Conservative Scientists & its Consequences

[TeaPotty]

No, I don't think it will help. What values are used to decide what emissions level is acceptable anyway? Some area of the world will fry at 2C, and we even know some feedbacks begin at 1.5C.

Again, it's a politically convenient way to twist the Science so we can continue the status-quo.

It's like using Mercury toxicity levels research to determine  that food companies are allowed to sell food with just enough Mercury not to kill them. This is not rational thought.

[Michael Hauber]

Yes, 5-7 degrees warming by 2100 seems quite possible. And yes, this would create massive natural feedbacks. But would these feedbacks be strong enough to cause another 10 degrees warming by 2200?

5-7 degrees of warming by 2100 would require massive natural feedbacks to have already occurred.  Two doublings of co2 is RCP8.5 and is about 2 degrees of warming due to direct co2 radiative effect.  Then add another 4 degrees of warming due to feedbacks for water vapour, cloud changes and albedo effects and you get the mid range for IPCC equilibrium climate sensitivity(a significant amount of which is still slower than a century, so just over 5 degrees is the maximum amount of warming that IPCC models predict.  Add another degree for a wost case methane feedback and then take away whatever amount of methane feedback is effectively included in the RCP8.5 concentration projections).  Feedbacks to take warming beyond this point are slow feedbacks that take centuries to have an impact and climate modelling in the IPCC beyond 2100 shows warming rates slowing down significantly.

[Michael Hauber]

The conservatism in science actually cut both ways.  This conservatism is really a healthy skepticism and resistance to new ideas.  Someone comes up with a clever new idea and publishes a nice paper and the scientific consensus says 'do I really have to believe that?'.  So Arrhenius and some others publish papers on Co2 warming more than 50-100 years ago and the consensus says 'what about saturation effects, what about the ocean being easily big enough to absorb basically all human emissions?'.  So many decades pass and this issue is worked out and finally in the late 20th century the consensus says 'ok I believe you Co2 does cause warming'.

An idea that at least one serious climate scientist has promoted is that the large number of papers measuring climate sensitivity can be used in a statistical analysis to narrow the measurement of climate sensitivity.  This is a valid idea to the extent that errors and uncertainties in the different papers are independent of each other, and problematic to the extent that errors and uncertainties are repeated from one paper to the next.  This idea has been used to significantly narrow the range of uncertainty around the central 3 degree estimate, which if valid would significantly reduce the possibility of upper range climate impacts.  However the IPCC being conservative have decided not to take this idea into account.  In this I support IPCC, as although I cannot find anything wrong with the Anan et al analysis, I'd rather err on the side of caution and not reduce the size of the climate sensitivity uncertainty window until we are absolutely sure.

James Empty Blog

[jai mitchell]

For RCP 8.5 there are two scenarios that lead to the temperature regimes that I am talking about, they are called pattern 41 and pattern 42 95.000 (I assume this is 95th percentile).



my understanding is that the multi model means will necessarily reduce the associated uncertainties to the average.  Therefore, the high end estimates of 2200 and 2300 temperatures in the graphic I posted previously rely solely on higher ECS values (4.5 max)

However, if my understanding of Durack et. al. implications for higher end uncertainty values for both GHG and Aerosol forcing are correct then the ECS is well above 4.5 and closer to 5.5.

I am looking for the parameters for pattern 41 and pattern 42 95th percentile but have not found them as a comparison with the scenario that I am sharing above.

[GeoffBeacon]

TeaPotty

No, I don't think it will help.

My aim was to show that the BBC has been pitting official scientists against climate skeptics rather than putting them up against those that think climate change is worse than the official line.

Is my judgment on this wong?

If true, is it counter productive to show it?

Is there a better way?

[TeaPotty]

Sorry Geoff, not sure I understand your point. Obviously this fake debate between Climate Change "believers" and cultural skeptics is dangerous theater. If your asking whether a debate between scientists about Climate Change's severity would be helpful to informing the public... I don't know.

We are all a part of this society today which runs its whole economy on anti-Science ideologies and ideas such as "endless growth" Capitalism. I think real change can only come from below, and right now I am inclined to believe that the only good potential motivator remaining is the collapse of this system. What other way to change the public's  skepticism/apathy/ignorance on sustainability/Anthropocene/Climate than the loss of what they value, their superstitious identities disconnected from their dependency on Nature. History shows this to be true as well.

Its not that I think this is desirable. Really what we lack is motivation. The question we need to answer to move forward is not "How?", but "What is our objective?". Conservatives mostly just want to "go to heaven", and believe God is the prime director, and not that we shape our own world. They certainly see themselves above nature that we experience in the corporeal world. Where to begin the discussion with people who are not headed in your direction (at least they believe they are not)?

[jai mitchell]

If my understanding of Durack et. al is correct and the large uncertainty of Aerosol forcing cloud effects are severely underestimated (negative), then this cloud cover effect from persistent contrail induced cirrus will be a likely contributor to the southern hemisphere energy gains.

If this is true then the forcing component of GHG (less aerosols) is much larger and ECS is 10-30% higher.

[crandles]

My aim was to show that the BBC has been pitting official scientists against climate skeptics rather than putting them up against those that think climate change is worse than the official line.

