Inkwell: Authors and Artists
William Calvin (william-calvin) Tue 9 Jul 02 10:42
What the repeated applications of dynamite buys you is keeping the meltwater coming out as a steady trickle, rather than a year's worth in a mere 24 hours. That's technically feasible, and we'll probably see some efforts at that up at 60N on the Alaskan coast in the next few years. The Hubbard glacier is about to close off Russell Fjord just as it did in 1986. There is no flood danger to thermohaline circulation in the North Pacific Ocean because it is already too dilute to have any. But the fate of the marine mammals trapped behind the dam, as the "lake" becomes less salty will likely spur some relief efforts. The last time, the dam broke after five months before they got their act together. This time, the tongue of ice is much broader and will make a much more resistant dam.
William Calvin (william-calvin) Tue 9 Jul 02 10:45
Just learned last night that there is a fine review of the book in the June 28 issue of <i>Science </i>. The links to both it and that long review in <i> Scientific American </i> are on my home page at www.williamcalvin.com (which is now on a new webserver, let me know if you find links that don't work right).
Andrew Alden (alden) Tue 9 Jul 02 11:23
I have an article on my site about the Hubbard Glacier surge of 1986-- actually it's about ice-dammed outburst floods in general. Geologists (and Icelanders) call them jokulhlaups. http://geology.about.com/library/weekly/aa041397.htm It also goes into Heinrich events, which are an important element in your book. Your book is an excellent summary of recent advances in glacial oceanography, which as far as I know are barely getting into the textbooks yet. Anyway, Heinrich events are big surges of icebergs from the great continental ice sheets out across the whole North Atlantic. We know they happen because of the grit and gravel the icebergs drop on the seafloor, where normally there's only muck. Sort of glacial diarrhea attacks on the continental scale. They appear to be one major cause of the big villain of your book, D-O events. But the big news you report--something geoscientists might not know yet--is that D-O events can happen today, even without huge ice sheets around. Hence the discussion of techno fixes, like dynamiting fjord glaciers to prevent buildups of fresh water in the wrong places, or even busting the dam between the seas that the Panama Isthmus represents. Do you get resistance when you bring up technological measures like this?
Indigo Mallard (blueduck) Tue 9 Jul 02 16:58
You know, while the measures might work, with the emphasis on might, they can only work for a relatively short time. The problem is that the more successful you are with them, in preventing a cold snap flip-flop, the higher the global temperature will rise. The higher the temperature rises, the more the ice melts. Catch - 22. You will buy time, but the end result is going to be worse. Something like using nukes to blow away a the land bridge between North and South America to a depth and width great enough to restore inter ocean circulation - that might be effective. Maybe. The main point is that everything that we do to keep the status quo is going to result in the current man-made greenhouse effect continuing. And that is a brand new monkeywrench in the machinery.
William Calvin (william-calvin) Tue 9 Jul 02 20:28
duck, there are a chain of "causes" in abrupt climate change, just as there are in most biological mechanisms. The good thing about them is that they give you a number of levels at which you might be able to intervene. Preventing fjord floods just buys time. But that's what medicine is all about, too. You hope to keep things from collapsing for a little longer in hopes you discover a better fix, to buy even more time, etc. Fixing up the "old Panama Canal" to be the way it was 3-4 million years ago is probably the last thing we'd try, where we'd need centuries of experience with climate simulations to build up the confidence that we could manage it. It's not even clear that it would work, even if we did it skillfully. What the closure seems to have done is to strengthen the Gulf Stream, which carried more heat into the high north Atlantic -- and so set up the precip that permitted ice mountains to form in Canada-Greenland-Scandanavia. Is that good? Or is it bad? The problem is when it collapses temporarily -- especially in the modern era where we have a house-of-cards built upon efficient agriculture.
