ice records longer than that if the ice had been there longer. i can no longer quote the site as its been years since i saw it, but from what i remember reading of it, there was indication that the ice there had melted off and has done so many times during that 40 million year period you refer to. but then since im not a god, i could be wrong. ive slept since then . im glad to know that the tempature has not changed that much since then.

the problem with going by the ice cores is that they only give the history for 800000 years. the smoking gun, as it were, of the theory of volcano/glacial period connection is the eruptions of super volcano's that occur when there is no interglacial period. i do agree that the glacial/interglacial period connection to volcano's of both the super and regular type is 70 percent as you pointed out.

1st off, i find it hilarious the fact that all the survivors were black and ws's have to deal with that.

from my reading of the volcanos i read there were two types, cone and caldera. the cone type are created by lava pouring out of a fisure and cooling, then having more come out above it. cones do have calderas in the top, but the size of their magna pools is not suffecent to cause a collapse of the entire cone. mostly the calderas are the result of the blast cause by the build up of pressure finally over coming the presure of the rock above it. caldera valcanos on the other hand are ones that the lava pool is extreamly large and when it releases enough pressure, then entire pool roof calapse into the remaining magna causing it to (bascially) immeadeately "splash" out though the miles of fisure created by the rock dropping miles (yellowstone has a magna pool as deep as 6 miles or more in places). what ever cones that were created in the short time between the first lava appearing and the final calapse are destroy by the calapse of the rock under neither them. the biggest difference between cone and caldera volcano are the amount of magna that is pumped onto the surface or into the atmosphere. i dont believe that cones can be bigger that vei 6 and few are in the top of that catagory. vei 8 pumps out 100 times as much lava and gas as most cones. the biggest problem with the caldera volcanos is that they keep the gases trapped in them until the eruption takes place. cones release the gas much slower and there for dont kick as much ash and dust into the upper atmosphere.

im not sure if the one in japan is counted as a caldera even though it did spew out the amount of lava that counts as vei 7. when the caldera valcano erupt they shoot the dust and gas out in a matter of hours that large cone do in weeks. as i said though i dont know if it is a cone or caldera. here is an example of what im saying. take a hose with some pressure on it and turn it upwards. imagine the water coming out is lava. as long as the water is not under pressure it will go up about 2 or three inches. now put presure on it such as putting your hand over a garden hose. the water will go up several feet. if the vei 7 in japan sent that lava and gas out over say a month, it would not have sent the majority into the upper atmosphere. yellowstone has been building the presure by not releasing the gas, when it goes off, it will release all that presure in 4 days. a large chunk of the sulpher dioxide will reach the upper atmosphere where it will stay for decades. it will form clouds that will reflect the a large chunk of sunlight for the majority of that time. that includes the part that heats the earth, the result is glaceral period.

actually its only the smaller volcanos that the particulate matter matters. in the smaller ones the sulpher dioxde remains in the lower atmosphere, while the particulate ash and stuff reaches the upper atmosphere. in larger caldera volcanos the sulpher can reach up to 20 miles, reacting with water that comes up with it and that is already there, to form long lasting clouds.


actually these are cone volcanos and no im not confusing them. yes, there are times when several volcanos can do the same thing, but it would be extreamly unusally for them to do so. caldera volcanos dont actually have that much pyroclastic flows since the vast majority of their early release is shot out at extreamly high presure. test have shown that the magna would be carried out with the gas as it shot out huge tunnels, carrying the ash, magna, and gas 20 miles into the upper atmosphere. that is something that few cones can do with much magna and ash. that is why mount st helen did not send ash more than a few miles, while yellowstone sent its ash as far away as lousiana. the ash will fall out over hours, and even that that stays in the atmosphere longest will fall out with in a few year. the sulpher dioxide on the other hand will not fall out as quickly and will remain in the ice form for decades. some cones can kick a small amount of dust and gas and magna up into the atmosphere, even in rare cases some of it going as high as 20 miles. pinatuba, in the phillapeans kicked some sulpher dioxide into the upper atmosphere that is still there, albet most of it fell out with in the year.

