Conservative Scientists & its Consequences

[TerryM]

A very good article Hefaisos


I've long thought that the goal should be the least carbon for the most BTUs,


With wood and coal the carbon costs of extraction, pelletization or crushing, transportation, as well as the energy required to dispose of the ash and keep other nasties from the atmosphere needs to be accounted for.


Burning trash seems a no brainer, as well as solar or wind, but is transporting wood halfway around the world preferable to burning piped CH4 which might otherwise escape or be flared off? According to the article gas produces but 1/4th the CO2 to produce an equal amount of heat, and transportation doesn't require much energy.


Replacing coal with something that produces half again as much CO2 doesn't sound like progress.
Terry

[Neven]

Sweden doesn't need to import wood, right? I just built window sills with Swedish pine (I saw the wood was from there after I had bought it, would've preferred from Czech Rep. or Austria itself).

Sorry for the OT.

[Sleepy]

We do import wood.
https://www.swedishwood.com/about_wood/choosing-wood/from-log-to-plank/
We are really green, on the surface...

[AbruptSLR]

As a follow-on to my last post (Reply #2048), cutting-edge climate scientists should repetitively remind consensus climate scientists that climate change is a dynamical coupled phenomenon that per Lovejoy (2017), https://doi.org/10.22498/pages.25.3.136, with an atmosphere that varies: "On scales ranging over a factor of a billion in space and over a billion billion in time ..." (see the first image).  Addressing the implications such scaling considerations requires a "Limit State" approach, especially when are combined with the facts as:

(a) We are radiatively forcing climate change at a rate over 100-times faster than any time in over 100 million years (see the second image from SciAm);

(b) Our current climate models omit numerous feedback mechanisms including freshwater hosing [e.g. Hansen et al. (2016), DeConto & Pollard (2016) and Bakker et al. (2017)];

(c) Our current climate models cannot replicate the relatively high climate sensitivities, and Arctic Amplifications, of Super Interglacial periods, which are most relevant to our future in 2100;

(d) Work such as Brown & Caldeira (2017), doi:10.1038/nature24672 shows that based on satellite cloud observations that the best CMIP5 projections indicate that the instantaneous climate sensitivity, ICS, is currently at least 3.7C (see the third image); while Proistosescu & Huybers (2017) demonstrate that when considering slow response feedback mechanisms, the best CMIP5 models indicate that the effective ECS could be between 6 and 8C this century (see the fourth image).

Pepijn Bakker et. al. (2017), "Centennial-scale Holocene climate variations amplified by Antarctic Ice Sheet discharge", Nature 541, 72–76, doi:10.1038/nature20582

https://www.nature.com/articles/nature20582

Abstract: "Proxy-based indicators of past climate change show that current global climate models systematically underestimate Holocene-epoch climate variability on centennial to multi-millennial timescales, with the mismatch increasing for longer periods. Proposed explanations for the discrepancy include ocean–atmosphere coupling that is too weak in models, insufficient energy cascades from smaller to larger spatial and temporal scales, or that global climate models do not consider slow climate feedbacks related to the carbon cycle or interactions between ice sheets and climate. Such interactions, however, are known to have strongly affected centennial- to orbital-scale climate variability during past glaciations, and are likely to be important in future climate change. Here we show that fluctuations in Antarctic Ice Sheet discharge caused by relatively small changes in subsurface ocean temperature can amplify multi-centennial climate variability regionally and globally, suggesting that a dynamic Antarctic Ice Sheet may have driven climate fluctuations during the Holocene. We analysed high-temporal-resolution records of iceberg-rafted debris derived from the Antarctic Ice Sheet, and performed both high-spatial-resolution ice-sheet modelling of the Antarctic Ice Sheet and multi-millennial global climate model simulations. Ice-sheet responses to decadal-scale ocean forcing appear to be less important, possibly indicating that the future response of the Antarctic Ice Sheet will be governed more by long-term anthropogenic warming combined with multi-centennial natural variability than by annual or decadal climate oscillations."

I will post more on the need for a "Limit State" approach in order to effective address such considerations.

