The CO2 concentration graph: Guesses solicited for its future shape and consequences

[intention]

@SentientMeat

[QUOTE=intention]

if we were able to magically freeze the level of added CO2 to the current level (we currently add about 7 gigatonnes of C to the atmosphere annually), the atmospheric level would not continue to rise indefinitely. As more is added, more is sequestered annually, and at some point they become equal. At that point, airborne CO2 levels out.

If that is true, why is the CO2 concentration rising? If more was sequestered as more was added, the concentration would remain constant. We are, surely, depleting the sequestered stores at a much faster rate than new stores can form?
[/quote]

It appears my writing is not clear once again, not surprising. “Sequestered” means removed from the atmosphere and stored in the earth system somewhere (e.g. limestone, biosphere, ocean, soil).

As the amount of CO2 in the atmosphere increases, the amount sequestered (removed from the atmosphere) also increases. This process is called an “exponential decay”. It can be seen in water running out of a container with a hole in the bottom. The more water that is in the container, the faster it runs out the bottom.

And just as with such a container, if we add a constant amount of CO2 to the air annually, eventually the amount of CO2 removed from the air annually will equal the amount added to the air annually. At that point, an equilibrium is reached.

[QUOTE=SentientMeat]

[QUOTE=intention]
The problem is predicting emissions, and I know of no way to do that.
[/QUOTE]

It is surely common sense that until we replace high-emission power stations, transport, construction methods and whatnot with low-emission counterparts, the emissions will either remain the same or increase, given China & India’s emission growth? (Of course, if high CO2 concentrations won’t have any significant consequences anyway, we needn’t bother.)
[/QUOTE]

Yes, it is true that emissions are rising, and likely to rise further. But how much they will rise, and how fast they will rise, and how far they will rise, are not known. The uncertainty becomes huge once we are looking more than a few decades out, because we cannot foresee future technologies.

For example, I support a nuclear option. Why? Because I think it is madness to have our entire economy at the mercy of truculent folks halfway 'round the planet. Now, we could wean ourselves off Middle East oil entirely in twenty years or so, by putting on a huge push to build nuclear power plants. Pick a few good designs so permitting is easy, and start building.

Will that happen? I sincerely hope so, but I haven’t a clue. Same is true for say algae-derived biofuel. Could be a huge part of the market in twenty years, with concomitant reduction in CO2 emissions. Or not.

That’s why I say we can’t predict emissions.

[QUOTE= SentientMeat]

[QUOTE=intention]
if we maintain emissions at the current levels we’d eventually burn all the carbon stores … but the level would never come close to 800 ppmv.
[/QUOTE]

Even if we depleted sequestered stores at a much faster rate than was being sequestered? I simply don’t see what mechanism causes a level-off below 800 ppmv if carry on as we are, since all the natural sequestration mechanisms I know of simply don’t work fast enough: the number of trees is shrinking, not growing, for example. That leaves only phytoplankton - are you suggesting that they will start to convert massively more CO2 to make their coccoliths or something? (This would presumably require you to deny increased ocean acidity as well, yes?)
[/QUOTE]

The point is that if we maintain emissions at current levels, at some point (around 450 - 500 ppmv) the amount sequestered will equal the amount emitted. This is a result of the exponential decay process, where the amount sequestered is proportional to the amount in the atmosphere. The more CO2 in the atmosphere, the faster it is taken up by all mechanisms - the soil, the phytoplankton, the trees, the limestone, and all the rest.

The amount of CO2 emitted each year is fairly well known. The amount in the atmosphere is accurately measured. This allows us to measure the amount sequestered (CO2 emitted less what remains in the air) with reasonable accuracy. The amount sequestered annually has been rising for at least the last hundred years or so, and has shown no sign of a change in the e-folding time (a measure of the amount sequestered as a proportion of the total amount in the atmosphere). So at present, we have no reason to think it sequestration will drop in future.

[QUOTE=SentientMeat]

[QUOTE=intention]
My guess of the consequences, regardless of the level of probable change, is that they will be minimal.
[/QUOTE]

Just to be clear here - you believe that the Greenhouse Effect itself is largely nonexistent? That if we magically removed pretty much all the CO2 from the atmosphere, the temperature still wouldn’t change? (You do accept that CO2 absorbs infra-red wavelengths, right?)
[/QUOTE]

The greenhouse effect is real. However, in terms of the earth’s climate, it has a very small effect. This is because the earth has a governor which controls the temperature.

As an example in another arena, consider a car. If you depress the gas pedal to a certain level and hold it there, the car will start to speed up. At some point the increasing air resistance (negative feedback) will equal the force from the engine, and an equilibrium speed will be reached.

But if you start up a hill at that point, the car will slow down, because of gravity.

Now consider a car with a governor, which in automobiles we call “cruise control”. We set it for a certain speed. It holds that speed on level ground. And if we start up the hill, it still maintains the same speed. Now, does that mean that “gravity is largely nonexistent”? No, not at all. It just means that as the load increases, so does the power added to the engine.

In the climate system, when the earth cools, we get less tropical clouds. This increases the power added to the system, by tens of watts. Conversely, when the temperature increases, so do tropical cumulus and cumulonimbus, cutting down the warming of the surface by tens of watts. In such a climate system, a system with a governor, the CO2 has no more effect than the hills in a car with cruise control. In a car with cruise control, going uphill slows the car, but by a barely perceptible amount. The same is true of the earth.

Again, I invite you to read my paper on this subject, which discusses all of this in detail.

Thank you for the interesting questions.

[SentientMeat]

@intention

As the amount of CO2 in the atmosphere increases, the amount sequestered (removed from the atmosphere) also increases. This process is called an “exponential decay”. It can be seen in water running out of a container with a hole in the bottom. The more water that is in the container, the faster it runs out the bottom.

Not if the input rate is greater than the output rate (eg. if hole is too small) – in that case the vessel fills up.

And just as with such a container, if we add a constant amount of CO2 to the air annually, eventually the amount of CO2 removed from the air annually will equal the amount added to the air annually. At that point, an equilibrium is reached.

Only if the sequestration mechanisms ramp up their performance to overtake our vast depletion of sequestered stores. I see no evidence of that happening, nor any reason why it should happen.