yes they can happen tomorrow, there are two super (caldera types) that are giveing off the warnings that a cone volcano gives off with in a year of an eruption, although scientist are not sure if that means they ill go off tomorrow or in 50 year. the things is they will go off in the next few decades and they are the type with enough gas presure to send the sulpher to the upper atmosphere and they have more than one hundred cubic miles of sulpher. that is the estimate of the supher content of them, not the magna, which is well over a thosand cubic miles. (yes, i said thousand cubic miles) and a large percentage of that will reach the upper atmosphere.

i can understand if there is a lava pool with in hundreds of feet of the surface how a change in tempature can cause it to go off, but the climate changing ones are much deeper than that. they are blocked by a simimolten layer that flow into any crack, blocking them off before the presure can make them bigger. that is how they build up such pressure. the cone volcanos have a much easier passage to the surface, with only solid rock blocking them. when this gives way explosively a caldera is created in the top of the cone. Krakatoa was a perfect example of this it was i beleieve a vei 5 but (according to one theory) the magna hit a water pocket (or group of them) causing super heated water to blast the top third of the volcano off. even though it was not big enough and did not have the sulpher dioxide to be a true climate changer, it shot enough dust into the upper atmosphere to cause eruope to have a year with no summer. its estimated that thousands died from stavation in various parts of the world.

perhaps because you misunderstood what i was saying. i did not say that it could not cause it, just that it is interesting that at the same time that they say that the current stopped, another supervolcano erupted. the current is sun driven, so if there is no sun, how is it going to be driven.

i agree that it could be something simple such as no sunlight for months. what i dont agree with is finding a very complicated theory that does not explain it completely and does not include all the facts.

i agree that the earth is way to complicate for something as insufficently advanced scientificly as human are to understand completely. what i do disagree with, is with anyone (appearantly not you) that tries to claim the answer to a global problem is simple or that the answer is simple.

on the other hand, i have seen what i believe is sufficent evidence that global warming is not going to be a problem for much longer.

Hi dehammer,

I do hope we don't get bogged down in volcanos because they really are not relevant to global warming. They change climate drammatically occasionaly in geologic terms. That is, every few hundred thousand years or million years or so. We live in a period where the climate flips much shorter than that and being humans, the human scale of time is what interests us. And in a discussion about global warming in this century and the odds of particular events, it really doesn't figure large at all.

Actually the VEI index relates to the release of all material. Any VEI-8 is going to be a huge upper atmosphere releaser. And the 1815 eruption was an upper atmosphere releaser. Pyroclastic flows are most common with sudden release, not so much with smouldering cone volcanos. And even steady slow large eruptions can and do release enormous upper atmosphere clouds.

The point to the 70% in this ice age is that these are increased volcanic activities over the earth, not single eruptions. The single eruptions are well known and they do not correspond, except once, with the evidence showing the activity. So you could say that major volcanic eruptions of a single volcano almost never correspond with interglacial ending.

I agree with you entirely if you are looking at massive climate shifts in a geologic time frame. Volcanos play a big part but that is not at all relevant to a global warming argument because we are discussing a much more short term cycle or climate shift and there just is no evidence that in this ice age super volcanos had pretty much anything to do with transitions between warm and cool periods.

Worse, from the point of view of arguing that volcanos will send us back to a cold period, some very major volcanic eruptions with massive amounts of high altitude releases have many times had absolutely no long term effect to climate.

Volcanos can and will start the next ice age or deepen this one but it is likely this will happen outside human time frames. Similarly, a major meteor impact will do the same but they seem to happen with even less frequency than volcanic eruptions of major extinction level proportions.

As to plates, the Pacific really isn't getting much smaller. Yes, the Altantic has two plates that are spreading but it is the Indian that seems to be the loser, with the Australian and Indian plates both moving north. This really is not relevant to global warming at all.

Currents are not particularly "sun driven". They arise because of heat transfer from the tropics to the high latitudes. The residual heat within the oceans is actually quite large. That is why an eruption such as Tambora, which really did have a large chilling effect for well over a year, did not effect the currents, even though it occurred right in the middle of the "mini ice age". Mt St Helens, was a very high altitude eruption. The cloud had a cooling effect for around three years and it was at exactly the right latitude to effect the Atlantic currents, as was the Mexican eruption not long afterwards that was far less reported but actually had a larger climatic effect because of the gas mixture and the very high altitude release. I guess you could argue they weren't big enough but once again they had no effect other than very short term.

