Following Phil, I, too, wasstruck by Bernard's comment: "As a secondary
researcher andnon-scientist, whilst I think the passion and knowledge in this
list is great,keep it coming, the really yawning gap is the collective failure
to synthesizethe range of proposals, data and estimates for the suite of CDR
interventions.Everyone seems to peddle their favoured intervention, without
much regard for(and comparative analysis of) other proposals. I think you would
findnon-profit foundations falling over themselves to fund syntheses, but they
needwell-thought through proposals!" First,syntheses are out there: The Royal
Society report, the NAS report, the IPCC AR5report, etc. Dowe really need more?
Secondly, all of these suffer from lack research/knowledgeabout the cost,
capacity, risk of many, specific CDR approaches as well as fromthe biases of
the authors. So I question what another synthesis will bring usunless there is
new knowledge to synthesize (or a reasoned unbiasing ofprevious reviews).
Meantime,in the absence of (or on the eve of?) formal funding for CDR research
(NERC program excepted), yes,everyone is “peddling their favorite” approach,
which at this stage appears tobe land biology, evident in present CDR reviews
and policy (what there is ofit). As I and few others on this list keep
repeating, this one approachis not the obvious, sole, winning technology
considering how excess air CO2 isnaturally consumed at the long term, planetary
scale (oceans and geochemical processes)
http://climatemodels.uchicago.edu/geocarb/archer.2009.ann_rev_tail.pdf
Ifnon-profits (including governments?) want to (and have the $ capacity
to)"fall all over themselves" supporting CDR, they would do well tofirst
convene a broadly constituted science and technology advisory board thatwould
then oversee a formal call for and evaluation of "well thoughtout" proposals
for CDR R&D. Research and practicing theart is how knowledge advances, not
another synthesis of a new field thathas had precious little research or
practice. And getting some promisingbreakthrough approaches/technologies in the
short time now required isn’t goingto happen for free, witness medicine,
pharmaceuticals, defense, big ag, etc. Dowe care enough about our one and only
planetary home to spend a small fractionof what we do in the preceding areas to
see if we have any safe and costeffective CO2 management options in the absence
of effective emissionsreduction? Or shall we instead continue to believe that
emissions reduction +/- miraculous adaptation of effected species will save the
day, while spending more on cosmetic surgery than we do on CDR? Gregps amazing
how my original “Arrows, LivePreservers...” post opened the floodgates of pent
up facts, opinion and emotion, including mine!
From: Phillip Williamson (ENV) <[email protected]>
To: "[email protected]" <[email protected]>; John Nissen
<[email protected]>; "[email protected]" <[email protected]>
Cc: David Lewis <[email protected]>; geoengineering
<[email protected]>; Kevin Anderson
<[email protected]>; "[email protected]"
<[email protected]>; Greg Rau <[email protected]>; Peter Wadhams
<[email protected]>; Sev Clarke <[email protected]>; Alan Gadian
<[email protected]>; Kevin Lister <[email protected]>; Kevin
Lister <[email protected]>; Adam Rutherford - Science
<[email protected]>; Hugh Hunt <[email protected]>
Sent: Thursday, November 17, 2016 11:08 AM
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard?
#yiv0545344046 -- P {margin-top:0;margin-bottom:0;}#yiv0545344046 Dear all
Two short comments on the latest postings in this very informative exchange:
1. With regard to Mike McCracken's email below, if all emissions were to be
very rapidly (instantly?) ended, the outcome is likely to be accelerated
warming over the short-term, since the cooling effect of aerosols would be
reduced more rapidly than the warming effects of greenhouse gases. See FAQ
12.3 of IPCC AR5 WG1.
