Science Talk

CO2 Rising: Follow the Bouncing Carbon Atom

Scientist and author Tyler Volk talks about his new book CO2 Rising: The World's Greatest Environmental Challenge. Plus, we'll test your knowledge about some recent science in the news. Web sites related to this episode include

Podcast Transcription
Welcome to Science Talk, the weekly podcast of Scientific American, for the week of January 28th 2009. I'm Steve Mirsky. This week on the podcast we'll talk with scientist and writer Tyler Volk about his new book CO2 Rising: The World's Greatest Environmental Challenge. Plus, we'll test your knowledge about some recent science in the news. Tyler Volk is science director of environmental studies and associate professor of biology at New York University. CO2 Rising explains the global carbon cycle, what happens to all the individual atoms that are constantly cycling into, out of and through the biosphere. That might sound very dry, but Volk brings it alive. We spoke in his office at N.Y.U.

Volk: When if the mind boggling facts This is no local pollutant: Every burst of CO2 that goes into the air from some power plant in Illinois is going to spread equally all around the world, and the same goes for CO2 emissions from China. They spread all around the world, and so it's unlike any other environmental substance we've ever looked at, perhaps.

Steve: Right, I mean Chernobyl's terrible thing but that is not a worldwide spread, what got spewed out there.

Volk: Yeah, the winds did spread it into the northern Europe and so that was very bad, but it wasn't a pure worldwide equal spread.

Steve: So what is there, how do you know that you're getting indeed a worldwide spread of the carbon dioxide? I mean, what kind of evidence do we have that the stuff I am breathing out right now is actually going to diffuse, disperse worldwide and how long will it take?

Volk: Right. It's about a year, and that the biggest bottleneck is between the two hemispheres, between the Northern Hemisphere and Southern Hemisphere. But the real sort of killer data on this is the fact that if you go to the South Pole—in which it's [where monitoring is] done, and [the] South Pole is one of the sites that it has been monitoring CO2 for the longest, back to the late 1950s—and compare that to Northern Hemisphere site, the one also from the late 1950s, and Mauna Loa, Hawaii (the big island of Hawaii). The two curves fall virtually one on top of each other. So the CO2 that's mostly being emitted in the Northern Hemisphere is circulating all the way down, and it's going to be the same increased greenhouse effect at the South Pole. [It] may not be the same temperature rise, that may even be larger, but the pure greenhouse effect locally from the increased CO2 is perfectly distributed worldwide.

Steve: Okay, so you differentiated just now between temperature rise and the CO2 concentrations. So, how exactly, I mean everybody hears about global warming or climate change and rising levels of greenhouse gases—how are the two actually related? How do you get a temperature rise because of the increased levels of carbon dioxide and other greenhouse gases?

Volk: Okay, Steve, so the CO2 molecule absorbs infrared radiation, which is exactly the kind of radiation that the Earth does not use to cool itself—it's a teleological thing but the Earth sends [it] off to space—that's what keeps the Earth's temperature not rising forever as the sun is coming in and heating up the Earth; so this [these] CO2 molecules are very special. They are not like the oxygen molecules or the nitrogen molecules in the atmosphere, which do not absorb infrared, but the greenhouse gases do. All the greenhouse gases absorb infrared, and they also release the infrared, so these act as blockades to the infrared, leaving the atmosphere and going off into space; and the Earth warms up to send off even more infrared from the surface in order to reach its state, sort of a steady state with regard to space.

Steve: You talk in the book about how three atoms in the molecules [are] really key to this whole business about the infrared and the vibrations within the molecule that are responsible for dealing with the heat, and that's the difference because nitrogen is N2.

Volk: Right.

Steve: Hydrogen is H2 but once you start with CO2 or CH4 with methane or H2O and water vapor or O3 in ozone, the fact that you have three atoms in your molecule gives you a much wider variety of vibrational modes to…

Volk: Yes.

Steve: Yeah.

Volk: Yes, it's perfectly said for this level of discussion.

Steve: So, because the thing can jiggle around, it acts as a little sponge for heat, basically.