It actually seems that the stability of interglacial periods and glaciations is really quite robust. They seem to survive quite significant events that should flip them to the opposite. Yet when the transition actually occurs, from current knowledge it seems that the triggers really are quite minor things (either that or the trigger is some effect that leaves no evidence available for human study such as solar radiation cycles we know nothing of). That parodox makes the prediction of any transition nigh on impossible.

It was actually this very strange stability and delicacy that fascinated me when I was first exposed to the study at Uni.

There are warning signs however. It would seem that jet streams become vertically unstable before a transition. That is one explanation for wooly mammoths found chewing grass. If you are slowly freezing to death you tend to swallow what you are eating and where did the grass come from in the first place if the transition is a nice slow progression?

Parodixically, especially after all my arguments that volcanic eruptions seem to almost never cause the end of interglacial periods, volcanic activity remains a very good indicator of the end of an interglacial period. For some reason volcanic activity seems to increase in the period before or just at the transition. The increased activity does not seem to be larger than other volcanic events that did not correspond with transitions. But even so, if you were actually looking at a particular period as a candidate for a transition then increased volcanic activity would certainly strengthen the odds of a correct prediction, even if the mechanism or the reason for the correlation was not understood at all.

There are biological indicators as well. Certain animals seem to have programming built in to rapidly adjust to the coming of a new glaciation (otherwise cool temperature environment animals would have little chance surviving each of the periods - and animals such as rabbits, stoats, foxes, wolves, deer, bears, etc seem to have managed quite well despite living three quarters of the time in a frigid world and the rest in a very seasonal one). Some of these indicators are as simple as the pelts turning white and staying that way year round; others are changing in herd behaviour; others are changes in body mass and group dynamics. If you are a bee and live in the sub Arctic region, if you did not change dramatically how the hive worked that species of bee would just cease to exist as soon as a glaciation occurred, yet the bees do exist so somehow they know how to adapt. But more importantly, it would seem they have some way of sensing the change in climate as opposed to seasonal variations (which they often do not cope well at all with). All of these things have actually been studied because evidence of these changes is often readily available.

The trouble is I have not seen one single study of global warming that includes any of this. Yet, it seems that the study of things seemingly totally unrelated to the science of climate is a much better indicator of just what is likely to be happening climate wise, if you are trying to divine the near future of climate change.

If a biologist released a major study showing specific changes in certain animals that suggested they were adapting to a coming warmer period, I for one, would really start to worry that the world is going to get much hotter. However, I would worry a great deal more if the study showed adaption to a colder period.

It has always interested me that the more advanced science becomes, the more specialised the experts and the more they end up knowing about less and less. Climate is a big picture thing. What is actually needed is a few studies that are done by generalist scientists. But unfortunately they would not be believed. By the very nature of attempting to understand several subjects in some depth but not become a world expert in the field, there is always going to be someone who really is a greater expert to dispute your findings in a very narrow field. Thus, a more generalist study will be attacked by a great many scientists all seemingly with much better credentials than the authors of the studies.

Bottom line. You really are never going to find out what the world's climate is doing until it actually does it, at least not on the basis of current studies imho.

Richard

Originally posted by RicS:
Hi all. [snip]
Polar Bears.
Yeah, sure, polar bears are going extinct because of global warming that is either 30 years old or maybe 80 if you really fudge the figures. Sorry, it just doesn't happen that way. Polar bears evolved to their modern form many hundreds of thousands of years ago and - without particular expertise in polar bears - I'm guessing they were not a great deal different for between 2 million and 10 million years.

From what I've heard, brown bears/grizzlies and polar bears are closely related. I don't know if polar bears evolved from browns, or if they both evolved from a common ancestor.

As to seals, these are just part of a polar bears diet but a really important part. Less ice actually means more seals but I won't go into the reasons why warmer conditions mean more seals.

I would guess that depends on the species of seal and their primary food source.

Less ice means the seals will travel further north, not that there will be less of them. And actually from what I understand, polar bears need breaking pack ice to easily catch seals. They do not hunt in packs at all. Males are solitary. Females may have cubs but large groups only get together in areas of abundant food supply but not to hunt in any pack. I would suggest global warming is not at all relevant to how many seals individual polar bears are able to catch and eat.

