Arguments
Global Warming: Not Reversible, But Stoppable
Posted on 19 April 2013 by Andy Skuce
Let's start with two skill-testing questions:
1. If we stop greenhouse gas emissions, won't the climate naturally go back to the way it was before?
2. Isn't there "warming in the pipeline" that will continue to heat up the planet no matter what we do?
The correct answer to both questions is "no".
Global warming is not reversible but it is stoppable.
Many people incorrectly assume that once we stop making greenhouse gas emissions, the CO2 will be drawn out of the air, the old equilibrium will be re-established and the climate of the planet will go back to the way it used to be; just like the way the acid rain problem was solved once scrubbers were put on smoke stacks, or the way lead pollution disappeared once we changed to unleaded gasoline. This misinterpretation can lead to complacency about the need to act now. In fact, global warming is, on human timescales, here forever. The truth is that the damage we have done—and continue to do—to the climate system cannot be undone.
The second question reveals a different kind of misunderstanding: many mistakenly believe that the climate system is going to send more warming our way no matter what we choose to do. Taken to an extreme, that viewpoint can lead to a fatalistic approach, in which efforts to mitigate climate change by cutting emissions are seen as futile: we should instead begin planning for adaptation or, worse, start deliberately intervening through geoengineering. But this is wrong. The inertia is not in the physics of the climate system, but rather in the human economy.
This is explained in a recent paper in Science Magazine (2013, paywalled but freely accessible here, scroll down to "Publications, 2013") by Damon Matthews and Susan Solomon: Irreversible Does Not Mean Unavoidable.
Since the Industrial Revolution, CO2 from our burning of fossil fuels has been building up in the atmosphere. The concentration of CO2 is now approaching 400 parts per million (ppm), up from 280 ppm prior to 1800. If we were to stop all emissions immediately, the CO2 concentration would also start to decline immediately, with some of the gas continuing to be absorbed into the oceans and smaller amounts being taken up by carbon sinks on land. According to the models of the carbon cycle, the level of CO2 (the red line in Figure 1A) would have dropped to about 340 ppm by 2300, approximately the same level as it was in 1980. In the next 300 years, therefore, nature will have recouped the last 30 years of our emissions.
Figure 1 CO2 concentrations (A); CO2 emissions (B) ; and temperature change (C). There are two scenarios: zero emissions after 2010 (red) and reduced emissions producing constant concentrations (blue). From a presentation by Damon Matthews, via Serendipity.
So, does this mean that some of the climate change we have experienced so far would go into reverse, allowing, for example, the Arctic sea ice to freeze over again? Unfortunately, no. Today, because of the greenhouse gas build-up, there is more solar energy being trapped, which is warming the oceans, atmosphere, land and ice, a process that has been referred to as the Earth's energy imbalance. The energy flow will continue to be out of balance until the Earth warms up enough so that the amount of energy leaving the Earth matches the amount coming in. It takes time for the Earth to heat up, particularly the oceans, where approximately 90% of the thermal energy ends up. It just so happens that the delayed heating from this thermal inertia balances almost exactly with the drop in CO2 concentrations, meaning the temperature of the Earth would stay approximately constant from the minute we stopped adding more CO2, as shown in Figure 1C.
There is bad news and good news in this. The bad news is that, once we have caused some warming, we can’t go back, at least not without huge and probably unaffordable efforts to put the CO2 back into the ground, or by making risky interventions by scattering tons of sulphate particles into the upper atmosphere, to shade us from the Sun. The good news is that, once we stop emissions, further warming will immediately cease; we are not on an unstoppable path to oblivion. The future is not out of our hands. Global warming is stoppable, even if it is not reversible.
Warming in the pipeline
Bringing human emissions to a dead stop, as shown by the red lines in Figure 1, is not a realistic option. This would put the entire world, all seven billion of us, into a new dark age and the human suffering would be unimaginable. For this reason, most climate models don’t even consider it as a viable scenario and, if they run the model at all, it is as a "what-if".
Even cutting back emissions severely enough to stabilize CO2 concentrations at a fixed level, as shown in the blue lines in Figure 1, would still require massive and rapid reductions in fossil fuel use. But, even this reduction would not be enough to stop future warming. For example, holding concentration levels steady at 380 ppm would lead to temperatures rising an additional 0.5 degrees C over the next two hundred years. This effect is often referred to as “warming in the pipeline”: extra warming that we can’t do anything to avoid.
The most important distinction to grasp, though, is that the inertia is not inherent in the physics and chemistry of the planet’s climate system, but rather in our inability to change our behaviour rapidly enough.
Figure 2 shows the average lifetimes of the equipment and infrastructure that we rely upon in the modern world. Cars last us up to 20 years; pipelines up to 50; coal-fired plants 60; our buildings and urban infrastructure a century. It takes time to change our ways, unless we discard working vehicles, power plants and buildings and immediately replace them with, electric cars, renewable energy plants and new, energy-efficient buildings.
Figure 2 Average expected lifetimes for equipment and infrastructure.
“Warming in the pipeline” is not, therefore, a very good metaphor to describe the natural climate system, if we could stop emissions, the warming would stop. However, when it comes to the decisions we are making to build new, carbon-intensive infrastructure, such as the Keystone XL pipeline, the expression is quite literally true.
Wrinkles
The Matthews and Solomon paper only deals with CO2. Short-lived greenhouse gases like methane are not considered in the study and nor are aerosols. Stopping fossil fuel burning, especially coal, would reduce aerosol (small particle) emissions, reducing their current shading effect and increasing warming. On the other hand, stopping fossil fuel consumption would decrease methane emissions and thus decrease warming even more than these authors have projected. It may turn out that these two effects balance out.
The other potential problem is that the carbon cycle model that Matthews and Solomon use may not be as well behaved as they predict. For example, MacDougall et al (2012) ran their own "industrial shutdown" experiments and found that future CO2 concentrations in their most likely climate sensitivity case remained steady, because emissions from the permafrost (see this SkS post, Figure 3) balanced the reductions from other carbon sinks. This means that a shutdown of human emissions could, in practice, look more like the blue lines in Figure 1.
The likelihood and severity of unexpected carbon-cycle feedbacks, including the way in which the ocean absorbs CO2, will be larger when there has been more warming—due to more emissions or higher climate sensitivities, or both—but this only increases the need for prompt and substantial action in reducing emissions.
Takeaway points
- The warming we have caused by our emissions of carbon cannot be undone.
- The additional future warming we will experience will be a result of our current and future emissions.
- The inertia in the climate system is not natural, but human.
- Emissions avoided today mean less warming tomorrow, and forever.
The confusion that many of us have with answering the two questions posed at the beginning of the article is probably rooted in our mental models, one being that the climate change will naturally revert back to normal; the other that the changes in the climate system have unstoppable momentum. Neither view is correct and they both favour inaction; one by implying that we can wait to fix the problem, the other by implying that it is already too late.
