RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
john gorman
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From: Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
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Stephen Salter
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
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Robert Tulip
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From:
Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative
development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
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Douglas MacMartin
Um…
1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.
2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.
3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.
4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.
5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.
Bottom line, it is completely inaccurate for you to refer to this conceptual diagram as being inaccurate or containing major errors. It is perfectly accurate to observe that none of the lines on the diagram are immutable. But given that there are no units, that’s hardly a criticism…
From: 'Robert Tulip' via geoengineering <geoengi...@googlegroups.com>
Sent: Wednesday, July 10, 2019 8:21 AM
To: geoengi...@googlegroups.com; s.sa...@ed.ac.uk
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Further to the needed corrections mentioned by John Gorman, Stephen Salter correctly points out that this diagram is inaccurate. It actually embeds a series of major myths
in climate politics. I read Benoit
Lambert's link but did not find the chart there.
Here is a revised version of the chart. It shows that every line of the previous version contains major error with strong potential to mislead decision makers and the public.
1. Full implementation of current Paris commitments (added) would only have small marginal effect on Business as usual,
2. Aggressive emission cuts do nothing about committed warming from past emissions, so do not flatline the climate effect
3. CO2 removal continues below the farcical imaginary floor of zero effect
4. Solar radiation management can produce net negative radiative forcing.
5. The BAU line (not changed here) should show ongoing exponential growth rather than the shown linear increase.
Robert Tulip
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland
S.Sa...@ed.ac.uk, Tel +44 (0)131 650 5704, Cell 07795 203 195,
WWW.homepages.ed.ac.uk/shs,
YouTube Jamie Taylor Power for Change
On 10/07/2019 09:35, john gorman wrote:
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From:
Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
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Andrew Lockley
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Robert Tulip
Response to comments from Doug MacMartin and Andrew Lockley
“1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.”
·
Sorry Doug, but you completely miss the point. Under the Paris Accord, Nationally
Determined Contributions have been made to 2030. These indicate a cut of <10% in annual
emission growth by 2030, from about 60 GTCO2e under BAU to 56.2 GT
(2016
report page 9), and still way above the current level. Including that in
the chart as I suggested would accurately reflect the marginal impact of current climate
policy. It does not in any way imply
that emission reduction could not be more than has been already agreed under
Paris, as shown with the “aggressive” line on the chart. It might ratchet up, and economic forces
might increase the cut to a still marginal 20%, but seeing the political
reaction to efforts to make energy more expensive I am not holding my breath
for more aggressive emission cuts.
“2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.”
· Firstly, the line was not about “net zero emissions” (which include CDR) but about emission reduction alone, so your “balancing” argument is not relevant to what the graph asserts. Further to that, I would like to see the source for your argument about balancing. Recent commentary I have read (eg from Kevin Lister) says the amplifying feedbacks from committed warming, seen in events such as the melting of the poles and burning of forests, mean that aggressive emission reduction alone cannot possibly cause the planetary temperature to flatline as you argue here. Given the sensitivity to initial conditions seen in the orbital drivers of long term climate, your hypothesis of balancing by residual drawdown looks highly unlikely and risky when we leave in place a massive driver of 700 GT of extra carbon in the air with no CDR.
“3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.”
· No, the choice of where to stop the line on CDR climate effect is far from obvious. There is a widespread false assumption in much climate literature, including from IPCC, that net zero emissions constitutes a hard floor. This assumption is reflected in how the original diagram shows a flattening as CDR effect approaches net zero climate effect. Showing CDR effect extending below zero on the Y axis reflects the need to work out how to remove enough carbon to get back to 280 ppm, to restore Holocene planetary stability. Assuming the X time axis is linear here means that CDR objective requires the line going well below the zero point on the Y effect axis. The misleading effect of the portrayal in the original diagram is to increase the imagined benefit of emission reduction and reduce the potential effect of carbon removal.
“4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.”
· But the problem is that the diagram falsely maximises the effect of currently promoted policies around decarbonisation while minimising the potential of geoengineering. That policy bias is reflected in this assertion in the diagram that SRM could not reduce climate effect.
“5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.”