The point is that if we maintain emissions at current levels, at some point (around 450 - 500 ppmv) the amount sequestered will equal the amount emitted. This is a result of the exponential decay process, where the amount sequestered is proportional to the amount in the atmosphere. The more CO2 in the atmosphere, the faster it is taken up by all mechanisms - the soil, the phytoplankton, the trees, the limestone, and all the rest.

How, if there are fewer trees, more acidic oceans and all the rest?

We have no reason to think it sequestration will drop in future.

Have we any reason to think it will increase massively?

The greenhouse effect is real. However, in terms of the earth’s climate, it has a very small effect.

How much colder would you guess the Earth would be without any CO2, might I ask?

[SentientMeat]

And to extend your “water in a vessel” analogy, intention, I accept largely everything you say about cycles, e-folding and exponentials if we’re talking solely about soil, trees and plankton for the last 100 million years, say.

The trouble with the analogy is that it ignores the fact that, throughout that period, huge stores of carbon were sitting undisturbed, underground. Suddenly, in the last few centuries, forests have been decimated and these undisturbed stores have been released all at once.

It is like running another, powerful hose into the vessel which wasn’t there before, while keeping the exit hole the same size.

You’re a clever guy, so I hope you don’t find it patronising of me to check that you understand this fundamental difference to what went on before the Industrial Revolution.

[Deeg]

@Blake

Only where one theory is adopted over a previous one. Clearly this does not apply to AGW which is the first theory adopted.

I disagree. In the early 1970’s, as skeptics love to point out, a few scientists opined that we could be headed towards a global cooling period. Further research, however, showed just the opposite. AGW as put forward as a theory 25 years ago, plenty of time for it to be shot down. At this point we (probably) will only refine AGW, not debunk it.

@Blake

In cases where science creates a theory to explain something previously totally unexplained its track record is very poor, especially where basic falsifiability is not or can not be applied, Freudian psychology being the textbook example, but the ether theory, Black inferiority and similar other examples are also numerous.

Freudian psychology was never considered a hard science. To my knowledge black inferiority was never a widely accepted scientific theory. Do you have a cite for that?

@Blake

Where an existing entrenched theory is replaced by a later theory the latter is usually correct. Where a theory becomes entrenched simply because it’s “the best we’ve got and explains what we think we see” it is usually wrong.

The current “best we’ve got” theory is usually refined (like classical physics), not thrown out altogether.

@Blake

That’s why science doesn’t work by consensus.

Complex scientific theories absolutely rely on consensus. Is quantum mechanics indeterminate? Most scientists think so. Get two evolutionary scientists together and they will likely have many disagreements over their theories and yet evolution on the whole has led to countless innovations. The Black Hole Information Paradox is resolving towards a consensus.

We’re probably getting too far away from the OP and evolving into YAAGW debate.

[intention]

@SentientMeat

And to extend your “water in a vessel” analogy, intention, I accept largely everything you say about cycles, e-folding and exponentials if we’re talking solely about soil, trees and plankton for the last 100 million years, say.

The trouble with the analogy is that it ignores the fact that, throughout that period, huge stores of carbon were sitting undisturbed, underground. Suddenly, in the last few centuries, forests have been decimated and these undisturbed stores have been released all at once.

It is like running another, powerful hose into the vessel which wasn’t there before, while keeping the exit hole the same size.

You’re a clever guy, so I hope you don’t find it patronising of me to check that you understand this fundamental difference to what went on before the Industrial Revolution.

SentientMeat, thanks for the question, I do not find it patronizing. And I do understand your point completely. However, it does not make the difference you think it does.

As I mentioned above, if you do the math you’ll find out that the amount of CO2 being sequestered annually has risen. Each year. Every year. For as far back as we have data.

Please, please, please do the numbers yourself. It’s the only way you can depend on the results.

The CO2 data is available at CDIAC.

The emissions data is also at CDIAC.

To do the numbers, first convert the annual change in atmospheric CO2 in parts per million by volume (ppmv) to Giga tonnes Carbon (GtC). One ppmv = 2.13 GtC, so multiply the annual change by 2.13 to see how much carbon was added to the atmosphere in that year.

Then subtract that from the total amount emitted that year, and that’s how much was sequestered in that year.

I just did that, took about ten minutes all up. Here’s the results:

Year, Emitted, Airborne, Sequestered
1960, 2.58, 1.98, 0.48
1961, 2.59, 1.55, 1.02
1962, 2.70, 1.73, 0.87
1963, 2.85, 1.15, 1.55
1964, 3.01, 1.24, 1.61
1965, 3.15, 0.99, 2.01
1966, 3.31, 2.85, 0.29
1967, 3.41, 1.66, 1.64
1968, 3.59, 1.90, 1.52
1969, 3.80, 3.37, 0.22
1970, 4.08, 2.24, 1.56
1971, 4.23, 1.36, 2.71
1972, 4.40, 2.41, 1.82
1973, 4.64, 4.75, -0.35
1974, 4.64, 1.21, 3.42
1975, 4.62, 1.92, 2.73
1976, 4.88, 2.13, 2.49
1977, 5.03, 3.73, 1.16
1978, 5.11, 3.43, 1.60
1979, 5.39, 2.85, 2.25
1980, 5.33, 3.92, 1.47
1981, 5.17, 2.64, 2.69
1982, 5.13, 2.56, 2.61
1983, 5.11, 3.51, 1.61
1984, 5.29, 3.49, 1.62
1985, 5.44, 3.15, 2.14
1986, 5.61, 2.66, 2.78
1987, 5.75, 3.79, 1.82
1988, 5.96, 5.43, 0.32
1989, 6.09, 3.05, 2.92
1990, 6.14, 2.73, 3.36
1991, 6.24, 2.98, 3.16
1992, 6.12, 1.66, 4.57
1993, 6.12, 1.43, 4.69
1994, 6.24, 3.94, 2.18
1995, 6.37, 4.24, 2.00
1996, 6.51, 3.75, 2.62
1997, 6.62, 2.39, 4.12
1998, 6.59, 6.11, 0.51
1999, 6.57, 3.58, 3.01
2000, 6.74, 2.49, 4.08
2001, 6.90, 3.28, 3.45
2002, 6.95, 4.43, 2.47
2003, 7.29, 5.41, 1.54
2004, 7.67, 3.71, 3.58
2005, 7.97, 4.88, 2.79
2006, 8.23, 4.62, 3.35

Note that some years the amount sequestered is greater than the amount remaining airborne. Since the rise in emissions is fairly constant, this means that the amount sequestered is highly variable.

