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
Sent from my iPhone
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!
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"
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
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
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!
Recent
modeling suggests that the oceans will
gradually release heat to the
atmosphere but not sure at what rate.
"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)."
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
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