· The difference between exponential and linear effects under BAU is minor, even though an exponential line showing amplified feedback would better emphasise the catastrophic risk. Happy to focus on the other lines which appear to have major politically inspired material errors.
On Andrew Lockley’s comments, Shepherd’s
Napkin Diagram shows a rough sketch that I would have hoped could have been
made more accurate over the decade since it was published. Unfortunately, it looks like the updated
version of the Shepherd diagram reflects the ongoing domination of politics
over science within climate advocacy, so it has not been properly revised to
reflect accurate scientific information.
Robert Tulip
Um…
1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.
2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.
3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.
4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.
5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.
Bottom line, it is completely inaccurate for you to refer to this conceptual diagram as being inaccurate or containing major errors. It is perfectly accurate to observe that none of the lines on the diagram are immutable. But given that there are no units, that’s hardly a criticism…
From: 'Robert Tulip' via geoengineering <geoengi...@googlegroups.com>
Sent: Wednesday, July 10, 2019 8:21 AM
To: geoengi...@googlegroups.com; s.sa...@ed.ac.uk
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Further to the needed corrections mentioned by John Gorman, Stephen Salter correctly points out that this diagram is inaccurate. It actually embeds a series of major myths in climate politics. I read
Benoit Lambert's link but did not find the chart there.
Here is a revised version of the chart. It shows that every line of the previous version contains major error with strong potential to mislead decision makers and the public.
1. Full implementation of current Paris commitments (added) would only have small marginal effect on Business as usual,
2. Aggressive emission cuts do nothing about committed warming from past emissions, so do not flatline the climate effect
3. CO2 removal continues below the farcical imaginary floor of zero effect
4. Solar radiation management can produce net negative radiative forcing.
5. The BAU line (not changed here) should show ongoing exponential growth rather than the shown linear increase.
Robert Tulip
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland S.Sa...@ed.ac.uk, Tel +44 (0)131 650 5704, Cell 07795 203 195,
WWW.homepages.ed.ac.uk/shs, YouTube Jamie Taylor Power for Change
On 10/07/2019 09:35, john gorman wrote:
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From: Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
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Douglas MacMartin
1. So agree with you that if you want to accurately characterize the Paris agreement on this plot, the line should corresponding to that should only go to 2030 and then stop. That is, not what you drew. Also agree that I was wrong in my interpretation of what you meant by that line; I was misled by the fact that you’d continued the line out towards the right-hand end of the plot rather than ending it in 2030 like you intended.
2. Agree that there is uncertainty associated with this, and uncertainty associated with nonlinearity in particular. I generally go back to Cao and Caldeira 2010, https://iopscience.iop.org/article/10.1088/1748-9326/5/2/024011/pdf, simply because Figure 1 has the nicest plot of the effect, but UVic is admittedly an old model with a lot missing and a questionable carbon cycle… but there is quite a bit of content on this in IPCC reports that would be good to digest before ignoring (that is, broadly the same behaviour is seen in current models, though again, I agree that there is potentially important physics missing from those models). But people (well, mostly John Nissen) keep making the argument you’re making on the assumption that zero emissions = constant concentrations, which is simply not true.
3. I think we agree that the choice is non-obvious, but I personally don’t think it is likely that <280ppm is going to be optimal, so I still don’t think it is particularly disingenuous to draw the line as it was. (Besides, the axis was climate effects, presumably relative to some baseline, and if that baseline is preindustrial, then going below 280ppm is likely to increase climate damages in the opposite direction… but agree that I don’t know that, and that it would be wonderful to ever be in a situation where that question matters.)
4. I would never use the word “assertion” with regards to a schematic figure like that… though as someone who uses (my own version) of this diagram frequently, I agree with you that when I talk about it I should be a bit more careful with regards to how I talk about where the SRM line goes.
(And yes, John’s napkin is the first I know of that diagram, I don’t know what paper that specific version came from, it looks nearly identical to the one that I typically use, but with different fonts. I think I more or less copied the version I use from one that David Keith was using, so it is hardly surprising that plenty of us have our own independent but very similar versions.)