Is my judgment on this wong?

If true, is it counter productive to show it?

Is there a better way?

Sounds like it should be useful to show it.

http://isthishowyoufeel.weebly.com/this-is-how-scientists-feel.html#pramod

seems to come up with similar feelings
often a mixture of feelings like
Hope, Despair, Frustration, Anger, Concern, Bemusement, Disgust

If these views are typical then perhaps the BBC ought to be pitching debate between mainstream views and those who feel it will be worse.

But does it become debate between those willing to talk about speculation of highly unlikely outcomes and mainstream opinion just dismissing these as very unlikely possibilities. Does this make interesting television? Also, does the dismissal of unlikely possibilities simply reassure people that climate change won't be too bad?

[wili]

If ANY significant body of respected scientists thought that there was ANY likelihood that a comet or meteor was soon going to hit the planet and wipe out most complex life, you better be damn well sure it would make some pretty f'n good TV!

Why should it be any less so if annihilation may be looming because of climate change rather than from extraterrestrial bolides??

[wili]

As hai's graph above shows, we are well on our way to barbequing our progeny.

GB, your instincts are right. Go with them. They are giving me ideas about how to reconfigure my course for the spring. Best of luck to you.

[GeoffBeacon]

wili
   thanks

crandles
   Reading between your lines, I guess you think that the IPCC AR5 projections are the best possible so any other view is an "unlikely possibility". Is that correct?

Do you agree with the UK Met Office summary?

Cumulative emissions from pre-industrial (1750-2012) have reached 590 ±75 GtC. This is an update to the IPCC 1750-2011 estimate of 555 [470 - 640] GtC as 2012 emissions are included and an upwards revision is made of early 20th century land use emissions (20 GtC). The IPCC estimates that with cumulative emissions of 1000 GtC, there is a two-thirds chance of staying below 2°C relative to pre-industrial. At current levels we are over half way towards this figure. If other non-CO2 gases are included the emissions budget reduces to 790 GtC.

http://www.metoffice.gov.uk/research/news/gcb-2013

I don't think this is right and I am sceptical of their implication that 2 deg C is safe.

[Michael Hauber]

If my understanding of Durack et. al is correct and the large uncertainty of Aerosol forcing cloud effects are severely underestimated (negative), then this cloud cover effect from persistent contrail induced cirrus will be a likely contributor to the southern hemisphere energy gains.

If this is true then the forcing component of GHG (less aerosols) is much larger and ECS is 10-30% higher.

If the warming impact of contrails is contributing to the increase in heating in the southern hemisphere, then that would imply ECS is lower.

[wili]

I hesitate to speak for him, but I assume that jai means that the contrail effect is to keep the Northern Hemisphere cooler than it would otherwise be. So they are artificially masking warming that would otherwise be happening. Hence the claim that ECS is higher than generally proposed.

[crandles]

   Reading between your lines, I guess you think that the IPCC AR5 projections are the best possible so any other view is an "unlikely possibility". Is that correct?

Do you agree with the UK Met Office summary?

Cumulative emissions from pre-industrial (1750-2012) have reached 590 ±75 GtC. This is an update to the IPCC 1750-2011 estimate of 555 [470 - 640] GtC as 2012 emissions are included and an upwards revision is made of early 20th century land use emissions (20 GtC). The IPCC estimates that with cumulative emissions of 1000 GtC, there is a two-thirds chance of staying below 2°C relative to pre-industrial. At current levels we are over half way towards this figure. If other non-CO2 gases are included the emissions budget reduces to 790 GtC.

http://www.metoffice.gov.uk/research/news/gcb-2013

I don't think this is right and I am sceptical of their implication that 2 deg C is safe.

I think there is some conservatism by scientists, but when AR5 is stated with 'high confidence' then you will only find a few suitably knowledgeable people who disagree.

I think it is quite a stretch to say this means AR5 projections are the best possible. There is always room for lots of improvement. Also there have been measurements, papers etc since AR5.

Generally I feel the scientists deserve a fair bit of respect. They know a lot more than me and I don't think they deserve a lot of the criticism they are getting from some around here. Of course others here may know enough to be in a position to criticise fairly.

>Do I agree?

Who am I argue? When AR5 is stated with high confidence, I trust that view. The quote seems an update since AR5 so obviously AR5 is out of date and we are nearer to danger now as a result of the update.

The quote simply states the science of this carbon budget leads to warming of X. Therefore I don't need to consider what is dangerous to agree with this quote. I do have to have considered whether I trust the modelling process, and I do.

It is, I think, politicians that defined dangerous as meaning 2C above pre-industrial.

> sceptical of their implication that 2 deg C is safe.

I think I would also dispute the characterisation '2 deg C is safe'. To me, saying over 2C is dangerous can easily imply that under 0.5C is relatively safe and 0.5C to 2C is unclear but has increasing chance of being dangerous.

We have nowhere near the knowledge to say x.y is safe and the next number x.z is dangerous. For all I know, there could be a small chance that 3C is not dangerous or there could be a small chance that 0.3C above pre-industrial is dangerous or maybe both.


