Oral History Transcript — Dr. Wallace Broecker
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Interview with Dr. Wallace Broecker
Session I | Session II
Weart:Okay, and I want to just— This is Wallace Broecker, I am Spencer Weart, and this is November 14th, and I’ve got to unplug this so we don’t get feedback here. Okay. And we’re going to talk about science, your scientific career. My own personal interest, you know there are so many different strands and so much going on that the thing that I am particularly interested in is following the history of the realization of abrupt climate change, which I guess at one time meant less than two thousand years, and now it means about less than two years. But there’s lots of other stuff, so we’ll sort of go back and forth with that. So that’s my, that’s the story I want to follow, but I don’t want to miss some of the other stuff that you’ve been involved in also. So I know Ron Doel has talked to you about some of your background and about some of life here, so I want to just launch right in with your doctoral thesis. So as I understand it, that began because Ewing and Kulp started a radiocarbon program and you got involved in that?
Broecker:Yeah. Kulp actually started the radiocarbon program. Ewing was the big boss.
Weart:By the way, I am just going to write down some of the names here for the transcriber.
Broecker:Right. And I came here as a summer intern in 1952 and helped in the radiocarbon lab, and they needed help, and even help at my level. Because he had some, you know, they weren’t, they were sort of very mediocre people running it. It wasn’t running very well, and I showed some initiative to help solve some of the problems they had, and you know after a few months I was running the Radiocarbon Lab.
Weart:So you were doing the extractions and things like that?
Broecker:Well, a woman named Barbara Eikelmann, who was the wife of one of my fellow students, did the chemical preparations. We were making black carbon, which spin it [?] on the inside of cylinders. That’s Libby’s method at that time. And I was sort of in change of the counting, the more electronic part. And then when we were going to move over to this building, which was two years later in ‘54, we had decided in the meantime that we had to get away from black carbon counting because we were getting terrible Strontium-90 [?] contamination, or cesium or something when we dried the carbon. There was so much fallout in those days that just all the dust had radioactivity on it, and so we would get counts from radiocarbon and God knows what else, so it was really bad news. So when we moved in here we went into gas counting, and I designed the Gas Counting Lab, basically using circuit diagrams and counter, you know, designs from Argonne National Laboratory. They were doing Krypton-85 measurements. Kulp and I made a Krypton-85 measurement and I suppose in 1953 probably, and Kulp went to Washington, very proudly announcing that we had found, you know, the fission products from the Alamagordo [?] and, you know, two Japanese bombs and krypton from the air. The FBI arrived here the next day and said, you know, “Forget it, fella. You never did that.” And then they told us—
Weart:That was 1953. Right, uh-huh.
Broecker:Well, the reason that— See, Kulp had just calculated from the kilotonnage and the fission curves how much there should be, and he predicted 10 dpm per liter or something and we measured 8. I mean, it was very, very close to what he predicted.
Weart:It was close to seeing the Russian bomb too, then.
Broecker:Well, there weren’t any then, but the high— But it wasn’t only the bombs. If you breed plutonium, you can’t get it out without letting the krypton off, so their game, Turkovitch’s idea was it was a great espionage technique, that we subtract U.S. and Britain from world total.
Weart:When you found out how much the Russians were making.
Broecker:Yeah. So that I went to Argonne I suppose around the summer of ‘54 probably and spent a few weeks there, and they taught me all they knew about gas counting, and I then introduced that to here and we went to counting gaseous CO2. So I did my thesis on various aspects of radiocarbon dating, so I worked on the ages of ocean cores and we wrote a paper on the abrupt change in climate 11,000 years ago.
Weart:Right. Right, ??? ??? ??? ??? ???.
Broecker:We worked on deep ocean water and we showed that Kulp’s early measurements were wrong, which is not a very pleasant thing for him to find out, and I worked on Great Basin Lakes one year high [?], I worked on Mississippi Delta sedimentation when it changed at the end of the glacial period. And so all those things have been, you know, part of my career ever since. I have studied, spent a lot of time on the Great Basin Lakes, I spent a lot of time understanding ocean circulation using radiocarbon, and I spent a lot of time on climate history. And radiocarbon and [?] the oceanography and the paleoclimate came together you might say with a conveyer belt—
Weart:Right. In the eighties really.
Broecker:It was utilized. You could, you know, these two things I’d been studying actually were one.
Weart:Well, actually I’m curious as to what the— Because even in fact at the beginning the two things were there in your thesis to some extent, and I’m curious why you chose, you know, curious— You’ve got the ??? ??? radiocarbon measurements, why you chose to study these particular things where ??? for example was one of the big, quick problems of that time and since has been trying to understand the cause of the Ice Ages, and I wonder if that was presented to you as one of the problems.
Broecker:Well, actually Kulp wanted me to have a last chapter in my thesis in 1957 written about the cause of the Ice Ages, but you know when I first came here it’s sort of a dead subject in that you know the Malonkovitch [?] thing, had been a big to-do about it, and then a lot of people said, “Ah, that’s bullshit,” and they sort of put it aside as— And Flint at Yale talked about a solar terrestrial hypothesis, which is really a lot of words. I mean, it didn’t have any quantitative meat in it. And then Ewing and Doun [?], I suppose they are the ones that got, you know, rejuvenated the world’s interest in the subject by creating this crazy theory about the Arctic being open during glacial times.
Weart:Yeah, I wanted to ask you whether that played any role in your thinking as you were writing your thesis, because they must have been talking about that about the same time, right?
Broecker:Well, yeah, actually I working with Ken Hunkins here and Dee Matthew [?] to kind of check out their idea, because if it was open the Arctic sediments ought to show it up like a sore thumb, you know. The Arctic has very low productivity today. And we did, Ken and Ghee [?] did coring up there, and I did the dating on it.
Weart:And when was this? Was this still while you were working on your thesis, or was this afterwards?
Weart:Because Ewing and Doun’s first paper was ‘56, so—
Broecker:Right. So I suppose this was probably in the early sixties that we first started. I could check that out ??? ??? ???.
Weart:But getting back to the time of your thesis, I’m curious—
Broecker:It was not, I mean at the time of my thesis it probably— Well, Ewing was very excited about my thesis work. He liked the idea of a big change 11,000 years ago, because he tied it into his idea about the Arctic. I don’t think I was ever captivated by that idea. I don’t— And eventually I wrote a paper, because I was kind of angry at Ewing at the time, and I sent him a preprint and I put a special title on it that it was a Nuod Gniwe [?] theory of climate change, and that’s Ewing and Doun spelled backwards, which he did not like that ???. He was smoked. But basically the work in the Arctic showed that the Arctic was even more tightly closed with ice during the glacial period, which is quite ??? ??? ??? expect.
Weart:Not too surprising.
Broecker:And—[phone is ringing]—does that bother the—?
Weart:No, you can get it if you want, but—
Broecker:No, I don’t want to get it.
Weart:Okay. Okay, so it was in the air, but it wasn’t necessarily anything that pushed you towards looking for abrupt changes.