From: Robert Tulip <rtuli...@yahoo.com.au>
Sent: Wednesday, July 10, 2019 9:35 PM
To: Douglas MacMartin <dgm...@cornell.edu>; Andrew Lockley <andrew....@gmail.com>
Cc: Stephen Salter <S.Sa...@ed.ac.uk>; geoengineering <geoengi...@googlegroups.com>
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Response to comments from Doug MacMartin and Andrew Lockley
“1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.”
·
Sorry Doug, but you completely miss the point. Under the Paris Accord,
Nationally
Determined Contributions have been made to 2030. These indicate a cut of <10% in annual emission growth by 2030, from about 60 GTCO2e under BAU to 56.2 GT
(2016
report page 9), and still way above the current level. Including that in the chart as I suggested would accurately reflect the marginal impact of current climate policy. It does not in any way imply that emission reduction could not be more than
has been already agreed under Paris, as shown with the “aggressive” line on the chart. It might ratchet up, and economic forces might increase the cut to a still marginal 20%, but seeing the political reaction to efforts to make energy more expensive I am
not holding my breath for more aggressive emission cuts.
“2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.”
· Firstly, the line was not about “net zero emissions” (which include CDR) but about emission reduction alone, so your “balancing” argument is not relevant to what the graph asserts. Further to that, I would like to see the source for your argument about balancing. Recent commentary I have read (eg from Kevin Lister) says the amplifying feedbacks from committed warming, seen in events such as the melting of the poles and burning of forests, mean that aggressive emission reduction alone cannot possibly cause the planetary temperature to flatline as you argue here. Given the sensitivity to initial conditions seen in the orbital drivers of long term climate, your hypothesis of balancing by residual drawdown looks highly unlikely and risky when we leave in place a massive driver of 700 GT of extra carbon in the air with no CDR.
“3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.”
· No, the choice of where to stop the line on CDR climate effect is far from obvious. There is a widespread false assumption in much climate literature, including from IPCC, that net zero emissions constitutes a hard floor. This assumption is reflected in how the original diagram shows a flattening as CDR effect approaches net zero climate effect. Showing CDR effect extending below zero on the Y axis reflects the need to work out how to remove enough carbon to get back to 280 ppm, to restore Holocene planetary stability. Assuming the X time axis is linear here means that CDR objective requires the line going well below the zero point on the Y effect axis. The misleading effect of the portrayal in the original diagram is to increase the imagined benefit of emission reduction and reduce the potential effect of carbon removal.
“4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.”
· But the problem is that the diagram falsely maximises the effect of currently promoted policies around decarbonisation while minimising the potential of geoengineering. That policy bias is reflected in this assertion in the diagram that SRM could not reduce climate effect.
“5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.”
· The difference between exponential and linear effects under BAU is minor, even though an exponential line showing amplified feedback would better emphasise the catastrophic risk. Happy to focus on the other lines which appear to have major politically inspired material errors.
On Andrew Lockley’s comments,
Shepherd’s
Napkin Diagram shows a rough sketch that I would have hoped could have been made more accurate over the decade since it was published. Unfortunately, it looks like the updated version of the Shepherd diagram reflects the ongoing domination of politics
over science within climate advocacy, so it has not been properly revised to reflect accurate scientific information.
Robert Tulip
To give credit where credit's due, this was originally Shepherds famous napkin diagram. The srm line has been adjusted somewhat, however. I don't think that Doug's claims regarding Paris Commitments not conceivably being exceeded is supported empirically. Swansons law suggests very steep falls in the cost of energy by mid century, perhaps low single figure percentages of current costs. It would be implausible if large-scale use of fossil fuels would continue when renewable energy was one or two orders of magnitude cheaper
On Wed, 10 Jul 2019, 17:12 Douglas MacMartin, <dgm...@cornell.edu> wrote:
Um…
1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.
2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.
3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.
4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.
5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.
Bottom line, it is completely inaccurate for you to refer to this conceptual diagram as being inaccurate or containing major errors. It is perfectly accurate to observe that none of the lines on the diagram are immutable. But given that there are no units, that’s hardly a criticism…
From: 'Robert Tulip' via geoengineering <geoengi...@googlegroups.com>
Sent: Wednesday, July 10, 2019 8:21 AM
To: geoengi...@googlegroups.com; s.sa...@ed.ac.uk
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Further to the needed corrections mentioned by John Gorman, Stephen Salter correctly points out that this diagram is inaccurate. It actually embeds a series of major myths in climate politics. I read Error! Filename not specified.