The politicians seem to have gone for using dangerous and over 2C interchangeably. What should be considered dangerous probably depends upon the position you are in. At some point doing anything other than the maximum possible becomes dangerous. That is a very late point of danger. Should dangerous be a moving target, starting well before that point and moving towards it as we get closer to danger?

Problem with a moving target might be that we are always 10 years away from burning the remainder of the carbon budget. To infer from that we can carry on burning carbon would be pretty silly but it would encourage a pov that these environmentalists are always crying wolf.

[TeaPotty]

Candles, you're not a very good apologist. It's nice that you have trust, but feelings wont change the conservatism of the IPCC, which is well established, with many scientists speaking up about it. Also, 2C is also not even a remotely safe target. And yes, it is IPCC scientists who agreed to it and continue to support it.

[crandles]

http://www.climateemergencyinstitute.com/uploads/2C_history.pdf

An analysis of the first appearance of the objective to limit temperature
rise to 2°C shows that it has no clear origin and that its adoption is due
neither to compelling scientific evidence nor to the negotiators’ informed
choice based on scientific date. Before the UNFCCC negotiations seized
on this value, 2°C was already used as a marker to concurrently address
scientific, economic and political apprehensions about climate change.

Does 'UNFCCC seized on this value' mean politicians or IPCC scientists?

I would say politicians but if it includes IPCC scientists then it is certainly a policy driven sort of science involved rather than WG1 science. IPCC don't decide policy, they do provide information to assist such decisions.

In case it hasn't been apparent, I do accept that the impacts do seem much more likely to come much earlier than previously thought. West and East Antarctica losing mass being a good example post AR5. I also said that I agree there is some conservatism. If I am in a small minority on this thread for not saying there is extreme conservatism, then we may have to agree to disagree.



 

[viddaloo]

LOL, extreme conservatism sounds like a contradiction in terms, but in IPCC's case it's probably adequate

[Lennart van der Linde]

On contrails: I'm not sure what's being argued. Are they warming or cooling? According to IPCC 2013 they're warming (Technical Summary, p.55):
"Persistent contrails from aviation contribute a positive RF of 0.01 [0.005 to 0.03] W m–2 (medium confidence) for year 2011, and the combined contrail and contrail-cirrus ERF from aviation is assessed to be 0.05 [0.02 to 0.15] W m–2 (low confidence). This forcing can be much larger regionally but there is now medium confidence that it does not produce observable regional effects on either the mean or diurnal range of surface temperature. {7.2.7}"

[Lennart van der Linde]

Jai said:

For RCP 8.5 there are two scenarios that lead to the temperature regimes that I am talking about, they are called pattern 41 and pattern 42 95.000 (I assume this is 95th percentile)... I am looking for the parameters for pattern 41 and pattern 42 95th percentile but have not found them

On the graph you show it says pattern 41 and 92, but I suppose that should be 42 then?

If you can't find the parameters for that graph, does that mean you made the graph yourself based on some parameters? If not, do you have a source for the graph itself?

[Lennart van der Linde]

Maybe David Wasdell is one of the least conservative in reading the available science, as shown by this presentation of June 2014:
http://www.apollo-gaia.org/Sensitivity%20and%20the%20Carbon%20Budget.pdf

For two doublings of CO2 he expects an ultimate warming of almost 16 degrees C, as shown by the attached image from his presentation. It's not clear to me on what timescale he thinks this warming could occur, and what the warming would be with three of four doublings of CO2 (as in RCP8.5). But since he's talking about Earth System Sensitivity, I suppose it would take at least many centuries or millennia to realize this ultimate warming.

[Lennart van der Linde]

Some conclusions of Wasdell, for discussion, since I've no idea if all of his reasoning is correct:

"One of the most profound implications of replacing the transient temperature response of the SPM with the full value of the Earth System Sensitivity, is the dramatic change in predicted temperature. Where the “Charney” sensitivity indicated that a 903 GtC level of total cumulative anthropogenic emissions would lead to a 2°C rise in temperature, that same total can now be seen to give rise to an equilibrium temperature response of 5.4°C. It is starting to become clear why the “New Metric” of the SPM is so politically and economically attractive, and why the pressure not to base GHG stabilization targets on the Earth System Sensitivity is so intense.

Another outcome of replacing the fast feedback sensitivity with the whole Earth System Sensitivity concerns the projected end-of-century temperature response to the current set of international commitments to reduction in CO2 emissions. With an expected total cumulative carbon emission of around 2000 GtC, the IPCC SPM indicates a transient temperature response of around 4°C. The ESS corrects this to around 10°C, with the extension to full equilibrium response of more like 15°C. An ice-free world and a sea-level rise of around 120 metres are in prospect.

In the light of the above, and taking into consideration the following facts:
1. That the Earth System Sensitivity in current conditions of the Anthropocene will be higher than the value used in this exposition
2. That the contributions from other non-CO2 greenhouse gasses have not been taken into account
3. That the 2°C target is now known to be set too high to avoid dangerous climate change
4. That equilibrium temperature increase predicted as a result of current concentration of atmospheric greenhouse gasses is already over 5°C

We note that climate stabilization at a level close to the required policy target of not more than 2°C above the pre-industrial benchmark, (let alone the essential reduction in that target to no more than 1°C above the pre-industrial benchmark) cannot be achieved simply by a programme of emissions reduction on its own. That is a necessary but not sufficient intervention.