However, the main point I wish to make is that the amount sequestered has been increasing since 1959. Yes, the amount added has gone way up, it is a “huge hose” as you say above.

But the amount sequestered has also gone way up, it is a “huge hole”. Both numbers represent gigatonnes of carbon, huge fluxes. And if you smooth the numbers, you’ll see that:

• The amount sequestered obeys an exponential decay, and

• There is no sign that the amount sequestered is decreasing (no change in e-folding time).

I wish to stress that this assumption of exponential decay is used by the IPCC in their calculations, and that both skeptics and supporters of AGW agree on this question.

A couple of lessons from all of this.

1. DO THE RESEARCH!!! People are always taking stands on these questions without doing the research. This is very dangerous, and leads to public embarrassment.

2. DO THE MATH YOURSELF!!! There is a host of people out there with an axe to grind. If you do the math yourself, starting from the original data, you are not depending on them to avoid errors, hype, and numerical inflation.

All the best.

[intention]

SentientMeat, one further note. You compare the increase to the historical “last 100 million years”, and you say:

It is like running another, powerful hose into the vessel which wasn’t there before …

Some numbers will give a sense of the size of the change you describe. The size of the natural flow is truly staggering.

Every year, some 120 GtC (gigatonnes of Carbon) are added to the atmosphere by various land based processes. Another 90 GtC are added to the atmosphere from the sea. This is a total of about 210 GtC which flows through the atmosphere every year. (A roughly equal amount, of course, is sequestered each year.)

Now, in 2006 (see my previous post) about 8 GtC were added from fossil fuels. This represents an increase of only about 4% over the natural background emissions.

So, while the fossil emissions are huge, they are dwarfed by the size of the natural emissions from plants, soil, and the ocean. I just did not want to leave readers with the impression that we had suddenly tripled the total emissions or something. In fact, fossil emissions are about 4% of the total. We have increase the total emissions … but not by that much. To date, the natural systems seem quite capable of sequestering that carbon in an exponential decay fashion, and there is no sign of any decrease in the rate of sequestration.

[WarmNPrickly]

In response to the OP. I think that there is no political will to moderate GHG emissions. The country that does restrict their use will be putting itself at a disadvantage to those that wont. The only real hope is in the price of oil. As the price of oil increases, alternatives will be improved. Efficiency will go up. The country that implements this technology will be at an advantage. I still think most of this technology is a ways away, but closer than you might think. The Chevy Volt and other partially electric cars will become popular and their prices will drop. It will be more difficult to get coal under control. It is way too cheap compared to the alternatives and both China and the US are full of it. Alternative technologies will need to be demonstrated as useful and economical. Additionally, the increased warming will cause frozen tundra and the like to release more CO2 and methane as they thaw.

For those reasons I expect the CO2 level will not level off soon. I expect 800 ppm to happen unless a technology is developed to actually remove CO2 from the atmosphere. I suppose an efficient sequestration technology would work too.

I expect the temperature increase to be slightly higher than the modest increases predicted by the IPCC. The reasoning behind this is the constant scrutiny of climate science has caused climatology to be overly cautious in their statements and predictions. There has never in the history of science been a subject so thoroughly scrutinized. No, the church saying its wrong 'cause the bible says so, is not scrutiny.

[Chief_Pedant]

@GIGObuster

You see that in the history of science?

Just to be clear, I’m talking about the history of all science…not necessarily AGW, which I do not follow. I’m OK with taking your word for the rest of your post. AGW is just not a topic I seem able to get very interested in–certainly not until I see actual behaviour changed. Believing the earth is going to cook to death from AGW is sort of like believing in hell, for me. Yeah; maybe it’s real–my gut says, “Nah.” But in any case I haven’t quite convinced myself that those who believe in it are substantially different in behaviour from those who don’t. So it’s a fabulous Great Cause, but…yawn.

I can’t help but look at this thread and other AGW threads bemused. The passions and the effort to persuade go way beyond, to my mind. The whole thing feels like the promoters (and perhaps the deniers) of AGW are pscyhologically attached to their positions the way a fervently religious person is attached to his. It is such a sexy Great Cause it seems irresistable for some folks to glom onto it that way. It is qualitatively different from anything I’ve seen since Y2K. Jonathan Edwards could thrive here.

But perhaps that’s just my own confirmation bias.

[SentientMeat]

@intention

But the amount sequestered has also gone way up, it is a “huge hole”.

intention, try as I might (and remember, I want to be convinced here and would publicly admit a change of mind), I simply cannot make sense of your conclusion. Of course I accept that if we burnt all the carbon stores it would eventually be sequestered again by natural processes. In fact, your links together with the realclimate site which stated that the CO2 concentration would be 500 ppmv from human emissions without “extra” sequestration - ie. over 100ppmv “extra” has already been sequestered - has actually made me more optimistic regarding a post-maximum CO2 world. (I had assumed a much slower resequestration rate taking centuries, at least, so thanks for that welcome insight.)

But the assumption that the “hole will continue to grow” seems to ignore completely any possibility that there is a limit to how much CO2 can be sequestered, and that we might be near it. I cannot see how soils and trees, in particular, can possibly sequester much more than they are already, especially given the desertification and deforestation processes which continue apace in so many important sequestering regions. I don’t know about limestone, but phytoplankton also surely don’t have a capacity much beyond their current capacity either, otherwise they’d simply work at that capacity instead of seeing the ocean around them fill with CO2 and acidify.

So perhaps a different graph might be useful for us here, in addition to that of CO2 concentration. Can you plot from your data, or find elsewhere (I’ll look too, and maybe jshore could help us out), a graph of annual sequestration? If over the next decade this looks like it’s levelling off, your assumption of an ever-growing “hole” would be shot down. If it stays roughly straight, then if we continue to emit 8 GtC per year we will reach CO2 concentrations of 600, 700, 800+ ppmv. The only way your prediction of a sub-800ppmv level-off for continued 8 GtCpa emissions would come to pass is if the sequestration rate increased exponentially while the emission rate stayed constant. Agreed?