[AbruptSLR]

This post is provides two examples [Mann et al. (2017) & Cvijanovic et al (2017), see the attached image], of recent references that demonstrate the importance of properly accounting for the influence of atmospheric Rossby waves (planetary waves) on rapidly changing climate (on the scale of decades) during the anthropocene; while current IPCC guidance does not adequately account for such recently identified behavior:

Michael E. Mann et al. (2017), "Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events", Scientific Reports 7, Article number: 45242, doi:10.1038/srep45242

https://www.nature.com/articles/srep45242

Abstract: "Persistent episodes of extreme weather in the Northern Hemisphere summer have been shown to be associated with the presence of high-amplitude quasi-stationary atmospheric Rossby waves within a particular wavelength range (zonal wavenumber 6–8). The underlying mechanistic relationship involves the phenomenon of quasi-resonant amplification (QRA) of synoptic-scale waves with that wavenumber range becoming trapped within an effective mid-latitude atmospheric waveguide. Recent work suggests an increase in recent decades in the occurrence of QRA-favorable conditions and associated extreme weather, possibly linked to amplified Arctic warming and thus a climate change influence. Here, we isolate a specific fingerprint in the zonal mean surface temperature profile that is associated with QRA-favorable conditions. State-of-the-art (“CMIP5”) historical climate model simulations subject to anthropogenic forcing display an increase in the projection of this fingerprint that is mirrored in multiple observational surface temperature datasets. Both the models and observations suggest this signal has only recently emerged from the background noise of natural variability."

&

Ivana Cvijanovic et al (2017), "Future loss of Arctic sea-ice cover could drive a substantial decrease in California’s rainfall", Nature Communications 8, Article number: 1947, doi:10.1038/s41467-017-01907-4

https://www.nature.com/articles/s41467-017-01907-4

Abstract: "From 2012 to 2016, California experienced one of the worst droughts since the start of observational records. As in previous dry periods, precipitation-inducing winter storms were steered away from California by a persistent atmospheric ridging system in the North Pacific. Here we identify a new link between Arctic sea-ice loss and the North Pacific geopotential ridge development. In a two-step teleconnection, sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California. These findings suggest that the ability of climate models to accurately estimate future precipitation changes over California is also linked to the fidelity with which future sea-ice changes are simulated. We conclude that sea-ice loss of the magnitude expected in the next decades could substantially impact California’s precipitation, thus highlighting another mechanism by which human-caused climate change could exacerbate future California droughts."

Extract: "The “low Antarctic ice” simulations show that the proposed mechanism can be triggered by sea-ice changes in either hemisphere. Since Antarctic sea-ice loss involves northward propagation in both teleconnection steps (i.e., Antarctic sea-ice affecting the tropical Pacific, which in turn affects the North Pacific) and no high northern latitude changes, it provides additional support for our conjecture that the sea-ice changes can influence North Pacific geopotential height through tropical convection changes. More generally, any high-latitude perturbation (northern or southern hemispheric warming or cooling) that impacts the position of the tropical Pacific ITCZ, will have an impact on California’s rainfall."

[AbruptSLR]

As a follow-on to my last post, the linked reference discusses that complex/dynamical interplay between: eddies in atmospheric planetary waves, ocean heat transport, Hadley cell expansion and the poleward migration of tropical precipitation; which indicates that tropical cloud cover is also migrating poleward; which is a positive feedback mechanism:

Masakazu Yoshimori et al. (2017), "The importance of ocean dynamical feedback for understanding the impact of mid-high latitude warming on tropical precipitation change", Journal of Climate, https://doi.org/10.1175/JCLI-D-17-0402.1


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0402.1?utm_content=bufferc45ef&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "It has been shown that asymmetric warming between the northern and southern hemisphere extratropics induces a meridional displacement of tropical precipitation. This shift is believed to be due to the extra energy transported from the differentially heated hemisphere through changes in the Hadley circulation. Generally, the column-integrated energy flux in the mean meridional overturning circulation follows the direction of the upper, relatively dry branch, and tropical precipitation tends to be intensified in the hemisphere with greater warming. This framework was originally applied to simulations that did not include ocean dynamical feedback, but was recently extended to take the ocean heat transport change into account. In the current study, an atmosphere-ocean general circulation model applied with a regional nudging technique is used to investigate the impact of extratropical warming on tropical precipitation change under realistic future climate projections. It is shown that warming at latitudes poleward of 40° causes the northward displacement of tropical precipitation from October to January. Warming at latitudes poleward of 60° alone has a much smaller effect. This change in the tropical precipitation is largely explained by the atmospheric moisture transport due to changes in the atmospheric circulation. The larger change in ocean heat transport near the equator, relative to the atmosphere, is consistent with the extended energy framework. The current study provides a complementary dynamical framework that highlights the importance of mid-latitude atmospheric eddies and equatorial ocean upwelling, where the atmospheric eddy feedback modifies the Hadley circulation resulting in the northward migration of precipitation and the ocean dynamical feedback damps the northward migration from the equator."