Metaphors and mental models are essential to understanding the way complex systems work. But they can mislead as well as illuminate. Here are a couple of analogies that I have come up with, but they are not perfect either. Maybe readers can do better.
- We can't put toothpaste back in the tube once we have accidentally squeezed too much out, but we can prevent any further waste by stopping squeezing.
- Like a bull in a china shop, we can't unbreak what we have already broken, but once the rampaging stops, no more damage will be done.
Other articles on the paper by Matthews and Solomon can be found at Climate Central (Andrew Freedman) and Serendipity (Steve Easterbrook).
Honestly, if they could actually develop and scale the technologies to remove CO2 from the open air (huge if in that), then fine. More power to them. But the cost of removing the CO2 absolutely must be borne by the emitters themselves. It should not be borne by the public at large.
Now, tell me if you think the fossil fuel industry would agree to such terms.
Mark Bahner - An interesting speculation. However, beyond hoping (1) the world economy increases by a factor of 1000x, and that (2) less than $1000/ton CO2 removal is achievable, this approach has more than a few issues.
First - the non-trivial cost of such removal invalidates Sarawitz and Pielke's major premise, that:
10% of world GDP is a major hit. WWII in the US, which you use as an exemplar, required energy rationing, intrusive government control of all sectors of the economy, material substitution due to war needs, and so on. I would consider those radical alterations.
Second, the idea of forever continuing the use of fossil fuels hits the limits of just how many reserves are present, and how much exploiting marginal sources will cost. Not to mention making carbon removal a permanent and repeating cost to the economy, whereas moving to a non-fossil fuel basis removes both the carbon problem and the need for the removal at the same time.
Finally - carbon removal takes energy. Using a fossil fuel source is a net loss - entropy is a bear, and a fossil fuel based carbon removal to, as S&P suggest, produce new fuels, will inevitably produce a net increase in CO2. Non-fossil fuel power sources are required for a net gain, for a drawdown in CO2.
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Face it - Just about every study made shows that mitigation, moving from a fossil fuel economy to one that isn't, will be far less expensive and altering of our lifestyles than adaptation, such as dumping CO2 we don't need to and then trying to remove it later.
Given the disparity in costs between mitigation and adaptation, these cries of economic hardship over mitigation are beyond silly. Business As Usual (BAU) with continued use of fossil fuels is the more expensive path, the one that will engender more hardship, more radical alteration of lifestyles. I find it just incredibly sad that those complaining most about the idea of mitigation are loudly beating the drums for a path that will actually cost us far more, and be more of a burden on rich and poor alike...
In my previous comment I mistyped - it should state "the world economy increases by a factor of 100x", not 1000x, to match Mark Bahner's post.
By comparison, the most agressive SRES emissions scenario (A1T) used in IPCC predictions of GHG levels indicates a maximum world GDP growth of only ~25x by 2100, with the lower emissions scenarios ranging from 11-16x. Those are based on quite reasonable assumptions and prior experience with the GDP growth of developing countries - I don't believe that 100x GDP growth by 2100 is even in the realm of possibilities. If it was possible, it would almost inevitably be accompanied by even more emissions, making a carbon capture approach more challenging.
Again, it seems to me that carbon capture is not a panacea, and that BAU is by far the more expensive path. Mitigation, emitting less to start with, is far less expensive than adaptation.
@KR #52 & #53:
Suggest that you check out: Kriegler, E., Edenhofer, O., Reuster, L., Luderer, G., Klein, D. (2013): Is atmospheric carbon dioxide removal a game changer for climate change mitigation?Climatic Change (online) [10.1007/s10584-012-0681-4]
I believe it bears directly on your ongoing dialogue with Mark Bahner.
OK, let's use the IPCC's numbers. Their economic growth numbers are very likely to be proven extremely wrong on the low side:
Third thoughts on economic growth in the 21st century
...but let's assume the economy grows by only a factor of 25 in the next 100 years. That means in the year 2113, it will be possible to remove 25 ppm of CO2 per year for an expenditure of 10 percent of the world GDP. (Since we now can remove 1 ppm for an expenditure of 10 percent of the world GDP...assuming $1000 per ton of CO2, which is probably too high, especially for 100 years from now.)
The concentration under the A1T scenario is projected to be about 900 ppm in 2113. Let's say they want to get down to 350 ppm. That would be a reduction of 550 ppm. At 25 ppm per year, they could get there in 22 years.
So once again, the Matthews and Solomon paper is based on a completely indefensible premise. They claim that global warming is "irreversible" over multi-century time frames (in fact 1000 years). This neglects the economic growth that's likely to happen even in the next 100 years (let alone the next 200+ years).
Responding to Mark Bahmer's various posts:
Assuming a continuation of the average economic growth durring the post war boom years of 3% per annum, the global economy will have grown to thirteen times its current value. In contrast, the IPCC estimate of 25 times the 2007 value requires as sustained growth rate of 3.5%. Growth of a hundred fold requires an economic growth rate of 5.4% per annum, a figure not achieved for global growth since 1973 and extraordinarilly unlikely to be achieved as a global average over a century, even absent any negative effects from global warming:
(Wikipedia)
Consequently the IPCC estimate is at least plausible, if a bit opitimistic. Yours are definitely over optimistic.
What is more, the standard assumption that you can increase CO2 in the atmosphere by 300 ppmv with no harmfull effects on economic growth is just bizzare. A certain consequense of such an increase is the loss of Arctic summer sea ice. An almost certain effect of such an increase will be the destruction of the great barrier reef. Another probable consequence will be the conversion of Amazon rainforest into a system of open forest and savannah. These large scale ecological catastrophes must inevitably have adverse effects on the human economy, and those effects will show up as reduced growth. In the latter half of this century, the economic issue is not whether we will be achieving 3% of 5.4% growth of the global economy, but whether we can avoid 3% to 5.4% contractions of the global economy, year in and year out.
Regardless of whether or not you consider the risk of a contracting global economy in the later 21st century with ongoing global warming to be real (and only the very foolish or thoughtless will dismiss that possibility out of hand), the fact remains that extra CO2 in the atmosphere has a cost. Consequently, if the cost of not emiting the CO2 equals the cost of removing it later; it is better to not emit it because it avoids that cost.
In addition to not taking into account the costs of increased CO2 concentrations (both to economic growth and as a raw cost), you fail to take into account the fact that various schemes to draw down CO2 from the atmosphere have an ecological impact as well. Simply framing it in terms of dollar values ignores half of the costs.
John Hartz - Thank you for the very relevant reference. They discuss in particular one of the lowest cost CO2 removal schemes, biological drawdown:
That works out to ~2 ppm/year, or roughly the rate of current emissions. Given the 550 ppm Mark Bahner discusses, that means 225 years of BECSS drawdown assuming no further emissions - with that drawdown competing with food production, and with its own energy/resource costs (including fresh water and soil nutrients that will be consumed in the process).