This is a total of about 210 GtC which flows through the atmosphere every year. (A roughly equal amount, of course, is sequestered each year.)

Now, in 2006 (see my previous post) about 8 GtC were added from fossil fuels. This represents an increase of only about 4% over the natural background emissions.

But those 4%'s per year keep adding up - the vessel keeps filling up. That is why CO2 concentrations are 35% higher than they used to be, and why (barring your natural Saviour) the concentration will be 100% greater, ie doubled, sometime next century without massive global efforts to switch to low-emission technology. 500 GtC in a couple of centuries is a big old whack off equilibrium even in a system with an annual “turnover” of 120 GTC, agreed?

To date, the natural systems seem quite capable of sequestering that carbon in an exponential decay fashion, and there is no sign of any decrease in the rate of sequestration.

But to stop these annual “profits” adding up, the sequestration rate must increase considerably, agreed?

I see how, after peak CO2, the concentration will come down quicker than I thought. I cannot see how the sequestration rate will increase fast enough to stop that peak being reached in the first place.

[intention]

@SentientMeat

intention, try as I might (and remember, I want to be convinced here and would publicly admit a change of mind), I simply cannot make sense of your conclusion. Of course I accept that if we burnt all the carbon stores it would eventually be sequestered again by natural processes. In fact, your links together with the realclimate site which stated that the CO2 concentration would be 500 ppmv from human emissions without “extra” sequestration - ie. over 100ppmv “extra” has already been sequestered - has actually made me more optimistic regarding a post-maximum CO2 world. (I had assumed a much slower resequestration rate taking centuries, at least, so thanks for that welcome insight.)

But the assumption that the “hole will continue to grow” seems to ignore completely any possibility that there is a limit to how much CO2 can be sequestered, and that we might be near it. I cannot see how soils and trees, in particular, can possibly sequester much more than they are already, especially given the desertification and deforestation processes which continue apace in so many important sequestering regions. I don’t know about limestone, but phytoplankton also surely don’t have a capacity much beyond their current capacity either, otherwise they’d simply work at that capacity instead of seeing the ocean around them fill with CO2 and acidify.

So perhaps a different graph might be useful for us here, in addition to that of CO2 concentration. Can you plot from your data, or find elsewhere (I’ll look too, and maybe jshore could help us out), a graph of annual sequestration? If over the next decade this looks like it’s levelling off, your assumption of an ever-growing “hole” would be shot down. If it stays roughly straight, then if we continue to emit 8 GtC per year we will reach CO2 concentrations of 600, 700, 800+ ppmv. The only way your prediction of a sub-800ppmv level-off for continued 8 GtCpa emissions would come to pass is if the sequestration rate increased exponentially while the emission rate stayed constant. Agreed?

But those 4%'s per year keep adding up - the vessel keeps filling up. That is why CO2 concentrations are 35% higher than they used to be, and why (barring your natural Saviour) the concentration will be 100% greater, ie doubled, sometime next century without massive global efforts to switch to low-emission technology. 500 GtC in a couple of centuries is a big old whack off equilibrium even in a system with an annual “turnover” of 120 GTC, agreed?
But to stop these annual “profits” adding up, the sequestration rate must increase considerably, agreed?

I see how, after peak CO2, the concentration will come down quicker than I thought. I cannot see how the sequestration rate will increase fast enough to stop that peak being reached in the first place.

SentientMeat, I greatly appreciate your reasonable approach to all of this. I did the research on this question a few years ago, and there’s a graph on my website from that time showing what you asked for.

The graph shows the increase in total cumulative CO2 emitted (blue line), the increase in the cumulative amount sequestered (orange line), and the increase in the atmospheric content (red line).

It also shows the theoretical calculated atmospheric content assuming exponential decay with an e-folding time of around 38 years (green line).

As you can see, the real measured atmospheric concentration is very, very close to the theoretical calculation. This means that there has been no slowdown in the rate of sequestration.

As my previous reference to Jacobson indicates, there is little dispute about whether or not the atmospheric CO2 decays exponentially. This is in part because the atmospheric CO2 content is one of the few metrics in the climate science discussion for which we have fairly accurate measurements. There is only difference of opinion about the value of the e-folding time.

Finally, atmospheric CO2 levels have been much higher in the geological past. Since sequestration rates are a function of atmospheric CO2 levels, it seems obvious that the globe can sequester much, much more CO2 than it is currently sequestering.

Where will it all go? Well, we don’t know … that’s just one of the many unsolved mysteries in climate science. a science that many people fatuously claim is well understood. We don’t understand the carbon cycle, do a google search on “missing carbon sink” to see what I mean.

[WarmNPrickly]

@intention

As you can see, the real measured atmospheric concentration is very, very close to the theoretical calculation. This means that there has been no slowdown in the rate of sequestration.

Why would anyone expect a slowdown in sequestration as long as the CO2 levels are rising?

[Blake]

@SentientMeat

But we do know where the Gigatons of carbon we burn every year go. Into the atmosphere.

Right, and that is also where the gigatons of carbon released naturally every year to provoke those natural 30-60ppm rises went to. And we know that it vanished at a rate of 30-60ppm/century too.

So I’m not sure what your point is. You asked where all this anthropogenic CO2 was going to go so rapidly that the concentration won’t increase indefinitely. I simply pointed out that we know the atmosphere can and regularly does lose CO2 at rates comparable to those at which it is currently being added. We don’t know how, but we know it does.

Now that I’ve established that the cycle can “absorb” these sorts of levels without long-term increases, you seem to have gone off on another tack, but I can’t figure what exactly it is.

I honestly think that intention is doing a better job explaining this than I am. The system has a large ability to rapidly absorb atmospheric CO2 increases by sequestering the carbon elsewhere. We don’t know what the elsewhere is, but we know it exists.

But if it is a significant proportion of the carbon stores that had been sitting there for millions of years, and there is no quick way to recreate those stores, that would constitute a strong force off natural equilibrium, yes?

What natural equilibrium? We’ve already established that atmospheric CO2 levels haven’t been at equilibrium for millennia, that this perception is just a result of the smoothing effect of ice cores.

Because those self same stores were sitting there for us to find, and had been for hundreds of millions of years.

Err, yes, and? I really don’t; follow this.

But the CO2 increase is leading not lagging now, is it not?

