NASA research scientist on peak oil and climate change (transcript)

MediaNASA research scientist on peak oil and climate change (audio)

Transcribed by Brian Magee

David Room: This is David Room for Global Public Media speaking with Pushker Karecha on Dec. 17, 2007. Well, thanks for being with me, Pushker. Tell me about the paper you wrote with James Hansen and how it came about.

Dr. Pushker Kharecha: Right. Well, it came about from a simple idea that I pitched to Jim just a few months after I started here, which was a couple years' ago. Basically, the question that we are looking at is, what are the implications of the peak in global oil production in terms of future atmospheric carbon dioxide levels and, therefore, future global climate. And, so the upshot of our paper is that we can actually keep, with some reasonable and technically feasible mitigation measures--that is, emissions reduction measures--we can keep CO2 from exceeding what we, and many others, consider a dangerous level for global climate, and that is about 450 ppm. But that's very dependent on what choices are made in terms of energy production and energy use after the peak in global oil production. So we look at peaks in the other two fuels, too, the other two fossil fuels--natural gas and coal--and we realize that conventional oil and natural gas by themselves, even if we take what are considered the highest, and what many people consider unrealistically high estimates of the Energy Information Administration, even if we take those as an upper limit, they by themselves--oil and gas by themselves--don't seem to be plentiful enough to take us past this CO2 threshold of 450 ppm. The minute we add continuing emissions from coal use or unconventional fossil fuel use the situation changes. That is to say, it's very, very likely that 450 ppm would be exceeded. In fact, it seems inevitable, if emissions from coal and unconventional fossil fuels are unconstrained.

DR: What is the significance of 450 parts per million in the atmosphere?

PK: Okay, just to keep it in context, remember that the current CO2 concentration is about 382/384 parts per million. So that level is about 100 parts per million higher than the pre-industrial level; that is the level at the time before which fossil fuel use became widespread. And, so, the significance of the 450 ppm stems from some other work of ours, and other people, which concludes that if you want to keep future global warming--that is, 21st century global warming--under a desirable threshold temperature, which is about 1 degree Celsius above 2000 levels or about 1 degree Celsius below present levels, then we have to limit the concentration of CO2 along with the concentrations of the non-CO2 greenhouse gases, most notably methane.

So, yeah, the 450 ppm threshold for CO2 is really just a measure of what we think is the allowable level at which we have the best chance at keeping 21st century global warming under 1 degree Celsius. And the rationale behind that, the 1 degree Celsius change, the threshold there is because when you look at Earth's history, the last time it was clearly greater than 1 degree Celsius, that is to say about 2 to 3 degrees Celsius warmer, was about 3 million years ago, an epoch of geological time called the Mid-Pliocene. And the problem is, at that temperature level, 2 to 3 degrees Celsius above the present value, global sea level--equalibrium sea level--was about between 15 to 35 meters, that is, between about 50 to over 100 feet higher than it is today. So the overall goal is to prevent that and to prevent other impacts of climate change, most notably species extinction.

DR: Generally, global warming and oil peak are thought of as separate issues, but you went ahead and pitched a report, or study, to look at them together. Why did you do that and how important is it that people think about peak oil in the context of climate change?

PK: Well, we think it's very important. And, yeah, you're right. We think it's unfortunate, but usually they are usually taken as separate issues. But we think the best way is to conflate them. Remember that fossil fuel use is really at the core, it's the root of the problem of global warming. It has caused roughly 80% of the CO2 rise since pre-industrial times. So fossil fuel use is at the absolute foundation of the whole problem of global warming, and it will continue to be the dominate root of the problem in this century if we don't do something about it.

And, so the question then becomes, okay, what are realistic, or at least somewhat reasonably plausible, trajectories of fossil fuel use this century, and that's where the issue of these peaks come in. And, by the way, we should note that we looked at the peaks in the other fossil fuels, too--peak in coal emissions and peak in natural gas emissions.

DR: In the first line of your abstract is: "The amounts of fossil fuel proven in potential reserves are uncertain and debated." And I'd like to understand what amounts are actually used in your model for recoverable quantities of conventional oil, coal, natural gas, heavy oil, tar sands, and oil shale. And for each of those I'd also like to know where your estimates sit in the range of estimate of experts and why.

