See also related thread on possible AMOC reversal this century mostly due to polar ice melt.
On Wed, Feb 14, 2024 at 5:57 PM Ron Baiman <[email protected]> wrote: > Hi Greg, > > And as you may recall, there was enormous push back on David Keith's view, > that I don't think is credible, at that HPAC meeting (see McKay, Lenton, > etc. papers). In any case, an easy response is that of Doug McMartin when > asked about David's view during his (Doug's) HPAC presentation. Can we > afford to risk the chance that warming above 1.5 C (or whatever warming we > have now!) will (is) leading to crossing irreversible and extremely harmful > tipping points (like sea level rise as you've pointed out)? The obvious > answer is that it would be (is) lunacy to assume this kind of risk for > human civilization and our fellow living species - whether it pans out or > not. > > Best, > Ron > > On Wed, Feb 14, 2024 at 5:40 PM Gregory Slater <[email protected]> wrote: > >> >> Hi Ron, >> >> Well, yes, the 'tipping point thing' is presumably key. From my >> pedestrian understanding, there's ~50+ ft of sea level rise in the >> Greenland and the West Antarctic ice sheets alone, so if indeed we've >> passed whatever relevant 'tipping point' for those ice sheets (for example, >> undercutting the coastal structure of these sheets in some way, or >> whatever) then, apparently, we could now cool the earth by 40 deg C at this >> point, and these sheets would still inexorably melt away. On the other >> hand, as you know, David Keith told HPAC staright up that ice sheet tipping >> points are bulls**t. Who has the final authoratative word on whether we're >> past those or other tipping points? Fas ar I can tell, it's all vapor at >> this point, and that therefore '*as far as we know*' SAI can stop (not >> just freaking 'mitigate' (hate that utterly defeatist word!) ) the >> inevitable 40+ feet of sea level rise - and I'm sticking to that until >> there's something authoratative on ice sheet tipping points. We're still >> not helpless victims of the inevitable ice sheet melt. >> >> Please correct any misinformed or delusion points in the above. >> >> Greg >> >> >> On Feb 14, 2024, at 2:09 PM, Ron Baiman <[email protected]> wrote: >> >> Hi Greg, The problem is that some melting processes, once set in motion, >> become irreversible on human time scales as reforming the ice would require >> extremely cold temperatures over extended periods of time. The ice will not >> be restored by simply going back to pre-industrial temps (technically >> called ‘hysteresis’ , ‘path dependency’ or simply irreversibility). >> My understanding is that we have likely started some of these >> irreversible tipping points. But totally agree that slowing and stopping >> melting as much as possible should be a priority. I think we can restore >> polar sea ice for example by urgent cooling. And if we can slow the >> melting down to centuries for example it would be much easier for human >> civilization to adapt. >> Best, >> Ron >> >> On Feb 14, 2024, at 4:41 PM, Gregory Slater <[email protected]> wrote: >> >> Hello Ron, >> >> Thanks for reply and link. I'll look at this. >> >> However. Ron. It totally depresses me when you write, "At this point it >> appears that it may be very hard to reverse substantial sea level rise over >> next centuries....". Seriously? Why? The only, only reason I am >> interested in SAI (and the other cooling technologies) is its capability to >> halt global warming *and sea level rise* immediately. Today. If we but >> choose to do so. Is there anyone who actually doubts that SAI can halt >> global warming and sea live rise immediately? Is there anyone who does not >> think we have the capacity to do this? This is my baseline assumption. >> That, whether or not we have the brains and the balls to do so, we have the >> technology to actually halt global warming ~instantly. We have that >> capacity. Now. Does anyone seriously disagree with that? >> Thanks, >> Greg Slater >> >> >> On 2/13/24 12:26 PM, Ron Baiman wrote: >> >> Agreed Greg! At this point it appears that it may be very hard to >> reverse substantial sea level rise over next centuries but we should at >> least be trying to slow it down and minimize it as much as possible! >> >> Jim's short summary of OTEC from (6/19/2023) from p. 15-16 of "The Case >> for Urgent Direct Climate Cooling" (slight mislabeling on the HPAC >> website): >> https://drive.google.com/file/d/1yHe2Fe6fU11odfcH-4GwdYDNTCk7uB-J/view >> is copied below. >> >> Best, >> Ron >> >> "Ocean Thermal Energy Conversion (OTEC) would utilize the temperature >> difference >> between surface and deeper ocean waters to cool the planet while >> generating baseload >> energy and removing CO2 from the atmosphere.76,77,78 Deployment of 31,000 >> one >> gigawatt OTEC plants has been estimated to: a) displace 0.8 W/m2 of >> average global >> surface heat from the surface of the ocean to deeper water for 200 years; >> b) produce 31 >> terawatts of electricity per year (67% more than total world use), and c) >> absorb about >> 4.3 GtCO2 per year from the atmosphere by cooling ocean surface waters.79 >> At an >> estimated cost of $2.9 trillion per year, it would take 30 years to ramp >> up to 31,000 >> >> 73 Nature Communications 12: 6713 (2021). >> 74 Sci. Rep. 6: 35070 (2016). >> 75 White-roofed greenhouses in Almeria have cooled the regional climate. >> 76 Rau, Greg and Jim R. Baird. 