It might be a helpful addition to mitigation, but again - CO2 removal is no panacea. And even that (relatively) low cost sequestration is still more expensive than mitigation.
Mark,
Your calculation for removal of CO2 is hopelessly optimistic. If you start to remove CO2 from the atmosphere then the ocean will begin to outgas CO2 instead of absorbing it. This means you have to remove much more CO2 to lower the atmospheric level than you estimate. Provide citations for your wild claims about how much carbon needs to be removed to lower atmospheric CO2.
Invariably the geoengineering people leave out half of the problem to make their proposals look good.
No, it's extremely pessimistic, because:
1) It relies on IPCC economic growth projections, which will be shown within the next 1-2 decades to be far, far too low. They neglect the economic effects of artificial intelligence, which will be spectacular. Probably the best work in this area has been done by Robin Hanson. He uses a standard neoclassical (Solow-Swan) growth model to estimate annual ecomomic growth that could approach 45% per year (see page 6) by 2025. Needless to say, the IPCC does not have anything close to that.
2) It assumes a cost of $1000 per metric tonne of CO2 removed. Humans have the rest of this century to get costs down, and I'm sure they will be well below that number when it is used.
Regarding outgassing...approximately 50% of emissions have remained in the atmosphere for the last 3-5 decades. So even if all the CO2 that was previously absorbed gets re-emitted, the amount needing to be removed would simply double. So if the cost was down to $500 per metric tonne, my analysis would be completely intact. And if the IPCC scenarios have economic growth projections that are far too low (which they almost certainly do), then even with outgassing of all material, my estimates would be pessimistic.
Mark Bahner @59 continues to live in an economic dream world! Who can blame him, it is a pleasant dream. No doubt soon he will ask us all to step into a glass elevator.
Meanwhile, back in reality, this is the pattern of economic growth over the last two millinia as J Bradford DeLong:
(Source)
The zero growth rate since 2000 is an artifact of a lack of data in that period. The rest of the curve is real and is significant. In particular, the decline in world economic growth from the 1950s and 1960s to the present day, as the world transitioned from vacuum tubes to silicon chips, is real. While the information revolution has had a real and beneficial effect on the world economy, that has been more than countered by other factors, primarilly an increase in the cost of energy and the fact that resource exploitation was essentially global by the 1960s, so that further economic growth could only be achieved by accessing resources with a lower return on investment.
For more recent data, here is the real growth in GWP from 1999-2011:
(Source, accessed today)
The effective growth real growth rate over that period turns out to be 3.5% per annum, although it would be slightly higher in PPP (Purchasing Power Parity) terms. PPP growth in GWP from 2005-2012 is 3.6% per annum.
Bahner's defence of his absurd growth rates now has two straws. The first is simple mathturbation on the 50 year average growth rate over recent history, a calculation that does not factor in the clear slide in growth rates since the 1960s, and is falsified by them. (Bahner actually throws out the results of his mathturbation as too conservative; and infates them artificially based on an assumption of the early achievement of full artificial intelligence; ie, his estimation proceedure has all the intellectual integrity of the classic "pick a number than double it" technique.) The second straw is based on an article which overstates recent real growth rate, and assumes that the introduciton of AI is the golden goose of economics without actually plotting the course of economic growth durring the information revolution. That is, it has no more intellectual credibility than Bahner's attempt, for all that the author is seeking to have it published.
[RH] Fixed image width.
I note that Robin Hanson's 2001 prediction of doubling of GDP every 0.5 to 1.5 years by 2025 is actually pessimistic compared to his 1998 predictions of economic doubling times of mere days. Over a period of just three years he increased the economic doubling time by an order of magnitude or more. If his pessimism continued to increase geometrically, I would expect his GDP doubling time to be rather large by 2013.
I wonder what an appropriate discount rate would be if we lived in a world where the economy doubled in size every few days? I suspect that it would be so high that there would be no economic case to be made for dealing with any externality, no matter how bad, because we would all be so much better equipped to deal with it in a fortnight's time when we would all be much richer and happier. We can all look forward to those times when we can convince our spouses that there's no need to take the garbage out, because everything will be different next week.
In such a world, even if you get the estimation of how much CO2 we need to sequester wrong by a factor of two, never mind, because we will have twice the means to deal with the problem in a few days' time.
Robin Hanson, in 1994, postulated that we will one day be living as disembodied immortals in a virtual world:
However in the real world, nearly twenty years later, Robin Hanson is (presumably) still putting on his trousers one leg at a time.
But just think about the consequences of living in a virtual world: our models would become indistinguishable from reality, there would be no telling the weather forecast from the weather itself!
I actually enjoy reading Robin Hanson's blog Overcoming Bias from time to time. He is a smart guy and his posts there are often stimulating and they lead to enlightening but often bizarre discussions. For example, there is a post in which he compares malnutrition to involuntary celibacy and which leads to commenters earnestly asking whether rape is theft, or instead a fair redistribution of goods from the haves (eg George Clooney) to the rest of us have-nots, with all of our unfulfilled cravings. Readers from the everyday world, especially women and mature men, may well recognize that, despite the cleverness, there's something missing in such discussions.
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More seriously, we inhabit a real world in which the Keeling Curve trends relentlessly upwards towards levels never before experienced by our superfamily of tailless primates. We humans, the most numerous in that family, find ourselves unable to arrest that rising trend, even as many of us accept that it could possibly lead to a planet that is largely uninhabitable. Let's not console or distract ourselves with crazy projections of a gilded future, one in which we will supposedly be able employ our infinite wealth to undo the damage we have done.
Completely off topic, but to cool not to mention: Hanson 94 at least got one prediction right:
Lo! The world's smallest movie!
Of course, this merely reminds me of what they say about stopped clocks, or, perhaps more aptly in Hanson's case, a clock I once saw whose hour and minute hands tracked the second hand, and hence was also right twice a day (and accurate never).
Andy Skuce: "if we lived in a world where the economy doubled in size every few days?"
That depends on exactly how you propose to measure the size of the economy. If you want to use GDP without accounting for inflation, then we have historical events that tell us how things will go. It's called hyperinflation, and it's not a pretty sight.
Bob Loblaw @63, point very well made.
In fact, even with "real" growth rates at those levels, the social and economic disruption would be difficult to distinguish from an episode of hyperinflation. I doubt sustained growth rates greater than 10% per annum without the social disruption caused by the rapid obsolescence of jobs and training that would accompany it rising to the point where it would kill the "growth". Further, such rapid growth would inevitably drive hyperinflation on those goods whose production could not keep up with the rate of economic development - such goods as food, for example.
Mark Bahner @ 59:
No, it's extremely pessimistic, because:
1) It relies on IPCC economic growth projections, which will be shown within the next 1-2 decades to be far, far too low. They neglect the economic effects of artificial intelligence, which will be spectacular. Probably the best work in this area has been done by Robin Hanson. He uses a standard neoclassical (Solow-Swan) growth model to estimate annual ecomomic growth that could approach 45% per year (see page 6) by 2025. Needless to say, the IPCC does not have anything close to that.