That is true about the social life of polar bears. But global warming is key to the numbers of seals polar bears can catch and eat. Polar bears are good swimmers, as land animals go, but their swimming abilities are no match for those of a seal. They don't hunt them while swimming, they hunt them by laying in wait at breathing holes in the pack ice. Less pack ice = fewer breathing holes = fewer opportunities for seal hunting.

Mammoths were pretty much the same for more than a million years. They went extinct during the last glacial period. It was actually the coldest period of the cycles between glaciations and interglacial periods. You certainly could not blame any type of warming for their extinction. Actually a great many large beasts went extinct in that 10,000 to 20,000 time frame, including a wombat like creature in Australia about 15 feet tall. (And that one really goes against climate change issues because Australia is very much immune to climate change of the extent that would threaten larger animals no matter whether it is a glaciation or interglacial period. It does not get covered with snow or ice nor does the climate dramatically change with world warming). None of these beasts went extinct because of warming.

I would avoid blanket statements like that, but you may be right. There is much speculation that many of the large Pleistocene mammals were hunted to extinction by humans.

Polar bears have managed to survive many periods of warm periods. Even in the middle of the warmest interglacial period, you still have ice over the Antarctic and over the North Pole and pack ice in the high northern latitudes. If it retreats so do the polar bears, and the seals. Indeed, if there is a late summer polar bears have real problems, food wise.

Polar bears need the pack ice for successful hunting, and they need it to be relatively close to land. Being forced to swim miles out to the pack ice takes a toll on their resources. Though adults are known to be able to swim 50 miles or more, they have to be in shape, and have the stored energy to do so.

dehammer wrote:
"that is because we are in an ice age."

Well stand me on my head and tell me its the South Pole.

dehammer ... let me break this to you gently ... ice does NOT retreat during an ice age.

Hi Daniel,

I rather like the South Pole. It is far more fascinating than the North Pole. Penguins are cute (just look at the Oscar winning documentary) and besides Antartica is owned by a bunch of Nations with the US owning only a small chunk. I like that concept.

"ice does NOT retreat during an ice age"

Wow. So the people in Northern Italy still live under several metres of ice huh? When I was last in Milan there was some snow around admittedly but not all that much and it melted pretty darn quick. Go back a measly 12,000 years and the ice would be there mid summer.

Glaciers retreat during ice ages. Ice disappears entirely from many places on the earth. That's why they call the warm bits interglacial periods - they are the bit between the major encroachment of glaciers. Actually that is a bit of a reach but it certainly holds true for ice.

I'm finding it interesting how much basic paleoclimatology seems to be missing from these last few bits of discussions on global warming.

I also think we have managed to wander well off the point. Global warming is a very short term thing. Looking back to before our ice age won't do anybody much good because the conditions were quite different then. Even looking at the transition around 11,000 years ago into this interglacial period doesn't seem that relevant to arguing about a current warming trend because there is nothing to study of a short term nature.

If there is global warming, the evidence will be in temperature changes (whether we can assume accuracy of the measurements is a different thing entirely). It might be in other fields as well but paleoclimatology really won't help. I don't even believe my field of interest, the transitions between glaciations and interglacial periods and their causes is all that relevant. We are not talking about a cooling of the planet that may flip us into a glaciation. Then transition study would be quite important. Global warming is the theory that the earth, already in a warm period within an interglacial period is getting hotter still. Then the theory is extended to say this is because of man's activities on the earth, specifically the generation of greenhouse gases.

But if the discussion is going to focus on paleoclimatology for a while, it seems to me that getting the basics right should be where anyone starts.

The Northern Hemisphere pack ice has been around for many millions of years, well before this ice age. The fact that so far ice cores have only been found to go back 800,000 years in the Antartic does not indicate that the Antartic was free of ice for any period in the last several million years, only that they have not managed to drill deep enough or in the right places to go back further than 800,000 years. And sheet ice can melt without the ground being exposed. If the sheet ice remains say around ten metres deep then no matter how much you look you will not find evidence of anything but when that first ten metres was formed.