Volk: Right. Its vibrational modes correspond to the vibrational modes of the infrared radiation; that determines what kinds of radiation a molecule can absorb and re-release, so that turns these molecules of three or more atoms in our atmosphere into the so-called greenhouse gases.

Steve: So, you did a really interesting thing in large portions of the book, and that is you kind of anthropomorphized— anthropomorphisized—one of those two words…

Volk: …sounds good…

Steve: …a few particular carbon atoms and your lead protagonist in the book is a carbon atom named Dave, and Dave's adventures are really quite amazing. And I don't mind the—I don't want to use that "anthro-" word again—I don't mind the imbuing of the inanimate carbon atom with sort of a personality, because it really makes it more like an adventurous story that you can grab on to. Just talk a little bit about how this particular carbon atom that you've named Dave travels around the globe and what kind of adventures it has as a member of the biosphere, or, you know, occasionally not in the biosphere.

Volk: Yeah, okay, so this was suggested by a friend of mine, because in our previous book Gaia's Body I had just [a] three or four paragraph description about [a] carbon atom's travels, and he said, "Why don't you have this in the new book?" And I thought about it; sounds a little nuts, but the more I thought about it, the more I thought, "Yeah, just see[ing] the circulation through the carbon atom's point of view might be a good way"; because in my own mind working on the carbon cycle for a long time, you know, I do track these carbon atoms in my own mind. It's a way to think about the CO2 going into the ocean from the atmosphere, going from the atmosphere back up into the ocean; so I start Dave off at the beginning of the book in a molecule of alcohol, in a glass of beer, that's where Dave is starting off. And I tracked that atom of carbon backwards through the alcohol molecule that came out as a waste product from the yeast that brew[ed] the beer. So what we might like as the effect in a beer or wine is a waste product from the organisms that are excreting this, and those yeast took in Dave as a[n] atom of carbon in a maltose sugar molecule that the brewmeister made—it's part of the beer-making process—and I tracked this back in a few paragraphs to being in the grain of the barley plant, in the starch of a barley plant and then coming from the atmosphere as a CO2 molecule that entered the leaf of the barley plant. So when you drink beer, since beer doesn't keep too well, you can pretty well know that sometime in the year before, that atom of carbon is in the alcohol molecule you were drinking was in the atmosphere within a CO2 molecule. So that's happening now in the beer. Early in the book, I have Dave in the early 1960s being in a pulse of air that is traveling over Hawaii, so this is, say 47 years ago; no problem with the carbon atoms. Dave has actually been in circulation for—according to my fictional story here, but it is very real, there is actually a Dave out there somewhere; you know, Dave, we're going to find you, but we know from the statistics that this is true. Dave has been around for 35,000 years circulating among atmosphere and ocean, so I have Dave in a CO2 molecule going through the infrared gas analyzer at Mauna Loa Hawaii and, in a sense, participating in the discovery of the increasing amounts of CO2 in the atmosphere. And by the way, I want to mention the word [name] Dave is not purely arbitrary; it comes from Charles David Keeling and his science friends and colleagues who used to call him Dave. The CO2 increase at Mauna Loa, Hawaii, is, we know that from Charles David Keeling, from Dave Keeling's efforts. He died a few years ago, but in some ways he was the father or grandfather of our understanding of the Earth's carbon cycle. So in a way it's in honor of him.

Steve: And you talk about Dave, the carbon atom being measured in this gas analyzer in Hawaii, but it was Charles David Keeling who actually did that measurement.

Volk: Right, that's right.

Steve: And then the measurement was corroborated in Antarctica.

Volk: Antarctica also, yeah. And now we have it being corroborated all over the world. But the first two places were the Mauna Loa, Hawaii and in Antarctica, and that was key, because you could see from that that in the Northern Hemisphere, the carbon dioxide was going up and down seasonally. So after the first half year or so, you can see that CO2 is going down; that was because of its sketching at the photosynthetic time of year in the Northern Hemisphere, but the main point is that the…

Steve: Which means that the green plants are taking up the carbon dioxide…

Volk: …yeah…

Steve: …to make the sugars.