Indigo Mallard (blueduck) Wed 10 Jul 02 11:21
That's exactly right. The problem is though, that there is no particular reason to think that letting the global heat engine wind itself up even more by intervening to "buy time" is going to have less of a damaging effect on our ability to grow crops. There is no reason to think that. Heat, as I am sure you are aware, is exactly as good as cold at killing crops. It really doesn't look good either way. Bottom line is, we have overshot the carrying capacity of the dynamic system at it's low points already. Maybe we can move agriculture all the way up into the Northwest Territories and Siberia, then restart it in lower latitudes when the cold snap hits. Maybe. I doubt that this will happen without several billion people dying in the process. What will happen after the artic ocean clears of ice? There are some weird things in ice archaeology, like the flowers in the stomachs of woolly mammoths. How did those mammoths freeze that fast? As the geologist you quoted said, there is evidence that such transitions occured in one year's time. Bang. A huge, month long superstorm that just doesn't stop.
Andrew Alden (alden) Wed 10 Jul 02 12:05
Just a tidbit: the buttercups in the mammoth's stomach is an ancient scientific urban legend. It started when a journalist misunderstood a reference to flower pollen being studied from a mammoth site. Also, the swift climate shifts are only very rarely a one-year switch. I wanted to mention that because realistically, climate shifts will take decades.
Indigo Mallard (blueduck) Wed 10 Jul 02 12:34
OK. I'll accept that lacking anything else. But I think that the point still holds. Our global heat engine is revving up, and there is no particular reason to think it will slow down before enough of us die to cut back on effluents. That, in itself, is going to kill a lot of people. Whether transitions occur in a matter of 1 year, 5 or 10, they are still likely to be looking us in the face, and quite possibly soon. Realistically, we have no reason to think that major climate shifts will take decades, except for our hope that this is so. After all, this book provides quite a bit of evidence of that - I assume you read it?
Andrew Alden (alden) Wed 10 Jul 02 13:00
The book is all about that evidence, and well worth the reading. How we should respond to the climate changes ahead of us, and the details of how they will affect us--those aren't primary subjects of the book, although they are touched upon. What our hominid ancestors did when their East African climate shifted was, basically, follow the grass and the grazers that lived on it. Today we're still limited to that, in a sense: we have to be able to shift grain farming over continental distances. That will be weird, because ideally we'd want to avoid territorial warfare. Our wheat farmers would teach the existing farmers in the new wheat-growing regions. Or maybe American agribusinesses would go multinational. It's a fascinating and important discussion, and it's going on in various places around the Well as you know. I wanted to bring up the hand-ax question. Blueduck, what did you think of william-calvin's idea? Anyone else, feel free to jump in here too. (Off-Well readers can submit questions by email.) I'm not sure I buy the book's explanation, which is that the ubiquitous stone disc-with-a-point is actually a throwing stone used to wound herd animals as they gather at waterholes.
Indigo Mallard (blueduck) Wed 10 Jul 02 14:31
Oh, snarf. If you just want to shut down interesting offshoots of discussion, you won't have many interested parties you know. Hand-axe idea sounded good. But, there is a conservation of momentum issue there. Ever try to knock over a 4 legged ungulate? While I read a description, I didn't see him talk about testing this thesis. I think his explanation is partly right, but mostly wrong. The obvious thing to do with such a rock, which doesn't weigh all that much, is to put it in a sling and hit old bobbin on the head. Whack. A nice sharp rock of that weight hitting an animal on the head would perhaps split it's skull when flung from a sling. Of course, for a really stupid proto-human, with big muscles, the result could have been similar. Surround the herd and start heaving them rocks until you hit something. But - back to the warming issue and what confronts us. It seems pretty likely that we are approaching a bottleneck. Most of the population alive today won't leave descendants that will be around 200 years from now. It could be pretty damn soon.
Randall T. Swimm (rtswimm) Wed 10 Jul 02 14:43
Any millenium now.
Indigo Mallard (blueduck) Wed 10 Jul 02 14:56
Strange. A book is written, giving, in voluminous detail, evidence for extremely rapid climate changes having occurred many times in the last few hundred thousand years, and the usual sort of plump blather appears. So much for intelligent discussion. The other thing wrong with the rock thesis as presented, besides that such a rock would not have enough momentum to knock over even a single animal, is that crowded into a herd, even IF you managed to catch a fold of skin as described, AND the animal pronked, AND it was pushed to the side, it would just bump into the animal next to it. Net result - one pronk. Nada. The head though - that would do it. Or, throwing this thing at the hindquarters of the bunched up animals. You will hit something, and likely hit a hamstring, thereby crippling the animal.