[Hefaistos]

Sweden doesn't need to import wood, right? ...

There aren't enough pellets or biomass produced in Sweden for all those heating stations that are being converted to run on those fuels, e.g. in our city most of it will be imported from the US/Canada, and some from Russia.

[AbruptSLR]

As noted in my Reply # 2053, climate change is dynamical and responds at numerous, and interacting, scales (both spatial and temporal), and thus is best addressed with a "Limit State" approach; in that the future responses of such complex systems cannot be definitively predicted but characteristic 'limit' states can be established to better guide climate policy.

While there are many different ways to define various limit states (typically based on impacts to human functions); here, I choose to define a Maximum Credible Scenario of cascading upper-limit climate states that could progressively/dynamically ratchet/tip the Earth Systems into states of high activity by 2100 and beyond.  In this regard, I plan to provide evidences in future posts for the following upper-limit states, all referenced to the first attached image from Hansen et al (2011).

1. Unmasking of the Slow Response Upper-Limit State from 1994 to 2017

2. Activation of Intermediate Response Upper-Limit State by 2030

3. Activation of Fast Response Upper-Limit State by 2080

4. Activation of Initial ESS Mechanisms by 2100

Also with regards to the unmasking limit state from 1994 to 2017, I note that Brown and Caldeira (2017) show that over this period ECS was at least 3.7C, and the second and third images, from the following two linked websites respectively, show that w.r.t. radiative forcing (with an IRF over 3 W/sq-m) we are currently well above the RCP 8.5 radiative forcing scenario:

http://sedac.ipcc-data.org/ddc/ar5_scenario_process/RCPs.html

Caption for second image: "Figure: Radiative Forcing of the Representative Concentration Pathways. From van Vuuren et al (2011) The Representative Concentration Pathways: An Overview. Climatic Change, 109 (1-2), 5-31. . The light grey area captures 98% of the range in previous IAM scenarios, and dark grey represents 90% of the range."

Title: "Forcings in GISS Climate Models"
https://data.giss.nasa.gov/modelforce/

Caption for third image: "Fig. Instantaneous radiative forcing at the tropopause (W/m2) in the E2-R NINT ensemble. (a) Individual forcings and (b) Total forcing, along with the separate sums of natural (solar, volcanic and orbital) and anthropogenic forcings. (Updated: 3/12/2016)"

Also, the last attached image shows that the GMSTA for 2017 is well above the trend line, since 1964:

Lastly, I note that the E3SM project (when complete in 2027), will likely be the only means to verify the accuracy of my Maximum Credible Scenario of cascading upper-limit climate states before they occur:

https://climatemodeling.science.energy.gov/projects/energy-exascale-earth-system-model
&
https://climatemodeling.science.energy.gov/e3sm/meetings/123511

Edit: The last image is by Dana Nuccitelli and presents GISS data thru the end of 2017, and to convert these values to a pre-industrial baseline one can add 0.256C to the values shown on the plot.  Furthermore, I note that NOAA declared a weak La Nina event in the winter of 2016-17 and also NOAA officially states that ENSO conditions in the 2017-18 season will likely result in another weak La Nina event.

[AbruptSLR]

As a follow-on to my last post, I note that Hansen et al 2011 assumed that the ECS for a slow response function was about 3C,  However, the first attached image shows that Skeptical Science estimates that with ECS = 4.5C, GMSTA (w.r.t. pre-industrial) should be about 6C by 2100; while the second image by Friedrich et al 2016 shows that using a dynamical interpretation of the paleo data from the past approximately 700,000 years would also result in a projected GMSTA of about 6C by 2100.  Which indicates ECS is likely currently in the process of increasing from Brown & Caldeira (2017)'s estimate of 3.7C up to 4.5C assuming that we are approaching conditions comparable to MIS 11 and the Eemian.