2018. Negative-CO2-emissions ocean thermal >> energy conversion. Renewable and >> Sustainable Energy Reviews 95:265-272. >> 77 Baird, Jim. 2022. The physics and economics of thermodynamic >> geoengineering. Available from the author upon >> request at [email protected]. >> 78 Gleckler PJ, Durack RJ, Stouffer RJ, Johnson GC, Forest CE. >> Industrial-era global ocean heat uptake doubles in >> recent decades.2016. Nature Climate Change: >> https://doi.org/10.1038/nclimate2915 >> 79 Renforth, Phil and Gideon Henderson. 2017. Assessing ocean alkalinity >> for carbon sequestration. Reviews of >> Geophysics. >> >> Healthy Planet Action Coalition Petition to World Leaders Page >> 16 >> plants.80,81,82,83 Economies of scale have been estimated to potentially >> reduce the cost of >> OTEC electricity to about 1.1 cents per KWh.84" >> >> On Tue, Feb 13, 2024 at 1:05 AM Gregory Slater <[email protected]> wrote: >> >>> >>> Hello Jim, >>> >>> Thank you for the reply and information about 'thermodynamic >>> geoengineering'. I do not know this technology. I am still learning. >>> Please send links to more detailed summaries of the technology. >>> >>> My bottom line is that the over-riding priorities must be to stabilize >>> (and reduce) global mean temperature, and stabilize global mean sea level. >>> Immediately. Not in years or decades. Whatever set of technologies can >>> realistically make that happen should be carefully but swiftly deployed, >>> with appropriate testing, modifications, and scale up, but as quickly as >>> possible. It is an emergency, an actual crisis, No time to lose. >>> Whatever gets this done the fastest I am in favor of. >>> >>> There should be a session on this technology along with all the others >>> at the 'effective geoengineering' conference/summit that I am proposing. >>> >>> Thanks, >>> Greg Slater >>> >>> >>> On Feb 12, 2024, at 10:04 PM, Jim Baird <[email protected]> >>> wrote: >>> >>> Gregory, what is the fault in this logic? >>> >>> >>> The thermal coefficient of expansion of seawater is about half at a >>> depth of 1,000 meter it is at the surface per the following graphic. >>> >>> <image002.jpg> >>> Heat moved into deep water to a median depth of 500 meters as >>> Thermodynamic Geoengineering would provides with heat pipes produces 25% >>> less sea level rise due to thermal expansion. And this heat would be >>> unavailable to melt icecaps, or the glaciers that accounted for about 21% >>> of the recorded sea level rise of the past two decades. >>> >>> I share your concern with coastlines. >>> >>> Jim Baird >>> >>> >>> *From:* [email protected] *On Behalf Of >>> *Gregory >>> Slater >>> *Sent:* Monday, February 12, 2024 8:55 PM >>> *To:* Ron Baiman <[email protected]> >>> *Cc:* [email protected]; >>> [email protected]; healthy-planet-action-coalition < >>> [email protected]> >>> *Subject:* Re: [HPAC] A general question about the thermal response of >>> the Earth's oceans.. >>> >>> >>> Hi Ron, >>> >>> Thanks for the link. I had not read this, though I am sure you and >>> others announced it when it came out. >>> >>> My question reflects my interest in understanding the likely net zero >>> 'end-state' that is the focus of the vast share of discussion around global >>> warming and climate change, and your paper discusses that. Certainly I >>> regard even the current state of the Earth with regard to atmospheric CO2 >>> to be unacceptable, let alone where ever we 'land' at net zero. My >>> specific interest in the question is where sea level ends up upon reaching >>> the (still quite hypothetical) 'net zero'. But of course, where ever we >>> 'land' at net zero, that's not the end of the story, nor of humanity's >>> suffering. The ice sheets are melting, and the ocean are rising due to >>> that melt, even where we are now. Net zero does not in any way stop that >>> melting and sea level rise (on any timescale that matters for the stability >>> of states and civilization). Nor of course, does the entire spectrum of >>> other increasingly catastrophic global warming-induced effects stop at 'net >>> zero'. This disconnect seems to pervade the global debate. Of course, you >>> and most people on this forum are more aware of all this than me. Without >>> one or more (or better, all) of the proposed methods of climate >>> intervention, we will definitely be 'giving up' on the coastal cities of >>> the world, and astonishingly, that fate seems increasingly to be being >>> actively embraced by activists, scientists, and leaders (at least in the >>> industrialized world). But I have absolutely no intention of docilely >>> embracing the inundation of the coastlines, complete with all of the >>> catastrophies, death, and suffering *(to be borne by the poor and >>> disenfranchised alone!)