The reason why there is 800,000 years of records is because in the Antartic, there are sections of the continent that have had layers of ice building up much like rings of a tree without being rethawed. That is actually an unusual phenominum.

None of this proves that there was not sheet ice continuously for several million years. The evidence that does exist suggests that sheet ice really has been around for 40 million years (although it might have melted completely off an on for a few million of those years). Oh, and the reason for the appearance of the ice 40 million years ago had little to do with climate change and a whole lot to do with the Antartic continent actually approaching the South Pole and staying around that region.

It seems in this argument, the fact that the Poles are hellishly cold places simply because almost no solar radiation reaches them even mid summer (not visible light because I'm the first to admit how much glare that ice can give off).

No matter how hot the period in the earth's history from well before the extinction of dinosaurs, ice caps have been around. It is the extent of snow and ice coverage that waxes and wanes. For the north pole, this means pack ice and thus finding old ice is not an option.

On this there is substantial geologic evidence. It is easily found in even basic text books on the subject.

Richard

DA:

The definition of "ice age" that dehammer is using is correct, though it is not the common definition that laypersons and those Earth scientists that don't need to look deeply into Earth's past use. Lay people and soil scientists tend to use the term "ice age" and "glaciation" interchangeably.

By ice age, dehammer is refering to long periods of time where Earth was subject to glaciations. While we're not in a glaciation now, we're still in an ice age. There is evidence for only four ice ages in the last billion or so years. There is evidence for perhaps two dozen glaciations in our present ice age.

I don't know if anyone has ever formalized the terms. If so, I must have missed that newsletter. The Illinois State Museum has a quick and dirty explanation for the terms.

See: http://www.museum.state.il.us/exhibits/ice_ages/

I am assuming dehammer is a layperson given what he has posted prior to this. Methinks you are assuming far too much but perhaps you are correct.

My impression is that he still hasn't made it through a K-12 science curricula.

let me break this to you gently too. there are two parts of ice ages. glaciation and interglaciaral. in the first the ice grows or becomes stagnate, while in the second, it retreats. we are in a interglaciarial period which has lasted for 14000 years with a few minor interuptions, some matter of months, others for decades. in other words we are in an ice age, but in the warming part.

im actually a college grad although it has been many years since i went to college. i understand a lot about science, and one of the things i learned early, which you should have been taught, is that all science are in some way or other interrelated. unfortunately many of the ppl that write those papers you choise to read, dont want others to beleive that any science but their own is important enought to be considered.

to quote soilsguy's site "During most of the last 1 billion years the earth had no permanent ice."

this is what ive been attempting to point out and this IS a science site. not just one of your scaremonger sites.

RicS wrote (in more than one post):
I also think we have managed to wander well off the point. Global warming is a very short term thing.

actually there are two parts of global warming, the natural long term and the man made short term. the problem is that its difficult to tell the difference. many ppl like some here, choise to claim there is no natural warming and that man is completely responsible for both.

(previously)
...Currents are not particularly "sun driven". They arise because of heat transfer from the tropics to the high latitudes. The residual heat within the oceans is actually quite large...

im afraid that i dont see how you could say this and not see that the heat comes from the sun. yes the ocean has a large residual heat, but that heat comes from the sun. since the tropics get the lions share of the heat, that is where the heat builds up most. then the current heads north where it releases its heat, melting the ice, and warming the northern parts of the hemishere. then the denser (cooler) water drops and flows along the bottom to replace the water the is heated up by the sun. if the sun is blocked by dense clouds of sulpher dioxide ice, there is no heating of the ocean and after several months there is no room in the tropics for the colder water to replace, so it cant go any where after the and the heated water cant melt off ice and heat the northern areas. it does not take rocket science to understand this, but the theory involving upper atmospheric air rushing down to freeze the lower atmosphere has even rocket scientist arguing over it.