Here is a revised version of the chart. It shows that every line of the previous version contains major error with strong potential to mislead decision makers and the public.
1. Full implementation of current Paris commitments (added) would only have small marginal effect on Business as usual,
2. Aggressive emission cuts do nothing about committed warming from past emissions, so do not flatline the climate effect
3. CO2 removal continues below the farcical imaginary floor of zero effect
4. Solar radiation management can produce net negative radiative forcing.
5. The BAU line (not changed here) should show ongoing exponential growth rather than the shown linear increase.
Robert Tulip
Error! Filename not specified.
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland S.Sa...@ed.ac.uk, Tel +44 (0)131 650 5704, Cell 07795 203 195, Error! Filename not specified.
Index of /shs
On 10/07/2019 09:35, john gorman wrote:
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From: Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
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Stephen Salter
Hi All
Some of my very best friends are vegetables and they really need CO2 especially if we have to grow more of them.
Suppose that we could
put temperature patterns, ice cover and sea level back to
pre-industrial but leave cabbage-friendly amounts of CO2 just
below the shell-fish point? Does anyone have a number?
Stephen
Kevin Lister
1. The correlation between cumulative emissions and atmospheric CO2 is effectively perfect with r^2=0.999, which is quite extraordinary. This strongly implies that all the CO2 emissions from fossil fuel burning are still in the ecosystem. That obviously doesn't imply that all the CO2 from fossil fuel burning is in the atmosphere, but it does reasonably lead to the conclusion that all interconnected carbon sinks are filling equally, such as the the ocean surface, soils, and the atmosphere. Given that this perfect correlation has been unaffected by the rate of emissions, then it would further imply that the rate of permanent sequestration must been extremely slow, and effectively negligible compared to fossil fuel emissions.
2. The immediate upwards rise of atmospheric CO2 at the start of the industrial revolution further indicates that the rate of permanent CO2 sequestration is very slow. At this time emissions were a fraction of what they are today and the ecosystem was in a considerably more healthy state.
3. The saw tooth profile of the Vostok Ice Core shows the rate of permanent carbon sequestration to be slow and averaged over the last 4 inter-glacial cycles it is around 6.7E-4ppm/year, which is negligible compared with the rate of increase.
4. Even if zero carbon led to CO2 concentration reductions, the cooling effect would be too small due to the logarithmic relation between forcing and concentration.
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Hawkins, David
Hi Doug et al,
On point 2 below, "But people (well, mostly John Nissen) keep making the argument you’re making on the assumption that zero emissions = constant concentrations, which is simply not true."
Let me come to John's defence.
1. The correlation between cumulative emissions and atmospheric CO2 is effectively perfect with r^2=0.999, which is quite extraordinary. This strongly implies that all the CO2 emissions from fossil fuel burning are still in the ecosystem. That obviously doesn't imply that all the CO2 from fossil fuel burning is in the atmosphere, but it does reasonably lead to the conclusion that all interconnected carbon sinks are filling equally, such as the the ocean surface, soils, and the atmosphere. Given that this perfect correlation has been unaffected by the rate of emissions, then it would further imply that the rate of permanent sequestration must been extremely slow, and effectively negligible compared to fossil fuel emissions.
2. The immediate upwards rise of atmospheric CO2 at the start of the industrial revolution further indicates that the rate of permanent CO2 sequestration is very slow. At this time emissions were a fraction of what they are today and the ecosystem was in a considerably more healthy state.
3. The saw tooth profile of the Vostok Ice Core shows the rate of permanent carbon sequestration to be slow and averaged over the last 4 inter-glacial cycles it is around 6.7E-4ppm/year, which is negligible compared with the rate of increase.
4. Even if zero carbon led to CO2 concentration reductions, the cooling effect would be too small due to the logarithmic relation between forcing and concentration.
