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Author Topic: IPCC possible scenario: 9 C over next century or so  (Read 78999 times)

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #50 on: October 18, 2014, 09:45:03 PM »
I am not seeing water vapor, I think it is also one of the main green house gazes ?! Generaly it is not considered because the molecules do not stay long in the atmosphere. If so then it is like the methane considering a 100 year range is purely statistical, if the water vapor is replaced like methane, the immediate effect has to be considered ?!

Laurent,

The contribution from water vapor to global warming is treated as a (positive) feedback factor in what I presented; therefore, this contribution is already included in the TCR, ECS, and ESS values that we are discussing (so we do not want to double count).

Best,
ASLR
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #51 on: October 18, 2014, 09:48:24 PM »

First, you are averaging emissions between 2040 and 2100, rather than referring to 2100 emission value.
Second, you neglect that 2% of the emissions are in the form of methane which has a 100-year GWP of 35 so your numbers contain a 2% x 35 = 70% error (on the low side).

Thus the authors of the paper that Robert Scribbler cites are correct.

Co2 equivelant means the methane is already taken into account.  Remember I calculated it as 15%  of 2012 Co2, so if I calculated as percent of 2100 human emissions under RCP8.5, and was able to consider that the 2040-2100 Arctic rate would be higher in 2100 than the average - I'm sure the figure would be lower still. 

I do not disagree with what the authors of the paper Robert cites.  Nowhere do they say 35%.  If I calculate on the figures the authors provide it is nowhere near 35%.

Michael (or other readers),

I suggest that you look at the following reference, as these authors make the matter very clear:

Schuur, E.A.G. and Abbott, B., (2011), "High risk of permafrost thaw", Nature, 480, 32-33, Dec. 2011.

Best,
ASLR
« Last Edit: October 19, 2014, 02:45:20 AM by AbruptSLR »
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #52 on: October 18, 2014, 10:02:11 PM »
While some may think that my discussion of some of the climate sensitivity implications of the potential collapse of the WAIS as being too extreme.  I note that in a world with a mean global temperature rise of 9 degrees C, the collapse of the WAIS is inevitable either this century, or next, and regarding the plausibility of a mean global temperature rise of 9 degrees C by 2100, I provide the following points:

A.  The anthropogenic forcing for the RCP scenarios do not come from scientists, they come from economists working together with policy maker.  Thus these RCP scenarios do not follow normal rigorous scientific procedures, and thus are subject to the wishful thinking of politicians (whom the policy makers work for) who do not want to excite their constituents.



The emissions scenarios 8.5 is enough to make large parts of the planet uninhabitable.  It is not an invention of the politicians trying to avoid exciting their constituents.

B. The IPCC AR5 projections to not use Earth System Model findings, as they felt that Earth System Models, ESMs, were to avant garde.  Therefore, while ESMs try to consider fast, intermediate and slow response feedback mechanisms (that parallel ESS values), the IPCC AR5 reports do not full capture such factors.


The IPCC do analyse ESM projections and note that for the next century they predict basically the same warming rate  as the AOGCMs that they do use.  (see here)
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #53 on: October 18, 2014, 10:13:07 PM »
The following linked Skeptical Science article (and associated extract) states that when Kummer & Dessler (2014) (see reference at bottom of this post) calculate that the best estimate of ECS is 3oC, they conservatively assume that climate is 33% more sensitive to changes in aerosols and ozone than greenhouse gases; however, Shindell (2014) showed that climate is more sensitive to changes in aerosols and ozone than greenhouse gases perhaps by as much as 50%.  Therefore, perhaps Kummer & Dessler are under estimating the best value of ECS by as much as 50%/33%, or by a factor of about 1.5.  If so then based on Shindell (2014) the best estimate of ECS may perhaps be 4.5 oC instead of 3oC.

https://www.skepticalscience.com/sense-and-climate-sensitivity-kummer-dessler-2014.html

Extract: "In short, Shindell showed that according to models, the climate is significantly more sensitive to changes in aerosols and ozone than greenhouse gases, perhaps by as much as 50%. Kummer & Dessler showed that if the climate is 33% more sensitive to changes in aerosols and ozone, then the 'instrumental' estimates are right in line with those derived from historical climate changes and global climate models, with a best estimate of 3°C warming in response to a doubling of atmospheric CO2."

J.R. Kummer and A.E. Dessler, (2014), "The impact of forcing efficacy on the equilibrium climate sensitivity", Geophysical Research Letters, DOI: 10.1002/2014GL06004

http://onlinelibrary.wiley.com/doi/10.1002/2014GL060046/abstract


Read what you just quoted again.  The 3 degree estimate of sensitivity is after the 50% increase in effectiveness of aerosols is taken into account.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #54 on: October 18, 2014, 10:40:05 PM »
To me the following linked reference, and extract, from a June 11 2014 Skeptical Science article indicates that: (a) The close match of the CESM1-CAM5 Large Ensemble Community Project, LE, mean global surface warming rates (in degrees C per decade) to the observed NOAA record indicates that the 4.1 degrees C ECS value used by the LE ensemble is a very likely value, and that ESS values this century could exceed this value; and (b) finds that"… a relatively unchanged planetary imbalance during the recent hiatus period is entirely consistent with analogous periods in LE simulations."

http://www.skepticalscience.com/challenges-constraining-climate-sensitivity.html

Caption: "Fig. 2: The range of decadal trends in global mean surface temperature from the CESM1-CAM5 Large Ensemble Community Project (LE, black and grey lines, 18) along with an observed estimate based on the NOAA-NCDC Merged Land and Ocean Surface Temperature dataset. Also shown are the mean (circle) and range (lines) of simulated planetary imbalance (right axis) from 2000 through 2010 for the 10 members of the LE with greatest cooling (blue) and warming (red)."
 
Extract: "The NCAR CESM1-CAM5 Large Ensemble Community Project provides a unique framework for understanding the role of internal variability in obscuring forced changes. It currently consists of 28 ensemble members in simulations of the historical record (1920-2005) and future projections (2006-2080) based on RCP8.5 forcing.
At 4.1 C, the ECS of the CESM1-CAM5 is higher than for most GCMs. Nonetheless, decadal trends from the model track quite closely with those derived from NOAA-NCDC observations (red line), with the model mean decadal trend (thick black line) skirting above and below observed trends about evenly since 1920. In several instances, decadal trends in observations have been at or beyond the LE ensemble range including intervals of exceptional observed warming (1945, 1960, 1980) and cooling (1948, 2009). The extent to which these frequent departures from the LE reflect errors in observations, insufficient ensemble size, or biases in model internal variability remains unknown. Nonetheless, there is no clear evidence of the model sensitivity being systematically biased high. Also noteworthy is the fact that the LE suggests that due to forcing, as indicated by the ensemble mean, certain decades including the 2000s are predisposed to a reduced rate of surface warming.

The LE also allows for the evaluation of subsets of ensemble members, such as in Fig 2, where the planetary imbalances for the 10 ensemble members with the greatest global surface warming (red) and cooling (blue) trends from 2000-2010 are compared. It is found that no significant difference exists between the two distributions and the mean imbalance for the cooling members is actually greater than for the warming members. Thus the finding of a relatively unchanged planetary imbalance during the recent hiatus period is entirely consistent with analogous periods in LE simulations. While the LE does suggest that recent trends have been exceptional, this is also suggested by the instrumental record itself, which includes exceptional El Niño (1997-98) and La Niña events (2010-2012) at the bounds of the recent hiatus."


It is not the only model to match observed temperature history.  I don't see any reason to prefer this model to other models with a lower ESS.

And an important point illustrated by this model is that a model run with a higher climate sensitivity has to have a slower transient response to match the climate history to date.  If you look at projections of this model using this model (link) the warming is significantly slower than your initial chart of RCP8.5 under a 4.5 ESS.  The model shows 4 degrees by 2080 (as far as it goes), whereas your scenario shows nearly 6 by around this date.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #55 on: October 19, 2014, 03:07:11 AM »
Michael H.,

You are welcome to retain your opinions, as I continue to retain my opinions; and it is my opinion that the longer that people choose to deny the seriousness of our current situation; the more certain that serious future becomes.  Furthermore, I do not believe that pointing to Intermediate ESM's cited in IPCC AR4, (as your link lead to) with lower complexities that the AOGCMs available at that time (prior to 2007) has any bearing on our current discussion regarding state-of-the-art science and modern complex ESMs (see the linked article about the ACME project).

http://www.scientificcomputing.com/news/2014/09/developing-most-advanced-earth-system-computer-model-yet-created

Obviously, state-of-the-art ESMs are works in progress, but hopefully if there ever is an AR6 issued by the IPCC, the findings of such complex ESMs will clarify the seriousness of society's situation; the seriousness of which I believe will become all to clear as the PDO and the AMO move into warming phases.

Best,
ASLR
« Last Edit: October 19, 2014, 04:45:37 PM by AbruptSLR »
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S.Pansa

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #56 on: October 19, 2014, 09:41:29 AM »
Thanks Michael & AbruptSLR for this very interesting discussion.

Just a short remark about the permafrost discussion in reply 51.

: Michael Hauber  October 18, 2014, 09:38:00 PM

    : AbruptSLR  October 17, 2014, 05:01:35 PM


        First, you are averaging emissions between 2040 and 2100, rather than referring to 2100 emission value.
        Second, you neglect that 2% of the emissions are in the form of methane which has a 100-year GWP of 35 so your numbers contain a 2% x 35 = 70% error (on the low side).

        Thus the authors of the paper that Robert Scribbler cites are correct.