... That is why an eruption such as Tambora, which really did have a large chilling effect for well over a year, did not effect the currents, even though it occurred right in the middle of the "mini ice age".....

it only blasted a mere 40 cubic kilometers of rock and gas into the atmosphere. while the larger ones shoot hundreds of cubic miles (not sure what the compairison is but i believe miles are considerably bigger than kilometers)

... Mt St Helens, was a very high altitude eruption. The cloud had a cooling effect for around three years and it was at exactly the right latitude to effect the Atlantic currents, as was the Mexican eruption not long afterwards that was far less reported but actually had a larger climatic effect because of the gas mixture and the very high altitude release. I guess you could argue they weren't big enough but once again they had no effect other than very short term....

neither of them massed a single cubic mile of ash and material into the upper atmosphere. while most volcanos will put some into that region, the caldera volcanos send a very large porportion of their gas and a large amount of ash there.

you previously mention the volcano in japan, ive since have found it listed. it was a vei 7 not 8 like the major climate changers. you might have mentioned that.


...Volcanos can and will start the next ice age or deepen this one but it is likely this will happen outside human time frames. Similarly, a major meteor impact will do the same but they seem to happen with even less frequency than volcanic eruptions of major extinction level proportions....

the problem with this atitude is that its simular to the person who is playing russian rollet (sp?) and has seen the gun click 5 times in a row already. yes its only one in 6, but its already missed 5 times.

it might be 722000 years between eruptions of long valley, but its giving warnings now that it will erupt, and soon. same with the one in indonesa, and a third (name forgotten) on a island in the middle of the south pacific.

heres another analagy simular to yours. meteors big enough to destroy a city only strick the earth every 100000 years or so, but if one was seen to be on a colision course with the earth, would you claim that there was nothing to worry about because they only happened every 100000 years? we are like that, with the meteor having been spotted and known to be going to hit, but not where.

yes, it has little to do with global warming right at this moment, but it will very soon.

Hi dehammer,

I really like your posts by the way. Our discussions stay interesting, at least to me they do. They might bore the pants off many that visit this forum. But, hey, they can choose not to read them, right?

Actually, I have great respect for the dangers of meteors and "super" volcanos. From an actuarial point of view, you have a greater chance of being killed by a meteor than eaten by a shark. Depending on who does the figures, the chance could be right up there with auto deaths. While a meteor kills people in long time frames, it kills a huge amount of them.

So, I agree completely. If they found a meteor heading for earth and the chances of that are not that high, it would worry the hell out of me. Well actually, my body is stuffed anyway so it probably wouldn't worry me personally a great deal but it would concern me on behalf of my family and manking in general.

That is something that does really bug me - all this money is being pored into global warming scares yet the relatively small amount requested so their could be a comprehensive scan of the skies for previously unknown meteors was denied as best as I understand it.

If I was on the eastern coast of the US, the Canary Island volcano that will slump into the ocean and drown pretty much everyone on that coast might cause me some concern as well. It too is showing "indications" that it might let go without warning in the near future.

But the trouble with worrying about that or a super volcano is currently there is absolutely no technology to do a darn thing about it. So why worry!

And as for super volcanos giving off indications they might erupt, that is the nature of volcanos. They grumble every once and a while and sometimes they actually go off. Vulcanology has advanced dramatically in recent times but it still cannot tell anyone whether a volcano is likely to erupt in the moderate term, only if it is likely to erupt after it has already given off pretty ominous warning signs.

So I do think we can agree that even if there is currently a significant risk of a super volcanic eruption there is stuff all anyone can do about it (well we could try and populate another planet but we don't have any particularly good candidates available - you might as well build the facilities on earth to protect against the consequences of a super volcano as one on the Moon or Mars).

As to my "sun driven" comment, I did not express that very well. From the scant evidence available, it would seem that even VEI-7's that really do block out the sun for a year or so over wide areas do not stop currents, because the heat that creates the major currents is not just the heat of one season but an accumulation of up to 10,000 years. Blocking sunlight for one season will not necessarily stop a major current. That was all I meant. Otherwise I do not disagree with a word you said about how currents work (actually I do but only in minor points such as "the tropics get the lion's share" - they don't - they near tropics do - too much permanent cloud at the tropics).

The point I was trying to make was about the general cause of climate change within an ice age. Volcanos are rarely the cause and if they are they cause cooling. This is a discussion about global warming.

I'm also not sure I agree with you about the statement: "actually there are two parts of global warming, the natural long term and the man made short term".