PK: Sure, yeah. So, first of all, in terms of coal, that's probably one of the most hot button issues at the moment. What we assumed was two different estimates, really. One is sort of an upper limit, which is the IPCC's... that's the Intergovernmental Panel on Climate Change, which is a body of the U.N. and its reports are considered the most authoritative synopses of the whole issue of climate change. The 2001 IPCC assessment report puts the number for coal, in terms of carbon units, which is what we're concerned about... So, in terms of carbon units the IPCC number is roughly just over a thousand gigatons of carbon. That is, a thousand billion tons of carbon contained in coal. And the lower limit we used was from the World Energy Council, and their actual number--this is a 2000 report from the World Energy Council--the actual number in terms of coal amount is about 850 billion tons of coal worldwide--this is conventional reserve, proven reserve. So, in our carbon units that translates to about--taking into account the different types of coal--that translates into about 450 gigatons of carbon.

So we looked at that range for coal and we also looked at a fairly wide range for oil and natural gas as well. The lowest estimate we used for oil was about just under 120 gigatons of carbon in oil, and that's also from the IPCC's 2001 report. And the lowest number for gas that we used was just over 80 gigatons of carbon, and that's the same source. And the highest number we used for oil was 250, roughly, gigatons of carbon. And the highest number for gas that we used is 139 gigatons of carbon.

And, so I should point out that those two later numbers were sourced from the Energy Information Administration and those take into account the EIA's estimates for proven conventional reserves plus proven conventional reserve growth. That is to say, likely additions based on either existing technology or feasible improvements in technology--oil and gas extraction technologies.

So, in other words, for each fuel we looked at sort of an upper limit, which is, in the case of oil and gas from the EIA, proven reserves plus proven reserve growth. And then for each fuel we looked at a lower limit, which is, in the case of oil and gas, from the IPCC, and in the case of coal the lower limit was from the World Energy Council, the upper limit was from the IPCC report.

And as far as how that differs from what other people have estimated, well, as I've already mentioned, a lot of people think that the EIA's numbers for even just the reserves, never mind the reserve growth for conventional oil and gas, are greatly overestimated. Which is fine, but we come up with reasonably similar peaks as a lot of even early peakists do. So, in other words, we predict an oil peak, using that upper limit of about... I shouldn't say we predict, but we assume. In other words, we assume certain emissions trajectories and certain reserve base and from that we can generate a peak, assuming Hubbert's peak, in terms of mid-point of the reserve base, and we get a peak for oil in about 2016, a peak for gas about 2026 or 2030, around there, and a peak for coal, if we use the upper limit, in around 2077, but if we use the lower limit it's about 2040 for coal.

DR: Now, with coal, how do those numbers that you spoke of correspond with the estimates that Dave Rutledge is putting out in his report, Hubbert's Peak, The Coal Question, and Climate Change?

PK: Rutledge's numbers are about, if you look at his numbers, it's about, for coal--conventional coal reserves--is about half of what our lower limit is. In other words, half of the World Energy Council's estimate for proven conventional reserves of coal. What was the other part of your question, how he...?

DR: Well, I guess I'm wondering with these recent reports coming out that say that there's much less coal available, this could potentially lead to the suggestion that we don't need to take dramatic policy measures since geology's going to force us to reduce our CO2 emissions anyway.

PK: Right, right. I can't deny the possibility of that. But the major concern for those of us worried about climate is that it might instill a sort of a very, very, possibly unwarranted, sense of complacency about the issue of having to mitigate CO2 emissions. In other words, if climate policy is framed around those, what I would call "low coal" people's estimates, then we could be in real trouble if they're wrong. 'Cause there is a real possibility, obviously, that we could be wrong, too, but if we're wrong, ultimately, the main problem--if you want to call it that--will be an earlier shift and greater measures taken to move beyond fossil fuels. If they're wrong and coal reserves are indeed much higher than what they predict, and as a result policies have already been locked into place that don't take into account mitigation of CO2 emissions of coal, then we're in serious trouble. And I, personally, don't want to take that risk. I think that's an unacceptable risk. In other words, the bottom line is, that really what's needed to resolve carbon problem is definitely proactive measures to reduce CO2 emissions and, most of all, from coal and unconventional fossil fuels.

And, again, they might also be wrong for another reason in that they seem to implicitly assume that countries might not be willing to go to desperate measures to extract every last drop of oil or mine whatever coal is possibly mineable, even if it's highly impractical to do so. In other words, there's a significant chance, in my view, that they might be underestimating the level of desperation that might be felt by coal-hungry countries.

DR: You said "serious trouble" and I'm wondering what concerns you most about climate change.