The gap between current and target concentration requires urgent and aggressive reduction in the airborne concentration of CO2, in concert with a termination of emissions from fossil hydrocarbon sources and a rejection of all other activity that increases the net radiative imbalance of the planet or that profits therefrom.

The inadequacies imbedded in the Summary for Policymakers of the IPCC AR5 WG1 clearly render it unfit for the purpose of policymaking.

The subsequent reports of Workgroups 2 and 3 of the IPCC AR5, depend on the output from Workgroup 1 for their scientific basis. As a consequence, their analysis of likely impacts, intensity, time-frame and proposed mitigation requirements are all subject to the limitations exposed above.

Substitution of the value of the Earth System Sensitivity in place of the limited fast-feedback sensitivity of the CMIP5 model ensemble amplifies all temperature predictions by a factor of 2.5. Major revision of the Reports from Workgroups 2 and 3 will therefore be essential if strategic policymaking by the international community is to achieve Climate Change Solutions that deal with the reality of Climate Change Problems."

[viddaloo]

If ANY significant body of respected scientists thought that there was ANY likelihood that a comet or meteor was soon going to hit the planet and wipe out most complex life, you better be damn well sure it would make some pretty f'n good TV!

Why should it be any less so if annihilation may be looming because of climate change rather than from extraterrestrial bolides??

My sentiments exactly! And very well put. TV would be all over it with funky graphics showing the hypothetical 'alarmist' meteor danger hitting the Earth as if it was already happening, and military top brass would be abundant in all channels planning to nuke the darn thing....

[wili]

LvdL, iirc people have identified some double counting in that Wasdell chart. But certainly, long term warming will be greater than what is generally discussed about stuff happening this century.

[GeoffBeacon]

This is my recent complaint to the BBC
 

BBC Complaints – Case number CAS-3013771-H8DMTT

I have complained about the BBC’s promotion of economic growth without explaining that it means more carbon pollution. In the Kaya identity predicting global CO2 emissions, the (CO2/energy) term may be reducing but this is not enough to keep below the carbon budget recently issued by the IPCC.

The concept of a carbon budget is not perfect but it is useful to policy makers and democratic knowledge. In practice, this budget is calculated by climate scientists using computer models – the CMIP5 models. A note by the Parliamentary of Science and Technology (POST note 454) has pointed out that these models had missing feedbacks. This means that the models were underpowered and overestimate the allowable budget before dangerous climate change is triggered.

There are several eminent scientists that would question the size of this budget and make different estimates. Their estimates would be a useful measure of the scope of opinion about the seriousness of climate change.  This is one measure on the “warmist” to “sceptic” scale (The WS scale?) that could be used.

I have made guesses to place prominent climate experts on the WS scale and noted their mentions on the BBC website. I find that there is a huge bias to experts with the “official” view in the middle of the scale.

The BBC is not allowing a balanced debate on climate change. I believe it is promoting a business/growth agenda which is dangerous to our future.

The test I suggest will help the BBC construct an essential debate.

[crandles]

I wish you luck with the complaint.

Myles Allen is ranked as official? Despite his 'climate sensitivity might be 11C' which some people like to still go on about. I think I would put him up to 'concerned' for a tendency to push the high end but maybe my knowledge of him is tainted by experience with him regarding CPDN and also regarding priors where James Annan took him to pieces.

[jai mitchell]

secondary cloud effects are cooling components with very high uncertainty.  Durack et. al. indicates that this source is likely higher negative, operating on the northern hemisphere.  This is why the warming effects acting on the southern hemisphere are higher.  However, since the northern hemisphere still operates within the models, then a higher positive forcing must be included to balance out the apparently higher negative forcing in the northern hemisphere.  This would be the uncertainty associated with GHG emissions forcing (they are now slightly more than previously asserted)

Both of these increase the ECS value.  Currently contrail associated effects are a (slight) warming mechanism in the models.  If the cloud forcing is much more negative then the contrail effects become a strong negative, not a positive forcing.

VAN

the pattern 41 and pattern 42 model runs were part of a spreadsheet of individual model runs used in the IPCC AR5 RCP 8.5 projections.

[jai mitchell]

It should be noted that the temperature regimes in this IPCC AR5 graphic are only 1 standard deviation of uncertainty.  So the red shaded RCP 8.5 temperature response is the 66% probability distribution.




Since we already know that the IPCC did not include frozen soil and long-range carbon cycle response as well as underestimation of other terrestrial carbon sources and polar albedo responses, the potential of a high ECS pushes the likely temperature response well above the shaded red portion of the graphic.

In the RCP 8.5 forcing scenario Methane abundances hold steady at 2100 and CO2 abundances hold steady at 2160.  Increased warming induced by ECS of 4.5 or more will produce significantly larger natural methane and CO2 emissions well into 2300.