I’m not sure what that means. Temperatures have been rising, and so have CO2 levels. How does one determine which follows which without engaging in circular reasoning about cause and effect? Insofar as CO2 levels have been unambiguously rising in a near-perfect exponential pattern exponentially since ~1600 and temperatures have been rising unambiguously only since 1900, I guess that CO2 levels have been leading. But that would seem to put the kibosh on any hypothesis that human CO2 is a significant contributor given the tiny amount emitted from 1600-1750.

Did too

No, you didn’t. But since you seem to concede that it is AGW patsies that are the first to jump on local phenomena when they are used to demonstrate global trends, we can leave it there.

I would guess forest growth and phytoplankton shell-formation, for the most part. So henceforth, if huge new forests didn’t grow, or phytoplankton didn’t dramatically ramp up their performance in this respect, I would wonder where this other mysterious saviour you speak of was going to come from, and pray for it to hurry up since I do not share your confidence/faith in its Coming.

So in other words if something for which there is shaky evidence is actually occurring, and something else which we know does occur but don’t understand, operates by the mechanisms you postulate it works by, despite having absolutely no evidence whatsoever, and if it is no longer able to operate by those mechanisms which we have no reasons to believe even exist…

Then we are in trouble.

Yes, and if the Venusians attack tomorrow we are all in deep shit. You are speculating about the worst case scenario for an event that may not even exist based on speculation about the breakdown of mechanisms which we don’t; even know exist, much less have evidence of the breakdown for.

The Venusians are every bit as credible a threat as this line of argument. At least we know Venus exists and that space travel is possible. That’s two credibility points higher than your scary story.

Rapid planet-wide fossil fuel-store formation would set my mind at rest nicely, thanks.

This is a total non sequitur. Unless of course you are proposing that the past 30-60ppm/century fluctuations were sequestered as fossil fuels. In which case it’s not a non-sequitur. It’s utterly ludicrous. A century is orders magnitude faster than the most rpidly proposed rate of fossil fuel formation. Fossil fuels simply don’t form that fast.

What?? You want the negative impacts predicted by AGW-accepters? That is quite despicable misanthropy, is it not?

No.

But your fence-sitting position seems to be immoveable by evidence, since you can always explain record temperatures and CO2 concentrations by shrugging your shoulders and saying “Ah, but it might all be natural”.

That’s what we call science. In science we don’t proclaim a hypothesis supported until we can differentiate it from natural events. That’s; what that 0.05 probability level is all in aid of. It’s designed specifically to allow us to say that the event isn’t natural and is the result of the treatment.

You’re certainly not insulting a scientist by saying that he wants to remain uncommitted and skeptical about your hypothesis until you can distinguish the treatment from natural events.

“Highly likely” is often as good as it gets in science, as you well know.

No, that isn’t true, and no I don’t know any such thing. If you can’t put a number on it, it isn’t science.

I simply don’t see how you can’t consider it highly likely that human activities have contributed significantly, if not overwhelmingly, to the CO2 increase since the Industrial Revolution. Same Facts, Different Views?

The total inability of the hypothesis’ defenders to separate the natural exponential increase observed since 1600 form the supposed increase since the industrial revolution.

I don’t see how anyone even looking at the Law Dome data could not see that CO2 concentrations have been rising in a nearly perfect exponential curve since 1600.

If he’s made of straw, that’s probably a good idea.

Dude, an analogy is not a strawman. A strawman is an attack on a caricature of your poisition. Nobody in their right mind thought that my analogy was a position that you actually held, nor did I attack that position. In fact I recommended it. That’s how you can tell it is an analogy.

Now would you care to address the obvious inconsistency ion your position highlighted by my analogy? If we should take irreversible action and remove rights based upon our potential inability to explain our lack of action to children, why shouldn’t you blow the stranger’s head off.

And the irreversible acts AGW-accepters propose are … ?

The one’s that have already been enacted include removing people’s rights to grow food on their own land and removal of their ability to spend their own income as they see fit.

Surely, if temperatures and/or CO2 drop due to some natural Saviour, we can just return to belching out the Gigatons?

And how are we going to compensate people for the billions of dollars, plus interest, plus loss of enjoyment, plus pain and suffering that all this has cost? Are you personally setting up the trust fund against such a day?
If you aren’t then don’t pretend this is in any way reversible.

[Blake]

@WarmNPrickly

Why would anyone expect a slowdown in sequestration as long as the CO2 levels are rising?

@SentientMeat

I cannot see how soils and trees, in particular, can possibly sequester much more than they are already, especially given the desertification and deforestation processes which continue apace in so many important sequestering regions. I don’t know about limestone, but phytoplankton also surely don’t have a capacity much beyond their current capacity either, otherwise they’d simply work at that capacity instead of seeing the ocean around them fill with CO2 and acidify.

So perhaps a different graph might be useful for us here, in addition to that of CO2 concentration. Can you plot from your data, or find elsewhere (I’ll look too, and maybe jshore could help us out), a graph of annual sequestration?

That’s why.

Of course it’s based on a boatload of fallacies and misunderstanding of the facts.
Firstly it’s based upon assumptions that we have any clue at all what this carbon sink is. We don;t.

It’s also based upon an assumption of deforestation, when in fact global forest cover is stable and is expected to nearly double within the next century. Moreover the number of actual trees and the basal area and hence biomass may well have been increasing for the last 200 years and looks likely to continue.

There’s just way to many assumptions and misunderstanding of the facts to give this particular objection any serious consideration.

Venusians are honestly more plausible and have a more concrete factual basis.

[SentientMeat]

@intention

SentientMeat, I greatly appreciate your reasonable approach to all of this. I did the research on this question a few years ago, and there’s a graph on my website from that time showing what you asked for.

The graph shows the increase in total cumulative CO2 emitted (blue line), the increase in the cumulative amount sequestered (orange line), and the increase in the atmospheric content (red line).

It also shows the theoretical calculated atmospheric content assuming exponential decay with an e-folding time of around 38 years (green line).

As you can see, the real measured atmospheric concentration is very, very close to the theoretical calculation. This means that there has been no slowdown in the rate of sequestration.

But the red atmospheric concentration line is going up and up! This graph demonstrates my concerns exactly! The blue line is steeper than the orange one.