So the evidence would support that zero emissions=constant concentrations, at least on for any timescale that matters, The things that matter to determine the timescale are the initiation of climate tipping points and points of irreversibly, beyond which climate and ecosystem recovery becomes impossible even with SRM interventions. We have certainly past the points of initiation of tipping points, and will soon be past the points of irreversibly.
So it seems to me that from a pragmatic risk management perspective, we should assume that zero carbon=constant emissions, and plan accordingly, which means identifying interventions in the climate system that can lead to cooling and CDR, as well as forcing much deeper cuts in anthropocentric emissions.
Kevin
On Thu, Jul 11, 2019 at 11:22 AM Douglas MacMartin <dgm...@cornell.edu> wrote:
1. So agree with you that if you want to accurately characterize the Paris agreement on this plot, the line should corresponding to that should only go to 2030 and then stop. That is, not what you drew. Also agree that I was wrong in my interpretation of what you meant by that line; I was misled by the fact that you’d continued the line out towards the right-hand end of the plot rather than ending it in 2030 like you intended.
2. Agree that there is uncertainty associated with this, and uncertainty associated with nonlinearity in particular. I generally go back to Cao and Caldeira 2010, https://iopscience.iop.org/article/10.1088/1748-9326/5/2/024011/pdf, simply because Figure 1 has the nicest plot of the effect, but UVic is admittedly an old model with a lot missing and a questionable carbon cycle… but there is quite a bit of content on this in IPCC reports that would be good to digest before ignoring (that is, broadly the same behaviour is seen in current models, though again, I agree that there is potentially important physics missing from those models). But people (well, mostly John Nissen) keep making the argument you’re making on the assumption that zero emissions = constant concentrations, which is simply not true.
3. I think we agree that the choice is non-obvious, but I personally don’t think it is likely that <280ppm is going to be optimal, so I still don’t think it is particularly disingenuous to draw the line as it was. (Besides, the axis was climate effects, presumably relative to some baseline, and if that baseline is preindustrial, then going below 280ppm is likely to increase climate damages in the opposite direction… but agree that I don’t know that, and that it would be wonderful to ever be in a situation where that question matters.)
4. I would never use the word “assertion” with regards to a schematic figure like that… though as someone who uses (my own version) of this diagram frequently, I agree with you that when I talk about it I should be a bit more careful with regards to how I talk about where the SRM line goes.
(And yes, John’s napkin is the first I know of that diagram, I don’t know what paper that specific version came from, it looks nearly identical to the one that I typically use, but with different fonts. I think I more or less copied the version I use from one that David Keith was using, so it is hardly surprising that plenty of us have our own independent but very similar versions.)
From: Robert Tulip <rtuli...@yahoo.com.au>
Sent: Wednesday, July 10, 2019 9:35 PM
To: Douglas MacMartin <dgm...@cornell.edu>; Andrew Lockley <andrew....@gmail.com>
Cc: Stephen Salter <S.Sa...@ed.ac.uk>; geoengineering <geoengi...@googlegroups.com>
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Response to comments from Doug MacMartin and Andrew Lockley
“1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.”
· Sorry Doug, but you completely miss the point. Under the Paris Accord, <~WRD147.jpg>Nationally Determined Contributions have been made to 2030. These indicate a cut of <10% in annual emission growth by 2030, from about 60 GTCO2e under BAU to 56.2 GT <~WRD147.jpg>(2016 report page 9), and still way above the current level. Including that in the chart as I suggested would accurately reflect the marginal impact of current climate policy. It does not in any way imply that emission reduction could not be more than has been already agreed under Paris, as shown with the “aggressive” line on the chart. It might ratchet up, and economic forces might increase the cut to a still marginal 20%, but seeing the political reaction to efforts to make energy more expensive I am not holding my breath for more aggressive emission cuts.
“2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.”
· Firstly, the line was not about “net zero emissions” (which include CDR) but about emission reduction alone, so your “balancing” argument is not relevant to what the graph asserts. Further to that, I would like to see the source for your argument about balancing. Recent commentary I have read (eg from Kevin Lister) says the amplifying feedbacks from committed warming, seen in events such as the melting of the poles and burning of forests, mean that aggressive emission reduction alone cannot possibly cause the planetary temperature to flatline as you argue here. Given the sensitivity to initial conditions seen in the orbital drivers of long term climate, your hypothesis of balancing by residual drawdown looks highly unlikely and risky when we leave in place a massive driver of 700 GT of extra carbon in the air with no CDR.