Just because an economist using a simplistic model can "estimate" ridiculous figures does not mean that the IPCC "will" be shown to be far, far too low because they neglect effects that "will" be spectacular.
Seriously, suggesting that AI will save the day is nothing more than a Deus ex Machine that deserves no more respect than Roy Spencer's belief that (literally) God will save the day.
There are two serious problems with this faith in AI:
1. Even if computing power increased enough to perform the necessary computation in realtime to simulate a human-level intelligence, we still have no idea how to write software that would harness that computer power to do so. A computer without software is just an expensive paperweight.
2. If we did manage to create such an artificial intelligence, there's no reason to believe even in principle that it would be limited to our own levels of intelligence nor that it would be benevolent. (The only computational models inspired by biological brains, i.e. artifician neural nets (ANNs), cannot be programmed — they must be trained, just like a biological brain; and just like a biological brain, you can't guarantee that the product of your training is what you would hope for and not, for example, a homicidal sociopath. You can't program Asimov's Three Laws into the ANN, you'd need to try to teach it moral behaviour and hope for the best.) How do we know that it won't decide that the best course of action is not to go all Terminator on our ass but instead let rising CO2 levels wipe out the competition? (See point 4.4.) Heck, if it were moral, it might decide that would be just punishment for our attempt to push the problem onto future generations to solve. In other words, such an outcome could well be an apocalyptic nightmare scenario just as easily as a get-out-of-jail-free card.
To go from "We really have NFI how to create such an AI" to "It will be developed in the next 20 years and will add x% growth to our GDP" is just ludicrous, especially when your own link warns "Since competitive wages are proportional to per-intelligence production, rapidly declining wages imply rapidly declining per-intelligence production, due to an intelligence population growing much faster than total production. Wages might well fall below human subsistence levels, if machine subsistence levels were lower." Oops.
2) It assumes a cost of $1000 per metric tonne of CO2 removed. Humans have the rest of this century to get costs down, and I'm sure they will be well below that number when it is used.
That seems like a big assumption. How do you know costs to remove CO2 will go down? After all, the inflation-adjusted price of oil has been rising over the longer term (Link), which is not an unsurprising outcome as the resources become more and more difficult to extract, and oil is likely to remain a key source of energy for a while yet. It would be challenging adjusting to the cost pressures of an important energy resource at the same time as having to dedicate an increasing share of our energy resources to bringing down the atmospheric levels of CO2. In addition, changes to the environment brought about by the rising CO2 levels could well increase the cost of methods that would remove it. You appear to be begging the question.
Deus ex Machine = Deus ex Machina. Autocorrect can be a pain sometimes. :-)
JasonB @65, excellent points about AI. I do, however, take exception to the tongue in cheek (?) claim that, "Heck, if it were moral, it might decide that would be just punishment for our attempt to push the problem onto future generations to solve." Hopefully if the AI were intelligent enough to employ a concept of justice, it would recognize that such an action would be punishing the future genearations for their forebears crime of not giving sufficient consideration to the well being of future generations, which would be ironic, but not just.
Further, given that carbon sequestration technologies are still novel, it is reasonable to assume that per unit costs will come down with time. Of course, it is also reasonable to assume an increasing marginal cost for each additional tonne sequestered (unless we decide we are going to simply ignore economics). Given that, further delay pushes up the mean per unit cost of sequestration. Bahner gives us no reason to think that improvements in technology will push down costs faster than diminishing efficiency with amount sequestered will push them up.
Tom Curtis @ 67:
Hopefully if the AI were intelligent enough to employ a concept of justice, it would recognize that such an action would be punishing the future genearations for their forebears crime of not giving sufficient consideration to the well being of future generations, which would be ironic, but not just.
It's an interesting philosophical question: exterminating humanity now as punishment for the crime of burdening future generations would, of course, prevent those future generations from ever existing, but does never existing mean they are being punished? The AI might take the view that the world has been screwed up so badly that those future generations would wish they'd never been born and that being born would actually be punishment. It might also take the view that, by definition, you can't punish someone who will never exist.
I don't know — given the differences of opinion we find even among our own species, I find it very difficult to imagine what a super-intelligent AI might find "moral". I do know that I wouldn't like to bet my future on it agreeing with me.
(As an aside, I'm not sure a concept of justice is something that has an intelligence threshold ("intelligent enough to employ a concept of justice"); that's why I talked about "morals" instead. I suspect the two concepts are orthogonal. Even if it were moral, there's a real risk that it could be so far advanced relative to us (due to the lack of inherent intelligence limits that we face) that it would care as much about us as we care about ants, or even the bacteria on our hands that we routinely wipe out with anti-bacterial soap, and simply not recognise that morals ought to apply.)
Further, given that carbon sequestration technologies are still novel, it is reasonable to assume that per unit costs will come down with time.
That's possible if better technologies can be found. But the reverse is also easily possible, as you note below. Think about CCS, for example — it makes sense that we'd start sequestering in the sites that would cost us the least to use. But as those sites became full, we'd need to start searching further afield, and using sites that were previously rejected because they weren't as cheap. How much of the cost of CCS is technology-related and how much is unavoidable due to the laws of physics?
The same logic would apply with reforestation, not only because we'd start with the cheapest land and gradually work our way up to the highly valuable land that is being used for other things, like growing food, but also because worsening drought, etc., might make it more and more difficult to achieve.
I think many options also use a fair bit of energy, and there's a real risk that energy will become increasingly expensive in real terms as the free ride we've all been one comes to an end.
Of course, it is also reasonable to assume an increasing marginal cost for each additional tonne sequestered (unless we decide we are going to simply ignore economics). Given that, further delay pushes up the mean per unit cost of sequestration. Bahner gives us no reason to think that improvements in technology will push down costs faster than diminishing efficiency with amount sequestered will push them up.
Not ony that, but the total number of units that need sequestration will of course also increase under BAU, so increasing the cost per unit and increasing the number of units doesn't sound like a recipe for cheapness to me.
Mark Banner,
I have made one comment and you have conceded that your original estimate is off by at least 100%. You are clearly aware of this issue since you conceded the point and replied immediately. Tom and others have made numerous other points that show you are hopelessly optomistic. Since you know your original proposal is off by at least 100%, why should I consider it until you include all the other costs you previously have not mentioned?
That is completely false. I made no such concession. I merely stated:
This in no way concedes that such a situation is even possible. In fact, the vast majority of CO2 that is absorbed is not absorbed as gaseous CO2 into the ocean. Sabine and Feely, 2007 provide the following best estimates for carbon emissions and sinks for the 1980-1999 period:
Emisions (fossil fuel and cement) = 117 PgC
Atmospheric Increase = 65 PgC (note that this is 56 percent, not 50 percent)
Ocean Inventory = -37 PgC
Net terrestrial = -15 PgC.