Broecker:No, but it pushed a lot of people toward thinking about it, because it created—Doun was a glib promoter of this, and he’d go around and give lectures that made everybody mad. But in making them angry, they really started to get into it, and Johannes Geiss started thinking about how important the albedo [?] was, and you know how could you really cool off the earth. And then ???, wait I’ll tell you why. In 1955 or ‘54, Emiliani published a paper showing that Malonkovitch cycles were probably really important. And he, for the first time, provided a long record which sort of had those frequencies, although, you know, it wasn’t well spelled out, but it looked like you had a 100,000-year cycle. And so I was already thinking about that, and some of the work in the sixties, you know, we were, we found eventually in Barbados those high shorelines and, you know, that—
Weart:Right. Whoa, whoa, whoa, we’ll get up to that, we’ll get up to that. We’ve still got a ways to go. Because even already in your thesis you said that one of your concerns was to check—
Broecker:Yeah. Woman: Sorry. Patricio is going to be leaving for Maine tonight— [tape turned off, then back on...]
Weart:A brief hiatus. Already in your thesis you mentioned that one of your concerns was the stability of the ocean circulation, that you wanted to check whether it was sort of the ??? the old, you know, sort of just a constant, steady stay flow [?] kind of thing versus the non-equilibrium model. And I wonder if—
Broecker:Oh yeah, I said, that’s right. You know more about my thesis than I do.
Weart:Well, I just read it. You probably haven’t read it for quite a while.
Broecker:I probably never read it again, but I know what you mean by—
Weart:But you’d even talked about there being possibly two stable states. I just don’t know where you know that idea came from at that point.
Broecker:Well, it all goes back. I mean, I have worried about what we call terminations from way back then that, you know, I used to think about it in terms that the glacial cycles were basically either rectangular or, later on when we got the O-18 and started looking ??? ??? the sawtooth.
Weart:You got the sawtooth, yeah.
Broecker:But there was a sharp change in the sawtooth, and the question is what the hell was that, and I have always had in my mind that it was a transition between two states and that— But it was never, until the eighties, it was never really well developed as to, you know, what I was really, you know, thinking about.
Weart:Yeah. Already in your thesis you found that there could be changes in as little as a thousand years. But where the idea of different—
Broecker:Right. ??? ??? overemphasized. I mean some of those were— You know, that’s—
Weart:Yeah, you were clearly looking for it.
Broecker:You know, it’s an interesting story connected with that that doesn’t— There was a guy over here named David Ericson who worked in the same, in part of the library in there, that nice, big room right in—were you over there before?
Broecker:Okay. Well, if you go straight in the doors and back in there, that was David’s lab, and he looked, and he had got, had realized that a species called globertalia menardia, and it’s mentioned in my thesis, was present in the interglacials and absent during glacials. And as he went back in time, it turned out in hindsight that worked well back through the last two cycles. But then he had a long, long period where globertalia menardia was absent all the time. He thought it was either a very long interglacial or glacial—I can’t quite remember—but I was using in my thesis, as an index of the end of the glacial period, the appearance of globertalia. Now it wasn’t until years later that a man at Woods Hole, Glen Jones, showed an interesting thing, that the onset of menardia in the cores is turned out when they were both measured in the same ??? ??? be reasonably close to where the O-18 change ???. Not exactly. But what he showed is— And, and that change in the O-18 was centered at about 11,000 years. That’s the midpoint of the melting. The actual date of the entry of menardia into the Atlantic was 6700 years ago, and the way he did that was by taking, going down core taking menardia samples with the accelerator. Now you could do that. I had to you know measure bulk stuff. And so the age gets older and older until you get to 6700 and then it stays the same, down maybe 10 or 15 more, 10 more centimeters, and that’s a tail of bioturbation. So Ericson by chance was looking at the 6500 years plus one bioturbation depth [?] and it put him right at the—
Weart:Right. Just by accident.
Broecker:Just pure accident, put him at about 10,000 years ago. But I looked at those curves of his and he used to plot them in a funny way that there was a big, when it went from rare to nothing, [laughs], it was beyond his grasp [?].
Weart:He sort of realized—
Broecker:Yeah. And I was, you know, he didn’t use numbers, so I guess I was never aware of the fact that there was an important increase in abundance through the Holocene [?], that must mean something. And so some of those curves, as he drew them, were like that, and that’s where I got the ???.
Weart:??? ??? ??? ????
Broecker:Many times in my career some of the discoveries have been based on false things, but still you go back around and actually the discovery itself was valid, even though the thing that led you to it was wrong, and that was one of them.
Weart:Well, there were a lot of step functions in the record. I mean, you know, just this latest paper that you loaned me, you talk about the sudden hiatuses in the geological record. One of the things that existed at that time but that nobody seems to remark [?] then was the pollen [?]. I didn’t notice if you mentioned pollens in your thesis, but were you sort of aware of those things at that time? Can you remember when you became aware of the Younger Dryas and those sort of things?
Broecker:Well, I think I was aware of Younger Dryas in my thesis, wasn’t I, or did you not notice it?
Weart:I didn’t notice it. You mentioned alarod [?] and ???.
Broecker:See, in the ocean records we never saw the Younger Dryas. In fact, because it’s short duration it would be bioturbated out in any sediments we were looking at then, because the bioturbation depths like that the sedimentation rate during Younger Dryas is ??? ???.
Weart:Is much shorter, uh-huh, so you just wouldn’t have seen it. So it just wouldn’t have been in your field of—
Broecker:I thought that the high stands of the lakes in the Great Basin might have been Younger Dryas, and I was wrong. That was, those samples of tufa from the high shorelines that I collected I just ran them; I didn’t then clean them up, I didn’t do anything. And subsequently when people did it more carefully and took the densest tufa and leeched it, the ages got about a thousand or so years older. So what I called 11,700 is more like 12,700. And so I put it—and of course we weren’t so sure what the age of the Younger Dryas was anyway.
Weart:Was anyway, right, right.
Broecker:No, I have been aware of the Younger Dryas for a long time, and I think I had it in my mind a lot of the time when I looked at these records, but there weren’t an awful lot of really good pollen records then. I mean pollen—
Weart:Right, it was just starting to come out.
Broecker:Just starting. There was Vanderhammen [?] and people that were looking at pollen. I always found some of those early diagrams looked kind of crazy. I’m a person that looks for unity in things. When I see a really noisy curve, I kind of turn off and say, “Well, God I don’t know what you can do with that.”
Weart:Yeah. Come back when you have it better. Uh-huh.
Broecker:Yeah. It doesn’t—I can’t trust it that it’s really telling me something that’s worth knowing.
Weart:Speaking of which, when you came out with your own thesis with these fairly abrupt changes, did you get any reaction to that? Do you recall whether anybody made anything of it one way or another?
Broecker:I remember people that traditionally studied the lakes in the Great Basin, although Russell had put the high stand to the—he was the one that did it in the late 1800s, he and Gilbert mapped ??? ??? Bonneville. He put the high stand at Lahoughton [?] very late. Subsequent workers got the idea that the lake came down in steps and that therefore the highest level is, you know—
Broecker:And when I got the really young radiocarbon dates, I got a letter from a guy, I can’t remember his name right now, but he said I proved at Lake Bonneville because it dried from the bottom up.
Broecker:That’s what he thought about it.
Weart:Do you remember anything else about the response to your thesis? Did it seem generally acceptable and successful?