“3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.”
· No, the choice of where to stop the line on CDR climate effect is far from obvious. There is a widespread false assumption in much climate literature, including from IPCC, that net zero emissions constitutes a hard floor. This assumption is reflected in how the original diagram shows a flattening as CDR effect approaches net zero climate effect. Showing CDR effect extending below zero on the Y axis reflects the need to work out how to remove enough carbon to get back to 280 ppm, to restore Holocene planetary stability. Assuming the X time axis is linear here means that CDR objective requires the line going well below the zero point on the Y effect axis. The misleading effect of the portrayal in the original diagram is to increase the imagined benefit of emission reduction and reduce the potential effect of carbon removal.
“4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.”
· But the problem is that the diagram falsely maximises the effect of currently promoted policies around decarbonisation while minimising the potential of geoengineering. That policy bias is reflected in this assertion in the diagram that SRM could not reduce climate effect.
“5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.”
· The difference between exponential and linear effects under BAU is minor, even though an exponential line showing amplified feedback would better emphasise the catastrophic risk. Happy to focus on the other lines which appear to have major politically inspired material errors.
On Andrew Lockley’s comments, <~WRD147.jpg>Shepherd’s Napkin Diagram shows a rough sketch that I would have hoped could have been made more accurate over the decade since it was published. Unfortunately, it looks like the updated version of the Shepherd diagram reflects the ongoing domination of politics over science within climate advocacy, so it has not been properly revised to reflect accurate scientific information.
Robert Tulip
To give credit where credit's due, this was originally Shepherds famous napkin diagram. The srm line has been adjusted somewhat, however. I don't think that Doug's claims regarding Paris Commitments not conceivably being exceeded is supported empirically. Swansons law suggests very steep falls in the cost of energy by mid century, perhaps low single figure percentages of current costs. It would be implausible if large-scale use of fossil fuels would continue when renewable energy was one or two orders of magnitude cheaper
On Wed, 10 Jul 2019, 17:12 Douglas MacMartin, <dgm...@cornell.edu> wrote:
Um…
1. Given that the Paris agreement commitments don’t actually tell you what’s going to happen towards even the middle of the century, drawing any line corresponding to those commitments is a guess, but regardless, it seems pretty remarkable to assert that no-one will *ever* cut emissions beyond what was agreed upon in Paris – that’s your hypothesis, and doesn’t reflect an “inaccurate” diagram.
2. Mostly wrong… actually, if net emissions are zero, then once you’ve paid the price for removing tropospheric aerosol cooling, the residual committed warming is mostly balanced by the residual drawdown of CO2… obviously not going to be exact, and depends a lot on whether there are nonlinear tipping points, but zero emissions is NOT the same thing as constant-concentration commitment, so to first order the original diagram is more accurate than your amended one.
3. The version of this that John posted has CDR continuing all the way down towards zero but not below it, your version goes below zero effects, so I’m not clear on what your point is here… Obvoiusly, that’s ultimately a choice where one stops.
4. Sure… again, that’s a choice, that doesn’t reflect an inaccurate diagram, simply that the diagram doesn’t show the full range of possible policy options.
5. Well, unclear given that there are no units or scales on the qualitative y-axis. Though RCP8.5, which is generally what people think of as BAU, does indeed result in roughly linear increase in temperature over time. Of course, the relationship between “effects” and temperature aren’t clear.
Bottom line, it is completely inaccurate for you to refer to this conceptual diagram as being inaccurate or containing major errors. It is perfectly accurate to observe that none of the lines on the diagram are immutable. But given that there are no units, that’s hardly a criticism…
From: 'Robert Tulip' via geoengineering <geoengi...@googlegroups.com>
Sent: Wednesday, July 10, 2019 8:21 AM
To: geoengi...@googlegroups.com; s.sa...@ed.ac.uk
Subject: Re: [geo] RE: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Further to the needed corrections mentioned by John Gorman, Stephen Salter correctly points out that this diagram is inaccurate. It actually embeds a series of major myths in climate politics. I read Error! Filename not specified.<~WRD147.jpg>Benoit Lambert's link but did not find the chart there.