Sabine and Feely, 2007
And even of the 37 PgC absorbed by the ocean, not all of it is absorbed CO2 gas. (As far as I know, much less than half of it is absorbed CO2 gas.)
...once again, that is completely false.
"...why should I consider it until you include all the other costs you previously have not mentioned?"
What other costs do you think I have "not previously mentioned"? Also, why do you think I should be advising you on what you should consider? Do you have some power to either beneficially or negatively affect me of which I'm not aware?
[JH] Please loose the snarky tone.
Mark Bahner @70:
"In fact, the vast majority of CO2 that is absorbed is not absorbed as gaseous CO2 into the ocean."
Most CO2 dissolved into the ocean is converted into other forms, as described in Doug Mackie's Reservoir Dogs article -part 5 of the OA is not OK series (see side bar) which I recommend to everyone. In fact Mackie claims that less than 1% of CO2 absorbed in the ocean is not converted to carbonate or bicarbonate. That is, however, irrelevant for all forms of Dissolved Inorganic Carbon (DIC) maintain equilibrium with each other. Therefore, if dissolved CO2 outgasses, the reservoir of dissolved CO2 is replenished by drawing down the other forms of DIC. Consequently the full amount of excess CO2 initially dissolved into the ocean can be outgassed. As such, Bahner's bringing it up is a complete red herring.
Even the excess carbon absorbed by the biosphere, to the extent that it is due to the CO2 fertilization effect, will be returned to the atmosphere if CO2 is returning to former levels. That means that for all intents and purposes, if we wish to return CO2 concentrations to preindustrial levels, we need to remove as much CO2 as we have emitted (give or take a small percentage). In the more likely event that we wish to only remove some of the excess CO2, natural reservoirs can be expected to retain some substantial fraction of the excess carbon, but we will need to draw down far more CO2 than the excess resident in the atmosphere.
Finally, the figure of 57% of CO2 emissions retained in the atmosphere commonly used, and reflected in Sabine and Feely's figures (55.6%) only account for industrial emissions. When emissions due to deforestation and land use change are included, only 42% of total emissions are retained in the atmosphere on average. That probably means Bahner's estimate was still of by 100%, and possibly more depending on the extent of the draw down as the airbourne fraction is 42% of total emissions, not 50%. In the scenario of a rapid draw down of CO2 concentrations to pre-industrial levels, he is of by 138%
I should add that if we try to rebury, in the form of carbon dioxide, the carbon that we have exhumed since the Industrial Revolution, the mass that we have to inter is about three times the mass that we have dug up and burned; because we have to bury two oxygen atoms along with every carbon atom. The hydrogen from fossil fuels is mostly already safely buried at sea.
Andy Skuce @72, the most practical way to bury "CO2" is to allow some life form or another to convert it into a cellulose, proteins or lipids; and bury those. Doing so significantly increases the proportion of Carbon by mass in the product buried, and more significantly, turns it into a solid which escapes burial far less easilly than pressurized gases. Although research is still being conducted into it, I believe the direct sequestration of CO2 is a dead end.
(moderation kvetching snipped). Such a environment exists at my blog. I'd be especially happy to discuss this matter with Rob Honeycutt, KR, Andy Skuce, Jason B., and others.
This is my blog post regarding the "irreversibility" (or lack thereof) of global warming.
In particular, it addresses Jason B's commment that, "Not ony that, but the total number of units that need sequestration will of course also increase under BAU..."
I'd also be interested in discussing discount rate with Andy Skuce, who might be able to fill in some of the estimates that Jason Pontin (at Technology Review magazine never did. See: "What is the morality of the less-well-off sacrificing for the better-off?
[DB] Note that Moderation Complaints are always off-topic.
Mark, perhaps you should try addressing the points made against your argument by Tom in particular.
I'd be happy to on my blog. You or he could point me to the particular comments y'all would like addressed.
[DB] To retain any credibility, those points needing responding to can be found here.
I have already addressed this issue. Even if the amount required was double the 7.8 Gt CO2 per ppm could be addressed either by:
1) Cutting the cost in half to $500/Gt of CO2,
2) Increasing the GDP by a factor of two,
3) Running twice as long,
So even if the value is 138% more, that does not fundamentally change the issue. Solomon and Matthews are wrong, because they ignore the possiblity of human beings reducing the atmospheric CO2 concentration by capture and sequestering atmospheric CO2.
Oops, that should have been: 1) Cutting the cost in half to $500/TONNE of CO2,
1) Cutting the cost in half to $500/Gt of CO2,
Why stop there? I propose cutting the cost to $0/Gt of CO2! Problem solved. Now that I've made eliminating CO2 free, is there anything anyone else needs me to sort out for them?
The answer of course is, "What evidence do you have to justfify the cost per ton of $0?
There is plenty of evidence to justify a cost estimate of $500 per ton. Some folks think it will be $1000 per metric ton of CO2. Other's think it will be as low as $100 per ton.
And the people who made the estimate of as low as $100 per ton are actually building a pilot plant. What sort of experience do you have Jason, to make your estimate?
For example, David Keith has PhD in Experimental Physics from MIT and now teaches Environmental Science and Engineering at Harvard University. He was named a 2009 Time Magazine Hero of the Planet.
Mark Bahner, in science you can generally find papers or statements from scientists supporting more or less any stance on any scientific subject. Picking the ones you agree with and ignoring the distribution of opinion (i.e. the scientific context) is cherry picking. Being able to point out that there are some that think that the cost is likely to be low doesn't mean that it actually is likely to be low. The majority of scientists (with relevant expertise) claiming it is likely to be low on the other hand would be good evidence that the cost is likely to be low.
So, to rephrase your question "what evidence do you have to suggest that the cost per ton is likely to be $500 (or less), and how does this compare with the evidence that it is likely to be more".
Note I am not making an argument for or against anything here, I am just trying to help you to make your case, a balanced survey supporting your argument is likely to be more successful than pointing out what are possibly a few outliers, so provide the context that shows they are not outliers.
Mark banner:
You say
What other costs do you think I have "not previously mentioned"?
According to your source:
Dr. Keith says he thinks it may be possible to lower the cost of capture toward $100 a ton as the company grows. (my bold)
You claim that carbon sequestration would cost $100 per ton but your source only states the cost for carbon capture. You have not mentioned the cost of pumping the CO2 underground. This is another cost you have convienently forgotten. When you account for all the costs we can have this discussion again.
I would welcome a CCS-led solution to the climate crisis and I think there is a reasonable chance that one day it could be employed in a marginal way and a faint chance that CCS could make a significant difference to reducing carbon concentrations in the atmosphere and oceans. I fully support the research being done by people like David Keith.