Broecker:Well, there’s a difference between then and now in that geochemists, we were not well connected with the geological establishment, and we generally made them mad. I remember we dated, and some of other people or students, when we dated the rocks at Bear Mountain that are about a billion years old, and there was some professor over at, I don’t know, NYU or something, who was really upset because he hadn’t picked the right rock and he said, “The age you’re going to get depends on the”—the whole damn area was metamorphose. I mean, you could date almost any rock and get the same age. But there was that kind of conflict. So when we swept in and with a few measurements upset— It would be like when the Alvarez’s [?] said they, you know, found the cause of— The establishment immediately gets their hackles up, because they can’t believe that something that they’ve been struggling over for two decades, you come along and solve the problem quickly with some dates.
Weart:With one measurement. Yeah. In a lab.
Broecker:And in many cases isotope work did that. So I would guess that we mainly went to meetings with isotope geochemists, and of course they were more interested in like the theory of the Ice Age, you know, in a more theoretical rather than a field point. And then with time these fields have nicely blended so that students now know the best of both worlds. And my success I think is I learned early on to appreciate the geology. I worked with that Phil Orr, and he taught me a lot of you know practical field geology, and so I paid more attention to results from you know, attained by different methods than a lot of people did and—
Weart:Well, another interesting feature is that you had both this field geology, and yet you also classify as an oceanographer in some respects, which is also combining things in I think an unusual way.
Weart:And while writing your thesis you were looking at, you know, you were doing a lot of dry land stuff but you were also looking at cores. Is this regarded as sort of jumping boundaries in those days?
Broecker:Well, when I was a student there were like 45 geochemists in the whole country. There’s probably now 5,000, or God knows how many, and so we covered everything from meteorites to, you know, atmospheric chemistry.
Weart:You’d just take any sample. Uh-huh.
Broecker:And so each of us cut a very broad swath. I was writing, I sent a thing for Turekian’s, uh, he had a birthday of 70 years I think, and I wasn’t able to go, but I said of all of us he was the one that maintained the greatest breadth of all, because he still, you know, worries about meteorites and the mantle of the earth and I’m pretty broad but I sort of shucked off all that kind of stuff and don’t really think about it very much.
Weart:Okay. One more question about oceanography in your thesis I just was wondering about I haven’t been able to track down exactly. You know, even to this day you read about your being warmed by the Gulf Stream and so on, and I wonder at what point, if you can think, did you at any rate become aware that the warm water is transported up on mass, that it’s this deep circulation rather than the surface currents that are the real story.
Broecker:Well, that gets to one— Oeschger pointed out that there were, you know, in the ice cores there were the two stable states. It’s much later, in the early eighties, that I tried to figure out what they were, and I said gee, said boy, if you turn down a, I just sat down, I said what if you turn down in [?] North Atlantic deep water? Well, from my thesis I knew you know it was something like 20 spare grips [?] and I knew that it came in at 13 degrees and went out at 3 degrees. It was an easy calculation, and I was astounded by the amount of heat that it had to get ??? ???.
Weart:So it really was ??? ???. You know, I’ve wondered, because you know it seems like it should have been something that was accessible to people already in the 1950s, and yet I don’t see anybody talking about it until—
Broecker:Well, it must have been done, but it was never talked about. ??? talked about it as the Gulf Stream.
Weart:As I say, yeah, to this day people talk about the Gulf Stream.
Broecker:Yeah, even now, and of course a lot of it he does move up with the Gulf Stream, and but more particularly probably deeper roots in that that warmest water doesn’t really get up there. But I mean that whole complex is moving up. But it, you know, one thing I never thought about, in the Pacific there are two gyres [?], and the water is doing, you know, the corrosiova [?] straight across the Pacific to North America and turned south. In the Atlantic the Gulf Stream, you know, a lot of it goes up into the Norwegian Sea, and probably during the glacial period the Atlantic was more like the Pacific, at least at times. And so that heat still is coming up in the Gulf Stream, but it was going straight out from New York here over to Portugal, and it wasn’t penetrating up into those higher latitudes, and that’s what’s getting warmed by this water. And of course the Gulf Stream I mean carries, I mean it’s what, 30 spare grips off, I mean it goes up to what, 50 or 60 spare grips, and it’s very warm, so ??? ??? ??? ???.
Weart:It’s very warm, yeah, it carries a lot. I’m not denying that. Yeah.
Broecker:A lot of it’s recirculated, and people were not—well, I don’t they were so much into heat budgets. And there probably was a wing [?] of the field that was, but the cross-over to the rest of this was—
Weart:I haven’t seen it yet. Okay.
Broecker:You haven’t seen it. Well, I haven’t thought about looking it up. I’m not good at doing history. I get too busy doing the present.
Weart:Right. Okay. Back to the fifties, I want to quote you something that Wenk wrote in his book on politics of the oceans. He talks about the oceanographic institutions at the time, Scripps and Woods Hole in here, and he said that, uh, he talks about a personality cult at each with internal loyalties expected and received from staff and students, and with a clear disdain for those in rival camps, little cooperation among the three labs. Does that sound right?
Broecker:Oh yeah. Yeah, I’ll tell you a classic story. The year that, you know, Stephen Jay Gould at Harvard got his job there as an assistant professor one of my student, Telu Reeves [?] now in Hawaii got a job there too. And we were very proud of him, because he, as a student he really did beautiful stuff. And I went to Ewing, and I was so proud, and I said, you know, “One of my students got a job teaching at Harvard.” Ewing’s reaction is, “Well, if he was so good, why in the hell did we ever let him get away to the enemy?”—and that’s the way he said it! And you know, our ships were only populated by Lamont people or their buddies. I was, in 1972 during GEOSECS, I was the first person to be chief scientist on a wood hull ship that wasn’t from Woods Hole. That’s how late that was. And I was given a big lecture about, you know, they’re not so, “They’re uneasy about this, Broecker. Don’t do any nutty things.” [laughs] Yeah, there was—
Weart:So when some came to do cores for example was there any sharing with cores, or did you work pretty strictly with cores that had been pulled by Lamont?
Broecker:Well, there was a lot of bitterness. David Ericson very generously gave Emiliani the key cores that he first did his O-18 on, and then without ever telling anybody Emiliani published a paper, and they were really, there’s some very bitter correspondence between Emiliani and Ewing.
Weart:This was back in the fifties?
Broecker:Oh, wow. And I know those directors used to have to divide up the pod [?], so I mean if you want to find out about those days, go to Dick Barber, who said—he was the young guy from Duke, you know, sitting in with Revelle and Ewing and Paul Fije [?].
Weart:Uh-huh. I guess I can go and look in Ewing’s correspondence too.
Weart:I can go back and look in Ewing’s correspondence, too.
Broecker:Yeah. But, I mean in, you know, from being a young person in those days, I wasn’t privy to what was really going on. One just picked up anecdotal things, and—
Weart:Right. Well let me ask you about one thing that is connected with this. You and Ericson and some others wrote up some of your stuff in Science 1956 and you reported this business about that there had been an end of the glacial about a thousand years, and then Emiliani came back with a paper the next year saying that wasn’t so. It must have been ??? ??? ???.
Broecker:Well, that’s that menardia versus O-18. Emiliani was right. Yeah.