[Michael Hauber]

secondary cloud effects are cooling components with very high uncertainty.  Durack et. al. indicates that this source is likely higher negative, operating on the northern hemisphere.  This is why the warming effects acting on the southern hemisphere are higher.  However, since the northern hemisphere still operates within the models, then a higher positive forcing must be included to balance out the apparently higher negative forcing in the northern hemisphere.  This would be the uncertainty associated with GHG emissions forcing (they are now slightly more than previously asserted)

Both of these increase the ECS value.  Currently contrail associated effects are a (slight) warming mechanism in the models.  If the cloud forcing is much more negative then the contrail effects become a strong negative, not a positive forcing.

VAN

Increase in ocean temperatures = total warming - aerosol cooling - warming of other clime components.

Therefore if oceans are warming more then total warming is higher, or aerosol cooling is weaker or warming of other components is weaker.  Based on Church et al analysis Total warming is calculated directly, and not by adding up the components, so repeating the Church et al analysis with the updated ocean increase of Durack et al must result in a lower aerosol cooling factor.

As already demonstrated the heat flux between the hemispheres is quite large enough to account for significant differences in the location between a change in heat input, and change in ocean heat storage.  Also consider that the heat budget may not have balanced on a hemisphere basis with the incorrect figures prior to Durack.  Durack shows a SH heat component equal to what is predicted in the models, and higher in the NH.  So Durack shows an increase in the SH heat component, but the extra heat in comparison to the models is in the NH, which is the opposite of what would be expected with a stronger aerosol cooling effect and no heat transport between hemispheres. 

Note that the surface SSTs in the SH are well sampled since the satellite era.  It is the deeper ocean heat content that is in question, and the location of the extra heat probably has more to do with the location of extra mixing from the surface to the deeper ocean beyond what is predicted in the models than it does to the geographic location of the source of the extra heat.

[Michael Hauber]

Since we already know that the IPCC did not include frozen soil and long-range carbon cycle response as well as underestimation of other terrestrial carbon sources and polar albedo responses, the potential of a high ECS pushes the likely temperature response well above the shaded red portion of the graphic.

While I agree that frozen soil and other responses are not included in CMIP modelling as feedbacks, this ignores the fact that the CMIP models are mostly concentration driven scenarios and not emissions driven scenarios.  So the question then is how much methane (if any) for natural processes is included in the IAM modelling that defines the RCP scenarios.  From my googling I haven't found a definite answer on this, but as IPCC gives significant discussions of how much methane could be emitted by such sources I would expect that methane for permafrost is included in the IPCC projections.

[viddaloo]

In the RCP 8.5 forcing scenario Methane abundances hold steady at 2100 and CO2 abundances hold steady at 2160.  Increased warming induced by ECS of 4.5 or more will produce significantly larger natural methane and CO2 emissions well into 2300.

And on that thought: I just saw the BBC Horizon docu «The Day the Earth Nearly Died» again this weekend. Recommend everyone to do the same, as the End–Permian seems to be where we are headed with this 'choice' of leadership.

http://www.ava360.com/the-day-the-earth-nearly-died-bbc-horizon-documentary-video_c8a892c3b.html

[Michael Hauber]

The only value for earth system climate sensitivity that I can recall being mentioned in this thread is 8 degrees.

However a quick google finds a few other values that have been claimed:

Penn State University 4.5
Real Climate 3  - 6
Pagani et al 6.1 - 11.0

[Lennart van der Linde]

Previdi et al 2013 estimate an ESS of 1.3-2.0 times ECS, so 4-6 degrees:
http://www.precaution.org/lib/previdi_climate_sensitivity_in_anthropocene.2013.pdf

I don't know about others, but to me this is about risk assessment based on scientific uncertainty ranges. So higher potential ECS and ESS implies more risk and a need for stronger mitigation policies to reduce that risk.

On permafrost feedback IPCC 2013 chapter 6, p.526 says:
"Overall, there is high confidence that reductions in permafrost extent due to warming will cause thawing of some currently frozen carbon. However, there is low confidence on the magnitude of carbon losses through CO2 and CH4 emissions to the atmosphere. The magnitude of CO2 and CH4 emissions to the atmosphere is assessed to range from 50 to 250 PgC between 2000 and 2100 for RCP8.5. The magnitude of the source of CO2 to the atmosphere from decomposition of permafrost carbon in response to warming varies widely according to different techniques and scenarios. Process models provide different estimates of the cumulative loss of permafrost carbon: 7 to 17 PgC (Zhuang et al., 2006) (not considered in the range given above because it corresponds only to contemporary tundra soil carbon), 55 to 69 Pg (Koven et al., 2011), 126 to 254 PgC (Schaefer et al., 2011) and 68 to 508 PgC (MacDougall et al., 2012) (not considered in the range given above because this estimate is not obtained from a concentration driven, but for emission driven RCP scenario and it is the only study of that type so far). Combining observed vertical soil carbon profiles with modeled thaw rates provides an estimate that the total quantity of newly thawed soil carbon by 2100 will be 246 PgC for RCP4.5 and 436 PgC for RCP8.5 (Harden et al., 2012), although not all of this amount will be released to the atmosphere on that time scale. Uncertainty estimates suggest the cumulative amount of thawed permafrost carbon could range from 33 to 114 PgC (68% range) under RCP8.5 warming (Schneider von Deimling et al., 2012), or 50 to 270 PgC (5th to 95th percentile range) (Burke et al., 2013)."