Lastly in provide the third image from NOAA indicating that anthroprogenic radiative forcing in 2016 was over 3 W/sq-m, and the fourth image from AR5 indicating that following RCP 8.5 that the effective radiative forcing should be approaching 4 W/sq-m between 2030 and 2040.

[AbruptSLR]

For those who are not certain why Friedrich et al (2016)'s estimate of paleo climate sensitivity should become relevant in 2017, I provide the first image from Friedrich et al (2016) that shows that the peaks for both MIS 11 and the Eemian become relevant when GMSTA is about 1.25C about pre-industrial; which occurred following the 2015-16 Super El Nino.

For those who do not understand why interaction between the tropical oceans and the high latitudes should result in increasingly positive cloud feedback [as documents by both Brown & Caldeira (2017) & PH(17)], I provide the second, third and fourth images, that respectively show:

1. Sherwood (2014) deep atmospheric convection above a warming tropical ocean, which move the associated clouds both higher and poleward;
2. Rossby wave train telecommunication of tropical ocean energy directly to high latitudes [which can increase either Arctic Amplification or WAIS ice mass loss depending on which hemisphere the telecommunication leads to], and;
3. Agulhas Leakage associate with an increase in the velocity of the westerly winds over the Southern Ocean and which contributes to both bipolar seesaw behavior and a short-term warming of the Caribbean Sea which cause increased local evaporation (the resulted in sustained trade winds in the Tropical Pacific) which contributed to the faux hiatus when the Tropical Pacific sequestered large amounts of heat into the ocean, thus temporarily masking the true value of ECS until after the 2015-16 Super El Nino.

[AbruptSLR]

For those who are still not convinced that ECS increases with global warming this century, the linked AGU session entitled: "A32B: Climate Sensitivity and Feedbacks: Advances and New Paradigms I", indicates that values of ECS are increasing with global warming, and see the quote by Kate Marvel below:

https://agu.confex.com/agu/fm17/meetingapp.cgi/Session/31025

See also the following associated article:

Title: "More about Equilibrium Climate Sensitivity"

https://andthentheresphysics.wordpress.com/2017/12/14/more-about-equilibrium-climate-sensitivity/

Extract: "… Kate Marvel says in her summary it’s essentially that

You might think we could estimate this from observations: we’ve emitted carbon dioxide, and the temperature has risen. But the future may differ from the past, and there’s reason to think that the warming we’ve experienced so far is different from the warming to come."

Furthermore, the linked "DominoES" project will explore the concept that ice mass loss from Antarctica can cause a domino effect on various Earth Systems.

Title: "DominoES project    Domino Effects in the Earth System: Can Antarctica tip climate policy?"

https://www.pik-potsdam.de/research/projects/activities/dominoes

Extract: "Tipping elements are components of the Earth system that could be pushed into qualitatively different states by small external perturbations, with profound environmental impacts possibly endangering the livelihoods of millions of people. There are indications for significant interlinkages between climate tipping elements and even the potential for tipping cascades or domino effects from the climate to the social sphere. We will assess these effects for a highly relevant tipping chain connecting climatic tipping elements like Antarctica and Greenland with potential social tipping processes in public opinion formation and climate policy changes, and their societal implications."

Regarding the DominoES concept, I note that the Friedrich et al 2016 reference indicates that GMSTA should reach 2.7C sometime between 2030 and 2040, while the first attached image shows that per DeConto 2016 reaching such a temperature would trigger a phase of rapid ice mass loss from West Antarctica, beginning with the rapid loss of ice shelves due to hydrofracturing (see the second image showing the extent of surface ice melt in West Antarctica last austral summer).


Edit: A couple of posts ago I noted that following RCP 8.5 would result in an ERF value of about 4 W/sq-m sometime between 2030-2040; which I just showed is the timeframe for GMSTA to reach about 2.7C assuming ECS ~ 4.5C.  Thus, the increase of about 2 W/sq-m of imbalance due to a collapse of the WAIS starting around 2040 (see the third image from Hansen et al 2016) would result in about 6 W/sq-m at the top of the atmosphere, and per the fourth image from PH(17) this could push the effective ECS into the 6 to 8C range by between 2080 and 2100.

[Daniel B.]

This site shows a constant update of computer models compared to observations.

https://www.climate-lab-book.ac.uk/comparing-cmip5-observations/

Observations were running on the low side, until the recent El Nino pushed temperatures into the middle of the range.  The 90% range for temperature rise by 2050 is 0.4 - 2.2 C above the 1986-2005 baseline.