    Co2 equivelant means the methane is already taken into account.  Remember I calculated it as 15%  of 2012 Co2, so if I calculated as percent of 2100 human emissions under RCP8.5, and was able to consider that the 2040-2100 Arctic rate would be higher in 2100 than the average - I'm sure the figure would be lower still.

    I do not disagree with what the authors of the paper Robert cites.  Nowhere do they say 35%.  If I calculate on the figures the authors provide it is nowhere near 35%.


Michael (or other readers),

I suggest that you look at the following reference, as these authors make the matter very clear:

Schuur, E.A.G. and Abbott, B., (2011), "High risk of permafrost thaw", Nature, 480, 32-33, Dec. 2011.

Best,
ASLR


I think Michael is right when he says that the estimates for the CO2 emissions from Schuur (2011) are equivalent numbers (even tough they seem to use an older estimate for the methane GWP100 of 25 and not the Shindell & AR5 number of 34); but the error in Michaels reply 31 seems to be that the numbers are not in CO2 equivalent, but in C equivalent. To quote from the paper, p33 (free pdf - http://sa.indiaenvironmentportal.org.in/files/file/permafrost%20thaw.pdf]):

Collectively, we hypothesize that the high warming scenario will degrade 9–15%
of the top 3 metres of permafrost by 2040 ...
The estimated carbon release from this degradation is 30 billion to 63 billion tonnes
of carbon by 2040, reaching 232 billion to 380 billion tonnes by 2100 and 549 billion
to 865 billion tonnes by 2300. These values, expressed in CO 2  equivalents, combine
the effect of carbon released as both CO 2  and as CH 4 .


So if i am not mistaken we would have to multiply these numbers by 3.664 to get the CO2 equivalent emissions. For 2040 I get: 110 to 230 Gt CO2 eq. and for 2100 it's 850 to 1.450 Gt CO2 eq. Is that correct or even possible? It seems quite high to me.

On the other hand MacDougall (2012) estimates permafrost emissions from permafrost soils by 2100 between 68 and 508 Pg carbon (same as Gt I think), with a best estimate of 174 Gt C, which would be ~640 Gt CO2.

from MacDougall: Significant contribution to climate warming from
the permafrost carbon feedback, Nature Geoscience 2012 (http://climate.uvic.ca/people/ahmacd/Publications_files/MacDougallEtAl2012.pdf)
« Last Edit: October 19, 2014, 03:42:29 PM by S.Pansa »

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #57 on: October 19, 2014, 05:32:32 PM »
S.Pansa,

Your conversion factors are correct, and you are also correct that when Schuur & Abbott (2011) published their finds no one knew that the 100-year GWP for methane is 34 instead of 25.  Furthermore, modern findings such as that cited below for Karhu et al (2014) the microbial activity in the permafrost (and many other soils) is higher than was previously (before 2014) understood, thus these earlier estimates also need to be increased to account for microbial activity in the soils worldwide:


Kristiina Karhu, Marc D. Auffret, Jennifer A. J. Dungait, David W. Hopkins, James I. Prosser, Brajesh K. Singh, Jens-Arne Subke, Philip A. Wookey, Göran I. Ågren, Maria-Teresa Sebastià, Fabrice Gouriveau, Göran Bergkvist, Patrick Meir, Andrew T. Nottingham, Norma Salinas & Iain P. Hartley,  "Temperature sensitivity of soil respiration rates enhanced by microbial community response", Nature, 513, 81–84, doi:10.1038/nature13604


http://www.nature.com/nature/journal/v513/n7516/full/nature13604.html


Abstract: "Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted."

Best,
ASLR

edit: The following are some carbon - CO2 conversion factors for reader's general use:

To Convert                    To                       Multiply By
Carbon (short tons)    CO2 (short tons)        3.667 or 44/12
CO2 (short tons)       Carbon (short tons)    0.2727 or 12/44
1ppm Atmospheric CO₂   GtCarbon            2.12

Note that the fraction of carbon in carbon dioxide is the ratio of their weights. The atomic weight of carbon is 12 atomic mass units, while the weight of carbon dioxide is 44, because it includes two oxygen atoms that each weigh 16. So, to switch from one to the other, use the formula: One ton of carbon equals 44/12 = 11/3 = 3.67 tons of carbon dioxide. Thus 11 tons of carbon dioxide equals 3 tons of carbon.
« Last Edit: October 19, 2014, 05:42:09 PM by AbruptSLR »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #58 on: October 19, 2014, 05:47:37 PM »
The following reference provides paleo evidence that equilibrium (Charney) climate sensitivity, ECS, is greater during warming periods and lower during glacial climates.  As researchers normally assume that ECS is equal during either warming, or cooling, climate phases, this implies that as we enter a warming period GCM projections are typically erring on the side of least drama (in other words current GCM projections are wrong given our warming situation, so as to encourage people to continue on a business as usual basis [that leads to 9 degrees C warming by 2100]):

A. S. von der Heydt, P. Köhler, R. S. W. van de Wal and H. A. Dijkstra, (2014), "On the state dependency of fast feedback processes in (palaeo) climate sensitivity", Geophysical Research Letters; DOI: 10.1002/2014GL061121


http://onlinelibrary.wiley.com/doi/10.1002/2014GL061121/abstract


Abstract: "Palaeo data have been frequently used to determine the equilibrium (Charney) climate sensitivity Sa, and — if slow feedback processes (e.g. land ice-albedo) are adequately taken into account — they indicate a similar range as estimates based on instrumental data and climate model results. Many studies assume the (fast) feedback processes to be independent of the background climate state, e.g., equally strong during warm and cold periods. Here we assess the dependency of the fast feedback processes on the background climate state using data of the last 800 kyr and a box-model of the climate system for interpretation. Applying a new method to account for background state dependency, we find Sa = 0.61 ± 0.07 K (W m − 2) − 1 (± 1σ) using the latest LGM temperature reconstruction and significantly lower climate sensitivity during glacial climates. Due to uncertainties in reconstructing the LGM temperature anomaly, Sa is estimated in the range Sa = 0.54 – 0.95 K (W m − 2) − 1."
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #59 on: October 19, 2014, 10:24:21 PM »
In order to clarify the nature of climate sensitivity probability distribution functions, one needs to understand how they are constructed, and one needs to realize that different researchers report climate sensitivity that mean different things. In this regard, the  first two attached images are from Roe and Baker (2007).  The first attached image shows (for the linear case) the probability function of a positive feedback factor hf(f) and how it translates into hT(ΔT) (the probability function of ΔT). The inverse relationship between ΔT and f means that hT(ΔT) (the probability function of ΔT) has a fat tail.  The second attached figure shows how multiple feedback factors can be combined to produce Climate Sensitivity (CS) (see left panel); and how feedback nonlinearity of the feedback factor can affect CS.  Note that these relations always: (a) result in fat tailed high-end CS probability distributions functions (PDFs), and (b) high nonlinearity of the feedback mechanisms can make the tail of the CS PDF even fatter (see the third attached image of the 2010 NASA estimate of a ECS PDF, with a fat-tail (ie high risk).  Furthermore, I note that different researchers combine different feedback mechanisms to produce different CS PDFs that then, strictly speaking, should not be compared; however, the IPCC goes ahead and compares (and combines) them anyway (let the buyer beware).
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #60 on: October 20, 2014, 03:07:07 AM »
The following reference by Hansen et al 2013 implies that equilibrium climate sensitivity, ECS, may be between 3 and 4oC, based on paleoclimate data:

Hansen, J., Mki. Sato, G. Russell, and P. Kharecha, 2013: Climate sensitivity, sea level, and atmospheric CO2. Phil. Trans. R. Soc. A, in press.

"Cenozoic temperature, sea level and CO2 co-variations provide insights into climate sensitivity to external forcings and sea level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise paleoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity 3±1°C for 4 W/m2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e., 3-4°C for 4 W/m2 CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state-dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapor elevates the tropopause. Burning all fossil fuels, we conclude, would make much of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change."
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #61 on: October 20, 2014, 12:30:47 PM »

Collectively, we hypothesize that the high warming scenario will degrade 9–15%
of the top 3 metres of permafrost by 2040 ...
The estimated carbon release from this degradation is 30 billion to 63 billion tonnes
of carbon by 2040, reaching 232 billion to 380 billion tonnes by 2100 and 549 billion
to 865 billion tonnes by 2300. These values, expressed in CO 2  equivalents, combine
the effect of carbon released as both CO 2  and as CH 4 .


So if i am not mistaken we would have to multiply these numbers by 3.664 to get the CO2 equivalent emissions. For 2040 I get: 110 to 230 Gt CO2 eq. and for 2100 it's 850 to 1.450 Gt CO2 eq. Is that correct or even possible? It seems quite high to me.

On the other hand MacDougall (2012) estimates permafrost emissions from permafrost soils by 2100 between 68 and 508 Pg carbon (same as Gt I think), with a best estimate of 174 Gt C, which would be ~640 Gt CO2.

from MacDougall: Significant contribution to climate warming from
the permafrost carbon feedback, Nature Geoscience 2012 (http://climate.uvic.ca/people/ahmacd/Publications_files/MacDougallEtAl2012.pdf)


Thanks for raising that point, I had neglected to consider it and it seems if I include it I should get closer to 35% (I'm getting over 100% at the moment and not in the mood to figure out what I'm currently doing wrong, but 3.5 x my original figure of about 15% of 2012 emissions should be somewhere in the ballpark).