When we say that the damage we have done to the chemistry of the atmosphere and oceans "cannot be undone", what we really mean is that is cannot be significantly undone using current technology and in the current economic environment. And, importantly, nor will the climate system itself clear up the damage done and restore itself to pre-industrial conditions over a reasonable human timeline, even if we could stop further emissions.
Mark's argument a bit like objecting to to a claim that we can't establish colonies on Mars. In the next decade or two we certainly couldn't and it is hard to imagine anybody doing it during the rest of this century. But of course we still could imagine a suitable technology and we could devise a scenario showing why people might be motivated to do it in the far future, and how they might be able to pay for it. And I hope that somebody, somewhere is thinking hard about how we might be able to do those things.
Climate change is real and it's getting worse in the here and now. It would be irresponsible to console ourselves that our inaction now is nothing to worry about, because we can dream of a day when carbon capture and storage becomes scalable and affordable and we will be able to twiddle the planetary thermostat to get the desired comfortable climate that everyone desires. That would be like driving recklessly beacuse you have had airbags fitted, or continuing to smoke because you have confidence in cancer research.
I'm happy to explore the potential of CCS here anytime. But I'm not going to waste any more time debating whether climate change is practically reversible or not, just because there is uncertainty about how big future economic growth may be or what marvellous advances in technology there will be in the far future. That's a distraction I don't need.
Mark... You state that, "[T]he people who made the estimate of as low as $100 per ton are actually building a pilot plant."
This brings up my previous question. Do you think the people emitting all the carbon into the atmosphere are going to willing to foot the bill for pulling it back down?
If we really want the marketplace to work with regards to addressing climate change, then we need to have a level playing field. Fossil fuel companies can't expect to put carbon into the air today and expect that people a generation later should foot the bill for extracting it.
And then, if you regulate in a way that says the FF industry must set aside those costs now, then you have more of a level playing field but the cost of FF energy is going to skyrocket.
Once again, if you add in any appreciable cost of the externalities associated with burning fossil fuels, then already renewables win hands down. That means the better solution is just to not add carbon into the atmosphere in the first place.
My suspicion is that the FF industry doesn't want to pay those costs. They don't pay them now. They want to continue to put carbon into the air for free, and then when the time comes to pay the piper, they will want society at large to foot the bill.
Mark,
And the people who made the estimate of as low as $100 per ton are actually building a pilot plant. What sort of experience do you have Jason, to make your estimate?
Sorry, I thought we were playing Make A Wish and couldn't tell from what you wrote that you actually had science on your side.
But then, looking at your own link, I found this comment from Dr Geoppert:
“There is a lot of speculation of how much it will actually cost,” he said, with estimates from $20 a ton to as much as $2,000. “We won’t know for sure until someone builds a pilot plant.”
And Dr Keith himself saying:
Dr. Keith says he thinks it may be possible to lower the cost of capture toward $100 a ton as the company grows. (Emphasis mine.)
So perhaps my initial impression wasn't so far off after all.
The other point, of course, is that they're talking about only half of the CCS equation, and I thought capturing CO2 (e.g. from coal-fired power-plants) was the easy part. The real cost is in the "S" part, which I is why that was the only part I mentioned in my comment 68 above:
Think about CCS, for example — it makes sense that we'd start sequestering in the sites that would cost us the least to use. But as those sites became full, we'd need to start searching further afield, and using sites that were previously rejected because they weren't as cheap. How much of the cost of CCS is technology-related and how much is unavoidable due to the laws of physics?
And how much energy is required? Estimates for coal-fired power stations range from 20-40% of the energy generated by the plant being used to capture the CO2 from that plant, and I have to assume that it's cheaper to capture it at the plant because the concentrations are so much higher. Given the challenges faced with declining use of fossil fuels in the future, should we burden them with having to divert a significant portion of their energy generation capacity to cleaning up our mess?
One final note: even your quoted figures are way above the current emissions costs of CO2. If your $500 figure turns out to be right, would you support a $500/tonne carbon tax right now as a fair reflection of the true cost of emission in order to fund that extraction? That would certainly set the fox among the chickens...
Of course not. I consider it profoundly immoral for the poor to sacrifice for the benefit of the rich and well-off. Don't you, too?
The current world life expectancy at birth is about 70 years. I think in 2100 it will be 110+ years. Currently, it is estimated that over 700,000 people die of malaria each year. I am quite confident that the number of malaria deaths in the year 2100 will be exactly zero. (Regardless of what any malaria model developed to scare people regarding the effects of global warming might say.) I think the world per-capita GDP will be over $1,000,000 (PPP, adjusted to 2013 International dollars). In fact, I put all these predictions on my blog:
Predictions for the 21st century
I'm so interested to get your answers in all of the cells of the table, that I'll send you $20 if you go to my blog and put your own predictions in the comments section.
P.S. All my predictions assume no takevover by Terminators or global thermonuclear war. Yours should too. ;-)
I think it is profoundly immoral to put off cleanup to future generation. What if
1)problem is worse than we think ... and every projection is coming in worse
2)what if they got other, unforeseen by us, problems
3)most bad, what right do we have to make the silent unborn clean up our mess ?
they cannot defend themselves. This attitude is, to put it baldly, "Grandkid is worth nuttn because of the discount rate."
Applying an intergenerational discount rate between generations is evil. I suppose that's an unfashionable Rawlsian, (or, gasp, even Georgist!) thing to say.
People who rely on others to pick up after themselves are leeches. Leeches on unborn "... have a special dung heap in the low rent section of hell..." with their name on it.
[ I am indebted to Hunter S. Thompson for that last quote ]
sidd
Mark said, "Of course not. I consider it profoundly immoral for the poor to sacrifice for the benefit of the rich and well-off. Don't you, too?"
Of course, everyone believes that. Tax structures do not inherently overburden the poor, if they're structured correctly. In fact, they generally benefit the poor and middle class.
It's one reason I'm more inclined to support a tax and dividend system.
But, JasonB has an important point that you casually dismissed. If the cost of removing CO2 from the atmosphere is $500 then that is the true cost of emissions. And that is the point I've been trying to address.
1) Given Mark Bahner's stated moral outrage about the poor being asked to sacrifice for the benefit of the rich. Given that, no doubt we can expect him to clearly state a desire that the US government should ignore the deficit, which afterall, will be payed of far more easilly by future, wealthier generations (given his assumptions).
2) I have been checking two scenarios to see if their is any merit in Bahner's approach.
In both scenarios, CO2 emissions grow at an initial rate of 2% per annum (compared to the average over the last decade of 2.7% per annum). That rate reduces such that the emissions in any given year (y) are:
Emissions(y-1)*(1.02-(1.0234^(y-2013))/100)
The constraints on emissions growth are expected to come from increasing cost of fossil fuels and increasingly competitive renewable energy. The total curve represents the combustion of approximately twice current proven economic reserves. For comparison, Bahner assumes peak emissions at 30% above current emissions in thirty years, followed by a rapid fall of. This scenario shows a peak of 17.5% above current emissions in thirty years, followed by a rapid fall of, and so is optimistic on his assumptions. I also believe it to be optimistic on a BAU approach, but not entirely implausible.