[jai mitchell]

The 90% range for temperature rise by 2050 is 0.4 - 2.2 C above the 1986-2005 baseline.

I think you mean 0.6  to 2.2
 

seeing that we are now above the low range value in 2017 with a whole lot of residual warming locked in (offset by aerosols, future feedbacks, 10-year lag time between emissions and full temp response) I think we can pretty much throw out the AR5 now.

[Daniel B.]

The 90% range for temperature rise by 2050 is 0.4 - 2.2 C above the 1986-2005 baseline.

I think you mean 0.6  to 2.2
 

seeing that we are now above the low range value in 2017 with a whole lot of residual warming locked in (offset by aerosols, future feedbacks, 10-year lag time between emissions and full temp response) I think we can pretty much throw out the AR5 now.

Yes, that is correct.

[AbruptSLR]

I think we can pretty much throw out the AR5 now.

Brown & Caldeira (2017)'s primary point is that AR5 projections include a lot of results from models that do not match the observed cloud behavior, so when they only keep the model results that match the observed cloud behavior, they get about a 50-50 chance of reaching 2.7C above pre-industrial by 2050 (see the attached image).  That said AR5 also ignore the impacts of freshwater hosing, and any carbon cycle emissions from high latitudes.  Also, many of the AR5 model projections do not adequately account for the slow response contributions to GMSTA cited by Cristian Proistosescu and Peter J. Huybers (05 Jul 2017), due to 267-years of anthropogenic global warming.

But you already know that (and much more) .

[Daniel B.]

As shown in your graphic, the models are still running much higher than the observations.

[AbruptSLR]

The linked reference discusses the threat of very-short-lived-substances to the expected recovery of the stratospheric ozone; which could mean that the AR5 ozone projections are wishful thinking.

Oram, D. E., Ashfold, M. J., Laube, J. C., Gooch, L. J., Humphrey, S., Sturges, W. T., Leedham-Elvidge, E., Forster, G. L., Harris, N. R. P., Mead, M. I., Samah, A. A., Phang, S. M., Ou-Yang, C.-F., Lin, N.-H., Wang, J.-L., Baker, A. K., Brenninkmeijer, C. A. M., and Sherry, D.: A growing threat to the ozone layer from short-lived anthropogenic chlorocarbons, Atmos. Chem. Phys., 17, 11929-11941, https://doi.org/10.5194/acp-17-11929-2017, 2017.

https://www.atmos-chem-phys.net/17/11929/2017/

Abstract. Large and effective reductions in emissions of long-lived ozone-depleting substance (ODS) are being achieved through the Montreal Protocol, the effectiveness of which can be seen in the declining atmospheric abundances of many ODSs. An important remaining uncertainty concerns the role of very short-lived substances (VSLSs) which, owing to their relatively short atmospheric lifetimes (less than 6 months), are not regulated under the Montreal Protocol. Recent studies have found an unexplained increase in the global tropospheric abundance of one VSLS, dichloromethane (CH2Cl2), which has increased by around 60 % over the past decade. Here we report dramatic enhancements of several chlorine-containing VSLSs (Cl-VSLSs), including CH2Cl2 and CH2ClCH2Cl (1,2-dichloroethane), observed in surface and upper-tropospheric air in East and South East Asia. Surface observations were, on occasion, an order of magnitude higher than previously reported in the marine boundary layer, whilst upper-tropospheric data were up to 3 times higher than expected. In addition, we provide further evidence of an atmospheric transport mechanism whereby substantial amounts of industrial pollution from East Asia, including these chlorinated VSLSs, can rapidly, and regularly, be transported to tropical regions of the western Pacific and subsequently uplifted to the tropical upper troposphere. This latter region is a major provider of air entering the stratosphere, and so this mechanism, in conjunction with increasing emissions of Cl-VSLSs from East Asia, could potentially slow the expected recovery of stratospheric ozone.

[AbruptSLR]

As shown in your graphic, the models are still running much higher than the observations.

Zeke Hausfather provides the attached image showing the first official Global Mean Surface Temperature Anom. (GMSTA) for 2017, and converting this to a pre-industrial baseline gives a value of approximate 1.15C for 2017; which is almost directly on Brown & Caldeira  (2017)'s projection for last year.