Volk: Right.

Steve: And then they are getting rid of it again, and you get this little kind of wiggly line, but the overall trend is up.

Volk: The overall trend is up, yeah. But this wiggly line that you referred to, that does turn out to be a couple of percent of the entire atmospheric CO2 on an annual basis and one of the messages from that is that the vegetation and the bacteria that are releasing the CO2 from the soil, the vegetation is taking it up from the atmosphere to the sugars. That is such a powerful force. The living things are such a powerful factor in the Earth's carbon cycle that they shift, they can remove and replenish several percentage of the Earth's entire atmospheric CO2 during the course of this six-month up and downs, six months up and six months down cycle.

Steve: And you have other smaller players in this drama besides Dave. You have Icille, who is really an interesting character because Icille the carbon atom is trapped in a gas bubble in the ice in Antarctica for how many thousands of years?

Volk: Yeah, so Icille was released into Earth's biosphere at the same time Dave was, from a limestone, from the calcium carbonate of a limestone cliff in the Dordogne valley of southern France about the same time that we have the earliest, very earliest cave art in the human prehistory; but Icille didn't last very long in the biosphere, she got trapped in this ice core. So she has been sitting in this core for the 35,000 years until fairly recently. Scientists released her when they were analyzing these bubbles trapped in the ice core and that gives us information about what the CO2 level was in Earth's atmosphere; actual sampling of the CO2 [that] was in the atmosphere 35,000 years ago due to Icille and her companions' release in recent years.

Steve: And then these other players, now these guys are really interesting because you have a couple of other carbon atoms— Methaniel…

Volk: Methaniel

Steve: …and Coaleen

Volk: Yeah.

Steve: And there is one more.

Volk: Oiliver….

Steve: Oiliver, right…

Volk: Oiliver.

Steve: And now they are different.

Volk: They are different.

Steve: Talk about why they are different and what they mean in this whole story.

Volk: Yeah, so you can tell from the names, these carbon atoms came from various fossil fuels: methane—Methaniel; oil for Oiliver; and coal for Coaleen. So I used them to emphasize the difference between a fossil fuel carbon atom that is coming out of the ground, which Dave did too in a sense from the limestone cliff, but these fossil fuel carbon atoms we dug up to burn fossil fuels to fuel our world civilization, and I do compare the total amount of fossil fuel carbon that we are putting into the atmosphere with nature's flux of carbon coming into the biosphere due to the limestone dissolution or volcanoes. And we are currently exceeding the natural flux of entry of new carbon by about a factor of 20, because you can't say that nature is not putting carbon up into the circulation and that we are doing it [all]. No, nature is doing it, too, but it's doing it only about 5 percent of the rate of what we are now affecting in terms of the flux of carbon.

Steve: And is that carbon flux, that is what we are now dealing with?

Volk: Right, right.

Steve: All those extra carbons are being released, and that would have possibly got into circulation but at this much slower rate, much fewer in any given year, and they would have been in a kind of a steady state with what's going back into the abiotic part of the planet.

Volk: Yeah.

Steve: And all of a sudden—boom. We have got all this stuff because of our industrialization and here, we're—the upshot is, things are getting warmer.

Volk: Yeah, things are getting warmer. We know from these measurements from the ice cores with Icille and her companions, from various ages of ice, that before 1850 the CO2 in the atmosphere was very steady for about 10,000 years going back in time. So even though the natural processes, the vegetation, the bacteria, the soil are enormous fluxors of carbon, in fact there are larger fluxors of carbon than our fossil fuel release, but we can see that they would have been in balance for the 10,000 years going back in time. And now we are putting this fresh CO2 into the atmosphere and it starts circulating around. One of the points is that it doesn't just stay there, the atmosphere is not just this closed box that you're stuffing for the gas and it stays there, the atmosphere has increased. It's only about half of what we are putting up into the sky and that is an interesting number because were it 90 percent then we will be at lot more trouble, but we[re] are at [it] 10 percent, we would barely think about it.