Weart:Uh-huh. Did you have any personal interactions with him about that?
Broecker:Not about that, but we had some personal interactions about some other things. In fact, we got into a bitter debate. He, Emiliani got some people, Piccioto and Geiss, and they took a core from the Gulf of, from the Caribbean, and they did uranium series ages on it to establish a better time scale, because radiocarbon didn’t go back very far. And they got an age for what we now call Termination 2 [?] of 80,000 years. And I picked that up and we did our own work here, and we showed that they were wrong, that it was 100,000 years. Now, this made a big difference when you compared it with Malonkovitch, or actually 120,000 years, so it was a big difference.
Weart:Right. This was in the seventies, right?
Broecker:No, that was in the sixties, wasn’t it?
Weart:I don’t know. Let me check here. Yeah, right, okay. The key paper was Broecker and Van Donk in 1970, so that was where you published.
Broecker:Right. But we’re already you know arguing about it before. There were some papers by Rona [?] and this dragged out a long time. Just about the time CLIMAP was starting, when IDOE started in the very late sixties. Emiliani had finally been beaten on all these things. Because he said two things. He argued with me about the time scale, and he argued with Imbrie, et al. saying that the main reason the O-18 changed—
Broecker:Was temperature, whereas people were by then saying ice ???.
Weart:Ice mass, uh-huh.
Broecker:And he fought— [glitch in tape here...]
Weart:Oh, it’s not ???. Okay, Emiliani was—
Broecker:Emiliani was a classic case of a person who—that paper of his in ‘54 or ‘55 in—was it in American Journal? No, in Geology—was, I would say, one of the all-time great papers, his first O-18. It’s a superb paper. Well, he was the kind of person that everything had to be right, you know, and so what we were arguing about was some minor points really. I mean it didn’t really take that much away from the paper. But he stuck doggedly through his whole career, and he ruined his career that way. I don’t think, after he left Chicago and went to Miami, he did very little of any significance scientifically, and here is a guy of great talent and so forth who loved to argue with people about anything, you know.
Weart:What kind of forums were these in? Are you talking about face-to-face at meetings, or mostly in the literature, or letters?
Broecker:He was funny. Emiliani never flew, so he didn’t go to that many meetings, but I remember we had a special like debate session at the Geological Society of America. It was held in Miami. Of course ??? ??? that’s where he was. And that was his Waterloo, because then everybody ganged up on him, and he was trying to hang onto a couple of these points, and when the world had sort of decided that that isn’t the way it was.
Weart:And that it was really ice volume [?]. Uh-huh.
Broecker:And after that CLIMAP, because he was such a difficult—I mean Emiliani was a real difficult person to get along with. I mean, you know, the same as Craig and—charming guy, I mean you know a really interesting person, but combative that he just drove people nuts. So CLIMAP I think very wisely did not let him in.
Weart:Is Emiliani still around, by the way? Could I go and talk with him about some of these things?
Broecker:A few years ago. I mean you could talk to Imbrie about his—
Weart:Well I’m interested of course as you say in that 1950s work, and—
Broecker:Yeah. Well had, I mean the way Imbrie got interested in this whole of late [?] Quaternary science was that we held in the mid-sixties sometime, the first meeting I ever organized was held here at Lamont, and it was a debate between Ericson who said his menardia stratigraphy was the best way to look at past glaciations, and Emiliani who said O-18 was the best way, and of course I think Emiliani had to win that hands down because it just made more sense, that why would you get oscillations that did go with the glaciers and then more oscillations that didn’t go with the glaciers. And but that was an important meeting in that it brought these two people who were angry with each, especially Ericson was angry with Emiliani, and we did get, Emiliani came up here by train.
Weart:This isn’t the Miami GSA meeting, this is another meeting now that you’re talking about.
Broecker:This is a meeting held here at Lamont much earlier, a few years earlier. It sort of—I think Imbrie must have left here about ‘68. It was just before he left, and that got him started, it got him interested in the whole Malonkovitch problem, and so, but—
Weart:I see. Well, let’s move on then to your work on Malonkovitch and so on, because we need to talk about how you got involved in it. Now I ran across a reference by Ericson and Wollin, in you know their book The Deep and the Past where it seems like their main interest in all these things was establishing a time scale for human evolution.
Broecker:You know, Wollin was a real piece of work. I mean, he was a Swedish journalist with no formal training in anything who came here to Palisades God knows why and was desperate for money, and he got a job opening cores for Ericson, and then you know worked his way up to being Ericson’s equal. But Wollin had this idea he wanted to win a Nobel Prize. I mean the guy was, you know, basically bonkers. And where were we about—?
Weart:Well, of course there’s the motivation. Why study time scales anyway? You know, what’s the reason for trying to get exact timing in these cores?
Broecker:Well, I think the reason that a lot of us were trying to improve the time scale is the correlation with Malonkovitch, you know, what was it, how did O-18 changes match with the insulation curves.
Weart:So you got inspired basically by Emiliani’s work then.
Broecker:Originally interested. And then, I mean what really turned me onto it was the, when Bob, Robley Matthews from Brown called me up and said, “Wally, would you be willing to date a couple of raised terraces in Barbados?” Now he was interested not in climate; he was interested in digenesis, how, how—because oil companies wanted to know how long it took you know coral to lose its porosity or whatever. So we dated two of these terraces and we got like 124 and 82, and I said— And the old Malonkovitch curves, Malonkovitch emphasized a 40,000-year cycle in his curves because he, the way he calculated it, he was looking more at ??? ???. In fact I’m not quite sure why he did that. Well, I called up Matthews and said, “My guys here got those two ages, and look, they’re right at the 40,000-year frequency,” and he said, “Well Wally, there’s a third terrace which is halfway in between.” So he sent me that, and that was 105. So then I redid, for that paper I wrote on this, I redid the—I may have ??? ??? Broecker and Van Donk or somewhere, in one of papers I redid the radiation calculations my own way.
Weart:The insulation calculations.
Broecker:Insulation. And I showed that if you looked at latitudes like 45 or 50 that there was a lot more 20,000-year power in there, and in particular a peak that was just a small shoulder on the original Malonkovitch curves became, you know, a decent-sized peak, and that was 105, so I said, “Aha, we’ve got, you know, pegged right on.” Those were the right, you know, right on the Malonkovitch dates. And of course those dates have stood the test of time. I mean now with the new mass spectrometry they get the same age with a much higher precision, so it’s— But that really got me interested even more so in Malonkovitch, and just moved a step along.
Weart:Did you encounter resistance to that? Did you find there were anti-Malonkovitch people? Did you find—?
Broecker:No, not at that time. [laughs] No. Well then, you know, I think the big— The people who were more mathematical probably weren’t yet convinced, and then Hays, Imbrie and Shackleton in that paper really swept them into the fold by showing that if you did a power spectrum you would get the proper frequencies.
Weart:Right. Well you also went and got those New Guinea terraces too. Did you go there, to New Guinea? No. You did.
Broecker:Yeah. That was great.
Weart:That was field work.
Broecker:??? ??? I was going on a test cruise for GEOSECS and I took a side trip over to New Guinea and spent a week with Bloom [?] and Shapelle [?], and we climbed around there and lived in the mission house. It was, I mean, this was when there were cargo cults [?], I mean it was really exciting. And there was, the coast we were on there were, I think there were only besides us three other white people within 50 miles. We went on a mission boat to, uh, that dropped us off at Seyalom [?], and it was rough as hell.