2. With regard to Bernard Mercer's separate email sent just a few minutes
earlier, I am particularly interested in "I think you would find non-profit
foundations falling over themselves to fund syntheses, but they need
well-thought through proposals!". That's because the UK Greenhouse Gas Removal
programme (http://www.nerc.ac.uk/research/funded/programmes/ggr/), led by the
Natural Environment Research Council, is likely to be in the situation in a few
months time that it is only able to fund a minority of high quality proposals -
including syntheses - considered worthy of support. If anyone has suggestions
for additional co-support partnerships, e.g. via foundations, I would be
pleased to explore such possibilities and bring them to the attention of the
current GGR programme funders
RegardsPhil Williamson
From: [email protected] <[email protected]> on
behalf of Michael MacCracken <[email protected]>
Sent: 17 November 2016 18:26
To: [email protected]; John Nissen
Cc: David Lewis; geoengineering; Kevin Anderson; [email protected];
Greg Rau; Peter Wadhams; Sev Clarke; Alan Gadian; Kevin Lister; Kevin Lister;
Adam Rutherford - Science; Hugh Hunt
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard? I would just add that if one considers the effects of
short-lived species like methane, black carbon, sulfate and tropospheric ozone
that also introduce substantial forcings, going to zero CO2 emissions would
also likely imply going to (near) zero emissions of these species as well, so
there is lots of potential for reducing forcing and stopping the increase in
temperature and even pushing it down (with all emissions going to zero)--the
challenge is doing something so large in a short time.Mike
On 11/17/16 12:25 PM, Knutti Reto wrote:
Dear John, Thanks for your comments. > I would love you to publish this result
if you can. Why would I want to publish it if it is wrong? To publish a result
you need to provide quantitative evidence. Claiming that someone else is wrong
is not enough. The figure you show is based on a climate carbon cycle model, so
please tell me what specifically is wrong in that model (and in all other
climate models that show similar results), and provide another model that is
more credible, then we can discuss again. In your letter to COP22 you
state:>The climate community and consensus of scientists, represented by IPCC,
had assumed that, by reducing net emissions of CO2 to zero, global warming
could be halted. They had also assumed that such a reduction would halt Arctic
warming, by the process which has kept Arctic warming proportional to global
warming but amplified by a factor of around two. Unfortunately evidence
indicates that these assumptions are no longer valid.So “evidence indicates”,
but where it that evidence? In your whole letter not one quantitative argument
or number is given that contradicts the scientific consensus as represented in
IPCC, not a single one. What is the evidence?You also assert that the
scientists “assume” things. These are *results* based on our best understanding
of the system, the best data we have, and the most objective and quantitative
models we can build. They may not be perfect, but they are *results*,
conclusions drawn from data, not assumptions. >The temperature curve in red is
complete nonsense, because the forcing from the ~500 ppm of CO2 will continue
the radiative forcing on the planet and hence the temperature will continue
rising. In my previous email I demonstrated that the forcing will decrease, and
that temperature will not increase for long if the forcing decreases, based on
basic conservation of energy and timescales of the carbon cycle. You can go
back to work by Wigley, Hansen and others thirty years ago and it’s there, and
nobody has disproven it. You provide no counterargument but simply restate your
claim. See my other email to Kevin. This is about science, not beliefs. I don’t
see this discussion going anywhere. Best regards, Reto From: John Nissen
[mailto:[email protected]]
Sent: Donnerstag, 17. November 2016 02:48
To: Knutti Reto <[email protected]>
Cc: Michael MacCracken <[email protected]>; David Lewis
<[email protected]>; geoengineering <[email protected]>;
Kevin Anderson <[email protected]>; [email protected];
Greg Rau <[email protected]>; Peter Wadhams <[email protected]>; Sev
Clarke <[email protected]>; Alan Gadian <[email protected]>; Kevin Lister
<[email protected]>; Kevin Lister <[email protected]>; Adam
Rutherford - Science <[email protected]>; Hugh Hunt
<[email protected]>
