I did not state that the models are not policy-relevant… both because
I don’t agree with that being a binary statement of either they are or
they aren’t (rather, they are useful for answering some questions and
less useful for answering others), and because the specific issue I
was responding to is not the most relevant factor in thinking through
that question.
I disagree completely with your assertion that if we don’t correctly
capture what the temperature would be in the year 3000, then it
follows that our models are utterly useless for making near-term
policy choices. Rather, I think that what happens in the next century
or two actually do matter. I agree with you that what happens beyond
then **also** matters, but I don’t think it is essential that a
climate model correctly capture that. You don’t need to run a climate
model to say that we’re in trouble if we maintain elevated CO2
concentrations for the next 1000 years, as this thread points out, and
climate models aren’t necessarily useless simply because they ignore
physics that isn’t (necessarily) relevant to predicting nearer-term
impacts.
And I do agree that the degree of uncertainty in heading into
uncharted territory is not well understood, including the possibility
of more rapid changes than are predicted in current climate models.
But I think there’s a lot of room between “climate models are perfect
representations of the future” and “climate models are not
policy-relevant”; just because they are obviously not perfect does not
make them totally useless as you seem to suggest…
*From:* Robert Chris <[email protected]>
*Sent:* Tuesday, April 11, 2023 8:23 AM
*To:* Douglas MacMartin <[email protected]>; [email protected];
Tom Goreau <[email protected]>
*Cc:* [email protected]; Planetary
Restoration <[email protected]>; 'Eelco Rohling'
via NOAC Meetings <[email protected]>; geoengineering
<[email protected]>
*Subject:* Re: [prag] Re: [geo] Are 1.5 c or 2.0 c thresholds
economically realistic in a voluntary NDC regime?
Doug
It seems that mistakenly I thought you were justifying the
appropriateness of the models. Apologies. On a closer reading, the
following emerges:
Your final words 'That isn’t what the models are intended to do', in
context, mean that we shouldn't criticise the models for not being
policy-relevant even though they exclude millennial factors because
the models are not intended to be policy relevant. They are just
models that produce certain outputs based on certain inputs and
certain algorithms. The degree to which the models are a faithful
predictor of the range of plausible futures is unknowable until that
future arrives, and made more so by the absence of the millennial
factors. Policymakers use these models at their (and our) peril.
Have I got that right? If so, it might be a good idea if someone told
the policymakers that they're basing their policies on the wrong data.
Regards
Robert
On 11/04/2023 17:31, Douglas MacMartin wrote:
Robert,
I agree with almost everything you write, except for your belief
that what you wrote is in any way in conflict with what I wrote.
doug
*From:* Robert Chris <[email protected]>
<mailto:[email protected]>
*Sent:* Tuesday, April 11, 2023 3:17 AM
*To:* Douglas MacMartin <[email protected]>
<mailto:[email protected]>; [email protected]; Tom Goreau
<[email protected]> <mailto:[email protected]>
*Cc:* [email protected]; Planetary
Restoration <[email protected]>
<mailto:[email protected]>; 'Eelco Rohling'
via NOAC Meetings <[email protected]>
<mailto:[email protected]>; geoengineering
<[email protected]>
<mailto:[email protected]>
*Subject:* Re: [prag] Re: [geo] Are 1.5 c or 2.0 c thresholds
economically realistic in a voluntary NDC regime?
Doug
There's a significant caveat in there - assuming we 'eventually
get to net zero', and a significant ethical assumption - that
policy relevance is limited to a century timescale. And a further
physical climate assumption - that cascading tipping events will
not be triggered on any plausible current and short term policy
regime.
If you set the rhetoric aside, there's little evidence to suggest
that by mid-century or even for a decade or more after that, we'll
get to net zero. Your 'eventually' is doing a lot of work here!
For this to happen requires us to start the decommissioning of
fossil fuel assets now and scaling GGR/CDR to close to or beyond
GtCO2e/yr within the next few years. Current geopolitics shows no
sign of substantive action to match the rhetoric on either of
those, or the likelihood of any imminent breakthrough that might
materially accelerate things.
