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On Feb 14, 2023, at 8:00 PM, 'Doug Grandt' via Healthy Planet Action Coalition (HPAC) <healthy-planet-...@googlegroups.com> wrote:
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On Feb 14, 2023, at 8:30 PM, James Hansen <jimeh...@gmail.com> wrote:
Not yet -- first will submit revised Pipeline paper soon -- clearer with some additional insight, IMHO, and hopefully more forthright w/o losing any co-author or reviewer - will be no holds barred in my book.Jim Hansen
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--Columbia University Earth InstituteJim Hansen, DirectorClimate Science, Awareness and Solutions Program
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On Feb 15, 2023, at 12:42 PM, H simmens <hsim...@gmail.com> wrote:
For those who may have missed Michael Mann's conversation an hour ago, there was not surprisingly little new. He did clearly and unambiguously support more research into solar geo engineering as long as it does not involve field testing. He invoked the familiar bogeymen - adverse unintended consequences, termination shock and moral hazard as reasons why it should not be deployed. He did not distinguish between SAI and other methods. To Smerconish’s credit he did bring up mount Pinatubo and Mann acknowledged that it lowered temperatures.
There was absolutely no discussion as is typical of these conversations of the relative risks and benefits of solar geoengineering versus ERA/emission reductions alone.
By the way Smerconish is one of the very few talk programs with a large base of listeners that is down the middle politically.You may be able to listen to the conversation at the link below, though you may need to be an XM subscriber. The conversation starts at 11:05 am.
Thursday 3am (AEDT)
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--Columbia University Earth InstituteJim Hansen, DirectorClimate Science, Awareness and Solutions Program
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Dear Prof Hansen
I have previously corresponded with Dan but not directly with you.
I note that you are working on a final revision of your Warming in the Pipeline paper. I regard this as one of the most significant pieces of climate research to have emerged for many years and is, or at least should be, a game changer in policymaking terms.
May I be so bold as to ask
you to consider two revisions. First, could you separate out
the effect of different GHGs, in particular CO2 and CH4. The
reason for this request is that many are arguing that because
of its high GWP and short residence, atmospheric methane
should be reduced by either or both reducing emissions and
enhanced atmospheric oxidation. It would be helpful to
understand the extent to which reducing one GHG against
another would accelerate reductions in surface temperature, if
at all. Might the system feedbacks compensate for the
different RF effects of different GHGs resulting in no
differential cooling effect?
Secondly, I and many others have found the policy conclusions in the paper a tangential diversion from the science to the extent that they undermine the significance of the science. Might the paper not have more impact if it stuck to the science and you issued a separate commentary that addressed its policy implications.
Regards
Dr Robert Chris
Not yet -- first will submit revised Pipeline paper soon -- clearer with some additional insight, IMHO, and hopefully more forthright w/o losing any co-author or reviewer - will be no holds barred in my book.Jim Hansen
On Tue, Feb 14, 2023 at 8:16 PM H simmens <hsim...@gmail.com> wrote:
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Hi Jim
Further to our correspondence below, your prepublication paper continues to deliver. I have some further questions that have arisen in discussion with others as to the real import of your conclusions.
In your Fig.4 you show the GMST response to an instantaneous doubling of CO2 from two versions of the GISS model. The equilibrium response for GISS (2020) is 3.5oC. This is within the range of accepted values for ECS. However, a key finding of the paper is that by accounting for the slow climate feedbacks, thereby adjusting ECS to ESS, the equilibrium response is closer to 10oC. Does it follow that a more accurate representation of GMST response to an instantaneous doubling of CO2 should be the Fig. 4 data scaled from 3.5oC to 10oC? If so, the 100-year e-doubling time would produce a GMST increase of ~6oC in that time and ~5oC in 30 years (ignoring the effect of aerosols).