But pp.530-531 then says:
"under sustained Arctic warming, modelling studies and expert judgments indicate with medium agreement that a potential combined release totalling up to 350 PgC as CO2 equivalent could occur by the year 2100... Modelling studies of permafrost dynamics and greenhouse gas emissions indicate a relatively slow positive feedback, on time scales of hundreds of years. Until the year 2100, up to 250 PgC could be released as CO2, and up to 5 Pg as CH4. Given methane’s stronger greenhouse warming potential, that corresponds to a further 100 PgC of equivalent CO2 released until the year 2100."

So the 250 GtC from permafrost CO2 and CH4 could add up to about 350 GtC in CO2 equivalent.

What I understood so far, these are not included in emission driven models. In concentration driven models they make the available carbon budget smaller.

[Laurent]

Viddaloo
I can't read the video on your link (says error can't read).
I suppose it is that video you want us to see ?
https://www.youtube.com/watch?v=TaQg0M1BhW4&list=PLD41DB1A87FF394D5

[sidd]

Annan and Hargreaves have a review article out in QSR doi:10.1016/j.quascirev.2014.09.019
free copy temporarily at http://authors.elsevier.com/a/1Pzm9-4PRZkpV

By comparison of LGM to now " ... implies an equilibrium sensitivity of around 2.5 C with a 90% confidence interval of about 0.5 to 4  C."

This is a mix of ECS and ESS since they put in the slow ESS feedback like albedo, in addition to CO2 and vegetation changes. Nice review.

sidd

[jai mitchell]

Therefore if oceans are warming more then total warming is higher, or aerosol cooling is weaker

not if the additional heat accumulation is attributed to the southern oceans.  I understand that you probably just "don't get this" as I have stated it over and over. (sigh) one last time.

Since the heat attributions of northern hemisphere follow the models and the southern hemisphere were GROSSLY underestimated, this implies a much greater aerosol cooling effect since the aerosols primarily act on the northern hemisphere.  What part of this statement don't you understand?

As already demonstrated the heat flux between the hemispheres is quite large enough to account for significant differences in the location between a change in heat input, and change in ocean heat storage.

That's correct, as the flow of heat by convection currents is predominately south to north, the amount of differential heat fluxes that would produce the observed SOUTHERN heat accumulation must be even greater!  This would further indicate a higher northern hemisphere component of aerosol negative forcing. . .VERY GOOD!!!


In future posts regarding Durack et. al.  I am requesting that you stop threadjacking and posting off topic posts to this thread and start posting on the appropriate thread found here:
https://forum.arctic-sea-ice.net/index.php/topic,1011.0.html

[Lennart van der Linde]

Rohling et al 2012 estimate climate sensitivity without slow feedbacks:
http://academiccommons.columbia.edu/download/fedora_content/download/ac:162782/CONTENT/Paleosens_Project_Members_2012.pdf

They conclude:
"we find overlap in the 68% probability envelopes that implies equilibrium warming of 3.1–3.7 K for 2 x CO2 (Fig. 4), equivalent to a fast feedback (Charney) climate sensitivity between 0.8 and 1.0 K W-1 m2. For longer, multi-centennial projections, some of the slow feedbacks (namely vegetation-albedo and aerosol feedbacks) may need further consideration. However, their impact is difficult to estimate from palaeodata, because uncertainties are large, and because responses during climates colder than present may differ from responses during future warming."

Including slow feedbacks may increase the sensitivity to more than 3 K W-1 m2:
"Inclusion of ESS values (approximated by S[CO2]) would extend the upper limit beyond 3 K W-1 m2 (Fig.3a)."

So ESS may be as high as 11 degrees C, although uncertainties are very large.

[Steven]

As already demonstrated the heat flux between the hemispheres is quite large enough to account for significant differences in the location between a change in heat input, and change in ocean heat storage.  Also consider that the heat budget may not have balanced on a hemisphere basis with the incorrect figures prior to Durack.  Durack shows a SH heat component equal to what is predicted in the models, and higher in the NH.  So Durack shows an increase in the SH heat component, but the extra heat in comparison to the models is in the NH, which is the opposite of what would be expected with a stronger aerosol cooling effect and no heat transport between hemispheres.

Note that the surface SSTs in the SH are well sampled since the satellite era.  It is the deeper ocean heat content that is in question, and the location of the extra heat probably has more to do with the location of extra mixing from the surface to the deeper ocean beyond what is predicted in the models than it does to the geographic location of the source of the extra heat.

From my reading of the Durack et al. paper,

1. The "extra heat" in comparison to the observations is in the Southern Hemisphere.

2. The "extra heat" in comparison to the models is in both the Northern and the Southern Hemisphere.  The paper suggests that both hemispheres contribute about the same amount of "extra heat", relatively, compared to the models.

See also Figure 5 of Durack et al., shown below.  The grey rectangles show the CMIP multi-model means, and the black vertical lines indicate the one standard deviation spread.  Note that the Southern Hemisphere contains about 60% of the world's oceans;  So Durack et al. suggest that the oceans in the Northern and the Southern hemispheres have been absorbing heat at a roughly equal rate (per unit area), which is in good agreement with the CMIP model results.