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard? Hi Knutti,I would love you to publish this result if you
can. A number of us have been trying to defy the modelling community which
seems to manage to get results which conflict with observations and, I
belatedly find, with basic physics. We have been bombarded with weasel words,
as Stephen Salter puts it. But it is this diagram attached that astonished me,
because it shows up the basic premise, promoted by IPCC, that cessation of
emissions will cause the temperature to peak and start falling. The
temperature curve in red is complete nonsense, because the forcing from the
~500 ppm of CO2 will continue the radiative forcing on the planet and hence the
temperature will continue rising. It is when we try to reduce CO2 from its peak
that we get into trouble, because the 50% CO2, absorbed by land and ocean when
we put a certain amount of CO2 into the atmosphere, will then be emitted by
land and ocean. We have to work twice as hard to reduce CO2 level as one might
have thought: taking two tons out to reduce the amount in the atmosphere by one
ton.It sounds like common sense to say that "our CO2 emissions caused global
warming, so ceasing our CO2 emissions will stop the temperature rising". I can
see why IPCC was tempted to promote this nonsense: they wanted a simple story
for the public. But it's simply not true.I am copying in Adam Rutherford as an
impartial scientist, not bound up in the politics of climate change or the
machinations of IPCC and COP. I have been putting my point to several
distinguished climate scientists, and they can't fault my physics. They will
argue endlessly about other points, but not my point on the basic physics: that
zero emissions won't halt temperature rise.I am also copying to Hugh Hunt, who
I hear is at COP22, so could pass on this message. Of course the implications
are huge: we have a colossal challenge to remove CO2 fast enough from the
atmosphere to avoid dangerous climate change. We have to start immediately on
a CDR initiative - which I had hoped COP22 would do (hence the letter to COP
which I wrote and attach again for Hugh's benefit). On the other hand the
rewards of restoring the Earth System to Holocene conditions would be
fantastic. The possibility of doing so is really good news for everyone on the
planet. BTW, I have been spending most of my energy over the past few years on
battling against the modelling community about the Arctic sea ice, observed to
be in exponential decline as should be expected from the physics of positive
albedo feedback. I only realised in January this year how badly we've also
been led astray on the CO2 front when I did a few simple calculations for
myself. Kind regards, John On Wed, Nov 16, 2016 at 9:34 PM, Knutti Reto
<[email protected]> wrote:
Dear John, > The arithmetic gives a frightening answer, which I expect is why
you never hear it and nobody publishes it. Nature and Science love frightening
results and would be happy to publish those if they are correct. But not if
they contradict the evidence we have. You seem to imply that scientists only
publish what they like or what people want to hear. I don’t see any evidence
for that. If I had strong evidence for things being much worse, I would publish
that tomorrow. Same if I could prove that climate change is a hoax. We are not
“selling a dream to the media, politicians, environmentalists and the UN”, we
publish and assess what the science and the data tell us. There are two main
errors in your analysis: > The CO2 would only fall very slowly for the rest of
the century, because of CO2's long life in the atmosphere. Thus the forcing
from nearly 500 ppm CO2 would persist for the rest of the century. First, the
initial decrease of CO2 isn’t that slow for zero emissions because the exchange
with the surface ocean and land is fast. CO2 doesn’t have a single lifetime,
and it’s the long tail that is slow. For a single pulse emission into the
atmosphere, after 50 years only half remains in the air (Joos,
doi:10.5194/acp-13-2793-2013, Fig. 1a). Second, other gases would also be
reduced and some have shorter lifetimes. Even without going abruptly to zero,
e.g. as in RCP2.6, the radiative forcing decreases after 2050. For zero
emissions in 2050 the forcing would drop more. > Even if the warming rate
remained at only 0.25C for the rest of century, temperature would rise a
further 1.25C to reach 3.2C above pre-industrial. That is simply wrong. There
is no reason for the warming rate to remain the same if the forcing decreases.