My main points about 9 C in a century are:

1) The emissions under RCP8.5 are highly unlikely.  They assume that no effective action is taken in the next century.  Considering that action has already been taken (if not as much as some would like to see) this seems highly unlikely.  This action has been enough to reverse the increase of Co2 in Europe and America even when the extra Co2 produced in China building imports is taken into account.  Under the 9 degrees by 2100 scenario RCP8.5 would mean failing to take action even when global warming reaches 5 degrees.  I'm not sure whether someone who thinks this could happen is overestimating human stupidity, or underestimating the serious damage that 5 degrees of warming would cause.

2)  Climate sensitivity may be at the high end of IPCC estimates and 50% or more above the central most likely estimate.  However we have been emitting Co2 and measuring the amount of warming for over 100 years.  If climate sensitivity is significantly higher than expected based on (among other evidence) this last 100 years, then one of two things must be true:
2a) The factors causing climate sensitivity to be higher have a significant lag - beyond 100 years, and are therefore not relevant to a projection of climate change for the next 100 years.  However it means that the amount of warming for this higher climate sensitivity will still happen eventually (unless geoengineering can fix it in the meantime)
2b) Something needs to change - for instance a threshold may be reached where serious +ve feedbacks that have not been occurring start to occur (or happen significantly more strongly than had previously been occuring).  Permafrost/methane hydrates are one possible candidate for such a feedback, although I have not read anything on this that convinces me that this is likely to be a strong enough effect to dramatically change the warming picture over the next 100 years.  For instance from the Schuur paper's conclusion:

But despite the massive amount of carbon in permafrost soils, emissions from these soils are unlikely to overshadow those from the burning of fossil fuels, which will continue to be the main source of climate forcing.  Permafrost carbon ... is in some ways more problematic: it occurs in remote places...Trappping carbon emissions at the source - as one might do with powerplants - is not an option.  And once the soils thaw, emissions are likely to continue for decades, or even centuries
Climate change:  Prepare for the worst, hope for the best, expect the middle.

S.Pansa

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #62 on: October 20, 2014, 02:52:45 PM »
AbruptSLR, thanks a lot for checking my numbers & for the links, interesting reads indeed.

@ Michael

I agree with your point 1 regarding the RCP 8.5, especially for the second half of the century. So the discussion of a 9,5 C warming in 2100 under RCP 8.5 seem to me more of academic nature.

But my concern is more about the shorter time frames, say until 2030 or 2040. Based on Friedlingstein, Le Quere, Anderson  and others it seems to me most likely  that we will continue with our emissions on the RCP 8.5 pathway at least until 2019 (of course baring a new global financial crisis). After that, we might get our act together, finally.
But by that time, +- a 5-10 years, the permafrost carbon feedback (PCF) is supposed to set in (Schaefer [2011], Vaks [2013] ...) . And while it is not likely to overshadow our fossil fuel emissions, it could easily be big enough to overshadow our emission reduction efforts.

If I allocate the estimated PCF emissions from Schuur over a period of 20 years (2020-2040), I get CO2-eq emissions between 5,5 and 11,5 Gt per year, that's about 10 to 20% of the total CO2-eq. emissions in 2020 (should be somewhere around 60 Gt while ff emissions alone might be around 40 Gt CO2). I think this is in the same ballpark as your numbers.
Of course there are a lot of uncertainties involved, but this could be enough to lock us in on the RCP 8.5 emissions pathway til 2030 or 2040. And that should be enough for some of the slow positive feedbacks  to kick in (Ice free Arctic Sea for a couple of months, a WAIS plunge,  permafrost and peatland smoking CO2 and CH4 ...).

Regarding climate sensitivity: I honestly have no clue what to make of all these different numbers and estimates and papers. To me, the most tangible summary on this matter I have read in one of Hansens recent papers, where he states that TCs, ECS ... were appropriate for the 20th century, but for the 21st century they might be the wrong measures.
In any event, this is way above a Pansas payroll, so I finally follow Boethius' advice: si tacuisses, philosophus mansisses. I fear it was too late :D

Cheers

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #63 on: October 20, 2014, 05:27:54 PM »
While my last several posts have focused on ECS, I concur that in the 21st century that ESS is much more relevant, as what many consider to be "slow-response" feedback mechanisms may be initiated this century, as discussed in the following Previdi et al (2013) reference:

Previdi, M., B.G. Liepert, D. Peteet, J. Hansen, D.J. Beerling, A.J. Broccoli, S. Frolking, J.N. Galloway, M. Heimann, C. Le Quéré, S. Levitus, and V. Ramaswamy, 2013: Climate sensitivity in the Anthropocene. Q. J. R. Meteorol. Soc., 139, 1121-1131, doi:10.1002/qj.2165.

http://onlinelibrary.wiley.com/doi/10.1002/qj.2165/full

Abstract
"Climate sensitivity in its most basic form is defined as the equilibrium change in global surface temperature that occurs in response to a climate forcing, or externally imposed perturbation of the planetary energy balance. Within this general definition, several specific forms of climate sensitivity exist that differ in terms of the types of climate feedbacks they include. Based on evidence from Earth's history, we suggest here that the relevant form of climate sensitivity in the Anthropocene (e.g. from which to base future greenhouse gas (GHG) stabilization targets) is the Earth system sensitivity including fast feedbacks from changes in water vapour, natural aerosols, clouds and sea ice, slower surface albedo feedbacks from changes in continental ice sheets and vegetation, and climate-GHG feedbacks from changes in natural (land and ocean) carbon sinks. Traditionally, only fast feedbacks have been considered (with the other feedbacks either ignored or treated as forcing), which has led to estimates of the climate sensitivity for doubled CO2 concentrations of about 3°C. The 2×CO2 Earth system sensitivity is higher than this, being ∼4-6°C if the ice sheet/vegetation albedo feedback is included in addition to the fast feedbacks, and higher still if climate-GHG feedbacks are also included. The inclusion of climate-GHG feedbacks due to changes in the natural carbon sinks has the advantage of more directly linking anthropogenic GHG emissions with the ensuing global temperature increase, thus providing a truer indication of the climate sensitivity to human perturbations. The Earth system climate sensitivity is difficult to quantify due to the lack of palaeo-analogues for the present-day anthropogenic forcing, and the fact that ice sheet and climate-GHG feedbacks have yet to become globally significant in the Anthropocene. Furthermore, current models are unable to adequately simulate the physics of ice sheet decay and certain aspects of the natural carbon and nitrogen cycles. Obtaining quantitative estimates of the Earth system sensitivity is therefore a high priority for future work."

In general terms I concur with S.Pansa thinking that as society makes efforts to reduce GHG emissions, the previously un-considered "slow-response feedback mechanisms" will kick-in to maintain the world at, or above, the RCP 8.5 scenario.  I would also like to emphasize that once these "slow-response positive feedbacks" are initiated they are extremely difficult (or impossible) to stop in less than several thousands of years.  While S.Pansa mentioned such slow-response factors such as: permafrost degradation [both CO2 and CH4], Arctic Sea Ice albedo degradation, WAIS collapse, and smoke from wildfires and burning peat; I would like to mention the following that are at least as serious:
(a) GCM forecasts indicate that after about 2030 the Equatorial Pacific will remain permanently in an El Nino-like condition, and as we are now entering a positive PDO cycle that will likely last until 2030, we may never see a high degree of La Nina conditions again.
(b) The boreal forests are currently under stress, which could reach a tipping point in the next few decades (following a RCP 8.5 scenario) due to such factors as: insects, wildfires, droughts, changing seasons that effect reproductive cycles, and heat stress.
(c) The Antarctic Bottom Water, AABW, production currently rate is dropping, and the AMO should enter a warming phase within 10-years [which will limit sequestering ocean heat content into the deep ocean in the North Atlantic for at least 30-years]; which could slow the rate of heat storage in the ocean; which would leave more heat at the surface.
(d) The tropical rainforests will be subjected to accelerated degradation both during the coming positive PDO cycle and due to increasing population growth near the tropical rain forests; which will lead to both reduced CO2 absorption and increased CO2 and CH4 emissions, this century.

edit: (f) while somewhat less certain I believe that it is important to mention that if the ocean water at the seafloor of the Arctic Continental Shelves/Slopes increases [say due to better ocean water vertical mixing, or due to changes in bottom currents] then it is plausible that methane emissions from marine methane hydrates, could also have a serious impact this century.

Furthermore, Michael neglected to mention the temporary nature of many current negative feedback mechanisms as a reason way the effective TCR is apparently less than the average TCR [particularly during the faux hiatus period].  Such temporary negative feedback mechanisms [masking factors] include:
(a) Aerosols [particularly in China] that are likely to be cleaned-up somewhat, soon.
(b) The recent negative phase of the PDO that accelerated storage of heat in the ocean [particularly in the Southern Hemisphere].
(c) The accelerated growth of shrubs in the tundra that is absorbing CO2, but which will soon drastically reduce the land albedo in the northern latitudes that are normally covered with boreal winter snow; and which will contribute to wildfires in the boreal summer.

Again, if we deny the seriousness of our situation, why should we cut back on of anthropogenic radiative forcing?  Therefore, OPEC may as well keep crude oil prices low to promote economic growth and to retard the growth of sustainable energy (and conservation).  Obviously, we are currently above the median RCP 8.5 scenario, and it will take serious effort (will power) to get off this trend, such as passing legislation for carbon pricing (such as a carbon fee with a dividend plan).
 