Weart:So the access was by way of the missionaries.
Broecker:Everybody was—I was the only one, except I suppose the captain, who wasn’t throwing up. It was awful! [laughs] Really. I don’t know how I kept my stomach. [laughs] But yeah, that was an exciting trip, and those are amazing terraces.
Weart:Had you done other field work in between on these things? There was the, oh, let’s see, Barbados I guess—
Broecker:Well, I worked in the Great Basin ??? ??? a dozen times and—
Weart:That’s right. But the Barbados ones they sent you those samples, you didn’t go there yourself?
Broecker:I went there later with Matthews to see them. I went there three times, because I, once I got interested I wanted to see them, and we, one of my students, Mike Bender who is at Princeton now, did helium-uranium dating and we put a lot of effort into trying to understand the whole sequence of—
Broecker:But the more I did, I mean the field work I did most of the time was mostly at sea. I mean I didn’t bomb a bank’s work. I was on the ODP drilling ship in Cariaco Trench, you know, went on a, I think I spent about two years of my life at sea. But the place I did the most field work other than that was the Great Basin.
Weart:You went back there several times.
Broecker:In 1988 or ‘87, whatever it was, I organized a field trip to the Southern Andes, which got Denton started down there.
Weart:Oh, is that so?
Broecker:Oh yeah. That was funded by Exxon, twenty-five-thousand-dollar field trip. We took 20 people. I think there were ten South Americans from various countries and ten people from other places. We had Australians—
Weart:This gets us out of chronological sequence, but what were you looking for? Why did you pick the Southern Andes?
Broecker:Well, I had realized that mountain glaciation was enormously important, because the snow line is—
Weart:The snow line went down, yeah.
Broecker:And then went down on both Hemispheres, by about the same amount. And there were lots of debates about the dating and this and that, and so I wanted to see them myself. And so we went from Wooshwaya [?] up to Mendoza, and we looked at six or seven localities and we had a marvelous, marvelous time. And Denton, because of that, went on. In fact, Mareno [?], one of his Chilean students, just gave a lecture. That was one of the things I had to do instead of see you was that he came and George said, “Please listen to this guy,” and I said, “Oh my God, how am I going to do that?” So, anyway.
Weart:Okay. Okay, now let’s get back to the 1960s. One of the interesting things that is starting to come out there is you had a paper in 1966 which is one of the places where you talk about the Malonkovitch triggering a mode shift, and that gets us back to the whole idea of various modes and so on.
Broecker:In ‘66 what was it—was that the one given in Colorado?
Weart:Yeah, I was going to ask you about that ‘65 Boulder Conference seems to have been interesting. A lot of people that’s I think—
Broecker:Yeah. That was Peter Weyl talked about the stagnation of the Atlantic and vapor transport across the—
Weart:Exactly. That was I think the first place he talked about that.
Weart:Was that where you, can you recall, do you think that was the first place you started to become aware of salinity [?] as being a major feature?
Broecker:The only thing I can think of is some gorgeous woman I met there. [laughs] I really don’t— I remember that meeting, but not very much.
Weart:You remember Weyl was there.
Broecker:Yeah. I mean I really, you know I look at that volume every now and then, and I remember being there, but I remember I went back many years later and tried to figure out where I had been on the campus, and either my mind had forgotten so much or the campus had changed so much, I could hardly place, you know, my first trip there.
Weart:Okay. Well let me mention a couple of other things that were sort of in the air at the time. There was ideas about bido [?] feedback, there were people so excited about that.
Broecker:That was Geiss and wrote a very nice paper, Johannes Geiss. He’s a sort of an asteroid or comet physicist at Bern, and he went to Miami for a sabbatical, and he wrote a paper on that. Because we’re all searching. I mean, we still are. What in the hell caused the, why, how could the earth ever get itself into such a different climate state? I mean, it seemed—
Weart:And there is no question that there was glacial and there was nonglacial. That’s clearly two modes.
Broecker:We knew the ice was in ??? ???. We may not have known how much the tropical temperatures. That was the big surprise of, of course, of CLIMAP that Emiliani didn’t like, that they maintained that the temperature change was quite small. Now the pendulum has swung back somewhat toward Emiliani.
Broecker:Because, you know, the tropical temperature change, CLIMAP said it was one or two degrees, and it probably was three or four degrees. And another thing about this, I got so interested in the snow lines, because there was no way CLIMAP could explain the lowering of snow lines that much in the tropics with one degree. So with Dorothy Petite [?] and David Rind [?], you know, we got into thinking more about the snow lines.
Weart:Right. Let me ask you now about this, when you realized that it was a sawtooth kind of a curve that, wow, your paper with Van Donk in 1970. Do you recall the origins of that, how you came to see things that way? Just did it naturally fall out of the curve?
Broecker:Just looking hard at those curves. I mean, one of the things that it was interesting to go back to Emiliani’s paper, the only curve that really didn’t look triangular was one, a core about 43 degrees north in the Atlantic, the only one he ran, and that had much more of the Malonkovitch you might say subfrequencies in it, and it may be because it was a higher deposition rate. See, a lot of this was how much of the record is sort of, you know, schmoothed [?] out, and but a lot of those early records looked like that. Then when people got into looking at higher deposition rate cores, then these curves assume more structure, you know, there’s more there. It just wasn’t found. And they also started to do Benthic, which Shackleton started, learned how to do Benthics, which are very rare. Emiliani did them, but only in cores that had incredible amounts of dissolution. I mean, in a normal deep sea core for every 400 plank tonics [?] there is one Benthic. So if you have to pick 200 of them to make an analysis, well it’s almost impossible.
Weart:It takes a lot of looking, yeah.
Broecker:So, but they don’t, when you dissolve away the carbonate, the Benthics tend to be the most resistant, so there are cores in the equatorial Pacific that there is one for one, and you pick those out, and you know, in hindsight you got a lot of funny numbers, and there may have been all kinds of bioturbation effects and things that we never thought about in those days, so, but Shackleton was the first one to come along and really show that there was— Because see, Emiliani said that the deep amplitude was very small, and therefore the ice volume change, he calculated sort of a minimum amount of ice with a minimum O-18 fractionation and got that that was only three or four tenths per mil, and all the rest of it was temperature. And he said, you know, that didn’t appear in the deep sea and therefore it couldn’t have been ice volume. And—
Weart:Okay. Now, getting back to this 1970 paper, one of the interesting things in there is that you sort of use this to extrapolate into the future. Now we’re getting where we haven’t mentioned before is the anthropogenic global warming story.
Broecker:I like that paper. That [laughs], I intend some day to wait a few more years and take, and put over my simple curve that I got in that ‘76 paper, and the actual temperature trend. Because what I predicted is that, you know, using just this funny thing from the ice cores were something that people probably was at one of these other false findings, that Donscart [?] said that there was appreciable 80 and 180-year periodicity [?], so I just took that and extended it. And I said well, that means that during the times when the globe wasn’t warming it was just in a natural cooling phase. And I said, “Boy, one of these years when they start to work together and CO2 has gone up a lot faster, it’s going to take off,” and basically it’s done that. I mean, that was a—
Weart:Mm-hm, mm-hm. But now I wanted to differentiate here between two papers, because your paper with Van Donk [?] in 1970 just talked about the broad track, which of course would be just taking the large scale Malonkovitch cycles, which would be for continual gradual cooling.