* that that 'embrace of death' entails. To hell >>> with the global warming accommodators. I refuse to give up on the >>> coastlines. I'll say it again. I refuse to give up on the coastlines! >>> That's insanity. It is this decision!, to abandon the coastlines, It is >>> this decision! and *not* the decision to seriously begin testing all >>> forms of climate intervention, that is being made by the rich and powerful >>> right now, the class that can protect itself from the consequences, without >>> any involvement of the billions of poor and disenfranchised of the world, >>> who will be forced to suffer as a result. As Thucydides so presciently >>> wrote about global warming 2500 years ago, the rich will resist global >>> warming intervention and the poor will be forced to 'suffer what they must'. >>> >>> When it comes to the 'debate' about whether to employ climate >>> intervention technologies, it's a totally rigged game, with the established >>> powers in science and politics playing the role of 'the house'. >>> >>> I believe that those of us who understand that intervention is not only >>> doable but absolutely essential, that stabilizing the global mean >>> temperature is the *single most important thing to be done right now, >>> today,* should organize our *own* conference on how we must proceed, >>> rather than begging the Davos-and-COP-attending activists, scientists, >>> socialogists, political 'scientists', celebrities, and politicians to >>> 'please, pretty please' at least consider what we say. *It is we, not >>> they, who speak on behalf of the poor and disenfranchised!* >>> >>> Greg Slater >>> >>> >>> >>> On Feb 12, 2024, at 2:54 PM, Ron Baiman <[email protected]> wrote: >>> >>> Hi Greg, >>> >>> Recent modeling suggests that the oceans will gradually release heat to >>> the atmosphere but not sure at what rate. >>> >>> This is from the HPAC cooling paper: >>> https://essopenarchive.org/doi/full/10.22541/essoar.169755546.65919302/v1 >>> >>> "Failure to begin deployment of direct cooling influence in the very >>> near-term necessarily >>> will lead to greater harm and increased risk, at least until net-zero >>> global GHG emissions are >>> achieved and legacy concentrations of GHGs are removed from the >>> atmosphere and oceans. >>> Recent modeling suggests that, in the absence of direct climate cooling, >>> if (anthropogenic and >>> natural) net-zero emissions were to be achieved after 3667 Gigatons of >>> CO2 eq GHG (or 1000 >>> Gigatons of carbon estimated to result in global warming of about 2.0°C) >>> were accumulated in >>> the atmosphere, global warming would remain at roughly 2.0° C for at >>> least another 50 years due >>> to continued thermal rebalancing from legacy ocean warming, even with >>> continued ocean uptake >>> of legacy CO2 from the atmosphere (MacDougall et al., 2020; Hausfather, >>> 2021). This suggests >>> that even after net-zero is achieved, a combination of continued direct >>> climate cooling and >>> drawdown of legacy GHG would be necessary to expeditiously restore and >>> regenerate a stable >>> climate and healthy ecosystem (Schuckmann et al., 2020; Baiman, 2021, >>> footnote 9)." >>> >>> Best, >>> Ron >>> >>> On Mon, Feb 12, 2024 at 3:14 PM Gregory Slater <[email protected]> >>> wrote: >>> >>> >>> Hello All, >>> >>> If we managed to reach 'net zero' by, say, 2050, so that, to zeroth >>> order, the concentration of CO2 ceased to increase due to human >>> activities after that time, how would the (mean) ocean temperature >>> respond (over years, decades)? >>> >>> I am happy to be directed to any published papers or group threads which >>> >>> discuss this. >>> >>> Thanks, in advance, for any help. >>> >>> Greg Slater, East Palo Alto, CA >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Healthy Planet Action Coalition (HPAC)" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] >>> . >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/healthy-planet-action-coalition/53b39682-29d1-4fc7-a0ee-c3814acdeb50%40gmail.com >>> . >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Healthy Planet Action Coalition (HPAC)" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] >>> . >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/healthy-planet-action-coalition/CD05CB11-5D11-4869-ADCD-197F07468434%40gmail.com >>> <https://groups.google.com/d/msgid/healthy-planet-action-coalition/CD05CB11-5D11-4869-ADCD-197F07468434%40gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> >>> >> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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