« Last Edit: October 20, 2014, 11:18:57 PM by AbruptSLR »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #64 on: October 20, 2014, 07:05:57 PM »
I would also like to point-out that if polar amplification is greater than the CMIP5 projections are accounting for, then ESS will be bigger than most scientists are currently assuming.  Furthermore, according to Cowtan & Way (2014) our current reports of mean global temperature are too low because we are currently not correctly including the rapid temperature rise in the Arctic due to Arctic Amplification.  Finally, as the attached image shows (LOTI Anomaly) we recently experienced the warmest September in recorded history [and it occurred with neutral ENSO conditions], and the attached image shows that Antarctic Amplification was largely responsible for this extremely warm September; which is not a good sign for future warming trends.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #65 on: October 20, 2014, 09:20:49 PM »
As a follow-up to my Reply #64:

The two attached images come from the linked report for the Clean Air Task force on recommendations for controlling Black Carbon, BC, and methane in the Arctic.  The first attached images short that short-term forcing components (including ozone, methane and BC) have a much larger impact on the Arctic than on the world on average; while the second image shows how BC gets into the Arctic (see the captions below).  While I applaud the concept of better regulating both BC and methane in the Arctic region, if key countries such as Canada and Russia do not follow the US lead in this regulation; then this report (and these figures) show how sensitivity Arctic Amplification is to these poorly regulated anthropogenic forcing factors, and how quickly global warming could accelerate unless effective action is taken.

"The Last Climate Frontier: Leveraging the Arctic Council to make Progress on Black Carbon and Methane: A Report Prepared for Clean Air Task Force"
by Lindsey Griffith

http://www.eenews.net/assets/2014/10/20/document_cw_01.pdf

Caption for first image: "Impact of Short-Lived Pollutants on Arctic Climate (Source: Quinn, AMAP 2008)"

Caption for second image: "Schematic illustration of processes relevant for transport of BC into the Arctic based on the study by Stohl (2006). Source: AMAP 2011"
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #66 on: October 21, 2014, 12:20:22 AM »

My main points about 9 C in a century are:

1) The emissions under RCP8.5 are highly unlikely.  They assume that no effective action is taken in the next century.  Considering that action has already been taken (if not as much as some would like to see) this seems highly unlikely.  This action has been enough to reverse the increase of Co2 in Europe and America even when the extra Co2 produced in China building imports is taken into account.  Under the 9 degrees by 2100 scenario RCP8.5 would mean failing to take action even when global warming reaches 5 degrees.  I'm not sure whether someone who thinks this could happen is overestimating human stupidity, or underestimating the serious damage that 5 degrees of warming would cause.


There is another possible positive feedback mechanism that is bothering me, and ties in with your objection here. The stress on human population will already be high at 5 degrees warming. And humans might react to that stress by using more energy per capita - more air conditioning, more water hauling and desalinization, more energy investments in producing food, etc. Taking the short term symptom fix over the long-term root cause fix. This feedback might keep us on a high emission path for longer.

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #67 on: October 21, 2014, 01:55:14 AM »

My main points about 9 C in a century are:

1) The emissions under RCP8.5 are highly unlikely.  They assume that no effective action is taken in the next century.  Considering that action has already been taken (if not as much as some would like to see) this seems highly unlikely.  This action has been enough to reverse the increase of Co2 in Europe and America even when the extra Co2 produced in China building imports is taken into account.  Under the 9 degrees by 2100 scenario RCP8.5 would mean failing to take action even when global warming reaches 5 degrees.  I'm not sure whether someone who thinks this could happen is overestimating human stupidity, or underestimating the serious damage that 5 degrees of warming would cause.



There is another possible positive feedback mechanism that is bothering me, and ties in with your objection here. The stress on human population will already be high at 5 degrees warming. And humans might react to that stress by using more energy per capita - more air conditioning, more water hauling and desalinization, more energy investments in producing food, etc. Taking the short term symptom fix over the long-term root cause fix. This feedback might keep us on a high emission path for longer.


The attached graph shows that the world is still following RCP 8.5 (despite all efforts made to date, see Fuss et al 2014 which is where this image came from).  Note that the temperature statements on the figure assume an ECS of 3 degrees C, and as we have just discussed ECS may well be around 4.5 degree C, and ESS could well reach 6 degrees C before 2100.

Sabine Fuss, Josep G. Canadell, Glen P. Peters, Massimo Tavoni, Robbie M. Andrew, Philippe Ciais, Robert B. Jackson, Chris D. Jones, Florian Kraxner, Nebosja Nakicenovic, Corinne Le Quéré, Michael R. Raupach, Ayyoob Sharifi, Pete Smith & Yoshiki Yamagata, (2014), "Betting on negative emissions", Nature Climate Change, doi:10.1038/nclimate2392

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2392.html
 
If policy makers were very wise, society would have gotten off the RCP 8.5 pathway at least 10 years ago.  Also, I agree with oren that people will likely use more GHGs  in order to counter act the stressed effects of climate change on a world population of over 10 Billion people by 2050.  Furthermore, another likely positive feedback factor will be the stress of wars and conflicts induced by the stresses on the world due to a 4 degrees C mean global temperature rise by 2050.

Just because a post-2050, RCP 8.5, world is frightening to consider, does not mean that mankind has the wisdom to get off this pathway any more than an alcoholic has sufficient wisdom to just stop drinking.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #68 on: October 21, 2014, 10:05:53 AM »
And that should be enough for some of the slow positive feedbacks  to kick in (Ice free Arctic Sea for a couple of months, a WAIS plunge,  permafrost and peatland smoking CO2 and CH4 ...).


The slow feedbacks will kick in regardless of what we do.  Basically its a question of to what extent they are linear, or to what extent there are thresholds beyond which they change.  Crudely speaking, for every degree of fast warming we see, we might expect another degree of warming from slow feedbacks over future centuries.  The biggest problem is if this changes.  Perhaps the first 3 degrees of fast warming will result in additional 3 degree of slow warming for future centuries, but then a threshold is crossed so that the 4th degree of fast warming will result in another 3 all by itself.

In a way I guess its the same thing as what you mean and I'm just being pedantic about terminology.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #69 on: October 21, 2014, 10:19:25 AM »

Furthermore, Michael neglected to mention the temporary nature of many current negative feedback mechanisms as a reason way the effective TCR is apparently less than the average TCR [particularly during the faux hiatus period].  Such temporary negative feedback mechanisms [masking factors] include:
(a) Aerosols [particularly in China] that are likely to be cleaned-up somewhat, soon.
(b) The recent negative phase of the PDO that accelerated storage of heat in the ocean [particularly in the Southern Hemisphere].
(c) The accelerated growth of shrubs in the tundra that is absorbing CO2, but which will soon drastically reduce the land albedo in the northern latitudes that are normally covered with boreal winter snow; and which will contribute to wildfires in the boreal summer.
 

My argument is not about feebacks.  I do not believe there are any significant negative feedbacks, and I believe there are strong positive feedbacks.  My argument is primarily about ocean inertia.  The inertia of the ocean means that not all the warming can happen at once.  It is also about the fact that we have seen over a century of warming, so have a reasonable handle on what to expect, unless we cross a threshold that changes the balance of feedbacks.

Further comments:
a) Do you take China's intention to cut back aerosol pollution and ignore their intention to cut carbon pollution?  If China cuts back carbon pollution it is definitely game over for rcp8.5.  RCP includes a big cut in aerosol pollution - at about the same rate as all the other scenarios.
b)PDO has been both up and down over the last century.  The PDO would have had very little effect over this time scale, and this is the time scale my argument relies on.
c)Perhaps so.  Has anyone put a number on this, and is that number high enough to matter?
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #70 on: October 21, 2014, 10:24:38 AM »

There is another possible positive feedback mechanism that is bothering me, and ties in with your objection here. The stress on human population will already be high at 5 degrees warming. And humans might react to that stress by using more energy per capita - more air conditioning, more water hauling and desalinization, more energy investments in producing food, etc. Taking the short term symptom fix over the long-term root cause fix. This feedback might keep us on a high emission path for longer.

Thats also a possibility.  Overall I think its a relatively minor concern.  Either we get our renewable energy on the path to 100% of all energy and solve the problem once and for all.  Or we don't, and any savings from efficiency will only delay the inevitable as Co2 keeps climbing.  Also balancing out increased power demand may be reduced power demand from slowing economic growth etc.  Will using more energy to survive mean we use more energy in total, or just that we use less energy for frivolous matters? 
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #71 on: October 21, 2014, 10:37:48 AM »

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2392.html
 


Up to 2013 co2 matches all the RCPs pretty much.  For 2014 there is a divergence onto the RCP 8.5.  However 2014 is not yet finished and the figure for 2014 is only a 'projection'. 



Just because a post-2050, RCP 8.5, world is frightening to consider, does not mean that mankind has the wisdom to get off this pathway any more than an alcoholic has sufficient wisdom to just stop drinking.


But the alcoholic does not have to give up his addiction, just change to a more expensive and cleaner product.  It is not the energy that we are addicted to that is killing us, its the pollution currently a byproduct of that energy. 

Imagine your hypothetical alcoholic was dieing not from the alcohol, but from a poisonous contamination caused by making the alcohol using the cheapest possible ingredients.  And that nice clean alcoholic beverages are available made from quality ingredients - but for a higher price.  Perhaps there might be exceptions, but I'd bet most alcoholics would quickly change to the cleaner drink once the health impacts became obvious.  And I mean obvious to the drunk, not obvious to the health specialist he goes to for a check-up once a year.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #72 on: October 21, 2014, 12:15:30 PM »
According to the IPCC the worst likely scenario under RCP 8.5 is about 5.5 degrees.  This is because they are looking at the highest model runs where the combination of sensitivity and time lag due to ocean thermal inertia allows the model to reasonably match the last century's temperature history.