In both scenarios, 1% of GWP is spent on carbon sequestration annually from 2014 until CO2 levels decline to 330 ppmv, at which level they are then maintained. The cost of carbon sequestration is set at an initial value of $1000/tonne and falls by 1% per annum, falling to less than $420 a tonne by 2100.
Growth in Gross World Product (GWP) in purchasing power parity (PPP) terms is assumed to be 4.5% per annum in the first, optimistic, scenario. That is greater than the average over the last 40 years (see graph @60 above), a period which has seen a slight but persistent decline in GWP despite the advent of the information technology revolution. Given the costs of ongoing global warming, not to mention the 1% of GWP spent on carbon sequestration every year, I think this assume growth is (very) optimistic.
In the alternative scenario, growth in GWP starts at 4.5% per annum, but the growth rate increases by 0.1% per annum. That acceleration of the growth rate means GWP by a factor of more than 2000 by 2100, or given standard estimates of population growth, in represents an increase in PPP GWP/capita by about 1000 by 2100. I therefore think it reasonably represents Bahner's (franky fanciful) assumptions.
Temperature response is set to track the Transient Climate Response to CO2 concentrations. This over estimates temperatures in the early stages of the scenarios (because it ignores sulfates) but will be approximately correct in later stages.
The results of the two scenarios are virtually indistinguishable from each other (and the no sequestration case) for the first 25 years (2014-2038) of the scenarios, with temperature climbing rapidly to more than 2 C above pre-industrial levels by 2035. They remain at elevated levels (> 2 C) for 57 years in the optimistic scenario and 33 years in the Bahner scenario. This is the key problem with Bahner's approach (even if we ignore his absurdly optimistic assumptions). Assuming PPP GWP growth of 4.5% per annum (let alone the approx 7% per annum in the Bahner scenario) in a plus 2 C world is absurd. If in fact, and very improbably, such high levels of growth can be maintained in a 2 C world, then, indeed, in strictly economic terms AGW is no problem. That, however, needs to be established - not used as a hidden assumption. If, as is more likely, growth in a plus 2 C world falls towards zero, or even becomes negative; sequestration will remain limited in its ability to draw down atmospheric CO2 and CO2 concentration will track closely the no sequestration pathway (ie, rising above 1000 ppmv and heading for a plus 5 C world).
So, at best, Bahner's solution to AGW works if, and only if, AGW is not a problem to begin with. If it is a problem, ie, if plus 2 C worlds will have negative impacts on the world economy, mitigation to avoid such scenarios is by far the better investment, although sequestration may become a viable alternative in the mid to later twenty-first century. Even then, sequestration will only be a viable strategy in the later twentieth century if we have significantly mitigated CO2 emissions in the first half of the twentieth century.
@Mark Bahner #87:
You stated, "I consider it profoundly immoral for the poor to sacrifice for the benefit of the rich and well-off."
The findings presented in the article, U.N. Finds “Little Appreciation” for Human Rights among U.S. Businesses" suggests that many U.S. business are acting immorally.
Do you agree?
Mark Bahner,
Of course not. I consider it profoundly immoral for the poor to sacrifice for the benefit of the rich and well-off. Don't you, too?
I consider it a meaningless slogan without context. With context, what you are saying is that not only should poor people throw their rubbish on the front lawns of the rich because the cost of cleaning it up as a proportion of income is less for the rich people than the cost of garbage collection is for the poor, but that it's actually "profoundly immoral" to ask the poor people to take care of their own garbage.
Where this analogy breaks down, of course, is that in the actual case in question you don't actually know for a fact that the recipients of the rubbish are rich. There are plenty of reasons to suggest they may actually be worse off than we are, economists' fantasies notwithstanding. Firstly, they will be dealing with the consequences of AGW, which we've barely had a taste of so far. Secondly, they won't be able to take advantage of the huge boon in cheap energy that we've benefited from over the past 150 years or so thanks to fossil fuels, which has had an enormous effect on our standard of living, because they are a finite resource anyway.
And even if GDP increases, that doesn't mean that everyone benefits. Those living on low-lying Pacific islands and places like Bangladesh may find their homelands and way of life destroyed forever. Those depending on sea-sourced protein may be suffering profoundly from the consequences of overfishing and the effect of ocean acidification on the food chain. What about those dependent on glacial run-off for their water supply? Surely it is profoundly immoral for them to have to sacrifice for the benefit of those of us now enjoying the benefits of the fossil fuel boom? It does seem a little self-serving to suggest that it would be immoral of us to lower our living standards for their benefit by making it seem as if they are the rich ones and we are the poor.
Mark Bahner sounds like an economist. Only they can postulate the future existence of wealth and then start using it as if it not only will come into existence for sure, but in fact already exists. That attitude, when it turns into a frenzy, was the cause of the largest market crashes in history. A sizeable amount of wealth in today's world is wealth that does not have any real existence. Of course, the really clever ones are those who can cash in on thesefrenzies on the very short term, because they keep the assets acquired even after the whole house of cards collapses.
I tend to trust economists that were able to predict bubbles and crashes before they happen, such as Jeremy Grantham. Unfortunately, that kind of clearsighted economist is unlikely to gather more attention about this subject than they did with the Japanese bubble, tech bubble, housing bubble, etc. People like easy and worry-free, so the Bahners of the World will always have a larger audience. Then when it hits the fan, the clearsighted ones will be under fire for not being more convincing.
http://www3.imperial.ac.uk/climatechange
http://www2.lse.ac.uk/GranthamInstitute/Home.aspx
Philippe Chantreau @93, I would not assume that Bahner is an economist, or indeed, that he has any university level economics training. His blog shows only 12 posts since it started in July 2007, none of which shows detailed economic reasoning, or detailed reasoning of any sort. The only thing it really shows is that he likes reading cornucopian futurists, and that he is almost completely ignorant of physics (he claims that what amounts to a 20 foot wide barrier of weighted corks could stop a storm surge, and that the weighing would stop it drifting of station in the face of a hurricane). HIs blog ("Random Thoughts") is well named, but could perhaps be better named "Thoughtless comments".
Thanks for the precisions Tom.I confess that I could think of so many other things to do with my time that I did not go explore M.B.'s blog. I did not assume that he was an economist but he did have an overall tone not too distinct from the overly optimistic ones who advocate for a solve-all, laisser-faire market, in spite of clear evidence that it does not work. Your account about his blog seems to be consistent with his attempts at bribing people to go comment there...