For *constant* forcing (today) the additional warming is about 0.5°C after 200
years (IPCC AR5 WG1 p.1103 bottom left). For 50 years it’s about half (Knutti,
2008 doi:10.1029/2007JD009473, Fig. 1b). That is for constant forcing, so
obviously for *decreasing* forcing it’s even less. RCP2.6 temperature is
constant after 2050, it doesn’t increase. As I said before, the climate system
is complex, but conservation of energy is not. Look at the simple Q=F-lambda T
discussed below: if forcing F is constant or even decreasing, then temperature
T only increases a bit because heat uptake Q reduces, but in equilibrium T is
proportional to F. So the assumptions that T would continue to increase at the
same rate if F is decreasing violates conservation of energy. We are in the
fortunate position to have dozens of simple and comprehensive climate models
which have run such scenarios, and the models do incorporate all those
timescales in the climate and carbon cycle, they include other gases, and the
feedbacks. RCP2.6 has zero CO2 emissions around 2075 (IPCC AR5 WG1 Fig. TS.19,
p. 94) and stays “likely” below 2°C relative to preindustrial (IPCC AR5 WG1 SPM
p.20). Zero CO2 emissions in 2050 would result in less warming than that. Even
if the models underestimate the Artic sea ice loss, that would not change those
numbers a lot. The albedo feedback is only about a quarter of the total global
feedback (IPCC AR4 WG1 Fig. 8.14, p.631). Even the models with the steepest sea
ice decline do not support your analysis. No model is perfect, but I’d rather
base my conclusions on the best possible representation of all processes, the
best data, and a quantitative analysis, than on a naïve and wrong extrapolation
of past trends. Climate change is a serious issue, but it doesn’t help if
people go out with scary extrapolations that have no scientific basis. Best
regards, Reto From: John Nissen [mailto:[email protected]]
Sent: Mittwoch, 16. November 2016 11:45
To: Knutti Reto <[email protected]>
Cc: Michael MacCracken <[email protected]>; David Lewis
<[email protected]>; geoengineering <[email protected]>;
Kevin Anderson <[email protected]>;[email protected];
Greg Rau <[email protected]>; Peter Wadhams <[email protected]>; Kevin
Lister <[email protected]>; Sev Clarke <[email protected]>; Alan
Gadian <[email protected]>
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard? Hello Knutti,The arithmetic gives a frightening answer,
which I expect is why you never hear it and nobody publishes it. Suppose the
CO2 level had got to 500 ppm by 2050, when net emissions reached zero. The CO2
would only fall very slowly for the rest of the century, because of CO2's long
life in the atmosphere. Thus the forcing from nearly 500 ppm CO2 would persist
for the rest of the century.
The current underlying trend rate of global warming is somewhere between 0.2C
and 0.3C per decade, given that the average rate over the past 45 years was
0.18C per decade [1]. Taking 0.25C as a conservative average till 2050, and
assuming we have had 1.1C global temperature rise since pre-industrial times,
the global temperature would rise 0.85C by 2050 to reach 1.95C above
pre-industrial. Even if the warming rate remained at only 0.25C for the rest
of century, temperature would rise a further 1.25C to reach 3.2C above
pre-industrial.Unfortunately leading climate scientists, in their efforts to
get CO2 emission reduced, sold a dream to the media, politicians,
environmentalists and the UN: that we can adapt to climate change providing net
emissions are reduced to zero over the next few decades. According to this
dream, the sea ice will last indefinitely, see the figure SPM.7(b) reproduced
in Peter W’s book, page 89. Sea level will rise about half a metre this
century: 44cm is the ‘best estimate’ in range 28cm to 61cm maximum according to
AR5 [2]. There is no need for interventions, except possibly some "negative
emissions" to achieve net zero emissions. We can make the planet safe for
future generations. But it is a dream. The reality is that we need to reduce
the net effect of climate forcing agents to zero, which includes restoring
Arctic albedo. Saving the sea ice is crucial. We risk losing a critical
element of the control of the planet’s climate system if we allow the Arctic
Ocean to become seasonally free of sea ice, since it will probably be locked
into this state indefinitely which could have catastrophic consequences for sea
level rise, methane emissions and NH weather extremes. The Arctic has already
warmed 7C according to Peter Carter. The most natural climate restoration CDR
involves putting carbon into trees, soil and marine biomass. This simply
involves improving forestry, agriculture and aquaculture practices on a massive
scale. It is also returning the planet’s biosphere to a state before human
population explosion when forests were cut down, soils denuded of carbon and
marine biomass reduced. Surely this can only be good for the planet – and
something positive that every environmentalist can work for. We can also use
weathering of crushed olivine rocks on a large scale to neutralise CO2 and halt
ocean acidification. This, together with local cooling, could save corals –
even possibly the Great Barrier Reef. (Diatoms might help purify the water.)