PK: Oh, well, it's basically what I mentioned before, namely the temperature threshold of 1 degree Celsius above the present being passed. And if that happens then we're really, as Jim Hansen, my boss, likes to point out, then we're headed for a different planet, in the sense that there will be no sea ice in the arctic in the summer--we seem to already be there, by the way; we seem to be headed there even with no additional forcing in terms of arctic sea ice melt, summer sea ice loss. But there might be no arctic sea ice, period, if we have greater than 1 degree Celsius over the present, not to mention the greatest fear being the very rapid disintegration of the great ice sheets, most notably west Antarctica and southern Greenland. And, so those combined--if both of those melt combined--they could add about 10-12 meters of sea level rise, that's almost 40 feet of sea level rise globally.

And, of course, this won't happen overnight but the point is if we keep adding CO2 into the atmosphere, unconstrained emissions from coal and unconventional fuels, then we, essentially, because of the long lifetime of CO2 in the atmosphere, we'd be essentially locked into a path beyond which we really can't reverse the changes that we've induced. So that's the major concern, the very real threat of irreversible changes to the climate system, most notably in terms of ice sheet disintegration and species extinction.

DR: Could you elaborate a little bit more on the ice sheet disintegration? How has this happened in the past? What are the non-linear processes that are working here?

PK: Sure, yeah. There are several notable non-linear processes. One is called the ice and snow albeto feedback. That is to say, that bright areas like ice and snow reflect a lot of incoming sunlight so the area doesn't warm as much. But when it melts it becomes darker. In other words, the albeto gets lower and, therefore, it absorbs more incoming sunlight and that causes further warming, which causes further melting, which causes further darkening, and further warming, and so forth. So that's called a positive feedback in the sense that it amplifies the background change, whether that change is negative--we call that a negative forcing, which has a cooling effect--or positive forcing, which has a warming effect. Right now the direction is the positive. In other words, it's amplifying the warming that's already going on at the poles. And so that's a major concern in terms of melting, accelerated melting.

The other major non-linear process in terms of ice sheet disintegration is what's called dynamical ice loss. That is, as melt water forms on the surface--and this is happening, we think, mainly in Greenland but it might eventually happen in west Antarctica melt water forms on the surface it eventually burrows down into the ice sheet and eventually it forms a more or less vertical shaft called a moulin. So that's basically a direct connection with the surface--surface melt water--to the base of the ice sheet, which is the bedrock. As more and more melt occurs the water has a direct point of access to the base of the ice sheet, which then lubricates the bottom of the ice sheet which accelerates ice flow into the ocean.

And so you have these two non-linear processes: accelerated melting, because of snow ice albeto feedback, and accelerated actual loss of ice mass itself into the ocean through this, what's called dynamical ice loss, melt water seeping through to the bottom of the ice sheet, lubricating the base.

DR: And this has happened in the past?

PK: Yes, this has happened in the past. To the best of our knowledge it's happened most notably... One of the best examples of what can happen, and one of the most often invoked is what's called the Meltwater pulse 1A. That was a period of melting... There were several great ice sheets around back then in addition to the ones today. There's only three real ice sheets left today: the west antarctic ice sheet, east antarctic ice sheet, and the Greenland ice sheet. But back then--this was just after the last glacial maximum about 20,000 years ago--there were also two other notable ice sheets: one in Eurasia, the Fennoscandian ice sheet, and one that covered, basically, all of Canada, actually, and even came down into the northern tier of the U.S., called the Laurentide ice sheet. And both of these were several miles thick, as are the west Antarctic and Greenland ice sheets.

And what happened was--this is around fourteen and a half thousand years ago, so this is as the world was coming out of the last ice age--we see an example of sea level rising very rapidly due to what's called eustatic sea level rise. That is to say, loss from the ice sheets. In other words, addition of actual mass into the ocean from the surface. What happened was, in about just under 500 years, between about 400-500 years, sea level rose by about 20 meters.

And so that just one striking example of what can happen when these non-linear processes are set into motion. They can be essentially impossible to reverse. So 20 meters in 400 or 500 years is about 4 or 5 meters per century; that's a meter every 20/25 years. So that could be very serious... if that happens again, it could be very hard to adapt to, if sea level's changing globally by a meter or so every couple decades there's no real practical way to avoid massive creation of refugees, and so forth. Could have massive, massive negative impacts globally, not just in terms of human society, of course, but in terms of the global ecosystem, too.

DR: Right. I'm starting to hear a number of experts such as Richard Heinberg and others use the term "climate chaos" as an alternative to "climate change." Do you have any thoughts on that?

PK: Well, I suppose a lot of it is just semantics. I'm not sure what he means by "climate chaos," so I can't really comment on that. But, if you want to clarify maybe I can comment, as far as what he means by that. But, yeah, certainly it could induce societal chaos in terms of, as I mentioned and others have mentioned, a massive refuge problem that might arise. So societal chaos, but also, of course, ecological chaos. Chaos is almost an alarmist term. Let's call it ecological... or maybe "disastrous" might be a better word. So, yeah, it could be disastrous.