Also consider that for the last century we have seen a forcing increase of 2w/m2.  This has raised temperatures globally by about 1 degree.  So 0.5deg for each w/m2.  RCP 8.5 will would increase forcing to about 8w/m2 by 2100.  That is 4 degrees of warming.  Probably not the most accurate method of prediction, but it is a reality check.  If we were to get 9 degrees of warming we see that something must change quite a lot to account for this extra 5 degrees more warming than we would expect if we got the same warming to forcing response as for the 20th century.

Perhaps that something is methane.  This is the recent history of methane emissions:

.

Nature has been able to do absolutely nothing at all to cause methane emissions to speed up.  If the lack of man's visible progress towards reducing global co2 emissions is a valid argument for the future, then natures lack of visible progress towards increasing methane emissions is a valid argument for the future as well.

But of course simplistic arguments like that don't work.  They ignore the fact that a small change can grow over time to become a large change.  What is needed is to put some reasonable numbers to the change, and its rate of growth.  When this is done for renewables we see that we can make a fairly dramatic difference in the next 50 years.  Just look at wind power.  It currently has 4% share of world electricity market.  Growth has been over 20% compound in the last few years.  Lets assume only 5% a year growth.  Assuming that the current growth rate stalls, then the next 50 years will increase wind power to 44% of today's electricity consumption.  That is certainly enough to put a big dent in RCP 8.5 within 50 years even if the growth rate does not compound any further.  Only a modest amount of compounding would be required to reach 100% renewable energy within a 50 year or so timeframe.

So has anyone put together a set of numbers on methane that equates to number of degrees warming by 2100?  Something a bit more specific than '50Gt of methane could re released at any time' and by golly isn't 50GT huge?  Does anytime mean once we achieve 0.5 degrees of warming?  (no or it would have happened already).  2 degrees?  5 degrees?  If 1 degree of warming does not release enough methane to be noticed, then how much warming is required to release enough methane to be a game changer?
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #73 on: October 21, 2014, 03:35:44 PM »
I wouldn't count a graph that cuts off at 2005 (right before the recent sharp increase) as "recent history of methane emissions."

Really, such cherry picking just makes you look like a troll. Is that the reputation you want to have around here?

Here's an actually recent graph:



And from a broader perspective (though do note that this cuts off at 2001):



From either graph it would not seem unreasonable to project an exponential rise in atmospheric methane going forward for quite a while, and there would be plenty of physics to back such a projection up. But no one really knows how fast or how far that train will run. Hence the debates.

In any case, at this point, human CO2 emissions are certainly the main driver, so we can only hope that your optimistic projections for renewables growth prove accurate (and that the renewables actually replace rather than simply supplement ff sources).


« Last Edit: October 21, 2014, 03:51:56 PM by wili »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #74 on: October 21, 2014, 05:17:47 PM »

Furthermore, Michael neglected to mention the temporary nature of many current negative feedback mechanisms as a reason way the effective TCR is apparently less than the average TCR [particularly during the faux hiatus period].  Such temporary negative feedback mechanisms [masking factors] include:
(a) Aerosols [particularly in China] that are likely to be cleaned-up somewhat, soon.
(b) The recent negative phase of the PDO that accelerated storage of heat in the ocean [particularly in the Southern Hemisphere].
(c) The accelerated growth of shrubs in the tundra that is absorbing CO2, but which will soon drastically reduce the land albedo in the northern latitudes that are normally covered with boreal winter snow; and which will contribute to wildfires in the boreal summer.
 


My argument is not about feebacks.  I do not believe there are any significant negative feedbacks, and I believe there are strong positive feedbacks.  My argument is primarily about ocean inertia.  The inertia of the ocean means that not all the warming can happen at once.  It is also about the fact that we have seen over a century of warming, so have a reasonable handle on what to expect, unless we cross a threshold that changes the balance of feedbacks.

Further comments:
a) Do you take China's intention to cut back aerosol pollution and ignore their intention to cut carbon pollution?  If China cuts back carbon pollution it is definitely game over for rcp8.5.  RCP includes a big cut in aerosol pollution - at about the same rate as all the other scenarios.
b)PDO has been both up and down over the last century.  The PDO would have had very little effect over this time scale, and this is the time scale my argument relies on.
c)Perhaps so.  Has anyone put a number on this, and is that number high enough to matter?


Bob,
 (a) The two attached images are from AR5 and clearly indicates that aerosols and precursors contribute significant negative forcing, that is sufficient to temporarily mask the magnitude of the true ECS value, until the aerosols are cleaned up, and to be clear I believe that the Chinese will clean-up their air pollution soon, while leaving their GHG emissions still high (say by using shale gas with leaks, synfuel from coal, or imported oil & gas to replace coal-burning):

Caption for first image: "Radiative Forcing (RF) and Effective Radiative Forcing (ERF) of climate change during the industrial era. Top: Forcing by concentration change between 1750 and 2011 with associated uncertainty range (solid bars are ERF, hatched bars are RF, green diamonds and associated uncertainties are for RF assessed in AR4). Bottom: Probability Density Functions for the ERF, for the aerosol, well-mixed greenhouse gas (WMGHG) and total. The green lines show the AR4 RF 90% confidence intervals and can be compared with the red, blue and black lines which show the AR5 ERF 90% confidence intervals (although RF and ERF differ, especially for aerosols). The ERF from surface albedo changes and combined contrails and contrail induced cirrus is included in the total anthropogenic forcing, but not shown as a separate probability density function. For some forcing mechanisms (ozone, land use, solar) the RF is assumed to be representative of the ERF but an additional uncertainty of 17% is added in quadrature to the RF uncertainty."

Caption for second image: "Radiative forcing of climate change during the industrial era shown by emitted components from 1750 to 2011. The horizontal bars indicate the overall uncertainty, while the vertical bars are for the individual components (vertical bar lengths proportional to the relative uncertainty, with a total length equal to the bar width for a ±50% uncertainty). Best estimates for the totals and individual components (from left to right) of the response are given in the right column. Values are RF except for the ERF of aerosol-cloud interactions (ERFaci). An additional rapid adjustment to aerosol-radiation interactions of –0.1 [–0.3 to +0.1] W m–2 is attributable primarily to black carbon (ERFari-RFari in Figure TS.6). CFCs= Chlorofluorocarbons, HCFCs= Hydrochlorofluorocarbons, HFCs=Hydrofluorocarbons, PFCs= Perfluorocarbons, NMVOC= Non-Methane Volatile Organic Compounds, BC= Black Carbon."

(b) I disagree that we have a century to sort things out.  I believe that unless we start immediately with putting a price on carbon (preferably with a carbon fee and dividend plan), then before 2035 we will exceed the 2 degree C limit, and I believe that the PDO will likely remain positive until about 2035.

(c) Yes, there is a lot of research on how the growth of shrubs reduce the albedo of the tundra, such as the following:

Elmendorf et al (2012), "Plot-scale evidence of tundra vegetation change and links to recent summer warming", Nature Climate Change  2, 453–457, doi:10.1038/nclimate1465

http://www.nature.com/nclimate/journal/v2/n6/full/nclimate1465.html
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #75 on: October 21, 2014, 05:55:48 PM »

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2392.html
 


Up to 2013 co2 matches all the RCPs pretty much.  For 2014 there is a divergence onto the RCP 8.5.  However 2014 is not yet finished and the figure for 2014 is only a 'projection'. 



Just because a post-2050, RCP 8.5, world is frightening to consider, does not mean that mankind has the wisdom to get off this pathway any more than an alcoholic has sufficient wisdom to just stop drinking.


But the alcoholic does not have to give up his addiction, just change to a more expensive and cleaner product.  It is not the energy that we are addicted to that is killing us, its the pollution currently a byproduct of that energy. 

Imagine your hypothetical alcoholic was dieing not from the alcohol, but from a poisonous contamination caused by making the alcohol using the cheapest possible ingredients.  And that nice clean alcoholic beverages are available made from quality ingredients - but for a higher price.  Perhaps there might be exceptions, but I'd bet most alcoholics would quickly change to the cleaner drink once the health impacts became obvious.  And I mean obvious to the drunk, not obvious to the health specialist he goes to for a check-up once a year.


Michael,

Your posts make it seem like you are already addicted to wishful thinking (magic thinking).  The attached Keeling Curve shows that atmospheric CO2 concentration as of Oct 16 2014 is already about 2ppm above the concentration for the same time last year, thus if you do not believe that the GHG concentration for 2014 will remain above the RCP 8.5 values for this year, then you are in serious denial (which is common for addicts of magic thinking).  While I do not have a crystal ball, and I cannot tell what the future will bring; I believe that any rational policy makers would acknowledge our serious situation and enact progressive carbon pricing (preferably a carbon fee and dividend plan) no later than 2016.

Best,
ASLR
« Last Edit: October 22, 2014, 04:43:19 AM by AbruptSLR »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #76 on: October 21, 2014, 06:11:54 PM »
According to the IPCC the worst likely scenario under RCP 8.5 is about 5.5 degrees.  This is because they are looking at the highest model runs where the combination of sensitivity and time lag due to ocean thermal inertia allows the model to reasonably match the last century's temperature history.