[viddaloo]

Viddaloo
I can't read the video on your link (says error can't read).
I suppose it is that video you want us to see ?

No, it's not that one. I'm sorry for posting a non–functional link, but it seems the Beeb has been pulling all versions of it from the face of the Web. (I found it on my hard drive.)

[jai mitchell]

steven:

the caption for the image (5) that you posted says:

The NH and adjusted SH estimates are summed to yield global estimates (upper inset). Uncertainty estimates show the range of adjusted values obtained using the one standard deviation spread of model-simulated ratios

the little bits on the bottom right above the white line? those are the adjustments.

[Lennart van der Linde]

Jai,
I think I found your graph with the 16 degrees C 95th percentile RCP8.5 temperature projection for 2200.

See figure A3 in this Appendix of Kopp & Rasmussen:
http://rhg.com/wp-content/uploads/2014/10/Appendix-I-Physical-Climate-Projections.pdf

It also contains the SLR-projections (in feet) published in Kopp et al 2014 (in metres).

[jai mitchell]

LV.dL

Yes, that is indeed the source of the spreadsheet, the pattern 41 and pattern 42 are indicated as a blue/grey line indicating a CMIP5/model surrogate combined run.

I wonder what parameters/assumptions/model tweaks they used to get this pattern shift. . .Still waiting back for an email.

I can't tell you how impressive it is that you were able to find that curve within a range of spaghetti lines on a graph within some obscure publication!!!

[jai mitchell]

I have migrated all Durack et. al. discussion topics to the Durack et. al thread.

I would appreciate all future discussion on this topic take place there:

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

[jai mitchell]

The Pattern 41 and Pattern 42 95th percentile temperature response to the RCP 8.5 concentration scenarios relied on a very high ECS.  7.2C per 2XCO2.  This is obviously well above the current IPCC range of potential ECS values.

However, the carbon cycle and frozen soil feedbacks are not yet known. I am still trying to get follow up on it.

Even though the ECS is very high in this scenario, I expect that some albedo and carbon cycle feedbacks are not adequately discussed.  However, this absolutely would be a worst case scenario.  Without exception.

[jai mitchell]

Even though the ECS is very high in this scenario, I expect that some albedo and carbon cycle feedbacks are not adequately discussed.  However, this absolutely would be a worst case scenario.  Without exception.

Just published today, Ken Caldeira says that a loss of all sea ice is equivalent to nearly 1 full doubling of CO2.
https://twitter.com/KenCaldeira/status/531979557343989760

But his paper does not reference this one:

http://www.pnas.org/content/early/2014/10/29/1413640111.abstract

Incorporating these far-IR surface emissivities into the Representative Concentration Pathway (RCP) 8.5 scenario of the Community Earth System Model leads to discernible changes in the spatial patterns of surface temperature, OLR, and frozen surface extent. The model results differ at high latitudes by as much as 2°K, 10 W m−2, and 15%, respectively, after only 25 y of integration

[Lennart van der Linde]

Jai,
I couldn't have found it without your pointers. The appendix by Kopp & Rasmussen belongs to a recent big input report for the Risky Business Project:
http://rhg.com/reports/climate-prospectus

They discuss small likelihoods with big impacts, up to a chance of 1 in 1000.

Kopp et al 2014 on SLR-risks apparently is also part of this work.

[Lennart van der Linde]

Some quotes from the full Kopp et al Oct 2014 input report for the Risky Business Project:
http://rhg.com/wp-content/uploads/2014/10/AmericanClimateProspectus_v1.2.pdf

P.8:
"In some contexts, we also discuss ‘tail risks,’ which our probability estimates place at less than 1% probability. While we judge these outcomes as exceptionally unlikely to occur within the current century (though perhaps more likely thereafter with continued warming), we could plausibly be underestimating their probability. For example, carbon cycle feedbacks of the sort discussed in Chapter 3 could increase the temperature response of the planet, or the destabilization of West Antarctica might amplify sea- level rise. Though our formal probability calculation places low likelihood on these possibilities, the true probability of these scenarios is challenging to quantify."

P.18:
"The possibility of a rapid collapse is included in the sea-level rise projections described below, which indicate a 1-in-1000 probability of eight feet of global mean sea-level rise by 2100 and 31 feet of global mean sea-level rise by 2200."

P.31:
"Under RCP 8.5, global mean sea level will likely rise by about 0.8 to 1.1 feet between 2000 and 2050, and by 2.0 to 3.3 feet between 2000 and 2100 (Figure 4.11) (Kopp et al., 2014). There is a 1-in-200 chance sea level could rise by 5.8 feet, and in a “worst-case” projection reflecting the maximum physically plausible sea level rise, global mean sea level could rise by as much as eight feet. It is important to note that the estimates of tail probabilities involve a particular set of assumptions about likely ice sheet behavior; feedbacks could render these extreme outcomes more likely than we project.