Here is a revised version of the chart. It shows that every line of the previous version contains major error with strong potential to mislead decision makers and the public.
1. Full implementation of current Paris commitments (added) would only have small marginal effect on Business as usual,
2. Aggressive emission cuts do nothing about committed warming from past emissions, so do not flatline the climate effect
3. CO2 removal continues below the farcical imaginary floor of zero effect
4. Solar radiation management can produce net negative radiative forcing.
5. The BAU line (not changed here) should show ongoing exponential growth rather than the shown linear increase.
Robert Tulip
Error! Filename not specified.
Hi All
Zero emissions do not immediately mean zero temperature rises, especially if we have passed tipping points.
Stephen
Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland S.Sa...@ed.ac.uk, Tel +44 (0)131 650 5704, Cell 07795 203 195, Error! Filename not specified.<~WRD147.jpg>WWW.homepages.ed.ac.uk/shs, YouTube Jamie Taylor Power for Change
<~WRD147.jpg>
Index of /shs
On 10/07/2019 09:35, john gorman wrote:
This diagram from the paper says it all in my opinion, and simply!!
With, of course some variation in angles. Eg SRM could be angled down and I don’t believe cutting emissions will ever result in zero emissions.
Good realistic paper!
John gorman
From: Benoit Lambert
Sent: 09 July 2019 18:39
To: Carbon Dioxide Removal
Subject: [CDR] blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
blog 28, Elon Musk vs regenerative development // Elon Musk vs le développement de régénération
Error! Filename not specified.<~WRD147.jpg>https://cologie.wordpress.com/2019/07/09/elon-musk-vs-regenerative-development-elon-musk-vs-le-developpement-de-regeneration-french-below-en-francais-plus-bas/
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Douglas MacMartin
Just to point out (in response to Kevin, and agreeing with David) that
1) We know, for example, that the surface ocean and biosphere have already absorbed about 50% of the CO2 that we’ve emitted, so you certainly can’t argue that the amount of permanent CO2 sequestration by the rest of the climate system is negligible – it’s unquestionably an enormous effect.
2) There are a wide range of timescales for both the climate warming to a given radiative forcing, and for the uptake of CO2. For both of those, if you vary the input slowly, the output roughly tracks the input. So observing that if I put some slowly-varying signal u(t) into a system that the output y(t) is roughly proportional doesn’t tell me whether y(t) is in equilibrium with u(t) or not. I could take Kevin’s arguments to *also* assert that the evidence is that there is no significant residual committed warming. (Aside from point #4, which I don’t follow why the logarithmic dependence matters; you can always linearize that about the current point if you want, and you’ll find a non-zero slope, definitely not a zero slope.)
If we abruptly cease emissions today, then
a) We lose the cooling from tropospheric aerosols (IPCC SR1.5 put that at 0.3C, but I’ve seen estimates as high as 1.2C, it’s uncertain)
b) The climate warms because the oceans (mainly) aren’t in equilibrium with the current forcing from increased CO2 (etc) concentrations
c) The CO2 concentrations decrease because the oceans (mainly, I think) aren’t in equilibrium with the current CO2 concentrations
d) And, also, if we stop all the rest of the SLCFs (methane, etc), then we lose some of the warming from them too, fairly quickly.
I don’t follow what the evidence is that argues that (b) is so much larger than (c) that we can completely ignore (c) in making future predictions. Happy to have someone tell me otherwise, but only if they can provide some evidence for why IPCC AR5 and SR1.5 got everything so badly wrong…
And, agree with David that having not conducted the experiment, we don’t actually know, that is, regardless of what our best guesses are, we shouldn’t be gambling the future of the planet on our best guess, so agree 100% with your ultimate policy conclusion anyway.
(Also, I don’t know what the basis for asserting that we have passed tipping points, and will soon pass irreversibilities. The latter we might well have already passed some, I don’t think we really know, and for the former I’ve seen the term tipping point used in so many ways that I no longer have any clue what people mean by it.)