Who is standing in the way of this progress towards a safer planet? It is the
scientists who continue to promote a dream: a totally unrealistic scenario of
the future and a plan to get there. COP is just doing what seems to be
required from this plan, though they know they cannot get to net zero emissions
quickly enough with current pledges. And Trump now could throw a spanner in
the COP works. However the plan is doomed, not because of Trump, but because
it is based on a dream. We now need to focus on reality and how we can use CDR
and albedo enhancement to restore the Earth System back to the Holocene norm,
with potentially huge benefits for humanity and biodiversity. Kind Regards, John
[1]
https://www.theguardian.com/environment/2016/oct/03/global-temperature-climate-change-highest-115000-years
[2]
http://www.realclimate.org/index.php/archives/2013/10/sea-level-in-the-5th-ipcc-report/
On Tue, Nov 15, 2016 at 11:38 PM, Knutti Reto <[email protected]> wrote:
Dear John, > an embarrassment to IPCC, as it conflicts with their story that
global warming can be restricted to 2C or even 1.5C by getting net CO2
emissions to zero. This is obviously not true from the physics, as I pointed
out to you and some other distinguished scientists a few days ago without
challenge! When net emissions fall to zero the rise in atmospheric CO2
flattens off but the climate forcing remains, so temperature will continue
rising. I wish I was wrong about this, and we could halt temperature rise so
easily. But, if we are halt global warming we have to reduce the net forcing
from all radiative forcing agents, including Arctic albedo loss, to zero. I
don’t deny the need for strong mitigation, but let’s try to inform decisions by
the best possible science. Where is the evidence that zero CO2 emissions soon
(say before 2050) would be insufficient to limit warming to 2°C. Please send me
the papers or your analysis. I’d like to know what is “obviously not true from
the physics”. If by “halt global warming” you mean limit/stabilize warming at
some level above preindustrial (e.g. 1.5 or 2°C), then your statement is simply
wrong: net forcing does not need to be zero as I showed below. By definition
net zero forcing implies zero warming in after sufficient time, because the
forcing is defined as an anomaly from a reference temperature, typically
preindustrial. Best regards, Reto Knutti From: John Nissen
[mailto:[email protected]]
Sent: Dienstag, 15. November 2016 14:53
To: Michael MacCracken <[email protected]>
Cc: Knutti Reto <[email protected]>; David Lewis
<[email protected]>; geoengineering <[email protected]>;
Kevin Anderson <[email protected]>;[email protected];
Greg Rau <[email protected]>; Peter Wadhams <[email protected]>; Kevin
Lister <[email protected]>; Sev Clarke <[email protected]>; Alan
Gadian <[email protected]>
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard? [Please excuse if this arrives twice]
Hi Mike,I suppose I might have expected you to loyally defend IPCC. But their
position is untenable.On the sea ice, Peter Wadhams presented the death spiral
to an audience of sea ice modelling experts at the Royal Society, and not a
single person rose to say it is not happening. The exponential trend of sea
ice volume decline has been followed until 2012, and even the subsequent volume
estimates (which are tricky due to so much broken ice and surface slush) are
within natural variability. Therefore on the precautionary principle we must
act on the expectation of losing sea ice at the end of summer within a few
years, despite what modellers might hope.Peter Wadhams points out in his book
that the trend towards nearly ice-free conditions in September is "blindingly
obvious" and he cannot understand why IPCC clings to models. "The trend in the
PIOMAS data effectively gives us a drop-dead date of about 2020 for summer sea
ice" [1].As Kevin Lister points out, a rapid demise of sea ice would be an
embarrassment to IPCC, as it conflicts with their story that global warming can
be restricted to 2C or even 1.5C by getting net CO2 emissions to zero. This is
obviously not true from the physics, as I pointed out to you and some other
distinguished scientists a few days ago without challenge! When net emissions
fall to zero the rise in atmospheric CO2 flattens off but the climate forcing
remains, so temperature will continue rising. I wish I was wrong about this,
and we could halt temperature rise so easily. But, if we are halt global
warming we have to reduce the net forcing from all radiative forcing agents,
including Arctic albedo loss, to zero. This means we have the huge challenge
of reducing levels of CO2, methane and other greenhouse gases to their
pre-industrial levels. And we have to restore Arctic albedo.When we have done
all this, we will have saved the sea ice, halted sea level rise from Greenland
ice melt and hopefully restored climate in the Northern Hemisphere, reducing
the weather extremes to their old level.Thus we should be close to restoring
the Earth System to the 'old norm' of the Holocene in which our civilisation
developed and flourished.In the process we can actually improve food
production, as I point out in the attached letter which I was hoping could be
presented to COP22.Restoration is the only path to a safe future for our