Broecker:Oh, predicting the future, oh yeah.
Weart:Where ??? ??? gradual cooling, and then in 1975 you put in these donsgard cycles, and also at that point you put in global warming, where there is carbon dioxide going on. Sometime in between there, I mean you had known about the idea of global warming since before. You know, you mentioned Craig, you knew Craig and ???, but at some point there you became aware of it as a problem.
Broecker:Well, you know, one of the things, I mean during that period when it wasn’t warming, various people said various things. Gordon MacDonald wrote a paper once where he said, huh, it’s interesting, because it’s one of these that nobody put much stock in it at the—well, they did and then they dropped it—was that sulfate was cooling the earth and these two things were canceling.
Weart:Yes. Right. And there was ???.
Broecker:And so I said well maybe it’s not the sulfate, because you know, and then sulfate sort of disappeared from the screen for what, almost 20 years, and then suddenly in the nineties has reemerged as a major issue.
Weart:Right, right. In the seventies there was also Bryson [?] talking about his particulate as a cooling factor.
Broecker:Oh yeah. Now that was a can of worms, because he took some data that apparently hadn’t been ever, the measurement technique hadn’t been recalibrated. There was some, and when they put the calibration in, a lot of what he said went away. Yeah, he said the sky was becoming a lot less transparent and— I mean maybe he— It’s interesting to go back and say in hindsight how close were the people and how much of it was true and how much of it was a hunch that they had they were defending with lousy data, because a lot of what we did turned out to be, you know, making wrong assumptions about what measurements were trying to tell you. That’s how I got in the whole abrupt change thing was through CO2 and the Greenland ice cores, and those big changes are phony. And so, but it led me into thinking about it.
Weart:Now just a minute, which change are phony?
Broecker:Well, the thing that really turned me on about abrupt changes was, and sent me to the ocean, was when in the early like ‘84 around there the Swiss showed a record during mainly stage three where they had CO2 changes that were rectangular. That’s a lot of noise, but they had a whole group of points of up here and a whole group down here. And it went from like 195 to 245, 195-245, and for a long time we thought those were correct. And so I said, “Well hell, if that’s the case, it’s got to be the ocean, and there’s got to be big time changes in the ocean to ever do this.” And so then I started to think in terms of well, you don’t do this with a minor change in the ocean; you better upset the whole circulation and do something different. So that’s— And Oeschger then, when he gave that talk showing these things, said that, “I think this is telling us it’s time it had two states.” So he was thinking in terms of those things too. Because a lot of us had passed all those stuff off in Greenland, I don’t know, it’s like the curves I was telling you about, I don’t know why in Greenland, it’s just something to do with Greenland. There was no repetition, you know, it was just a one ??? ??? ???.
Weart:Right. It could have been something happening in the ice, the ice slipping and so on.
Broecker:Yeah, who knows. And so we didn’t really, it was so different and it was very interesting, but we didn’t put any stock in those things. At least I don’t think any of us, until the CO2 measurements were made, and that caught everybody’s attention, because we knew CO2 screened ocean.
Broecker:And if those were real— Well, I remember the meeting we had in Florida in 1984. It was—we discussed this, and it was almost impossible to think of how in the hell you could ever change atmospheric CO2 so fast. Well it turns out now that we’re almost positive that those intermediate high CO2s were the fact that the ratio of acid to dust in there was such that after the, during some time of the lithification or thereafter the acid released some CO2 from the dust.
Weart:So it was the dust events you were seeing, uh-huh.
Broecker:And so it was false [?]. Yeah, and one of the things we should have known is there are no lag, there was no offset in the ice between the O-18 changes, which are in the ice, and the CO2 changes, which are in the bubbles. And how could you do that? I mean unless by coincidence the offset and time balance the offset in the—
Weart:In the uptake?
Broecker:Yeah. So, and then Oeschger at one point had a student who did very detailed measurements, and they found that this whole change occurred in 2 centimeters in the ice or something, and it became more and more ridiculous. Then they went and looked in Antarctica, and the Bern group wrote a paper where they didn’t have the chronology very well, but they hammered away so many points and said no way we could have missed it, we were in the right section of the core. And they did like 200 points, and they were, none of them showed the 240 values; they all showed the low glacial value. But it was, it’s interesting that that’s how this whole thing got started.
Weart:Okay. Getting back to the seventies, I want to ask you now, getting more into the area of the sort of political kind of things. You began to write some articles, you know, are we on the brink of global warming, you gave testimony to Congress and so on. How did you get involved with the idea of warning people about global warming? What got you—? Is there any particular person who was involved in getting interested in that, or—? This is a period when other scientists, too, were starting to do that.
Broecker:I was thinking the other day, because I was a little bit pissed off at Jim Hansen for something he did, that you know I stopped that after ‘75 whenever I wrote that article, because Jim Hansen at GISS really picked it up and he went into it with more vigor and you know he looked at volcanos and you know he looked at all aspects of it, of you know what might have been controlling the natural fluctuations. And I went away from it, but um—
Weart:Were you concerned about government funding for these studies?
Weart:Government funding for climate studies.
Broecker:Well I think—that’s what I was just thinking about. We were trying to get that CO2 program going, because we wanted the research money for one thing, but well, I sort of, I never would have said it if I didn’t believe it, because that’s not the way I am. I mean, you know, I really—
Weart:No, but there is reasons for going and trying to affect the public and talking to Congress and so on. Because this is a CO2 program, the CO2 monitoring program in the early seventies. And what was your involvement with that? Did you have anything to do with getting that started?
Broecker:Well, I had been involved all along in trying to understand the fate of the CO2. I mean I just, you know, because of the, I’ve done gas exchange in the ocean, vertical mixing at GEOSECS was all about trying to get ??? data ???.
Weart:Yeah, we have to get to GEOSECS. Yeah.
Broecker:But I mean I was very much involved in trying to understand the carbon cycle, and of course that involved trying to understand the fate of fossil fuel CO2, so it’s a natural thing to think about. I used to teach in my classes, I remember using— One paper that had a lot of influence on me was a paper that Manabe wrote with his professor back in like ‘63, where they did a one-dimensional model of the atmosphere and they calculated the water feedback. And I found that fascinating, you know, how do you go about doing that, and that, you know, they came to the conclusion that it was sizeable, and that that kicked up the warming from one degree to four degrees or something. I mean, they had about the same kind of result you’d get in a general circulation model.
Weart:Yeah. It’s always puzzled me that that one-dimensional model already gave the—
Broecker:Yeah. It already gave it. And I think that convinced me that this was a thing to worry about, if this water vapor feedback was so strong. And so I suppose it came out of teaching courses, for one thing. A lot of what I do comes out of teaching courses, because it makes you think about things a lot more than you would if you didn’t teach courses.
Weart:You have to go back to the basics. Yeah. Well let me ask you about what relationships you may have had with people in Washington. First just to check off some things, did you have any, did you do any work for the DARPA program? Because DARPA was doing some things.