Tom Curtis (#94) writes:
I ask this because of your opinion that I am “almost completely ignorant of physics” and because you have said things like this about Robin Hanson, and his paper on "Economic Growth Given Machine Intelligence":
Just for folks who don’t know: Robin Hanson has a PhD from the California Institute of Technology (aka, Caltech). He’s an associate professor of economics at George Mason University and a research fellow at the Future of Humanity Institute at Oxford University. He’s an expert on idea futures and was involved in the creation of the Foresight Exchange and DARPA’s FutureMAP project. And though the analysis of the economic aspects of artificial intelligence is a small field, I’d say he’s one of the leading thinkers in that area. So I’m curious what your credentials are? Have you ever published any papers on either economics or artificial intelligence?
And I’m also curious to get your expert opinion on what economic growth will be like in the 21st century. (You're obviously an expert, given your easy dismissal of Robin Hanson's and my analyses.) In October 2004 I made the following predictions for inflation=-adjusted world-wide per-capita GDP growth rates in the 21st century::
2010-2020 = 3.5 %/yr
2020-2030 = 4.5 %/yr
2030-2040 = 6.0 %/yr
2040-2050 = 8.0 %/yr
2050-2060 = 11.0 %/yr
…2060-2100 > 11.0 %/yr
In November 2005, after I made those predictions in October 2004, I did calculations of the number of human brain equivalents (HBEs) added each year by computers
Nov. 2005: Why 21st century economic growth will be spectacular
After doing those calculations, I think the economic growth is likely to be much higher from 2030 onward than I even predicted in 2004. (Barring takeover by Terminators or global thermonuclear war.)
I’m so interested to get your expert opinion on what economic growth will be like in the 21st century, that I’ll send you $20 if you’ll provide your predictions in a similar manner to mine. That is, if you provide your predictions for inflation-adjusted world per-capita GDP growth for every decade in the 21st century, I’ll send you $20. When we get your predictions, we can figure out whether Robin Hanson, I, or you are right about world GDP growth in the 21st century. It makes a big difference regarding whether removing CO2 from the atmosphere will be viable in the 22nd century.
P.S. Though I should again note that even if the IPCC economic growth rate and CO2 projections are correct, it’s pretty clear that removing CO2 from the atmosphere will be viable in the 22nd century.
I appear to have hit a nerve (Mark Bahner @96). So much so that Bahner is resorting to the implicit argument that Hanson must be right because he has good credentials. I am more (un)impressed by Hanson's claim that:
The interesting feature is the prediction of a 4.3% growth rate per annum, doubling every 16 years with technological advancement in computers, but no AI. That is an emperical prediction that can be compared to the economic record since the advent of commerical computers in the 1960s:
or the penetration of computers (or at least computer chips) into all aspects of the market in the 2000s:
The simple fact is that the world has seen declining, or at best steady economic growth over a period in which Hanson's theory predicts a doubling of economic growth every 16 years. Therefore his theory is falsified empirically, and was falsified when he published it as he would have known had he done any retrodiction with the theory to compare with empirical data. Given that it does not matter what his credentials are; we have no empirical basis to accept his theoretical projections.
However, given that Bahner likes credentials, perhaps he will like the predictions of the Noble Prize winning economist, Rober Lucas Jr:
No, I'm asking who you are, that you can write things like:
[-snip-]
That's not a prediction. It's an observation of the recent growth rate (up to the time of the paper, of course...which I think was 2001).
Yes, Robert Lucas Jr. has a Nobel Prize in Economics. And who wouldn't respect that (except you, perhaps)? But I bet he's wrong:
Long Bets Prediction #194 (Circa 2004)
That prediction is:
Again, what are your predictions?
P.S. I don't have the Journal of Economic Perspectives paper in front of me, but I'm pretty sure the figure you cite is of per-capita income growth (so population growth would need to be included to get the total world GDP growth rate).
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See the Climate Troll Illustrated Bestiary, Breakthrough Boys. Mark Bahner seems to assume that we will economically rocket out of our own problems with no other effort.
I find this approach delightfully optimistic in its child-like charm, yet completely unrealistic. Real economics, looking at the potentials for growth in the developing world and with a more grounded evaluation of technical change, are less likely to predict magic growth that will wipe away all issues due to excess capacity - rocket cars in every garage, AI's that do the hard work for us, etc, would be great, but experience doesn't support such a cornucopian view.
Mark Bahner @ 96:
And though the analysis of the economic aspects of artificial intelligence is a small field, I’d say he’s one of the leading thinkers in that area. So I’m curious what your credentials are? Have you ever published any papers on either economics or artificial intelligence?
I can't speak for Tom but I have published (a long time ago) in the field of AI and I make a living today creating technology that greatly enhances productivity so I guess I'm one of the "doers" (as opposed to "thinkers") in that area. In fact, a couple of months ago a free trial I offered was turned down out of concern that the "amazing efficiency" gained would result in management taking the opportunity to downsize the department in question, which highlights the flip side (also mentioned in the paper you linked to): productivity gains often result in job losses and the need for humans to find another niche to fill that the machines aren't yet capable of performing. GDP could well rise while a few get incredibly rich and the rest struggle to find work and survive.
But back to an earlier point I made: I get annoyed by so-called "futurists" predicting wonderful advances in the technology, usually based on the ever-diminishing cost of computing power, who appear to have no idea that the thing that makes that computer power actually useful is a much harder nut to crack. As someone who has spent a long time and lots of money developing "intelligent" software — although I wouldn't classify it as "artificial intelligence", and I would regard as clueless anybody who tried to — I can tell you that that's where the real challenge lies.
Allow me to explain:
Estimates vary on the processing power of the human brain, from about 10 petaFLOPS up to about 100 petaFLOPS, but somewhere in the middle seems reasonable. Titan, the current fastest computer in the world, is about half that. In theory, then, Titan could run a human-equivalent AI at about half real-time. Except it can't, because we don't know how to write such a program.
Put the top two supercomputers together and they actually have enough power to run a human-equivalent AI in real time. The top five, combined, have enough power for two human brains or, presumably, one really smart one. Even Folding@home has approximately 12 petaFLOPS at its disposal, which would put it at #3 in the world.
The computing power is there. It already exists. In the future it will just get cheaper. (It's still hard to compete with ~50 petaFLOPS that can be mass produced by unskilled labour, of course.)
But we don't know how to harness it to create an artificial intelligence; we use it for simple number crunching. I don't think any of these supercomputers has ever deduced the existence of rice pudding nor income tax on their own.
I’m so interested to get your expert opinion on what economic growth will be like in the 21st century, that I’ll send you $20 if you’ll provide your predictions in a similar manner to mine.
Why? You've made that offer a couple of times now and I can't see what possible value there would be in any of our predictions of future GDP growth, just as I see very little value in any of the economists' predictions of future GDP growth. You seem to place a lot of value in something that is utterly worthless. At least with the IPCC's temperature projections there's some physical models underlying them; I tend to view economic forecasts as coming under the heading "Just Making Stuff Up". They have a hard enough time predicting the present, let alone the future.