This thread is all about prediction – specifically, the predicted course of the red line. We both seem to agree that, absent a worldwide push for low-emission technology, the blue total emissions line will continue its straight course (or, if China and India make emissions grow further, bend slightly towards the vertical). But our agreement diverges utterly on the future course of the orange line: How can you be so sure that it will even continue its current course indefinitely, given desertification, deforestation and ocean acidification?

Finally, atmospheric CO2 levels have been much higher in the geological past. Since sequestration rates are a function of atmospheric CO2 levels, it seems obvious that the globe can sequester much, much more CO2 than it is currently sequestering.

Yes, when it is almost literally covered in forests, and conditions are such that phytoplankton capture carbon at their optimum rate. Again, if the globe can sequester at a rate fast enough to prevent the red line heading upwards, why isn’t it?

Where will it all go? Well, we don’t know …

Neither do I. That’s why I’m concerned.

@Blake

Now that I’ve established that the cycle can “absorb” these sorts of levels without long-term increases, you seem to have gone off on another tack, but I can’t figure what exactly it is.

I honestly think that intention is doing a better job explaining this than I am. The system has a large ability to rapidly absorb atmospheric CO2 increases by sequestering the carbon elsewhere. We don’t know what the elsewhere is, but we know it exists.

Well, I don’t understand his reluctance to talk about the actual sequestration mechanisms either, and his faith in the mysterious non-soil, non-forest, non-phytoplankton sequestration Saviour seems every bit as devout as yours. Must I simply Believe, despite the lush, forest-covered world in which the Saviour Mechanism operated, where hundreds of Gigatons of hydrocarbons sat undisturbed, clearly being very different to our own?

Err, yes, and? I really don’t; follow this.

You asked how I knew that a natural mechanism didn’t release these huge underground carbon stores into the atmosphere – I must say, I found the question a little strange too.

I’m not sure what that means.

The CO2 concentration has increased 35%, but there has not yet been a similarly dramatic temperature rise. You said “We simply don’t know what drove these rapid shifts in atmospheric CO2 levels, except that they seem to be caused by an increase in temperature, or at least they followed increases in temperature.” This means that whatever is happening now is different to those past CO2 rises in this respect. I’m saying that’s because, this time, humans have dug up Gigatons of buried stores and burned them. That you find this so unreasonable a suggestion is mystifying.

No, you didn’t.

Well, my quote says what it says. And I admitted that both sides are guilty of premature jumps. Which side one considers most guilty is clearly affected by who you’re exposed to, and Deniers do regularly pull some impressive legerdemain in my experience but I’ll leave you the final tu quoque on this point.

So in other words if something for which there is shaky evidence is actually occurring, and something else which we know does occur but don’t understand, operates by the mechanisms you postulate it works by, despite having absolutely no evidence whatsoever, and if it is no longer able to operate by those mechanisms which we have no reasons to believe even exist…

So, just to clarify, you’re suggesting that soil, forest and phytoplankton based sequestration mechanisms might be nonexistent?? It’s one thing to Believe in a Saviour, but this looks like Berekely’s attempt to deny the existence of the world.

It’s utterly ludicrous … Fossil fuels simply don’t form that fast.

Precisely! That’s why I’m concerned that we’ve burned so much of them so quickly.

No.

No, wanting AGW-accepter’s predictions to come true isn’t misanthropic?

In science we don’t proclaim a hypothesis supported until we can differentiate it from natural events … If you can’t put a number on it, it isn’t science.

But there is a number: 500 Gigatons. Now, that number, which is arrived at by essentially knowing how much CO2 is given off by burning a ton of hydrocarbons or clearing an acre of forest and scaling up, might not be precisely correct. But for human activity not to be a significant contribution to current CO2 levels would require such gross overestimation on the part of such “accountants” to constitute outright lies, would it not?

The total inability of the hypothesis’ defenders to separate the natural exponential increase observed since 1600 form the supposed increase since the industrial revolution.

I don’t see how anyone even looking at the Law Dome data could not see that CO2 concentrations have been rising in a nearly perfect exponential curve since 1600.

But that rising curve could surely have a significant anthropogenic component increasing the steepness of the exponential curve, could it not?

Now would you care to address the obvious inconsistency ion your position highlighted by my analogy? If we should take irreversible action and remove rights based upon our potential inability to explain our lack of action to children, why shouldn’t you blow the stranger’s head off.

If the stranger could grow another head perfectly easily, indeed in a way which encouraged technological innovation and resource-independence, let’s fire away. Yes, perhaps “strawman” was an inaccurate description of your analogy. “Fucking stupid” is probably better.

The one’s that have already been enacted include removing people’s rights to grow food on their own land and removal of their ability to spend their own income as they see fit … And how are we going to compensate people for the billions of dollars, plus interest, plus loss of enjoyment, plus pain and suffering that all this has cost?

Your hysterical doom-mongering over such a complex, dynamic and poorly-understood system as the global economy is merely the attention-seeking alarmism du jour. Relax, it’ll all be fine.

[SentientMeat]

@WarmNPrickly

Why would anyone expect a slowdown in sequestration as long as the CO2 levels are rising?

Because the actual sequestering mechanisms seem, to me at least, to be near capacity already. For example, "the world’s forests have shrunk by some 40 percent since agriculture began 11,000 years ago. " (citation).

Soil is another, since “desertification claims a Nebraska-sized area of productive capacity each year globally” (citation).

And the increased acidity of the oceans due to dissolved CO2 provides anothe example of how natural carbon-capture mechanisms might be retarded: “Future changes in ocean chemistry, resulting from enhanced atmospheric CO2, specifically the likely reduction in the concentration of carbonate ions, will make it more difficult for animals to produce hard structures such as carbonate skeletons and shells. The evidence available suggests that this will probably adversely affect most of these organisms … many coastal animals and specific groups of phytoplankton and zooplankton will be affected.” (citation, p.39)
Of course, I hope that the mysterious natural Saviour mechanism that intention and Blake have faith in will kick in any time now and start taking vastly greater amounts of CO2 from the atmosphere than is currently happening, such that the CO2 graph will level out. But if there is no such Coming, we will all feel as foolish as one who burns his entire fortune in a year because he believes the Rapture is on the way.