The paper is entitled Warming in the Pipeline but it is unclear (to me at least) whether that warming from past emissions is committed irrespective of their future trajectory, or assumes that either future emissions continue their historical growth trend that would increase atmospheric GHG concentrations, or be moderated only enough to maintain those concentrations at the doubled level. The comment on p.31 that ‘The 7-10°C global warming is the eventual response if today’s level of GHGs is fixed and the aerosol amount is somewhere between its year 2000 amount and preindustrial amount.’ (emphasis added) is somewhat ambiguous in this regard. Does the ‘level’ refer to the GHG emissions or the concentration, and similarly for aerosols?
Moreover, it would be helpful if a clearer distinction could be made between constant concentration and zero emission scenarios. The ZEC argues that within a few decades of reaching net zero emissions, GSAT response would be at or close to zero, i.e. the temperature anomaly would remain more or less where it had got to when net zero was reached. Current global net zero policy is predicated on the almost certainly unsound supposition that cessation of further warming by early in the second half of this century would be sufficient to declare the global warming problem solved. Might your paper have more impact if the relationship between its conclusions and the net zero by 2050 policy regime were explicitly addressed. It seems important to distinguish between the climatic effects of continuously rising GMST, albeit at a slower rate of increase, a stable elevated GMST , and a return to the typical GMST of the Holocene.
The pipeline analogy raises an important question. In simple terms, what comes out of a full pipeline is a function of its cross-section and the pressure forcing its contents along its path. If the pressure is reduced to zero the flow more or less immediately stops - if you stop pumping more stuff into the pipeline, what’s in it stays there and doesn’t come out the other end. But what’s in the pipeline is separated from the rest of the world by the pipeline, and so long as it stays in the pipeline, it has little or no impact on its environment. This construction doesn’t seem to translate well across to global warming.
There is no physical barrier that separates the ‘warming in the pipeline’ from the rest of the environment and that warming will continue to impact the climate system until the relevant forces have equilibrated. Does this suggest a confusing limitation of the ‘pipeline’ metaphor?
In the real world, GHG concentrations did not double in an instant, nor will their post-industrial increase disappear to zero in an instant. Would constructing some illustrative scenarios more closely aligned to the likely future trajectories for emissions and atmospheric concentrations better inform policymakers as to the likely climatic consequences of these more realistic scenarios. Might this reduce misunderstandings outside the confines of climate science that may have arisen from the difficulty in relating notional scenarios convenient for climate modelling purposes, to scenarios more likely to be experienced in the real world?
It would be of great help to me if you could find the time to respond to these questions. I hope they may also be of help to you in making the final version of the paper more impactful, something that is so desperately needed.
Robert
Hi Robert,
Thanks for suggestions -- I will respond to these -- must finish science revision -- there is a new fundamental twist, that makes the story more complete -- I'm wordsmithing and reorganizing the paper to improve clarity, while using as few words as consistent with that objective.
Best, Jim
Robert
Strictly your comment about the pipeline analogy and flow stopping immediately that pressure is reduced is not quite right because of fluid inertia. There is a phenomenon called water hammer if a valve is shut too quickly. There is a similar result for inductance trying to keep an electrical current continuing. Perhaps we should think of the storage of oceanic CO2 as being like a capacitor. If you put a square wave through a resistor into a capacitor you get an asymptotic approach to a final value with a time constant just like the 40 year one from Hansen. It would be very useful to know what fraction of the CO2 we put into the ocean remains available for return. Champagne and beer are not quite right because they make their own CO2 but expect that Coca Cola gets it injected.
Stephen
From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com>
On Behalf Of Robert Chris
Sent: 29 March 2023 15:09
To: James Hansen <jimeh...@gmail.com>
Cc: Dan Galpern <dan.g...@gmail.com>; Planetary Restoration <planetary-...@googlegroups.com>; healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>
Subject: Warming in the Pipeline (previously -Re: [geo] Re: Michael Mann - SIRIUS - geoengineering)
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No problem. Look forward to seeing the finished article.
Robert
No. But, the story can be made much clearer and is in the version of the paper that is nearing completion. It really will be done within a couple of weeks, but only if I ignore emails. Sorry to be short, but I hope you will appreciate the story when you read it. Jim