children and grand-children. It can be done. It must be done. Best wishes,
John [1] Wadhams (2016) "A farewell to ice" page 88. On Tue, Nov 15, 2016 at
7:38 PM, Michael MacCracken <[email protected]> wrote:
Dear Knutti--Thank you for your note and full explanation. I have been trying
to point out these misconceptions of John's for a number of years now. I hope
your note will finally convince him.I have also been trying to convince him
that the really significant drop in albedo leading to large amounts of
additional solar absorbed comes when the fresh snow on ice melts (presumably in
late spring), reducing the surface albedo from something like 70-80% to or
order 20-30% and that the albedo effect of going from melting ice surface
albedo to the albedo of open water (with Sun at low slant angle) will not lead
to a catastrophic increase in the absorbed heat in the fall (though it may well
set the situation up for an earlier melting of the snow surface in the spring,
etc.). What would be really interesting to have is a graph of the amount of
solar heat uptake at the surface over the warm season (I guess, as well,
actually having a comparison of what the uptake is now with what it would be
were there no sea ice).Best regards, Mike MacCracken On 11/15/16 2:18 PM,
Knutti Reto wrote:
Dear John, all As a coordinating lead author of IPCC AR5 WG1 (and someone how
has done work on these topics) I’m surprised to read such comments. > Blunder
1. IPCC has ignored the increasing loss of Arctic albedo, which is already
contributing the equivalent of 30 ppm CO2 to the radiative budget, i.e. a
quarter of the forcing from CO2. […] The first blunder is symptomatic of
IPCC's treatment of the Arctic sea ice, where they refuse to accept the
observations that it is in a death spiral, preferring to rely on models of
proven inadequacy which predict that the sea ice will last for decades. You
can read all about it in Peter Wadhams' new book "A Fairwell to Ice". The
change in albedo is part of every climate model as snow cover and sea ice
change. Indeed some many models show smaller Arctic sea ice decline than
observed. But the natural variability is very large (e.g. Kay 2011, Swart 2015,
Screen 2013, 2016). There is no reason why short term trends could simply be
extrapolated, and the predictions by Peter Wadhams of sea ice disappearing by
today have not happened so far
(https://www.theguardian.com/environment/2012/sep/17/arctic-collapse-sea-ice,http://www.independent.co.uk/environment/climate-change/arctic-could-become-ice-free-for-first-time-in-more-than-100000-years-claims-leading-scientist-a7065781.html).
Maybe the models are missing something, but it’s just as plausible (and in
most scientist’s view more likely) that the models are largely consistent with
observations within natural variability.Many studies have used observations to
recalibrate and weight models, and even IPCC has explicitly made projections
for Arctic sea ice based on those models that best reproduce various aspects of
sea ice (section 12.4.6.1). All of these studies indicate that using
observations point to a somewhat steeper decline of Arctic sea ice (Boe 2009,
Massonnet 2012, Mahlstein 2012, Wang 2013, Notz 2016), but not a “death
spiral”.I’m not downplaying the strong changes in the Arctic, but the science
suggests a fairly linear (and reversible) relationship between Arctic sea ice
and temperature with large variability superimposed. In my view they do not
support a “death spiral”. >Blunder 2. IPCC has ignored the warming effect of
accumulated CO2. They say that global temperature rise will be halted when net
CO2 emissions have fallen to zero, ignoring the effect of accumulated CO2 and
other forcing agents in the atmosphere.[…] The second blunder can be
illustrated by AR5 WG1 figure 6-40 attached and available here [1]. The red
curves are supposed to show the effect if net emissions were to suddenly fall
to zero at 2050, when CO2 has reached about 500 ppm. The temperature (red
curve in bottom diagram) should continue to rise as a result of the forcing
from 500 ppm CO2; but instead the temperature flattens off as if the
accumulated CO2 ceased to have a warming effect! Of course CO2 continues to
have an effect, but as emissions are set to zero the atmospheric concentration
and therefore forcing decrease. >It is absolutely astonishing and frightening
that such a fundamental mistake can be made.Where is the evidence for a
fundamental mistake? >If we want to halt global warming at any particular
temperature, then we need to bring net forcing down to zero by the time that
temperature has been reached.No, that is simply wrong. The forcing has to
decrease to compensate the slowly decreasing ocean heat uptake, but it does not
have to be zero at any time to limit warming, not even in equilibrium. The
global energy balance is Q=F-lambda*T where Q is heat uptake, F is forcing,
lambda is the inverse of climate sensitivity and T is warming (see Knutti and
Hegerl 2008 for example). If today F~=2.3 Wm-2 and Q~=0.9 Wm-2 and we want to
keep T constant and Q=0 towards equilibrium then F needs to decrease to about
2.3-0.9=1.4 Wm-2 on the timescale on which the ocean warms (decades to
centuries), but not zero. Climate is complex, but conservation of energy isn’t.