As to the ethical assumption, if the ethics are constrained to
consider only the scenarios in which we get to net zero, then you
need to be pretty damn sure you're going to get there. But we're
far from being sure about that. So limiting policy relevance to
the century timescale is tantamount to declaring that what happens
beyond that is no concern of ours. This is like setting a
discount rate that reaches infinity on 1 Jan 2100 (or maybe 2103)
- all benefits and costs thereafter have no present value today so
we don't need to worry ourselves about them. An ethics so
constrained seems to me seriously dysfunctional.
On the tipping events, the literature on this suggests that we are
already treading on thin ice. Is it sane to base our policy
regime on the assumption that there are no tipping points that
might derail our smooth but slow transition to net zero?
Regards
Robert
On 11/04/2023 01:07, Douglas MacMartin wrote:
Also, of course, the long-term response is only realized if
nobody ever develops and deploys any CDR over that long-term
timeframe.
If you believe that we will eventually get to net-zero and
that some level of CDR will get deployed to go below net-zero,
then it’s the century-scale warming that matters, not the
millennial-scale.
There are of course millennial-scale processes that are not
included in climate models, so there’s neither any reason to
expect them to match on that time-scale, nor any reason to
criticize them on that particular basis, or to use that
particular argument to suggest that the models aren’t
policy-relevant. That isn’t what the models are intended to do.
*From:* [email protected]
<[email protected]>
<mailto:[email protected]> *On Behalf Of
*Michael MacCracken
*Sent:* Monday, April 10, 2023 1:54 PM
*To:* Tom Goreau <[email protected]>
<mailto:[email protected]>; Robert Chris
<[email protected]> <mailto:[email protected]>
*Cc:* [email protected];
Planetary Restoration <[email protected]>
<mailto:[email protected]>; 'Eelco
Rohling' via NOAC Meetings <[email protected]>
<mailto:[email protected]>; geoengineering
<[email protected]>
<mailto:[email protected]>
*Subject:* Re: [prag] Re: [geo] Are 1.5 c or 2.0 c thresholds
economically realistic in a voluntary NDC regime?
Well, in that the climate depends on the radiative forcing and
the radiative forcing is logarithmic with the CO2
concentration, doing a linear regression of CO2 and
temperature would give an estimate of the rise in temperature
that is far from linear, so the 16 C would be way too high.
There is then the issue that the change in temperature in high
latitudes is well above the global average change in
temperature, and so that would be another contribution to
giving a rate too high for the change in global average
temperature. So, if regression were to get temperature change
in high latitudes ad not the global average, one would have a
value more than the change in the global average temperature.
Mike
On 4/10/23 1:29 PM, Tom Goreau wrote:
It’s just the regression of Antarctic Ice temperature
versus CO2 data. The sea level regression implies +23 meters.
When I did it in 1990 there was only one glacial cycle of
data, but Eelco Rohling independently did the same
analysis when there was 800,000 years of data, and got
essentially identical values.
The models must be serious underestimates to fall so far
off the actual long term climate data.
*Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance*
*Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.*
*Technical Advisor, Blue Guardians Programme, SIDS DOCK*
*37 Pleasant Street, Cambridge, MA 02139*
*[email protected]
www.globalcoral.org <http://www.globalcoral.org>
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)*
*Books:*
*Geotherapy: Innovative Methods of Soil Fertility
Restoration, Carbon Sequestration, and Reversing CO2 Increase*
http://www.crcpress.com/product/isbn/9781466595392
<http://www.crcpress.com/product/isbn/9781466595392>
*Innovative Methods of Marine Ecosystem Restoration*
http://www.crcpress.com/product/isbn/9781466557734
<http://www.crcpress.com/product/isbn/9781466557734>
*No one can change the past, everybody can change the future*
**
*It’s much later than we think, especially if we don’t think*
**
*Those with their heads in the sand will see the light
when global warming and sea level rise wash the beach away*
**
*Geotherapy: Regenerating ecosystem services to reverse
climate change*
*From: *Michael MacCracken <[email protected]>
<mailto:[email protected]>
*Date: *Monday, April 10, 2023 at 4:23 PM
*To: *Tom Goreau <[email protected]>
<mailto:[email protected]>, Robert Chris
<[email protected]> <mailto:[email protected]>
*Cc: *"[email protected]"
<mailto:[email protected]>
<[email protected]>
<mailto:[email protected]>,
Planetary Restoration
<[email protected]>
<mailto:[email protected]>, 'Eelco
Rohling' via NOAC Meetings
<[email protected]>
<mailto:[email protected]>, geoengineering
<[email protected]>
<mailto:[email protected]>
*Subject: *Re: [prag] Re: [geo] Are 1.5 c or 2.0 c
thresholds economically realistic in a voluntary NDC regime?