The current argument is about whether the planet has become warmer in the last hundred years or so and why. Within interglacial periods there are many fluctuations, some long, some very short. Last century we had three warming periods. These are measured in only a few years. (We also had cooling periods which is something I think seems to get glossed over with any argument that man is dooming this planet because of global warming - perhaps because it fails to fit into the nice neat theory that greenhouse gasses are warming the planet when obviously for significant periods including in the 70's quite the opposite is true).

The current warming period we are in is just on 30 years. The "mini ice age", a cooling period was around 300 years. The warming trend before that was also in the hundreds of years.

If you had said, there is natural warming of various durations and the argument that man has caused warming of very short duration, I would agree with you. Its the "natural long term" bit that I can't quite fathom.

What I do find amusing is that we both seem to be in basic agreement about global warming issues overall. I don't want to put words in your mouth but from your various statements I think we agree on the following: That natural cycles seem to be ignored completely. Any evidence that is contrary to the popular theme of global warming seems to be ignored or rubbished. That there are really major events that could plunge us into a full blown glaciation, killing most of the population, that don't seem to enter any of the arguments (even if we disagree on the likelihood of the event being a super volcanic eruption).

I go one step further. IMHO, we should be back in a glaciation by now. That would doom most of the population. The warning signs are quite significant, including the "mini ice age", which really had a big effect on agriculture in Europe etc. There is the cooling trends last century seemingly without any significant cause. That is especially true for the short sharp 70's trend. There are biological indicators (once again especially in the 70s which have since been somewhat but not fully reversed).

The last 30 years has indeed been a warming period on this earth but in absolute terms, a really really small one, both in duration and in percentage difference in temperatures. We are talking about 0.06 degrees per decade here. The last cooling trend, if we could have measured it accurately, whether you pick the longer one of the last century or the mini ice age was of a magnitude several times larger than this warming trend.

Finally, I wonder about the doom and gloom to global warming. It always seems to be "Malaria will run rampant. Dengue fever will spread to these areas. Hurricanes will be bigger". I hate to say this but four million people die each year from Malaria now and the would does not seem to give a stuff. If it actually started to affect richer populations, perhaps something might actually be done. Hurricanes strike the same areas. If you live in Florida or New Orleans, or Darwin, or the Coral Sea, or Fiji, once and a while your area is going to be flattened. That is not a maybe. It will happen. So is it really all that important if Hurricanes do this a little more frequently, especially if the same warming trend allows 18 to 20% more crop yields, saving millions from starvation.

What the doom and gloom from global warming is all about is a 1st World - Third World argument. It will benefit the Third World countries far more than the First World ones. It will destroy some of the most expensive housing in the world (the coastlines will retreat - Malibu is not going to be a great place to live). Malaria is OK, it seems as long as it does not affect us rich folks, but is the end of the world if it does.

Look at any of the estimates of the damage global warming will cause and think about it in geopolitical terms. I assure you it will look a great deal different.

The preceding was an unpaid semi political rant by Richard.

hi RicS. first off, let me say that my purpose in coming here was to have a nice adult scientific discussion, and you have given me that. thanks. its very enjoyable.

for the most part we are in total agreements.

one part we disagree on is that man has (IMHO) cause a small part of the warming trend. say about .0006 degrees a decade. more or less.

as far as florida and areas like that being flattened, that will only happen as long as they are above sea lvl.

now the real things i disagree with is that the sun could not cause a stopage of the ocean current. a vei 7 would only stop it for may be a short while, perhap if it were in the same area as the current, as in this case the gulf stream is mostly near us for a large part of its cycle. the volcano that went off in that time periods was very near the gulf. this means the sun would be blocked off for more than a year, possibly as many many as 4 year being darken signifacantly enough to cause large drop in tempature sufficent to steal that much heat. i not going to say that his had to be the only cause if it, but it was obviously a major contributing factor. the time was too close together for it to be a coincidence.

also the science has had signicancant advances that they are almost certain when a normal volcano eruption is going to occur because, while it will grumble for years, it will give specific warnings that the magna has begun rising only within a certain time frame. example. yellowstone is grumbling, it has have many earthquakes and magna displacements, but they are not significant in that they are not the type that precede an eruption.

long valley on the other hand has had the same type of earthquakes that indicate magna rising, not just moving. plus it has had an increase in so2 and co2, with an increase in the percentage of so2. in a normal volcano this only happens in the last few days before an eruption, but with the depth and size of the magna pool, they believe caldera type volcanos do this for decades before an eruption. the worrisome thing about it, its started in 1985 and has continued since. more recently their have been crevices formed and things that are precursors of eruptions.