[ralph124c]

Japan has acknowledged that instead of a 7% CO2 reduction (in 10 years), its emissions have risen instead.
This leads me to ask: if we really want to limit CO2 production, why don’t we expand our nuclear power output, and help China and India build reactors?It is clear that there is no international will to cut back the use of fossil fuels, why not do the on thing that would really reduce emissions?

[SentientMeat]

@intention

We don’t understand the carbon cycle, do a google search on “missing carbon sink” to see what I mean.

Strangely enough, when I do this I actually get more articles claiming to have solved the mystery than articles claiming its spooky intractability.

This report in Nature is pretty typical, suggesting that tropical forests absorb more CO2 than previously thought. (These, of course, being the self same tropical forests that are disappearing at a rate of a football field per second.)

I’m happy to accept that the details of the carbon cycle are obscure, but to suggest that forests, plankton and the like are insignificant compared to some Invisible Sink of Uniform sequestration rate sounds truly mystical.

Again, I want to be convinced, but I’m seeing only faith and spookiness. Please help.

[intention]

Thanks for your comments, SentientMeat. I see I have not been understood. Not the first time, clarity in these matters is hard to achieve.

@SentientMeat

[QUOTE=intention]

SentientMeat, I greatly appreciate your reasonable approach to all of this. I did the research on this question a few years ago, and there’s a graph on my website from that time showing what you asked for.

The graph shows the increase in total cumulative CO2 emitted (blue line), the increase in the cumulative amount sequestered (orange line), and the increase in the atmospheric content (red line).

It also shows the theoretical calculated atmospheric content assuming exponential decay with an e-folding time of around 38 years (green line).

As you can see, the real measured atmospheric concentration is very, very close to the theoretical calculation. This means that there has been no slowdown in the rate of sequestration.

But the red atmospheric concentration line is going up and up! This graph demonstrates my concerns exactly! The blue line is steeper than the orange one.
[/quote]

Whoa, whoa. You asked me for a graph showing the steady course of the sequestration. You said you want to be convinced that the sequestration rate is not changing. I show it, and now you want to talk about something else?

[QUOTE=SentientMeat]
This thread is all about prediction – specifically, the predicted course of the red line. We both seem to agree that, absent a worldwide push for low-emission technology, the blue total emissions line will continue its straight course (or, if China and India make emissions grow further, bend slightly towards the vertical). But our agreement diverges utterly on the future course of the orange line: How can you be so sure that it will even continue its current course indefinitely, given desertification, deforestation and ocean acidification?
[/QUOTE]

Well, yes, desertification, deforestation and ocean acidification, those have been happening in spades over the last century … but as the graph shows, that hasn’t affected the sequestration rate in the slightest. I repeat: there is no historical change in the sequestration rate. Deserts increased, and trees were cut down, but there was no change in sequestration rate. Go figure …

When there is a change, we’ll have something to talk about. Until then … well, your theory about deforestation and desertification affecting the sequestration rate is totally contradicted by the historical evidence. Those things have happened, and the sequestration rate hasn’t changed.

[QUOTE=SentientMeat]

[QUOTE=intention]
Finally, atmospheric CO2 levels have been much higher in the geological past. Since sequestration rates are a function of atmospheric CO2 levels, it seems obvious that the globe can sequester much, much more CO2 than it is currently sequestering.
[/QUOTE]

Yes, when it is almost literally covered in forests, and conditions are such that phytoplankton capture carbon at their optimum rate. Again, if the globe can sequester at a rate fast enough to prevent the red line heading upwards, why isn’t it?
[/QUOTE]

Point me somewhere that I ever said that if the emissions continue to increase, the atmospheric content will not continue to increase. That’s a straw man. This is the nature of “exponential decay”. Until emissions level off, atmospheric CO2 (the red line) will continue to rise … and so will the sequestration rate. However, the exponential decay is a function of atmospheric CO2 concentration, so it will not stop the increase, only slow it down, until emissions level off. The fact that the earth can sequester much more CO2 than at present doesn’t set the current sequestration rate. That’s set by the atmospheric CO2 level, not by the size of the sinks.

[QUOTE=SentientMeat]

[QUOTE=intention]
Where will it all go? Well, we don’t know …
[/QUOTE]

Neither do I. That’s why I’m concerned.
[/QUOTE]

If you wish to be concerned about all of the things we don’t know in climate science, you’ll spend all of your time worried. We don’t know if the earth has a thermostat. We don’t know how much CO2 is sequestered by plankton. We don’t know where the sequestered CO2 goes now, much less where it will go tomorrow. We don’t know when the PDO will next swing to the warm phase, or when the next El Niño will hit. We don’t know the climate sensitivity, and thirty years of modeling have not significantly improved our estimates of climate sensitivity. I could go on and on, the list is huge. Worry about that all you want … I’ll pass, I’ve spent much of my life working in third world villages. I worry about real threats, and we have plenty of them already. We have every predicted climate disaster already: floods, and droughts, and sea level rising, and diseases, and all the rest of what the AGW supporters are constantly warning us about.

You want me to worry about the damage from a predicted increase in these that may possibly happen in fifty years?.

Thanks, I’ll pass. I worry about the damage these are doing today.

Money is always short. We have limited resources to do anything about the damage done by weather in all of its forms, today or next century. For me, a dollar spent on CO2 in the hopes of a possible 0.1°C cooling in fifty years would be far, far better spent training African farmers to improve their farming practices so they can fight the droughts and floods today. That will make a difference whether the world warms or not. You can sit in the western world, cozily insulated from those things, and be concerned, and propose fanciful expenditures to fight imagined disasters a half century away.

Call me crazy, but I’d rather spend that money to help people fight those same identical disasters today.

[SentientMeat]

intention, this thread has had precisely the effect I hoped for. You see, I now struggle to see where we disagree!

@intention

Whoa, whoa. You asked me for a graph showing the steady course of the sequestration. You said you want to be convinced that the sequestration rate is not changing. I show it, and now you want to talk about something else?

No, look at precisely what I said, especially the bolded part:

@SentientMeat

If over the next decade [the graph] looks like it’s levelling off, your assumption of an ever-growing “hole” would be shot down. If it stays roughly straight, then if we continue to emit 8 GtC per year we will reach CO2 concentrations of 600, 700, 800+ ppmv. The only way your prediction of a sub-800ppmv level-off for continued 8 GtCpa emissions would come to pass is if the sequestration rate increased exponentially while the emission rate stayed constant. Agreed?