DR: Yeah. My sense is some of the people using that term are objecting to the use of "change" since it could either be beneficial or detrimental. It's kind of a neutral term for something that could be disastrous.

PK: I see. In that case, yeah, the point is well-taken. It's just a conventional usage. That's the main reason it's still used is because usually people know what we're talking about... everyone knows what we're talking about when we say climate "change," but the use of these might imply some subjectivity. But, yeah, no doubt that their ultimate point is correct in the sense that the climate "change" that we're talking--induced by humans--if it goes unconstrained in the future, could well be climate chaos, ecological chaos, societal chaos, climate catastrophe, whatever you want to call it. But, yeah, it will be very, very disruptive, no doubt, on both society and the ecosystem.

DR: I'm going to read three recommendations from your report and follow each of them with a question. The recommendation 1 is a freeze on new construction of traditional coal-fired power plants by 2010 with a linear phase out of all such existing plants between 2010 and 2030. And the question is: The world, and especially countries like China and India, seem to be committed to rapid economic growth which requires increasing amounts of energy. The near term reality is most of that energy can only be provided by burning coal and gas. Is it reasonable to expect that economic growth will be sacrificed for a freeze on coal-fired power plants?

PK: Well, I'm not sure how reasonable it is to expect it, but we can hope for it, certainly. And, I should also mention that the suggestion that you mentioned is really sort of a corollary in a sense that our main scenarios focus on a global phase out of coal emissions starting from 2025 and becoming zero by 2050, with developed countries taking the lead. In other words, making their emissions constant and then declining between now and the next decade or so, and then giving developing countries another decade to catch up. So that's sort of the main scenario we've assumed. And then the whole world declining their emissions from coal between 2025 and 2050.

But what you mentioned was if the world decides that the 450, even, is an unacceptable level--450 ppm CO2--and instead wants to lower the CO2 or aim for a target CO2 level that's even lower, that's when we might want to initiate an earlier phase out of coal. So, in other words, instead of 2025 to 2050 being the phase out period for coal, shift it to 2010 to 2030.

But as far as the issue of economic sacrifice and so forth, yeah, you can never tell, obviously, with governments and short-sightedness. After all, we ourselves--that is, the developed world--have been fairly short-sighted until now because the environmental problems we've caused over the decades and centuries. So as far as expectations all I can say is we hope for the best. In other words, that they realize it's really not only the world's own but even their own best interest to really limit future human-induced climate change by as much as possible. And if that means a little bit of economic sacrifice or slower economic growth today, if it means saving the future, preventing what we talked about, climate disaster, chaos, and so forth, then we could hope that they think it's worth it, but I wouldn't expect that.

DR: It is true that economic recession is one of the most certain ways of dramatically reducing carbon emissions, and if so, should climate campaigners be advocating for such economic contraction?

PK: Well, obviously that gets into an area that I don't have much expertise, in economics and economic theory and engineering, and so forth. But I certainly don't want to go on record advocating a recession. But the fact is we don't really need major disruptions to the economy, I don't think, to achieve the relatively tepid goals that we have outlined. In other words, all we really need is just a will, a global will. The means are there, arguably, even now. In other words, the basic sort of cornerstone of our recommendations is carbon capture and sequestration from traditional coal-fired power plants. And that's being done as we speak in certain areas, but on a very, very, very limited basis. And so what we're suggesting is just people really get into gear and, in other words, ramp up the will to use these existing means and along the way develop better means to address this issue of carbon capture and sequestration. We think it's perfectly feasible and a reasonable goal.

DR: Tell me what we've learned about carbon sequestration in the last decade and what you think is possible and what some of the potential dangers might be, as well, if it's not done correctly.

PK: Right, sure, and again this is slightly outside my areas of expertise. But, basically, there are various ways to achieve capture and sequestration and the main question is whether the CO2... the main, sort of, point of debate is where and how to do the sequestration. It all involves, of course, burying CO2, injecting CO2, somewhere under the surface of the earth. Whether that surface is on land or on the sea floor is what's debated and some people even suggest just injecting it into the deep ocean itself, into the water column. As far as land, the most common proposal seems to be to inject it into existing oil and gas reservoirs. So, in other words, as we remove the oil and gas just replace that with CO2 and do our best to plug the outlets, the conduits to the atmosphere.