Hi Tom--I'd be interested in seeing your 1990 paper
because 16 C would take temperatures to much higher than
they have ever been, and yet there have been periods when
the CO2 concentration has apparently been well above 1000
ppm, so the 16 C value seems seriously inconsistent with
what we know of Earth history.
Best, Mike
On 4/10/23 5:02 AM, Tom Goreau wrote:
BEFORE UNFCCC was signed, it was clear from
paleoclimate data that +16 degrees C or so is the
equilibrium temperature for 400ppm CO2 (Goreau 1990),
but all governments ignored the real data because they
preferred the fictitious claim from models that
warming would “only” be around 1-4 degrees C, and
occur well after a new leader emerges from the next
election, selection, or coup.
I briefed the Association of Small Island States just
before they signed on to a treaty that was an
effective death sentence for low coasts and a suicide
pact for low lying island nations to that effect, but
their heads of states were told by the rich countries
to sign or they would lose their foreign aid,
something none could afford. They were effectively
bought off to sacrifice their own people’s futures for
worthless promises of financial support for adaptation
that never came. No politician ever turns down money,
no matter how insufficient.
Instead what they got from the funding agencies was
sea walls made from concrete and rock imported half
way across the world, which have all fallen down due
to erosion caused by wave reflection scouring. Their
consultants keep promising that the next seawall,
built to armor the ruins of previous seawalls, will
last forever, it’s another shell game with peoples
futures.
*Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance*
*Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.*
*Technical Advisor, Blue Guardians Programme, SIDS DOCK*
*37 Pleasant Street, Cambridge, MA 02139*
*[email protected]
www.globalcoral.org <http://www.globalcoral.org>
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)*
*Books:*
*Geotherapy: Innovative Methods of Soil Fertility
Restoration, Carbon Sequestration, and Reversing CO2
Increase*
http://www.crcpress.com/product/isbn/9781466595392
<http://www.crcpress.com/product/isbn/9781466595392>
*Innovative Methods of Marine Ecosystem Restoration*
http://www.crcpress.com/product/isbn/9781466557734
<http://www.crcpress.com/product/isbn/9781466557734>
*No one can change the past, everybody can change the
future*
**
*It’s much later than we think, especially if we don’t
think*
**
*Those with their heads in the sand will see the light
when global warming and sea level rise wash the beach
away*
**
*Geotherapy: Regenerating ecosystem services to
reverse climate change*
*From: *Michael MacCracken <[email protected]>
<mailto:[email protected]>
*Date: *Sunday, April 9, 2023 at 9:37 PM
*To: *Tom Goreau <[email protected]>
<mailto:[email protected]>, Robert Chris
<[email protected]> <mailto:[email protected]>
*Cc:
*"[email protected]"
<mailto:[email protected]>
<[email protected]>
<mailto:[email protected]>,
Planetary Restoration
<[email protected]>
<mailto:[email protected]>,
'Eelco Rohling' via NOAC Meetings
<[email protected]>
<mailto:[email protected]>,
geoengineering <[email protected]>
<mailto:[email protected]>
*Subject: *Re: [prag] Re: [geo] Are 1.5 c or 2.0 c
thresholds economically realistic in a voluntary NDC
regime?
Hi Tom--Indeed, which is why I don't understand why
the mainly island nation accepted, even insisted upon
1.5 C, as an aspirational goal. From paleoclimatic
analysis, the equilibrium sensitivity for sea level
rise is of order 15-20 METERS per degree C increase in
the global average temperature. And how it is somehow
justified that the curve shape for the sensitivity is
a cubic and we are presently in the low sensitivity
part of the curve does not at all seem justified to me
(though perhaps the type of major ice sheet matters).