Michael,

If you focus, you will notice that you are posting in a thread entitled "IPCC possible scenario: 9 C over next century or so" and wili's first post indicates that this requires the assumption of an ECS of 4.5 degrees C together with a RCP 8.5 forcing scenario.  The RCP 8.5 value of about 5.5 degrees C by 2100 assumes an ECS of about 3 degrees C; which is not the topic of this thread.  The attached figure from Wikipedia about Climate Sensitivity indicates that about 3 degrees C may be the median of the ECS normalize probability frequency, while the mean is closed to 4 degrees C, and there are many NASA simulations that resulted in ECS values above 4 degrees C.  This means that current policy makers are gambling on a somewhat low value of ECS, while the purpose of this thread is to explore the consequences and probabilities that the average ESS for the rest of the century is closer to 4.5 degrees C (or above), and I have provided many references that provide both observational and model data indicating that this may be the case:

http://en.wikipedia.org/wiki/Climate_sensitivity

Caption for attached figure: "Frequency distribution of climate sensitivity, based on model simulations. Few of the simulations result in less than 2 °C of warming—near the low end of estimates by the Intergovernmental Panel on Climate Change (IPCC). Some simulations result in significantly more than the 4 °C, which is at the high end of the IPCC estimates. This pattern (statisticians call it a "right-skewed distribution") suggests that if carbon dioxide concentrations double, the probability of very large increases in temperature is greater than the probability of very small increases."

Best,
ASLR
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #77 on: October 21, 2014, 06:43:49 PM »
As a follow-up to the possible importance of the current positive PDO, I note that the Australian Bureau of Meteorology, BoM, reported today that the Nino 3.4 index for the week ending Oct 19 2014 had a value of +0.62 (while a sustained Nino 3.4 value above +0.5 indicates an El Nino event).  Furthermore, the attached CFSv2 Nino 3.4 forecast issued by NOAA today (Oct 21 2014) indicates a good chance that a strong El Nino event will develop by July 2015; which (if this were to occur) will present the possibility that 2015 could experience a Super El Nino before December 2015.  If a Super El Nino were to occur next year it would almost guarantee that 2015 would be the warmest year on record (as 2014 is currently on track to be warmest year on record); which would likely increase many positive feedback mechanisms into greater activity (such as GHG emissions from tropical rainforests); which would likely keep the world on (or above) the RCP 8.5 scenario.
« Last Edit: October 21, 2014, 07:44:44 PM by AbruptSLR »
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ritter

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #78 on: October 21, 2014, 07:10:43 PM »
The attached graph shows that the world is still following RCP 8.5 (despite all efforts made to date, see Fuss et al 2014 which is where this image came from).  Note that the temperature statements on the figure assume an ECS of 3 degrees C, and as we have just discussed ECS may well be around 4.5 degree C, and ESS could well reach 6 degrees C before 2100.

Sabine Fuss, Josep G. Canadell, Glen P. Peters, Massimo Tavoni, Robbie M. Andrew, Philippe Ciais, Robert B. Jackson, Chris D. Jones, Florian Kraxner, Nebosja Nakicenovic, Corinne Le Quéré, Michael R. Raupach, Ayyoob Sharifi, Pete Smith & Yoshiki Yamagata, (2014), "Betting on negative emissions", Nature Climate Change, doi:10.1038/nclimate2392

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2392.html
 
If policy makers were very wise, society would have gotten off the RCP 8.5 pathway at least 10 years ago.  Also, I agree with oren that people will likely use more GHGs  in order to counter act the stressed effects of climate change on a world population of over 10 Billion people by 2050.  Furthermore, another likely positive feedback factor will be the stress of wars and conflicts induced by the stresses on the world due to a 4 degrees C mean global temperature rise by 2050.

Just because a post-2050, RCP 8.5, world is frightening to consider, does not mean that mankind has the wisdom to get off this pathway any more than an alcoholic has sufficient wisdom to just stop drinking.


Scary stuff. Here's a link to the article that is not paywalled.

http://sites.biology.duke.edu/jackson/ncc2014.pdf

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #79 on: October 21, 2014, 08:07:11 PM »
ritter,

Thanks for the no-paywall link to the Fuss et al (2014) article.  The potential need to deploy large-scale sustainable bioenergy with carbon capture and storage (BECCS) before 2050 in order to just avoid reaching 2 degree C of warming this century, is even more frightening when one considers that if the effective ECS is as high as 4.5 degree C; then by 2050 warming would be about 4 degrees C, at which point plants are subject to so much heat stress that mass vegetation die-offs would contribute to carbon emissions rather than capturing and storing carbon.

Furthermore, the following National Geographic article (and associated image and extract) indicate that crop production will need to more than double by 2050 to meet projected meat consumption for over 9 billion people (note that current mean forecasts project 10 billion people on Earth by 2050).

http://www.nationalgeographic.com/foodfeatures/meat/

Extract: " … by 2050, when the world’s population is expected to surpass nine billion, crop production will need to double to provide feed for livestock as well as direct human consumption."

As meat projection is a significant source of GHG emissions, the indicated increase in meat consumption will accelerate global warming, and if the effective ECS is 4.5 degree C, or more, then it is likely than non-GMO crops will start failing around 2050, leading to mass hunger (or worse).

Best,
ASLR
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #80 on: October 21, 2014, 08:17:58 PM »
Great chart, ASLR. And thanks for the link, rit. I had no idea just how low meat consumption was in most of Asia up till recently--basically around 10-20 calories per day per person on average! It was essentially a rare flavoring agent. If we could all just go to South and East Asian norms of meat eating from the middle of the last century, it would be a huge step toward getting this thing under control.

The other point about the graph of scenarios is that they are from the IPCC, so don't they not fully count carbon feedbacks? And doesn't the recent finding of extra heat in the southern oceans put is even above the 8.5 track now? (How did those tracks get those cryptic numerical names, by the way?)

(ETA: I got off my metaphorical butt and found the answer to my parenthetical question: "Representative Concentration Pathways (RCPs)...are named after a possible range of radiative forcing values in the year 2100 relative to pre-industrial values (+2.6, +4.5, +6.0, and +8.5 W/m2, respectively)." http://en.wikipedia.org/wiki/Representative_Concentration_Pathways ...Good old Wiki!)

The main point of the article at rit's link seems to me to be:

Anything other than the direst projections for temperatures over the next century more and more have to rely on unproven or non-existent carbon sequestration technologies being rapidly developed and massively produced.

For the viability of the planet to sustain future generations we are now depending essentially on pixie dust (i.e. wishful thinking, much in evidence recently on some of these threads).
« Last Edit: October 21, 2014, 08:41:44 PM by wili »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #81 on: October 21, 2014, 08:51:24 PM »
For the viability of the planet to sustain future generations we are now depending essentially on pixie dust (i.e. wishful thinking, much in evidence recently on some of these threads).
Excellent summary, wili. A couple teenths of hopium will get us through.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #82 on: October 21, 2014, 11:22:38 PM »
The other point about the graph of scenarios is that they are from the IPCC, so don't they not fully count carbon feedbacks? And doesn't the recent finding of extra heat in the southern oceans put is even above the 8.5 track now?


wili,

First, the RCP scenarios were developed by the IPCC shortly after AR4, and they are held constant after that so as to allow for comparison of findings from different researchers.  Therefore, the RCP scenarios are never updated to reflect any new research findings.  Also, the following linked thread discusses how the new heat content identified in the Southern Hemispheric oceans implies that the ECS is probably above 4 degrees C.  Furthermore, while the RCP scenarios assume set amounts of anthropogenic and natural radiative forcings, they roughly assume an ECS of 3 degrees C, but as the graph in your first post indicates it is possible to assume an ECS of say 4.5 degrees C (with the same radiative forcing), which should result in higher warming potential.  While the graph in your first post indicates higher mean global temperature by 2014 than have been currently measured, this can be accounted for by the cycles of the ocean temporarily absorbing more heat (such as that in the Southern Hemisphere) than on average (which is what the graph in you first post represents), and by the unusually high concentrations of aerosols (air pollution) in Asia and Africa (that temporarily act as negative feedback factors).

Thus society may not know what the true effective ECS is for several more decades (allowing us to collect more data):


http://forum.arctic-sea-ice.net/index.php/topic,1011.0.html

Best,
ASLR
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viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #83 on: October 21, 2014, 11:38:43 PM »


Just from the look of the graph, the purple curve seems too conservative. We've clearly initiated exponential temperature changes, and the neutral expectation is then to see exponential curves, not straight lines.

This also harmonizes with the known facts that the IPCC never includes snow, ice, albedo, methane or any other life–or–death factors for our planet. Add those, and the curves will be exponential (and go way beyond 9 degrees).
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #84 on: October 22, 2014, 12:07:05 AM »
With regard to combining traditional equilibrium (Charney) climate sensitivity and albedo, as indicated by the attached figure from Hansen and Sato (2012), which indicates that as radiative forcing increases for a period the reduction in albedo resulting from such events as the loss of Arctic Sea Ice, and a decrease in winter snow cover, will significantly increase the effective climate sensitivity of the earth.  Also note that while Hansen and Sato assume a fast feedback climate sensitivity (ECS) of 3 C, Fasullo and Trenberth (2012) indicate that this fast feedback climate sensitivity (ECS) is likely to be closer to 4.5 C rather than 3 C.  While such assessments are not definitive, they do clearly identify a significant increase in the real risk of abrupt climate change as compared to the probabilities cited by the IPCC.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #85 on: October 22, 2014, 10:26:04 AM »
I wouldn't count a graph that cuts off at 2005 (right before the recent sharp increase) as "recent history of methane emissions."

Really, such cherry picking just makes you look like a troll. Is that the reputation you want to have around here?

Here's an actually recent graph:



And from a broader perspective (though do note that this cuts off at 2001):



From either graph it would not seem unreasonable to project an exponential rise in atmospheric methane going forward for quite a while, and there would be plenty of physics to back such a projection up. But no one really knows how fast or how far that train will run. Hence the debates.