Bob 'rab' Bickford (rab) Wed 10 Jul 02 15:46
I take it you've never actually thrown a stone into the midst of a herd of animals -- or thrown several at once. I saw some kids cause a minor "stampede" of about twenty cows that way once -- I don't doubt that sharpened stones would magnify the effect. Okay, so we believe there can be rapid climate shifts. So what? Some people here appear to think that this means we should put our heads between our legs and kiss our asses goodbye -- that we not only *cannot* do anything to change it or deal with it but also that we *should not* try. I consider that attitude profoundly ridiculous.
Cynthia Dyer-Bennet (cdb) Wed 10 Jul 02 16:06
So what *can* be done to alter the course of rapid climate shifts?
Indigo Mallard (blueduck) Wed 10 Jul 02 16:33
Andrew Alden (alden) Wed 10 Jul 02 17:09
Blueduck, that was part of my skepticism too--it's well argued and nicely imagined, but who has tried it out? And I wondered about slings. You could even put the rock into a leather sleeve so as not to cut your hands while you fling it around. But it's an intriguing mystery--as the book says, these stones are lying around practically in drifts in some places, in deposits hundreds of thousands of years apart. This was a major technology. And what replaced it? I don't want to choke off a discussion of how we should cope with climate change, but I wanted to cover some more of the book's other interesting points while we have time. It would be great to keep talking about long-term climate strategy after the formal interview period ends on Friday. This material is too important to drop after two weeks.
Randall T. Swimm (rtswimm) Wed 10 Jul 02 17:45
Just wanted to inject a small clarification, after an email exchange with <blueduck> that my comment "any millenium now" was intended as agreement not disagreement, but with a nod to uncertainty as to just how close we are to the onset of the next ice age.
Bob 'rab' Bickford (rab) Wed 10 Jul 02 18:49
Andrew Alden (alden) Wed 10 Jul 02 19:32
That reminds me. <rab>, I don't see much, if any of the fatalism you mention, anywhere on the Well, and certainly not in this topic. What I see around the Well is mainly two groups of people: a "green" side that wants to curtail CO2 emissions drastically in hopes that the ogre will creep away, and a "silver" side that urges further study into the climate system and technological steps to get our hands on the controls. There's also a practical side, to which most scientists and agency officials belong, that is devoting its efforts toward finding ways to cope with the changes ahead. None of these groups professes kiss-your-ass-goodbye fatalism.
William Calvin (william-calvin) Wed 10 Jul 02 22:01
Various points: The handaxe model concerns an early period when throwing accuracy isn't like it is now, where you need a way that a side-of-the-barn throw can yield dinner somehow. The point is not momentum so much as sit-down from back pain. I thought that I covered it in more detail than was really necessary. Throwing with a sling is a very advanced technique, even when you already have throwing accuracy. The last handaxes are seen about 100,000 years ago, Javellin-like spears were seen 400,000 years ago, suggesting that accuracy had gotten better by then. Global warming per se: you get more rainfall with it, overall. The problem with the abrupt "coolings" is that they are also worldwide droughts even in the tropics where the cooling is minor. Apropos rearranging agriculture, the problem is lead time. Were a climate change to ramp in over a few centuries time, all sorts of technofix might be possible. It's those unpredictable 5-year transitions to drought that topple civilization. To head off that, one priority is to figure out how to slow down the abrupt transitions.