Weart:There was the CIA climate study.
Weart:Okay. Any work with JASON [?] or those people?
Broecker:No. I never. I mean—
Weart:Okay, well then let’s—
Broecker:I’ve never done classified work, and I’ve never been a consultant to any, you know, except for four or five times in my whole history where I sold my brain to somebody else. I’ve been a real ivory tower academic.
Weart:Uh-huh. Okay, well then let’s talk about DOE, or maybe also we should ask about your and Harmon Craig [?] and GEOSECS. Do you want to talk about how that got started?
Broecker:Well I was just writing about that in that little chapter. I was at Woods Hole for some meeting, and Henry—
Broecker:And there was one of Paul Fije presenting the Bigelow Medal, and he had this thing in his hand, you know, with a black leather thing, and opened up showing the medal, and so we cut out a piece of paper wrote a bubble like you’d have in a comic strip. It says, “I’m Paul Fije from the FBI.”
Weart:[laughs] Like showing a badge.
Broecker:And it looked exactly like a badge, and Paul Fije had the very much a look of a, you know, FBI guy and— [tape abruptly ends here and then begins again...]
Weart:So you’re in his office at Woods Hole.
Broecker:Yeah. And so we went in and talked to him, and he explained the IDOE to us, and he said there was a committee, an interim committee, that was going to choose the programs, but they said they really liked the idea of having a pilot program, because these were exactly the kind of thing where you’d start to think about to do an ocean survey. And so we moved in on the ground floor and were, you know, we got what we wanted, and we expanded it from just radiocarbon to you know almost every geochemical property we could think of that would be valuable to measure.
Weart:The “we,” was this you and Craig who worked this up or—?
Broecker:Well, originally John Hunt worked with us at Woods Hole, and then Derrick Spencer [?] took over for John, and we were the triumpherate [?].
Weart:By the way do you have, you know, these people were all spread out, right? You were here, Craig was at Scripps, and these people—
Weart:Do you have correspondence remaining from those days?
Broecker:I don’t know. I never—I suppose we do. I never look at stuff like that. God knows what’s in there or whether we’ve thrown it all out.
Weart:Would your secretary know about that?
Broecker:Know. I mean, she could go look, but she, I mean, Ellen Cox [?] died about, too bad she died about a year ago. She would have known.
Weart:Maybe we ought to go to look for it sometime. Because that would be interesting, give you a good way to see how it evolved.
Broecker:I don’t know how— We did a lot of stuff by telephone and in meetings, but we agreed to run this program, and we hired a man named Arnold Bainbridge, who was a scientist at Scripps, and he turns out to be the most important person in the whole thing, bar none.
Broecker:Because he put together all the apparatus, hired all the technicians, wrote all the computer programs, I mean did all of this in a period of like 18 months. Absolutely incredible. Because they had so many things to do, and they racheted [?] up the whole field in technology by like an order of magnitude. And you know it hasn’t really racheted another order of magnitude since then. We’re using a lot of, you know, basically a lot of the same things that we installed in the early seventies. And he made it work, as I said in my chapter, never missed a beat. I mean, everything went off as it should. We made very few mistakes. The quality of the data was universally high. We’d pick people—we were allowed in those days to do things you couldn’t do now. In other words, we orchestrated it; we decided who the people would be; we had test cruises; and anybody was allowed to compete, but then we picked the best analyst. Of course in many cases we knew already who was the best analyst, because we wanted high quality data.
Weart:Again, who is the “we” here?
Broecker:Spencer and I and Craig and a committee of about eight geochemists, Osland and Striver, who did the radiocarbon, Karl [?] Turekian at Yale, and the four of us, Bainbridge, Spencer, Craig and I.
Weart:So would you get together on the phone or—?
Broecker:Well, we had, no, we ??? ??? all over the place. No, we did a lot of personal meetings, and that’s when we accomplished things. And then Bainbridge put all this group and stuff together at La Jolla, and then we did a test cruise off California, and we did a test cruise off Woods Hole, and we did a third test cruise off Samoa. That’s when I went to New Guinea on that same trip.
Weart:Oh, oh, it was ??? stopped off there.
Broecker:Yeah. And then we did the real thing starting in what, September 1972. And that went on until 1978 with somewhat of a hiatus where NSF couldn’t decide whether they wanted to let us do the Indian Ocean, so luckily we did.
Weart:Oh. It was just a matter of waiting for them to decide and pounding on them?
Broecker:Oh, yeah, getting the money together, I don’t know. F??? Jennings, who managed the IDOE, has to be, he was just, boy, talk about a guy who knew how to do it, and kept us all happy and at least our program—what was it called? Mode, the Physical Oceanographers Program and CLIMAP were all very successful. I mean one reason was that this kind of thing had never been done, and the power of putting all these people together where you have a virgin field in a sense, nobody’s ever done this. Now it gets crowded, and you know, everybody, you know, there’s a lot of competing programs and territories, you know, the cream has been skimmed off. Well, we skimmed off a huge amount of cream in those years, you know.
Weart:Right, and for GEOSECS there was sort of room for everybody.
Weart:There weren’t that many people.
Broecker:We had institutions all over the country. I mean, and we had people from Germany, India, Law [?] from India was a big part of it, Ka Munich [?] from Germany, and people from every oceanographic institute in the U.S. Yeah, we weren’t, we didn’t try to keep it at all within our institution. We picked for each property the best person, wherever they were. And—
Weart:Was there ever any question about ownership of the data, who would get to publish or whether things should be approved for publication?
Broecker:Well actually it turned out not to be a big problem, because I was the only big publisher. I mean, Craig didn’t write many— You know, I would say not as much as there is now, there was— Minzie Striver was a bit pissed off with me a couple times because he thought he wrote about things that I shouldn’t have, but I said well, you know, this is five years after we gave you the samples. You’ve had the results for two years. How long we got to wait? But that was, you know, Minzie and I have remained really good friends, so it was just one of those— I think that was a minor problem; it was not a major problem, a very minor problem.
Weart:And you were satisfied when the money ran out that it was more or less at the point you expected and you had enough money to do it?
Broecker:We had enough money to finish it. I mean, what I calculated originally would be a half a million dollars, which ??? ??? a million came to twenty-five million. [laughs] And but I mean it was a bargain. God, the number of properties we measured. I mean, it is the foundation for all chemical oceanography and tracer oceanography. Everybody builds on that original dataset and expeditions are planned according to it. I mean it’s the standard, and so that was a real Camelot. I mean those were really heady days. I mean we all got along well, we had a lot of fun, we traveled around the world, the technical group that Bainbridge put together was— I don’t know how he ever found such a group of wonderful people—hard workers, you know, pleasant to be with.
Weart:They were here?
Broecker:No, they were all Californians mainly.
Weart:Uh-huh, so at Scripps.
Broecker:They were hired from— Yeah, because Bainbridge was located there. It’s now become, it’s changed names, but it’s still an oceangoing logistics group that does nutrients, temperature salinity. And Bob Williams runs it now. He was a key member. I’ve got to go at about ???-thirty.
Weart:Yeah, yeah, I was going to say. I wondered if we have—
Broecker:That’s okay. We can go to 5:30 [?].