In any case, at this point, human CO2 emissions are certainly the main driver, so we can only hope that your optimistic projections for renewables growth prove accurate (and that the renewables actually replace rather than simply supplement ff sources).


Careless me.  Here is a graph which includes 1985 to 2012ish and shows current emissions are way slower than in the late 80s and early 90s.


Remember my point is not that methane can't grow, but that anyone smart enough to realise that methane can grow despite lack of recent impact on the global scale should be smart enough tor realise that renewable energy can also grow despite lack of recent impact on the global scale.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #86 on: October 22, 2014, 10:39:45 AM »

 (a) The two attached images are from AR5 and clearly indicates that aerosols and precursors contribute significant negative forcing, that is sufficient to temporarily mask the magnitude of the true ECS value, until the aerosols are cleaned up, and to be clear I believe that the Chinese will clean-up their air pollution soon, while leaving their GHG emissions still high (say by using shale gas with leaks, synfuel from coal, or imported oil & gas to replace coal-burning):

Caption for first image: "Radiative Forcing (RF) and Effective Radiative Forcing (ERF) of climate change during the industrial era. Top: Forcing by concentration change between 1750 and 2011 with associated uncertainty range (solid bars are ERF, hatched bars are RF, green diamonds and associated uncertainties are for RF assessed in AR4). Bottom: Probability Density Functions for the ERF, for the aerosol, well-mixed greenhouse gas (WMGHG) and total. The green lines show the AR4 RF 90% confidence intervals and can be compared with the red, blue and black lines which show the AR5 ERF 90% confidence intervals (although RF and ERF differ, especially for aerosols). The ERF from surface albedo changes and combined contrails and contrail induced cirrus is included in the total anthropogenic forcing, but not shown as a separate probability density function. For some forcing mechanisms (ozone, land use, solar) the RF is assumed to be representative of the ERF but an additional uncertainty of 17% is added in quadrature to the RF uncertainty."

Caption for second image: "Radiative forcing of climate change during the industrial era shown by emitted components from 1750 to 2011. The horizontal bars indicate the overall uncertainty, while the vertical bars are for the individual components (vertical bar lengths proportional to the relative uncertainty, with a total length equal to the bar width for a ±50% uncertainty). Best estimates for the totals and individual components (from left to right) of the response are given in the right column. Values are RF except for the ERF of aerosol-cloud interactions (ERFaci). An additional rapid adjustment to aerosol-radiation interactions of –0.1 [–0.3 to +0.1] W m–2 is attributable primarily to black carbon (ERFari-RFari in Figure TS.6). CFCs= Chlorofluorocarbons, HCFCs= Hydrochlorofluorocarbons, HFCs=Hydrofluorocarbons, PFCs= Perfluorocarbons, NMVOC= Non-Methane Volatile Organic Compounds, BC= Black Carbon."

I stated that IPCC predict a strong reduction in Aerosol forcing.  I expect the IPCC will be right.  I ask you how you can believe China's intention to reduce the pollution that will cause this drop in aerosol's, but not believe China's intention to reduce the carbon pollution that will result in RCP 8.5 never happening.


(b) I disagree that we have a century to sort things out.  I believe that unless we start immediately with putting a price on carbon (preferably with a carbon fee and dividend plan), then before 2035 we will exceed the 2 degree C limit, and I believe that the PDO will likely remain positive until about 2035.

I also agree that we don not have a century to sort things out.  My point was that the PDO goes up and down many times over a century and is not particularly relevant to projections over a century.

(c) Yes, there is a lot of research on how the growth of shrubs reduce the albedo of the tundra, such as the following:

Elmendorf et al (2012), "Plot-scale evidence of tundra vegetation change and links to recent summer warming", Nature Climate Change  2, 453–457, doi:10.1038/nclimate1465

http://www.nature.com/nclimate/journal/v2/n6/full/nclimate1465.html


I asked whether someone has put a number on it and whether that number is high enough to matter.  Is it really that hard to figure out that I'm asking whether anyone has calculated how much extra global warming we can expect due to this factor? 

You seem to be constantly misinterpreting what I say.  Is what I say that unclear or are you just not paying attention?
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #87 on: October 22, 2014, 10:48:15 AM »

Michael,

Your posts make it seem like you are already addicted to wishful thinking (magic thinking).  The attached Keeling Curve shows that atmospheric CO2 concentration as of Oct 16 2014 is already about 2ppm above the concentration for the same time last year, thus if you do not believe that the GHG concentration for 2014 will remain above the RCP 8.5 values for this year, then you are in serious denial (which is common for addicts of magic thinking).  While I do not have a crystal ball, and I cannot tell what the future will bring; I believe that any rational policy makers would acknowledge our serious situation and enact progressive carbon pricing (preferably a carbon fee and dividend plan) no later than 2016.

Best,
ASLR


Keeling curve shows Co2 concentrations for the last 3 years in Sep:

2014: 395.28
2013: 393.51
2012: 391.06

That makes the growth figures up to September:
2014: 1.77
2013: 2.45

Which suggests that if everything else is equal, Co2 concentrations have fallen alot in 2014.  Of course everything else is not equal(variations in co2 between atmosphere and ocean), so I wouldn't read too much into this figure.  However if you think this is evidence that co2 emissions for 2014 will be higher than 2013 then you are a complete idiot.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #88 on: October 22, 2014, 11:02:16 AM »

Michael,

If you focus, you will notice that you are posting in a thread entitled "IPCC possible scenario: 9 C over next century or so" and wili's first post indicates that this requires the assumption of an ECS of 4.5 degrees C together with a RCP 8.5 forcing scenario.  The RCP 8.5 value of about 5.5 degrees C by 2100 assumes an ECS of about 3 degrees C; which is not the topic of this thread.  The attached figure from Wikipedia about Climate Sensitivity indicates that about 3 degrees C may be the median of the ECS normalize probability frequency, while the mean is closed to 4 degrees C, and there are many NASA simulations that resulted in ECS values above 4 degrees C.  This means that current policy makers are gambling on a somewhat low value of ECS, while the purpose of this thread is to explore the consequences and probabilities that the average ESS for the rest of the century is closer to 4.5 degrees C (or above), and I have provided many references that provide both observational and model data indicating that this may be the case:

http://en.wikipedia.org/wiki/Climate_sensitivity

Caption for attached figure: "Frequency distribution of climate sensitivity, based on model simulations. Few of the simulations result in less than 2 °C of warming—near the low end of estimates by the Intergovernmental Panel on Climate Change (IPCC). Some simulations result in significantly more than the 4 °C, which is at the high end of the IPCC estimates. This pattern (statisticians call it a "right-skewed distribution") suggests that if carbon dioxide concentrations double, the probability of very large increases in temperature is greater than the probability of very small increases."

Best,
ASLR


The IPCC does not make projections by plugging climate sensitivity into a model.  They run a range of models with a variety of climate sensitivities and the upper range of all these runs will determine the upper range of their projection which is about 5.5 degrees.

Any climate model with a high climate sensitivity must have longer lags in it, otherwise it will predict too much warming for the last century.  If it has longer lags in it then it will not predict as much warming for the next century as you claim.

I already agree that there are climate models with sensitivity of 4.5, and that such a sensitivity is possible.  You do not need to keep providing evidence for why sensitivity may be that high.
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #89 on: October 22, 2014, 12:43:45 PM »
More recent than the 3rd:
Week beginning on October 12, 2014: 395.55 ppm
Weekly value from 1 year ago: 393.60 ppm

Or "about 2ppm above the concentration for the same time last year"

But really, individual weekly numbers are essentially irrelevant.

Here's the very clear long-term trend:

Decade                 Total Increase        Annual Rate of Increase

2004 –  2013              20.71 ppm                     2.07 ppm per year

1994 –  2003               18.70 ppm                     1.87 ppm per year

1984 –  1993                14.04 ppm                     1.40 ppm per year

1974 –  1983               13.35 ppm                     1.34 ppm per year

1964 –  1973               10.69 ppm                     1.07 ppm per year

1960 –  1963                 3.02 ppm                     0.75 ppm per year


http://co2now.org/Current-CO2/CO2-Trend/acceleration-of-atmospheric-co2.html

One week or even a couple years one direction or the other is not enough to know whether there has been a significant change in this long-term trend.