Fuzzy Logic (phred) Wed 10 Jul 02 23:00
My sense on the hand-axe issue is that it's important not to overdetermine potential artifact usage. I studied with one of the best modern flintknappers, Errett Callahan, who in turn had learned from Francois Bourdes and Don Crabtree, the modern rediscoverers of stone-working. I was a bad student -- "two left thumbs" would be kind -- but I learned a lot from a semester with Errett and much of that involved the amazing plasticity of stone tools combined with an inventive human mind and the hominid hand. Even with two of those opposable "left thumbs" I was able to make some crude but serviceable pieces, certainly enough to pack a wallop if thrown or draw blood if used to slice. There's a whole field of experimental archeology now; in 1977 it was just Errett and a few others who were trying to graft the lessons of the flint-knapping hobby back into the rigorous academic traditions of archeology. It's not just a matter of conjecture, is what I mean -- there is serious study on these issues. Meanwhile, a propos of the earlier discussion about hominid evolution, and endorsing my disdain for the simplistic "evolutionary tree" motif that got a boost from the Eve Hypothesis, we have: In an appraisal accompanying the journal report, Dr. Bernard Wood, a paleoanthropologist at George Washington University, favored a "bushy" model of hominid evolution over a simple linear model. The many branches reflect evolutionary diversity in response to new or changed circumstances. So Dr. Wood said the bushy, or untidy, model "would predict that at six to seven million years ago we are likely to find evidence of creatures with hitherto unknown combinations of hominid, chimp and even more novel features." Dr. Wood further predicted that Toumai was "just the tip of an iceberg of taxonomic diversity during hominid evolution five to seven million years ago." http://www.nytimes.com/2002/07/11/international/africa/11FOSS.html But look at what's so interesting about this -- the new skull wasn't found at Olduvai or some even more obscure branch of the Rift Valley -- it was over in central Africa in an area now more or less part of the Sahara. I think this lends additional credence to wcalvin's sense of a strong climate-forcing factor in spurring on the evolution of the hominid lineages. Not that it seems at all surprising in view of common sense and the available evidence. By the way, my old teacher has a Web page now, of course. The oldest and the newest in human technology combined together... http://www.errettcallahan.com/
Indigo Mallard (blueduck) Thu 11 Jul 02 07:57
I think that I said a great deal more about the rock throwing thesis than just talking about using a sling. That this hypothesis doesn't hold up to fairly straightforward mental modeling of the scenario presented. It is a simple enough matter to run some field tests in Africa.
William Calvin (william-calvin) Thu 11 Jul 02 09:30
phred, I agree with Bernard Wood on this. I'd go even further, and say that there is a lineage between the chimp common ancestor and Homo erectus that hasn't been discovered yet. At the two ends, you have modest teeth (australopithecines and Kenyaanthropus have big teeth) and minor sexual dimorphism (australopithecine males can be twice the size of females, not 15%). It makes you wonder if there is some lineage in the 7-2 myr time frame with modest teeth and 15% dimorphism, that hasn't been discovered yet. BTW, the two skulls in the illustration in the Wall Street Journal (borrowed from Nature) is a very misleading comparison because the australopithecine is a juvenile (a much heavier face would have developed if it had survived more than 3-4 years), the Sahelanthropus is an adult.
Andrew Alden (alden) Thu 11 Jul 02 12:05
I guess I'm missing some background on the hand-axe problem. You're saying, Bill, that pre-sapiens humans could not throw as well as we can? In fact you seem to be saying that the hand-axe isn't even a Homo sapiens technology. Maybe this is old hat to anthropologists, but it bends my mind... I saw the news about the new African skull this morning too, and the location--in Chad!--was the first thing to strike me. We have so little data, really, on hominid evolution, and now the line of succession is going beyond the Pliocene into the late Miocene. In fact we're opening the possibility that the biggest environmental catastrophe of the last umpty- million years, the Mediterranean desiccation 6 m.y. ago, challenged our forebears. Phred, all these years on the Well and you continue to surprise me. You studied with Errett Callahan.
one man's astrolabe is another man's sextant (airman) Thu 11 Jul 02 16:29
And yet we have only explored the surface. One wonders what we would find it we could sift the entire earth's crust for archeological finds. Perhaps in another 100 years. My question pertains to mitochondrial Eve. It appears the DNA from many different groups have a common link. Can you expand on the current status of this DNA link?
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