IPCC WG1 chapter 12 has an long discussion of the difference concepts of
commitment warming (section 12.5.2) with plenty of references from different
models going back many decades. There is even an FAQ 12.3 discussing that, and
it also does discuss non-CO2 forcings. There are models which show some warming
after zero CO2 emissions, and others that show some cooling, but in general
these concepts of commitment warming are well understood. IPCC isn’t perfect,
but it’s probably the best reviewed document on climate, with hundreds of
scientist contributing. It seems rather unlikely that it would contain
“fundamental mistakes”, and in my view the claims you made here have no
scientific basis. Best regards, Reto Knutti, ETH Zurich
http://www.iac.ethz.ch/people/knuttir Swart, Neil C., John C. Fyfe, Ed Hawkins,
Jennifer E. Kay, and Alexandra Jahn. 2015. “Influence of Internal Variability
on Arctic Sea-Ice Trends.”Nature Climate Change 5 (2). Nature Publishing Group:
86–89. doi:10.1038/nclimate2483.Kay, Jennifer E., Marika M. Holland, and
Alexandra Jahn. 2011. “Inter-Annual to Multi-Decadal Arctic Sea Ice Extent
Trends in a Warming World.”Geophysical Research Letters 38 (15): 2–7.
doi:10.1029/2011GL048008.Screen, James a., Clara Deser, Ian Simmonds, and
Robert Tomas. 2013. “Atmospheric Impacts of Arctic Sea-Ice Loss, 1979–2009:
Separating Forced Change from Atmospheric Internal Variability.”Climate
Dynamics 43 (1–2): 333–44. doi:10.1007/s00382-013-1830-9.Screen, James A., and
Jennifer A. Francis. 2016. “Contribution of Sea-Ice Loss to Arctic
Amplification Is Regulated by Pacific Ocean Decadal Variability.”Nature Climate
Change 6 (9): 856–60. doi:10.1038/nclimate3011.Boé, Julien, Alex Hall, and Xin
Qu. 2009. “September Sea-Ice Cover in the Arctic Ocean Projected to Vanish by
2100.”Nature Geoscience 2 (5). Nature Publishing Group: 341–43.
doi:10.1038/ngeo467.Mahlstein, Irina, and Reto Knutti. 2012. “September Arctic
Sea Ice Predicted to Disappear near 2°C Global Warming above Present.”Journal
of Geophysical Research 117 (D6): 1–11. doi:10.1029/2011JD016709.Notz, Dirk,
and Julienne Stroeve. 2016. “Observed Arctic Sea-Ice Loss Directly Follows
Anthropogenic CO2 Emission.”Science, November, 1–9.
doi:10.1126/science.aag2345.Overland, James E., and Muyin Wang. 2013. “When
Will the Summer Arctic Be Nearly Sea Ice Free?”Geophysical Research Letters 40
(10): 2097–2101. doi:10.1002/grl.50316.Massonnet, F., T. Fichefet, H. Goosse,
C. M. Bitz, G. Philippon-Berthier, M. M. Holland, and P.-Y. Barriat. 2012.
“Constraining Projections of Summer Arctic Sea Ice.”The Cryosphere 6 (6):
1383–94. doi:10.5194/tc-6-1383-2012.Knutti, Reto, and Gabriele C. Hegerl. 2008.
“The Equilibrium Sensitivity of the Earth’s Temperature to Radiation
Changes.”Nature Geoscience 1 (11): 735–43. doi:10.1038/ngeo337.
From:[email protected] [mailto:[email protected]]On
Behalf Of John Nissen
Sent: Montag, 14. November 2016 16:06
To: David Lewis <[email protected]>
Cc: geoengineering <[email protected]>; Kevin Anderson
<[email protected]>;[email protected]; Greg Rau
<[email protected]>; Peter Wadhams <[email protected]>; Kevin Lister
<[email protected]>; Sev Clarke <[email protected]>; Alan Gadian
<[email protected]>
Subject: Re: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver,
and/or Moral Hazard? Dear David,I think Klaus et al have the voice of realism.