" if you think this is evidence that co2 emissions for 2014 will be [lower] than [long term rates] then you are a complete idiot." Fixed that for you.
« Last Edit: October 22, 2014, 12:50:35 PM by wili »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #90 on: October 22, 2014, 04:38:18 PM »
I think that a little bit of background information about the Recommended Concentration Pathway, RCP, scenarios would help some of our discussions (the attached images are from the following references), and as I am traveling, I will not be posting very much for a few days:

Meinshausen, M., Smith, S.J., Calvin, K., Daniel, J.S., Kainuma, M.L.T., Lamarque, J-F., Matsumoto, K., Montzka, S.A., Raper, S.C.B., Riahi, K., Thomson, A., Velders, G.J.M., and van Vuuren, D.P.P., (2011); "The RCP greenhouse gas concentrations and their extensions from 1765 to 2300", Climatic Change, 109:213-241, doi: 10.1007/s10584-011 -0156-z.
Rogelj, J., Meinshausen, M. and Knutti, R., (2012), "Global warming under old and new scenarios using IPCC climate sensitivity range estimates", Nature Climate Change - Letters, doi: 10.1038/NCLIMATE1385.
Van Vuuren, D.P., Edmonds, J., Kainuma, M., Riahi, K., Thomson, A., Hibbard, K., Hurtt, G.C., Kram, T., Krey, V., Lamarque, J-F., Masui, T., Meinshausen, M., Nakicenovic, N., Smith, S.J., and Rose, S.K.; "The representative concentration pathways: an overview"; Climatic Change (2011) 109:5-31, doi: 10.1007/s10584-011-0148-z
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viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #91 on: October 22, 2014, 06:07:13 PM »
Decade                 Total Increase        Annual Rate of Increase

2004 –  2013              20.71 ppm                     2.07 ppm per year

1994 –  2003               18.70 ppm                     1.87 ppm per year

1984 –  1993                14.04 ppm                     1.40 ppm per year

1974 –  1983               13.35 ppm                     1.34 ppm per year

1964 –  1973               10.69 ppm                     1.07 ppm per year

1960 –  1963                 3.02 ppm                     0.75 ppm per year
This annoys me no end. When I was still in gymnasium/college, our polluticians — and especially a certain Ms Brundtland — started pretending this problem was in good hands, that it was taken care of. Just trust the polluticians and all will be well. Turns out her famous emphasis on the word 'sustainable' was morphed and perverted, also by herself, to the more pro–business term 'sustainable economic growth' (as if!). And the rest, as they say, is climate history. They've done nothing, or even worse, they've done less than nothing to solve the problem.
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #92 on: October 22, 2014, 08:24:19 PM »
Just in an attempt to be a total panglossian pollyanna for a moment and torture the data a bit to get some slight thin glimmer of good news--

Can we say that the rate of increase in the rate of increase appears to have slowed in the last ten years? (2.07 - 1.87 = .2 ppm rate of increase in the rate of increase, while for the previous two decades, 1.87 - 1.40 = .47 ppm...)

Of course, that last ten years included a major world recession. So perhaps we do have to hope for ever deeper ever more frequent world recessions going forward??

The other likely factor is that the '94 -'03 time period included the '97 Super El Nino, and iirc hot surface waters absorb CO2 less efficiently than relatively cooler ones. So I guess we have to hope that, even as total ocean waters get warmer, surface waters somehow get cooler over time (and somehow less acidic)!?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #93 on: October 22, 2014, 09:11:55 PM »
More recent than the 3rd:
Week beginning on October 12, 2014: 395.55 ppm
Weekly value from 1 year ago: 393.60 ppm

Or "about 2ppm above the concentration for the same time last year"

But really, individual weekly numbers are essentially irrelevant.

Here's the very clear long-term trend:

Decade                 Total Increase        Annual Rate of Increase

2004 –  2013              20.71 ppm                     2.07 ppm per year

1994 –  2003               18.70 ppm                     1.87 ppm per year

1984 –  1993                14.04 ppm                     1.40 ppm per year

1974 –  1983               13.35 ppm                     1.34 ppm per year

1964 –  1973               10.69 ppm                     1.07 ppm per year

1960 –  1963                 3.02 ppm                     0.75 ppm per year


http://co2now.org/Current-CO2/CO2-Trend/acceleration-of-atmospheric-co2.html

One week or even a couple years one direction or the other is not enough to know whether there has been a significant change in this long-term trend.

" if you think this is evidence that co2 emissions for 2014 will be [lower] than [long term rates] then you are a complete idiot." Fixed that for you.


And who said anything about 2014 being lower?

ASLR posted a chart which he claimed showed we were following RCP8.5.  I said that up to 2013 the figures followed the other RCPs just as well, and that it was only in 2014 that co2 jumped up to follow RCP8.5, and that 2014 is only a projection that hasn't happened yet.  ASLR countered with the fact the 2014 co2 keeling stats.  I stated that the 2014 stats showed a decrease in growth over the last year and noted that you can't read much into one year due to other factors, such as the ocean. 
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #94 on: October 22, 2014, 09:16:49 PM »
Just in an attempt to be a total panglossian pollyanna for a moment and torture the data a bit to get some slight thin glimmer of good news--

Can we say that the rate of increase in the rate of increase appears to have slowed in the last ten years? (2.07 - 1.87 = .2 ppm rate of increase in the rate of increase, while for the previous two decades, 1.87 - 1.40 = .47 ppm...)

Of course, that last ten years included a major world recession. So perhaps we do have to hope for ever deeper ever more frequent world recessions going forward??

The other likely factor is that the '94 -'03 time period included the '97 Super El Nino, and iirc hot surface waters absorb CO2 less efficiently than relatively cooler ones. So I guess we have to hope that, even as total ocean waters get warmer, surface waters somehow get cooler over time (and somehow less acidic)!?

I see you have spotted the slight tendancy of Co2 concentrations to fall away from an exponential growth pattern which would be followed if rcp8.5 was going to happen.

Of course this must be bad news and due to recessions and other doomy stuff.  Couldn't possibly have anything to do with statistics such as wind energy producing 4% of the worlds power in 2013 and growing at 20% a year could it?  I mean only panglossian pollyannas would believe that we can generate electricity using the wind.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #95 on: October 22, 2014, 10:31:54 PM »


looks to be continually increasing in rate of accumulation to me.  anyone who claims a 4.5C high end projection for ECS is not credible in my book anymore.  4.5C is the new median, credible high is +6.5C due to arctic albedo forcing and winter temperature regime changes.
« Last Edit: October 22, 2014, 11:16:54 PM by jai mitchell »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #96 on: October 22, 2014, 11:45:58 PM »
anyone who claims a 4.5C high end projection for ECS is not credible in my book anymore.  4.5C is the new median, credible high is +6.5C due to arctic albedo forcing and winter temperature regime changes.


Not a median of 1.6C as per Lewis and Curry then ? {pretents to look innocent  ;) )

There's a new paper in Climate Dynamics, by Lewis and Curry, with a central sensitivity estimate of 1.6C with a 90% range of 1-4C, based on energy budget analyses over the instrumental period, updated to the present day, also taking account of the newer AR5 forcing estimates. I don't find it particularly exciting, the authors cite several recent papers with similar results including Aldrin and Otto et al. I wrote about those papers some time ago, and I think these posts (1, 2, 3) still stand. I've commented before on my objections to Lewis' method, and especially the sleight-of-words with which it is described, but (as I've also emphasised) I don't think this substantially affects the results in this application.


http://julesandjames.blogspot.co.uk/2014/10/much-ado-about-sensitivity.html

Csnavywx

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #97 on: October 22, 2014, 11:55:31 PM »
Careful here, part of the "de-inflation" of this decade over the last was due to a reduction in airborne fraction. There are a few theories as to why this happened (Hansen, for instance: http://www.huffingtonpost.com/dr-james-hansen/doubling-down-on-our-faustian-bargain_b_2989535.html).

Note here too that there's significant interdecadal variability within that list. Note the 84-93 rate was barely higher than the 74-83 rate, despite a strong increase in emissions over the period.

From a political and statistical point of view, using 2005 is a logical choice if you want to show the biggest decreases possible. It was the last great pre-recession year (the bubble started bursting in 2006). Trends for labor force participation rate and employment have been down since that time, and we also started our gas boom shortly thereafter. If we were more serious about a real statistical representation, we'd be using a decadal average for a starting baseline for CO2 reductions.

And as a kind of side bar: Remember, cumulative emissions are what counts.
« Last Edit: October 23, 2014, 12:00:46 AM by Csnavywx »

wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #98 on: October 23, 2014, 12:31:06 AM »
Thanks for the reflections folks. Good to hear that I am not alone in my panglosian pollyannishness, mh, to get so excited at an apparent decrease in the rate of increase in the rate of increase... :-* :-* :-* :-* ::)

Meanwhile:

Recently discovered microbe is key player in climate change


   
As permafrost soils thaw under the influence of global warming, communities of soil microbes act as potent amplifiers of global climate change, an international study has shown.

    Tiny soil microbes are among the world's biggest potential amplifiers of human-caused climate change, but whether microbial communities are mere slaves to their environment or influential actors in their own right is an open question. Now, research by an international team of scientists from the U.S., Sweden and Australia, led by University of Arizona scientists, shows that a single species of microbe, discovered only very recently, is an unexpected key player in climate change.
    The findings, published in the journal Nature, should help scientists improve their simulations of future climate by replacing assumptions about the different greenhouse gases emitted from thawing permafrost with new understanding of how different communities of microbes control the release of these gases.

    Earlier this year, the international team discovered that a single species of microbe, previously undescribed by science, was prominent in permafrost soils in northern Sweden that have begun to thaw under the effect of globally rising temperatures. Researchers suspected that it played a significant role in global warming by liberating vast amounts of carbon stored in permafrost soil close to the Arctic Circle in the form of methane, a powerful greenhouse gas trapping heat in the Earth's atmosphere. But the actual role of this microbe—assigned the preliminary name Methanoflorens stordalenmirensis, which roughly translates to "methane-bloomer from the Stordalen Mire"—was unknown.

    The new research nails down the role of the new microbe, finding that the sheer abundance of Methanoflorens, as compared to other microbial species in thawing permafrost, should help to predict their collective impact on future climate change.


http://phys.org/news/2014-10-microbe-key-player-climate.html

Oh, how many ways are we f'd. Let me count the ways... oops, I can't!
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #99 on: October 23, 2014, 12:56:24 AM »
Tiny soil microbes are among the world's biggest potential amplifiers of human-caused climate change, but whether microbial communities are mere slaves to their environment or influential actors in their own right is an open question.

I vote for designing a 'Summary for Soil Microbes' from the 5th IPCC report. If they truly are influential actors in their own right, they need to read this and realize what they're doing.
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