I once asked the chief US negotiator (Todd Stern) at
the Paris COP if they had viewed as a value that would
be an upper limit and the subsequent goal and actions
would be aimed at forcing the global average
temperature back down, or if the vision was that
actions would be taken to keep the increase in global
average temperature to be 2 C and this would be an
allowed long term value for the Earth. He indicated,
as I recall, that what would happen after the value
was reached was not discussed, they were so happy to
have a number to consider an upper value they just
never discussed the issue.
Best, Mike
On 4/9/23 7:40 AM, Tom Goreau wrote:
The 1.5 degree “goal” like the 2.0 goal, is beyond
the capacity of corals to adapt so it means the
extinction of coral reef ecosystems, which already
reached their high temperature tipping point in
the mid 1980s.
Coral reefs, and the species and people who live
from them, have been consciously selected for
sacrifice, rather than interrupting profits from
fossil fuels.
Coral reefs may be the first ecosystem to
collapse, but they certainly won’t be the last!
*Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance*
*Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.*
*Technical Advisor, Blue Guardians Programme, SIDS
DOCK*
*37 Pleasant Street, Cambridge, MA 02139*
*[email protected]
www.globalcoral.org <http://www.globalcoral.org>
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)*
*Books:*
*Geotherapy: Innovative Methods of Soil Fertility
Restoration, Carbon Sequestration, and Reversing
CO2 Increase*
http://www.crcpress.com/product/isbn/9781466595392
<http://www.crcpress.com/product/isbn/9781466595392>
*Innovative Methods of Marine Ecosystem Restoration*
http://www.crcpress.com/product/isbn/9781466557734
<http://www.crcpress.com/product/isbn/9781466557734>
*No one can change the past, everybody can change
the future*
**
*It’s much later than we think, especially if we
don’t think*
**
*Those with their heads in the sand will see the
light when global warming and sea level rise wash
the beach away*
**
*Geotherapy: Regenerating ecosystem services to
reverse climate change*
*From:
*<[email protected]>
<mailto:[email protected]>
on behalf of Robert Chris <[email protected]>
<mailto:[email protected]>
*Date: *Sunday, April 9, 2023 at 10:35 AM
*To: *Michael MacCracken <[email protected]>
<mailto:[email protected]>
*Cc:
*"[email protected]"
<mailto:[email protected]>
<[email protected]>
<mailto:[email protected]>,
Planetary Restoration
<[email protected]>
<mailto:[email protected]>,
'Eelco Rohling' via NOAC Meetings
<[email protected]>
<mailto:[email protected]>,
geoengineering <[email protected]>
<mailto:[email protected]>
*Subject: *Re: Fwd: [prag] Re: [geo] Are 1.5 c or
2.0 c thresholds economically realistic in a
voluntary NDC regime?
Mike, you point to a key distinction that I had
perhaps ignored. The dynamics of setting goals
are not the same as those of realising them.
Economics may have been a major factor in setting
the Paris targets but they are not an enabler of
their realisation. If the political will was
there among a sufficient number of leading
economies to deliver on the Paris targets, they
would find a way of doing that that would overcome
any economic constraints that might otherwise have
been thought to be impediments.
Regards
Robert
As I loosely recall, when the 2 C goal was
approved in Paris, the value
was chosen because it was thought that it would be
realistically/economically achievable. The
goal could not be higher due
to thoughts about tipping points or lower due
to economic
realities--though they did set 1.5 C as an
aspirational goal as the
developing nations felt the impacts of 2 C on
them would be unbearable.
So, I'd say economics played a goal
there--indeed, even the primary
rationale for the choice.
Mike
On 4/8/23 9:54 AM, Robert Chris wrote:
> David, you've put your finger right on it.
Being economically
> realistic is not a sufficient condition to
enable the realisation of
> any goal. For some goals, it isn't even a
constraint because for
> them, what is economically realistic is made
to fit the goal, rather
> than the goal being tailored to fit what's
economically realistic.
> Money is not the only store of value.
>
> Regards
>
> Robert
>
>
> On 08/04/2023 18:26, David desJardins wrote:
>> If the goal is always economically
realistic, then it follows that
>> looking at the goal through an economic
lens will always enable it,
>> not prevent it.
>
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