But the major concern is, of course, leakage of the CO2 from either the sub-surface of the earth, of the land, or of the ocean sediments or deep ocean water column back into the atmosphere. And, so, of the various proposals out there, at least that I have cursory knowledge of, the one that seems fairly sensible to me is injection of the CO2 beneath ocean sediments, deep ocean sediments. That seems the best way to guarantee that the CO2 will remain there essentially forever. And forever, in human terms, is anything more than several centuries. But this is still obviously an ongoing debate; it's becoming an intensely researched issue, so the jury's still out as far as the most viable option, but those are the ones that I'm familiar with.

DR: So, when you speak of your main recommendation being a phase out of coal-fired generation starting in 2025, that is assuming that generation will transition to be coal-fired with carbon sequestration working correctly.

PK: That's right, yeah. So, in other words, this is all assuming that carbon capture and sequestration of coal and unconventional fossil fuels, if they're used, is effective in the sense that it doesn't allow any leakage of the CO2 wherever it's injected back into the atmosphere. So, yeah. And, of course, it doesn't necessarily imply a shutdown of coal use, although that would be ideal, presumably, since we eventually need to move off of all fossil fuels anyway, simply because they're finite. No matter what estimates you use, even the rosiest estimates are obviously finite. So, yeah, we'll eventually have to get off of all fossil fuels. The question is when to do it and what's the best way to do it. And certainly resolving the climate issue is one way to kick start this era beyond fossil fuels.

DR: I know you've already told me that you're not an economist, so I'll just ask you this question and if it's not comfortable that's fine, too. I'm just wondering, do you see a transition to renewable energy over the next 4-5 decades being able to be done without harming economic growth?

PK: As you mentioned, this is necessarily highly, highly speculative. But I don't want to predict any transition because that would be major restructuring of the energy systems worldwide. But I'll just say that I think it's not out of the question. In other words, we'll have to, again, move in that directly ultimately anyway. In other words, simply because the fossil fuels are finite we will eventually have to get all of our energy... effectively, revert to pre-industrial energy portfolio. But as far as when that might take place your guess is as good as mine.

As to whether it'll take place in the next few decades, personally, I don't think there's going to be a major shift. In other words, renewables, for instance, in the U.S., I think, are only about 5% of the total energy supply and worldwide I think it's about 20% of the world energy supply, the rest coming from fossil fuels and nuclear. But, yeah, I don't think those ratios, for instance, are going to reverse in the next 50 years. But I certainly think that it's in our best interest, and I think it's even likely that the renewable share of both the global and individual or national energy supplies will begin to increase, yeah. But, obviously, I don't want to pinpoint a time.

DR: So, we've talked about the transition to renewable energy and I'm wondering also do you see potentially localization being part of something that happens naturally? We talked about going back to pre-industrial energy mix. Do you see us going back towards more local economies, or at least more focus on local economies as opposed to almost complete focus on globalized economies?

PK: Okay, by localization do you mean, for instance, not importing your energy from the Middle East?

DR: That would be one aspect of it, but also it could be not importing so many goods, as well as food, from other places in the world; just reducing the amount of transport that's necessary for the things that we need on a regular basis.

PK: Oh, I see. Yeah, yeah. I think that type of transition is also going to be highly likely. In other words, I think the main thing that will remain global, I think, is information. In other words, information sharing and maybe to a very, very much lesser extent, trade, as you've mentioned, might be much less global, instead much more local or, let's say national, and so forth. But, yeah, as far as other things, I'm sure other things will remain global, like tourism, and so forth. Certainly information sharing will always remain a global thing. But as far as the nuts and bolts of the economies, I think a lot of this fossil fuel limitation will likely necessitate some downscaling of the global-scale processes.

DR: Is there anything else that you'd like to add?

PK: No, that's really it. Just one of the main points being that, again, as far as these low coal estimates that are out there, they might be right, but the risk is unacceptable to me and I know for a fact many other climate scientists, a vast majority of other climate scientists, if they're wrong... In other words, if climate policy is framed around the assumption that coal is not nearly as plentiful as people think and therefore we don't have to worry about pro-actively curtailing emissions from coal then we could be in serious trouble because they really might be underestimating the desperation of coal-hungry countries. And the other thing is in terms of resolving these two problems of peak fossil fuels and climate change, I think mitigation policies for the two problems should really be conflated. In other words, mitigation policies for peak oil and peak coal, peak gas, should be done in tandem with mitigation policies for climate change. And I think there's no reason that shouldn't happen. In fact, it makes the most sense to me.

DR: This is David Room for Global Public Media.

MediaNASA research scientist on peak oil and climate change (audio)