Steve: We might not even have noticed it.

Volk: Yeah, right…. Right.

Steve: But at 50 percent, it's interesting we are not even really sure where that 50 percent that is being released into the atmosphere, well doesn't stay in the atmosphere. We are not really sure where it goes.

Volk: Well, yeah, some is going into the ocean, but as you point out, there are mysteries still there about what the land ecosystems are doing to the CO2. We know that when we cut down forests, when we deforest various places that is a release of CO2 into the atmosphere from the decay of the twigs; or if the forests are burnt for farmland that's a release of CO2, but on the other hand places near where you and I are talking in the New York State, in Massachusetts, Vermont those places where the forests are growing, and that's being a net carbon storage. So, when you add all those up the deforestation is a little bit more, but we also know that somewhere else in the vegetation, CO2 is being taken from the atmosphere and that uptake, that's still debated whether it's primarily in the tropics or primarily in the boreal forest of the Northern Hemisphere. Technical papers being written on these various subjects, this is not important for us. It's important for us, but it is not important for this big picture.

Steve: We should also know that just because the ocean is doing a terrific job, possibly soaking up a lot of this CO2, that's not without consequence because it changes the pH of the ocean.

Volk: Yeah, yeah that's becoming more and more of a concern as people are realizing that there is not just the greenhouse effect of CO2 being a greenhouse gas and warming the Earth up, but there is a direct chemical effect of its dissolving in the ocean as carbonic acid, and this is going to affect many marine creatures in the coming decades. I do want to say about the soaking up process: It's somewhat remarkable that this 50 percent soaking up that has happened, it has been remarkably constant over about since we have had our measurements through the 40 years, and that is hopeful in the sense that it allows us to make some fairly good predictions into the future. We have to go into details of the carbon cycle, but at least we can know nature is behaving fairly predictably so far. The long term picture could be different, of course.

Steve: So, let me ask some questions that I know I am going to get listener mail about, and they're going to go something like this: "So what's the problem? So what if it is going to get warmer? Isn't that good? You know, it's freezing today. I wish it were a little warmer. Maybe the trees like it warmer, may be they will grow better. Maybe they'll grow better and soak up some of that CO2 faster, maybe the whole thing's going to be self-regulated. Why are we so worried about it, how do we know that if we start messing around with it trying to fix it, we just will make it worse somehow?"

Volk: Right. Well, I don't think we should start messing around fixing it in the sense of sending them miles up into the space; [in] fact I make some arguments why that's not going to happen, because we can't even agree on CO2 now, the world's nations are not going to agree upon how much to try to turn the thermostat back, particularly when the crops might be growing better with higher CO2, right now when the temperature effects haven't kicked in fully. But here's your question: why we should be concerned even with the global temperature rise that has been predicted, let's say by 2050, of probably around 2 degrees C; one should understand that in the Ice Age—the depths of the Ice Age—the Earth was colder on a global average by about 5 degrees C.

Steve: From what it is today.

Volk: From what it is today, and yet it was massively different with ice sheets where you and I are talking right now; in New York City would have been covered with an ice sheet that was taller than the Empire State Building, that would have been right here, you know, over 20,000 years ago, and the distribution of trees and all kinds of organisms, these distributions were very different from what they are today. So if you think of going in [a] warming direction of 2 degrees C compared to a cooling direction of 5 degrees C, one can say that we might be changing the Earth, you know, like 40 percent of the kind of change that went on between the Ice Age; and now are going back in time and so a 2-degree change, which is about 4 degrees F on a global average, is going to be very significant in terms of change in the distribution of vegetation, change in the kind of climate zones in certain areas, wind patterns can change, so where rainfall happens is going to shift. So there is a lot of unknowns.

Steve: Another question that I know is going to come in, because they come in whenever we do this kind of subject. You got this IPCC that's a U.N. thing, The International Panel on Climate Change.

Volk: Right.