the point ive been attempting to get out is that there are things that can be done. it is know, as an example that the ice that causes the freeze is the sulpher dioxide reacting with the water to form low density ice. its this ice that reflects so much of the suns radiation, which is the cause if the cool down. its also know that the sulpher could react with water at that altitude to form more dense sulpheric ice which is not as reflective and would fall out much faster, if the so2 were to break up at that altitude. lasers of the right frequency could do so, but which is the best frequency, power and things like that. if we wait until the sun is gone, we might not have much of a chance to find that info. what would the harm be in looking for it now, even if we dont need it for years.

Hi dehammer,

I do wonder what the user name actually means by the way.

I still don't agree about prediction of major eruptions. I think they can predict that it is more likely to happen and in the short term can get pretty accurate but whether a huge eruption is going to happen in a year or more, I do believe is still beyond vulcanologists. But I am not a vulcanologist and you may well be right and I am wrong.

I do like the idea of thinking of ways to limit the damage of a super volcano. They might be pretty rare but it would be just our luck that one came along right when we were on the verge of being able to sustain life no matter how hostile the environment but not quite there.

I would have thought that releasing pressure in a super volcano before it blew its top would be the most sensible approach. It might still erupt and do a lot of local damage but world devistation would be averted. Technology has advanced probably enough to think of ways of doing this.

As to how to counter the effects of a glaciation suddenly returning due to a volcano or even series of eruptions, I like thinking outside the square. Working out how to get rid of particularly reflecting cloud formations is a very good idea. You could also spray huge areas of ground ice with black dye of the type that is biodegradable but stable as a sheet. That way as the ice melts under it it does not just drip away. Even with a really big loss of sunlight, you still need the engine of the albedo being at very high numbers to keep the cooling going.

Actually I have thought of quite a number of ways to reverse a glaciation because transistions to glaciations are what interest me and what will happen on this earth in the not too distant future. I must admit I have not thought of how to reverse warming because I figure that you really have a good chance of getting it wrong and plunging us into a glaciation, which would be far worse.

I would not suggest blowing up the side of a super volcano with a nuclear device and painting ice black unless it really was desperation time but these are things that could be planned for, just as watching for meteors seems to be a sensible thing. Pity governments do not necessarily do what is sensible.

Richard

Climate and the Carboniferous Period

from what i have read my understanding is that vulcanologist can predict with large certainty eruptions within 6 months for regular volcanos, and with in a certain degree of certaincy for up to a year. mind you, this is not to say, they will give you the day of the eruptions, just that it will happen within that year or within 6 months and then within a month, and finally within a day.

super volcanos are a different story. all they have for it are computer models based on smaller volcanos. vie 1 can only be predicted within a few weeks, and then only a limited success, while vie 4's are as much as a year, and with fairly good success. by extrapalation the computer models say the warnings will be going off for anything between 10 to 100 years, depending on the model. part of the problems is while yellowstone is not giveing off those warning, our goverment is spending a lot of money to study it. long valley is giving off those warnings and could be studied with the possiblity of giving us considerable more warnings, but because its not as widely know of as a super volcano, it does not have the same draw for money that yellowstone has. for that reason it will give little warning when it goes off. that is other than the warnings it has been giving off since at least the mid 80's. if it had been a normal volcano, vulcanologist would have warned at that time that it was going to erupt within the half year. as you said, the goverment does not do a lot of things that would be sensible.

also to correct something said before, the south pole does get direct sunlight, for several months it gets it 24 hours a day, 7 days a week, just like the north pole, and then has 6 months of darkness.

as far as the land mass contributing to the ice age, i do agree, but i dont believe they cause it. the reason i say this is that there are periods where they land mass is there too, but no ice age exist, then it happens when there is not the full land mass connections.

i do like the idea of a biodegradeable dye, esp one that does not degrade until it gets warm. say one that had an degrade inhibiter that evaporated after tempature got up to a certain point.

There was more to the post then was stated, thus the link therein~



Please let me know if the format of this post is objectionable to anyone ~regards