On the graph you provided, both total emissions and total sequestration follow a straight line, but the total emissions line is steeper, clearly indicating a continued rise in CO2 concentration.

This is not a change of subject or emphasis on my part – look at the thread title, for crying out loud. At post 59 you then say

@intention

if we were able to magically freeze the level of added CO2 to the current level (we currently add about 7 gigatonnes of C to the atmosphere annually), the atmospheric level would not continue to rise indefinitely … For example, if we maintain emissions at the current levels we’d eventually burn all the carbon stores … but the level would never come close to 800 ppmv.

…yet your graph is telling me that it will, since even if the orange line keeps its course it is not steep enough to catch the blue line. You then repeat that “The point is that if we maintain emissions at current levels, at some point (around 450 - 500 ppmv) the amount sequestered will equal the amount emitted.” Again, I cannot see how the blue and orange lines meet like this without a change of course in one of them.

And it is this point that I have been making repeatedly throughout the thread:

@SentientMeat

We are, surely, depleting the sequestered stores at a much faster rate than new stores can form?

I simply don’t see what mechanism causes a level-off below 800 ppmv if carry on as we are, since all the natural sequestration mechanisms I know of simply don’t work fast enough

That [equilibrium] will only happen if the sequestration mechanisms ramp up their performance to overtake our vast depletion of sequestered stores. I see no evidence of that happening, nor any reason why it should happen.

Have we any reason to think it [the sequestration rate] will increase massively?

But those 4%'s per year keep adding up - the vessel keeps filling up. That is why CO2 concentrations are 35% higher than they used to be, and why (barring your natural Saviour) the concentration will be 100% greater, ie doubled, sometime next century without massive global efforts to switch to low-emission technology.

But to stop these annual “profits” adding up, the sequestration rate must increase considerably, agreed?

I see how, after peak CO2, the concentration will come down quicker than I thought. I cannot see how the sequestration rate will increase fast enough to stop that peak being reached in the first place.

I still do not understand your answer to these questions. Again, this is not “something else” I want to talk about, it is precisely what I have been talking about all along. Please, have patience and explain it again: How can the red line in your graph not increase to 500+ ppmv if the blue line remains steeper than the orange line?

@intention

as the graph shows, that hasn’t affected the sequestration rate in the slightest. I repeat: there is no historical change in the sequestration rate. Deserts increased, and trees were cut down, but there was no change in sequestration rate. Go figure …

When there is a change, we’ll have something to talk about. Until then … well, your theory about deforestation and desertification affecting the sequestration rate is totally contradicted by the historical evidence. Those things have happened, and the sequestration rate hasn’t changed.

Well then, I’m glad to be wrong so far, so thanks for that welcome insight. However, you’ll note in my OP that my intended focus here was prediction, not historical correlation. And even if the rate doesn’t decrease, ie. the orange line continues straight, that is still not enough to prevent CO2 concentrations rising dramatically. The orange line would have to bend towards the vertical to prevent a 500+ ppmv level-off, and I don’t see how anyone can seriously make such a prediction.

Point me somewhere that I ever said that if the emissions continue to increase, the atmospheric content will not continue to increase. That’s a straw man.

By this I assume you mean the emission rate, not just emissions period (as in the blue line of your graph). But the blue line in your graph isn’t showing an increase in rate, yet it’s still steeper than the orange line, causing the red line (atmospheric content) to increase. Again, I need you to explain how the red line won’t keep its course if the slope of the blue line remains constant (ie. the emissions rate remains constant).

If you wish to be concerned about all of the things we don’t know in climate science, you’ll spend all of your time worried. We don’t know if the earth has a thermostat. We don’t know how much CO2 is sequestered by plankton. We don’t know where the sequestered CO2 goes now, much less where it will go tomorrow. We don’t know when the PDO will next swing to the warm phase, or when the next El Niño will hit. We don’t know the climate sensitivity, and thirty years of modeling have not significantly improved our estimates of climate sensitivity. I could go on and on, the list is huge. Worry about that all you want … I’ll pass, I’ve spent much of my life working in third world villages. I worry about real threats, and we have plenty of them already. We have every predicted climate disaster already: floods, and droughts, and sea level rising, and diseases, and all the rest of what the AGW supporters are constantly warning us about.

You want me to worry about the damage from a predicted increase in these that may possibly happen in fifty years?.

Thanks, I’ll pass. I worry about the damage these are doing today.

Money is always short. We have limited resources to do anything about the damage done by weather in all of its forms, today or next century. For me, a dollar spent on CO2 in the hopes of a possible 0.1°C cooling in fifty years would be far, far better spent training African farmers to improve their farming practices so they can fight the droughts and floods today. That will make a difference whether the world warms or not. You can sit in the western world, cozily insulated from those things, and be concerned, and propose fanciful expenditures to fight imagined disasters a half century away.

Call me crazy, but I’d rather spend that money to help people fight those same identical disasters today.

You see, I agree with you almost completely in all you say here. Of course undeveloped countries find life without climate change much harder than developed countries will find life with climate change. Personally, I think a dollar spent on renewables or nuclear is a dollar invested, not squandered, such that we will be able to provide that same technology to Africa in future more cheaply as economies of scale drive production costs down, but there’s very little in those paragraphs of yours that I’d take particular issue with.

Have a quick read of the OP again, and you’ll see I’m not so far from you at all. I think high concentrations will come to pass absent a huge push for low-emission technology (ie. a rightwards bend in your blue line). I’m optimistic about the temperature rise that will cause since I’m opting for a fairly low sensitivity. I think that developed nations will bear such consequences pretty well.

If there’s one point we do disagree on, intention, it’s our level of concern for the Third World if high CO2 concentrations do bring about negative consequences. Yes, life is hard now. But my concern is that life will be much, much harder. If hindsight shows that we could have ameliorated such future suffering, I want to be able to say that at least I tried.

[SentientMeat]

Incidentally, Blake, do you still feel you’re on the same page as intention here? At the very least, his graph shows unequivocally that humans are responsible for the current CO2 concentration.

It’s tricky for me to remember which of you two holds which position, so I might post a brief summary with your premission.