Steve: That's not a scientific organization, that's a political organization, that's the U.N. They have their own agenda and their agenda—let me channel some listeners—their agenda is to make the United States poor, and why should I believe their statements about climate when it's not really a scientific organization?

Volk: Okay, well there are thousands of scientists involved in this IPCC effort. So even though it is funded by the U.N., there are thousands of scientists involved and scientists are [a] pretty competitive, contentious bunch and there's a lot of young scientists that could make their names by proving the other findings for the last decades wrong; and so the fact that these predictions of warming and run by a dozen different models all over the world, any one of which would love to prove that the other models are wrong, you know, we have to see science as a kind of an evolutionary process in terms of variation and natural selection.

Steve: You've got a problem there.

Volk: I'm saying, yeah, I've got a problem…

Steve: Because people who don't buy global warming also don't buy evolution.

Volk: Okay.

Steve: But carry on.

Volk: Carry on. So this self-correcting of a process, I mean, there is debates about the actual impacts of the CO2 on climate; but what I am trying to do in the book is to get people to understand the carbon cycle, because I find that, at least for myself and for people I talked to, that if that's well known these other concerns, you know, fall into place more, even though the details of the warming are not known, the fact that it will warm and will make effects. It is enough and that really is an established scientific fact.

Steve: You have some really interesting graphs in the book that show these correlations between wealth and CO2 production.

Volk: Yeah.

Steve: And there's a third thing in these graphs; you['ve] got wealth, CO2 production and…

Volk: …energy.

Steve: … and energy, right.

Volk: Yeah, and I look at these not on a country level but per capita level because countries vary in their populations.

Steve: So, what China is now the largest CO2 producer but on a per capita level?

Volk: Yeah and this really gets me going Steve, when I start reading in the paper that China has now surpassed the U.S. as the number one CO2 emitter, and they don't seem to be willing to do anything about it, but it's 1.2 [billion]to 1.3 billion people in China. If you look at their per capita, they are about one-fifth or one-fourth the U.S. So this is known, that the US is relatively wealthy and we use a lot of energy and we emit CO2; when you graph it out of the per capita of the US compared to the per capita numbers for the world, it's more than just a subjective sense of yeah, that's how it is. You read that the correlations are really phenomenal, that the U.S. is between four and five times the world average per capita income, between four and five times the world average per capita energy consumption and between four and five times the world average per capita CO2 emissions. And then you look at a place like China, which is just now—despite it's phenomenal growth in recent decades at 9 or 10 percent per year—is just now reaching about the per capita world average on all those factors, energy consumption, wealth and CO2 emissions, and they clearly want to do more. And this is really a serious thing to think about because, Africa, for example, is way down there, barely off the graph, and India too, which is now in the top ten CO2 emitters, is nowhere near the global per capita emissions. For a country, for example, of what the world's average country is, China or Mexico or Turkey, I mean those are the sort of the world averages is those countries.

Steve: Right and hiking it up is the U.S., Canada, European Union, Australia, New Zealand

Volk: And Japan

Steve: And Japan.

Volk: Those are the ones that are significantly above the global average and others are too. Russia is above but those are the ones. So those are the models for where the world should be going and one of the sort of major perplexing graph[s] that's on my mind everyday. In fact I was just talking to an economist this morning; you extrapolate the gross world product, the world economic activity and it has been just phenomenally consistent at about 3 percent growth rate over the last 30 years. You extrapolate that in 2050 and you get a world economic activity that's four times higher than today and people say that and many people just say, if not it can't happen. You know, four times the cars, the computers, the agriculture. Of course you have to look at these in great detail, but what that means for 2050, when I worked out the numbers, assuming our world population of 8 or 9 billion in the year 2050, is that if this world economic growth rate continues to 2050 the way it has been in the past 30 years, you get an average person in the world in 2050 being like today's average European or Japanese. So it would take this growth rate just to get the average world to 2050 up to today's Europe or Japan. Presumably today's Europe or Japan is not going to be enough for a 2050 European or Japanese or U.S. So the whole world is not going to even be at Europe or Japan today in 2050, so many people are still going to be poor. So Steve, I have concluded that I have to support that pace of growth to 2050 just to make the world a better place for the billions that are in poverty now. Therefore the problem is going to be how we are going to do that in terms of our energy needs and what that is going to mean for CO2 emissions and how we can perhaps hold CO2 emissions constant during that period while there is this growth rate, bringing in the renewable energy systems or rethinking the world in some fundamental way. So we have a tremendous challenge ahead of us to bring the world's people out of poverty, increase the wealth all over, which seems to be needed by people and desired by people and at the same time keep the Earth safe in maintaining it in the climate regime and which is not throwing huge ringers into the climate system that we are not controlling.