Weart:Okay. Well, let’s just talk about one or two other things. I don’t think we’ll get quite through this, but I guess this just flows to some extent out of GEOSECS. As you started to get interested you and Peng did some carbon cycle box models, you got interested in the oceans as a sink for carbon and not the ???. So first of all, who is Peng, and where did he come into this?
Broecker:Peng was a student of mine, and he did a thesis on gas exchange in the lab and also did work with me on radon measurements at sea. And he stayed on here as a postdoc for, or a young scientist, for a number of years. And I think it was in 1980 when I got lymphoma, and I didn’t know whether I was going to survive or not. Eventually it went to the third stage. I’m a lucky person.
Weart:Yeah. I had noticed, and I was going to ask you, there was a period in the eighties when you didn’t produce very much. Was that because you were laid up?
Broecker:No. I wrote [?] tracers in the sea ??? ??? ??? ???—
Weart:Oh, oh, you were writing.
Broecker:It was entirely written. So that sort of was a summary of GEOSECS.
Weart:I see. So you were busy writing, doing that.
Broecker:Well, in the early eighties. And I don’t know what controls that, but I was looking, trying to update my Vita. I noticed I have three hundred and forty-some papers now in about 40 years, so I suppose about nine a year. And if you look, I ought to make a histogram sometime of how many in each year and what were the high years and what were the low years. But anyway, Peng got into modeling, and he is very good at, I mean we worked very well as a team. I mean he could do the programming and run the stuff, and keep up with the improving computer world, and I could do the thinking, and so in 1980 he got an offer at Oakridge, and I said, “For Christ’s sake take it, Tsung-Hung, because funding is getting difficult, and you’re getting expensive, and it’s hard to keep you on soft money,” and I said, “I don’t know what’s going to happen to me, so you know, you ought to, we can still work together.” And so we did. And we worked together up until a few years ago when he want down to Miami, and I guess, you know, the things that we could do well together we’d done. And we’re still good friends, but we’re, that collaboration went for, God, a long time. There were a lot of Broecker and Peng papers.
Weart:Yeah, there certainly are, right. And especially—
Broecker:And he’s a really nice guy. I remember when he first came here, Jim Simpson, who still teaches here, Mike Bender who is now at Princeton, he used to tease him, and they said “Look, Tsung-Hung, when Broecker tells you something, he expects you to respond in the right way. You’ve got to show him you realize what he said was important.” So Tsung-Hung says, “What do I say?” They said, “Just say ‘bullshit’.”
Weart:[laughs] Show you’re paying attention. Okay, you do these models for how the carbon goes into the ocean, and then at some point in there you—
Broecker:Bomb [?] radiocarbon was the king, is the king of all these tracers, and the carbon cycle, it carries the most information. So a lot of stuff we’ve done on various aspects of the radiocarbon cycle, both natural and but particularly the bomb. And then that’s the time tracer that tells us how to make a model that more or less replicates what’s really going on. And the box models we made and other people made are amazingly close to general circulation models for CO2 uptake. And that’s because there’s a lucky—the ocean— Oeschger first pointed this out, that he made a model with a mixed layer and then a diffusive ocean below it, and so all you had to have in that model was the thickness of the mixed layer and the diffusivity of the underlying—
Weart:Oh, it’s just the two-layer models, uh-huh.
Broecker:And Tsung-Hung and I showed later that this model works amazingly well, even though it violates, you know, if you had the ocean operating that way it would be warm at the bottom. And that is that natural radiocarbon gives us an overall ventilation time of the ocean of about a thousand years, and that’s for a thickness of 3800 meters. A bomb radiocarbon set on the time scale of ten years, the ocean mixed to about, on the average, 350 meters. Well, a thousand, uh, 3800 over—
Broecker:That’s the square root relationship between time and distance. So that that approach worked very well, and I don’t know whether the general circulation models give a better number or a worse number, but that number is certainly within the error of both. We both for the period of the eighties got like 2 gigatons going in the ocean. And there was this huge debate, you know—
Weart:Yeah. And don’t just jump pass that. Tell me about that. When did that, how did that start? This is Woodwell and the other people?
Broecker:This was that asshole Woodwell, yeah. You can put that in.
Weart:Okay. That’s on the tape now.
Broecker:I mean he went to Venezuela, and he found this area which is 113/100th of the total global area or continental area, I can’t remember. It was on the border between Venezuela and Columbia, and it was being heavily logged, really heavily logged. He took that number and extrapolated it—
Weart:Multiplied it by the area of the— Uh-huh.
Broecker:By 1300, you know, and he got originally that the amount of CO2 being released by deforestation was five times higher than the amount. He used to drive me nuts. And then this number gradually came down, and there is a paper that Simpson and I and Tower [?] I think wrote, and I think we had, the last line was pretty good. We said, “When we do the budget it appears that the global biosphere has, biomass has stayed about the same. And so that means that any forest cutting, whatever it was, had to be balanced by some kind of ???”
Weart:By uptake somewhere, mm-hmm.
Broecker:And you know, and up until Keeling’s work— I mean it wasn’t Keeling, I mean Keeling started to make a better, do it better, because he could do the oxygen, but up until about nineteen—the late eighties, that was probably about right. And then for some reason, probably a climate change, the biosphere is packing away carbon like beJesus and, but that’s not going to persist. It can’t. I mean that stuff’s got to be eaten so that you know it won’t go on for very long.
Weart:But for quite a period there people were quite uncertain as to—
Broecker:Missing ???. So people proposed all kinds of things, and everything they proposed was shot down. I mean, the best—I mean one of the neatest things Garrels [?] is just saying, “Well, if you take all the nitrogen that’s ever been fixed and say that no matter where it went each nitrogen atom mated with ten carbon atoms, because that’s the average for plankton and so on,” but he said, “That’s an upper limit on how much that the nitrogen could have done.” And that turned out to be a couple tenths of a gigaton. It was small. And so that was a way to look at the whole damn thing. And then if you used the CO2 growth enhancement that came out and did models that way was— Because, you know, during— I’ve always been interested in soil radiocarbon, and Trumbore is now a superstar at Irvine, and another student after her, Kevin Harrison, I mean were able to establish the turnover time of the humus in soil. And that’s an important— Because if you’re perturbing it by adding more carbon, then that gives you the time that you have to have that time in order to figure out how it’s going to evolve.
Weart:What I’m not sure about is what was at stake here. Why did this become, you know, there’s a lot of uncertain numbers. Why does it become—?
Broecker:It was biologists [?] versus oceanographers. They used to say, “Your ocean models are wrong,” and we used to say, “Bullshit. Our ocean models are good,” and we’d just say, “You’re just overestimating what’s happening on the continents.”
Weart:So it was because they weren’t able to follow your models and you weren’t able to argue in their language?
Well, I would say there was no way in hell they could evaluate with the information they had what was going on in the continents. I mean time is— And the, of course when this all started in the seventies, the ocean, you could argue about the ocean models, but we were always vigorously defended that because of the argument I just gave you that we could not be very far off. We knew the gas exchange through a gnat’s eyebrow, really, and then the natural radiocarbon and the tracer tritium and bomb radiocarbon really— [phone rings] That might be George. Let me see— [tape turned off and interview not resumed on this tape]
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