The uncertainty in ice sheet physics plays a larger role in sea-level projections than scenario uncertainty, but lower greenhouse gas emissions will lower projected sea-level rise, particularly in the second half of the century. Under RCP 2.6, global mean sea level will likely rise by about 0.7 to 0.9 feet by 2050 and by 1.2 to 2.1 feet by 2100. Under RCP 2.6, there is a 1-in-200 chance of a sea-level rise 4.6 feet, and the worst-case projection is reduced to seven feet."

[Lennart van der Linde]

Just for the record I attach figure A3 from Kopp & Rasmussen, which has the following caption:
"Figure A3: (Top) Global mean temperature trajectories for RCP 8.5 from MAGICC (blue), CMIP5 model output (red) and model surrogates (grey). Heavy blue = median, light blue = 17th/83rd percentile, dashed blue = 5th/95th percentile, dotted blue = 1st/99th percentiles."

Also attached their figure A1, which shows the probability distribution for climate sensitivities. The caption reads:
"Figure A1: Survival function of climate sensitivities from MAGICC. Red squares indicate the statements made by AR5."

Like Jai said earlier, the 95th percentile climate sensitivity would be about 7 degrees C. For RCP8.5 this could give a circa 5% chance of 16 degrees C warming by 2200. Not a negligable risk, it seems to me, also in light of the new papers on potentially larger than thought Arctic amplification, that Jai linked to above.

[Lennart van der Linde]

IPCC 2013 fig.12.40 below shows the chances under RCP8.5 of 5-7 degrees C warming by 2100 above recent and pre-industrial temperatures.

IPCC 2013 fig.12.44d shows potential ocean thermal expansion this millennium under the four RCPs.

[Steven]

steven:

the caption for the image (5) that you posted says:

The NH and adjusted SH estimates are summed to yield global estimates (upper inset). Uncertainty estimates show the range of adjusted values obtained using the one standard deviation spread of model-simulated ratios

the little bits on the bottom right above the white line? those are the adjustments.

The little bits above the white lines in the figure are the Durack et al. adjustments to the observations in previous decades (which were data-sparse in the Southern Hemisphere).

However, this is irrelevant to my point.  The discussion was about how the findings of Durack et al. compare to the models (CMIP3 and CMIP5).

Durack et al. find that the Northern Hemisphere was responsible for roughly 40% of the total global ocean heat uptake (between 0 and 700 meters depth), and the Southern Hemisphere roughly 60%.  As I said, this is in good agreement with the CMIP models.

So Durack et al. suggest that the hemispheric distribution of ocean heat uptake in the CMIP models is (broadly) correct.  The paper does suggest that there was an incorrect infilling of data-sparse regions in the Southern Hemisphere, but that was a problem of the observations and has nothing to do with the CMIP models.

I have migrated all Durack et. al. discussion topics to the Durack et. al thread.

I would appreciate all future discussion on this topic take place there:

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

Apparently you forgot to copy my yesterday's comment to that thread, as well as the comments preceding it.  If you copy those comments to that thread, then I will post any further responses at that location.

[TeaPotty]

Scientists, Speak Up On Climate Change
http://www.bostonglobe.com/opinion/2014/11/09/scientists-speak-climate-change/Ht0r44A5PWPmr4uJL8167N/story.html



Quotes

One could almost feel the breeze stirred by the broad population’s collective shrug at this news coming from the IPCC meeting in Copenhagen. Almost as astonishing as the looming threat that carbon poisons pose for the planet is the indifference that average Americans seem to feel about it.

Hundreds of scientific societies, academies, agencies, and NGOs have weighed in without ambiguity. Yet reliable polls show that fewer than half of Americans know of this overwhelming scientific consensus.

What would it take for the public to get clear both on the unanimity of climate scientists, and on the urgency of what they see coming? An answer from the recent past suggests itself: scientists, instead of merely providing activists and journalists with irrefutable climate data, must leave their cloistered laboratories to become activists themselves. Scientists must take to the streets and lead, even if that means taking hits in the contentious public square.

It happened before, when scientists helped steer the human species away from suicide. The Cold War nuclear arms race might well have run on to Armageddon had not a remarkable cohort of physicists, astronomers, mathematicians, and physicians put their detached analysis at the service of moral fervor. They became passionately engaged advocates of disarmament — organizing international meetings, sounding alarms, headlining demonstrations, and demanding action from politicians. They brought incomparable authority to the debate because they had the ultimate insider knowledge — empirical evidence that the worst nuclear fears were, in fact, not bad enough for what threatened.

Once nuclear annihilation was on the agenda, Soviet and Western scientists began an astounding collaboration, with intermingled groups like The Pugwash Conferences on Science and World Affairs and the Physicians for the Prevention of Nuclear War. For the sake of the formerly “unscientific” question of morality, scientists risked their reputations for analytical objectivity. In some cases they risked careers.

Having learned from the publicly engaged scientists, and having been pressed from below by masses of citizens who embraced what the scientists taught, Reagan and Gorbachev together steered the world away from nuclear war.

Such a transformation must happen again. The Union of Concerned Scientists is still at it, and so are some others. But compared to the Cold War era, the voices of scientists today are mute. Yet the danger is equivalent. Who but climate scientists can effectively refute the lies of the carbon lobby? Where are you?