Steve: So what's the goodness? Why should I leave your office today feeling, you know, like everything is on a loss [not lost]?

Volk: I wrote the book and came away feeling more optimistic than I was when I started. Because it's going to be slow. There has been lot of it in the news recently, but the CO2 rates are going up slowly and the climate change is going to be slow and changing the industrial situation of the world is going to be slow. And so we have time in the sense that we can't do very much immediately. The CO2 is going to keep going up for a while, and so we have to watch it very carefully; watch what climate is doing, understand a lot better and bring online in a gradual but persistent way to the best of our industrial abilities, new kinds of energy systems; to not have the CO2 emissions from fossil fuel combustion increase as much as they might were everything just to go hog wild without any kind of restriction or any kind of consciousness about it. So I am very hopeful that the human consciousness, which is really awakening to the situation, can work these issues out in time. I became more optimistic.

Steve: Tyler Volk has produced a couple of videos that explain some of the key concepts in his book, CO2 Rising. Just go to YouTube and search for Tyler Volk, V-O-L-K.


Now it's time to play TOTALL……. Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL……. Y BOGUS.

Story number 1: Cows that get called by name by dairy farmers produce more milk than unnamed cows.

Story number 2: Drinking coffee regularly is associated with a decreased risk of urinary tract infections.

Story number 3: A California woman gave birth to octuplets this week—that's eight.

And story number 4: The far side of the moon may once have faced Earth.

Time is up.

Story number 1 is true. Bessie will produce an average 258 more liters of milk over the 10-month lactation period than will cow number 17, in England at least. That's according to research published in the journal Anthrozoos, in which one studies about the interactions of humans and other animals. For more, check out the January 28th item on our blog by Jordan Lite called, "Cows with Names Make More Milk".

Story number 4 is true. The moon's far side may once have faced Earth; that's according to research to be published in the journal Icarus. The evidence has to do with the distribution of craters which should consistently smash into one side preferentially, like rain hitting your windshield as you drive. For the full discussion, see John Matson's January 23rd article on our Web site called, "Flip-Flop: Did the Moon Do a Turnabout?".

And story 3 is true. A woman in California did have octuplets this week. Lisa Belkin in the Times has a nice piece on the challenges the mother will face as she apparently plans to breast feed. She will need to produce some two gallons of milk per day. Can it be done? The article concludes yes, but it won't be easy; then again neither was having the eight kids in the first place.

All of which means that story number 2, about coffee being related to a lower risk of urinary tract infections is TOTALL……. Y BOGUS. But what is true is that regular coffee drinking is linked to a decreased risk for dementia later in life. That's based on a study of more than 1,400 people followed for an average of 21 years published in the journal of Alzheimer's disease. People who had three to five cups a day had a 65 percent lower risk of dementia then those who had two or fewer cups a day. Now this is a correlational study; future studies will try to see whether taking up coffee drinking can ward off dementia in someone who otherwise might develop it.


Well, that's it for this edition of Scientific American's Science Talk. Check out for the latest science news including our look at the science musings of the late John Updike. For Science Talk, I'm Steve Mirsky. Thanks for clicking on us.

Science Talk is a weekly podcast, subscribe here: RSS | iTunes

Scientist and author Tyler Volk talks about his new book CO2 Rising: The World's Greatest Environmental Challenge. Plus, we'll test your knowledge about some recent science in the news. Web sites related to this episode include

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