Global warming is far more serious than we have been led to believe, and
without several rapid interventions, we are heading for many degrees of global
warming this century.
IPCC are guilty of two colossal blunders in their projections of global
warming. The effect has been to lull the international community into a false
sense of security. Rapid interventions are now required to avoid a lethal
combination of climate change, ocean acidification and rising sea levels. Here
are the facts:
Blunder 1. IPCC has ignored the increasing loss of Arctic albedo, which is
already contributing the equivalent of 30 ppm CO2 to the radiative budget, i.e.
a quarter of the forcing from CO2. Blunder 2. IPCC has ignored the warming
effect of accumulated CO2. They say that global temperature rise will be
halted when net CO2 emissions have fallen to zero, ignoring the effect of
accumulated CO2 and other forcing agents in the atmosphere.The first blunder is
symptomatic of IPCC's treatment of the Arctic sea ice, where they refuse to
accept the observations that it is in a death spiral, preferring to rely on
models of proven inadequacy which predict that the sea ice will last for
decades. You can read all about it in Peter Wadhams' new book "A Fairwell to
Ice".
The second blunder can be illustrated by AR5 WG1 figure 6-40 attached and
available here [1]. The red curves are supposed to show the effect if net
emissions were to suddenly fall to zero at 2050, when CO2 has reached about 500
ppm. The temperature (red curve in bottom diagram) should continue to rise as
a result of the forcing from 500 ppm CO2; but instead the temperature flattens
off as if the accumulated CO2 ceased to have a warming effect! It is
absolutely astonishing and frightening that such a fundamental mistake can be
made. If we want to halt global warming at any particular temperature, then we
need to bring net forcing down to zero by the time that temperature has been
reached. This involves bringing all GHGs down to their pre-industrial level
and restoring Arctic albedo, unless their residual heating (positive forcing)
is counteracted by an equal amount of cooling (negative forcing), e.g. from
aerosols. CDR has to suck CO2 out of the atmosphere faster than it is being
emitted into the atmosphere, in order to bring the level down from over 400 ppm
to pre-industrial 280 ppm.Methane emissions have to be suppressed (including
fugitive emissions from coal, oil and gas extraction) in order to bring the
level down from 1850 ppb to pre-industrial 750 ppb. The retreat of sea ice has
to be halted and then Arctic albedo has to be restored to its level of at least
thirty years ago. Thus our best chance to halt global warming is through CO2
emissions reduction (better than already committed) combined with several
immediate and aggressive interventions: CDR, methane emissions reduction, and
rapid cooling of the Arctic.
As Klaus Lackner et al say in their comment, CDR is indeed like throwing a
lifebelt to a drowning person. We need to start CDR as quickly as we can, to
be as certain as we can be to save the planet.In parallel we must suppress
methane and cool the Arctic before we lose any more albedo from snow and sea
ice retreat. The ultimate objective must be to restore the Earth System to
Holocene conditions of climate stability, ocean alkalinity and sea level
constancy. Cheers, John
[1]
http://www.ipcc.ch/report/graphics/images/Assessment%20Reports/AR5%20-%20WG1/Chapter%2006/thumbnail/Fig6-40.jpg
On Mon, Nov 14, 2016 at 4:55 PM, David Lewis <[email protected]> wrote:
Anderson could maintain his stance as a voice for realism while adding his
voice to those calling for research into all forms of geoengineering. He could
compare the cost of reducing emissions to the current cost of removing them
from the atmosphere, call for a vigorous program of further research, then
state that it is still his opinion that civilization needs to urgently and
fundamentally transform its social, economic, and political relations if it
wants to continue to exist.
Moral: Do not ignore or downplay potentially useful actions, especially if you
have the time and resources to carefully evaluate them.
From: Greg Rau <[email protected]>
To: Geoengineering <[email protected]>
Sent: Friday, November 11, 2016 4:50 PM
Subject: [geo] Negative Emissions: Arrows in the Quiver, Life Preserver, and/or
Moral Hazard? --
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http://science.sciencemag.org/content/354/6313/714.1
GR: Disclaimer - I was a co-signer.
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