Also, I note that 2016-17 was an official La Nina event, and NOAA projects that 2017-18 will also be a La Nina event, so it is not reasonable to claim that the GMSTA value for 2017 was biased by the 2015-16 Super El Nino event.

[AbruptSLR]

The linked article indicates that new research indicates that the Amazon rainforest like cannot absorb as much CO₂ as previously assumed by climate scientists:

Title: "Ancient human sites may have distorted our understanding of the Amazon’s natural ecology"

https://news.mongabay.com/2018/01/ancient-human-sites-may-have-distorted-our-understanding-of-the-amazons-natural-ecology/

•   Extract: "Scientists have traditionally based their knowledge of the Amazon rainforest on surveys from fewer than 1,000 plots of land, which they had assumed were representative of the rest of the forest.
•   Research now shows that many of these sites were occupied and modified by ancient peoples, and the trees are still regrowing from those disturbances.
•   These recovering trees absorb carbon at a faster rate than mature trees, so estimates of how well the rainforest can absorb carbon dioxide may be too high."

[gerontocrat]

We are going to be OK !! (Maybe?)

Climate sensitivity study suggests narrower range of potential outcomes

[/b]

https://www.theguardian.com/science/2018/jan/18/worst-case-global-warming-scenarios-not-credible-says-study

A revised calculation of how greenhouse gases drive up the planet’s temperature reduces the range of possible end-of-century outcomes by more than half, researchers said in the report, published in the journal Nature.

“Our study all but rules out very low and very high climate sensitivities,” said lead author Peter Cox, a professor at the University of Exeter.

But then, right at the end -

One wild card not taken into consideration by the new model is the possibility of rapid shifts in climate brought on by the planet itself. “There is indeed evidence that the climate system can undergo abrupt changes or ‘tipping points’,” Cox said.

The collapse of the gulf stream, the thawing of carbon-rich permafrost, or the melting of ice sheets on Greenland and Antarctica – any of these could quickly change the equation, and not in the Earth’s favour.

Wild card? - it is global warming that is causing the changes mentioned.

[AbruptSLR]

We are going to be OK !! (Maybe?)

Climate sensitivity study suggests narrower range of potential outcomes

[/b]

https://www.theguardian.com/science/2018/jan/18/worst-case-global-warming-scenarios-not-credible-says-study

A revised calculation of how greenhouse gases drive up the planet’s temperature reduces the range of possible end-of-century outcomes by more than half, researchers said in the report, published in the journal Nature.

“Our study all but rules out very low and very high climate sensitivities,” said lead author Peter Cox, a professor at the University of Exeter.

But then, right at the end -

One wild card not taken into consideration by the new model is the possibility of rapid shifts in climate brought on by the planet itself. “There is indeed evidence that the climate system can undergo abrupt changes or ‘tipping points’,” Cox said.

The collapse of the gulf stream, the thawing of carbon-rich permafrost, or the melting of ice sheets on Greenland and Antarctica – any of these could quickly change the equation, and not in the Earth’s favour.

Wild card? - it is global warming that is causing the changes mentioned.

To me, the linked reference is a classic example of the wishful thinking (by relying on 16 overly simple climate models) of consensus science.  This is just more of the same thinking that has got the world in the high risk situation that it currently is in:

Cox et al (2018), "Emergent constraint on equilibrium climate sensitivity from global temperature variability", Nature 553, 319-322, doi:10:1038/Nature25450.

http://www.nature.com/articles/nature25450

See also:

Title: "Global Warming Predictions May Now Be a Lot Less Uncertain"

https://www.wired.com/story/the-dizzying-science-of-climate-change-gets-a-bit-clearer/

Extract: "So, the numbers. What the researchers landed on was an ECS range of 2.2 to 3.4°C, compared to the commonly accepted range of 1.5 and 4.5°C.
…
But hold up, says Swiss Federal Institute of Technology climate scientist Reto Knutti, who wasn’t involved in the research. “What's the chance of something fundamentally being wrong in our models?” he asks. “Is that really less than 1 percent? I would argue there's more than a one in a hundred chance that something has been forgotten in all of the models, just because our understanding is incomplete.”

[Daniel B.]

We are going to be OK !! (Maybe?)

Climate sensitivity study suggests narrower range of potential outcomes

[/b]

https://www.theguardian.com/science/2018/jan/18/worst-case-global-warming-scenarios-not-credible-says-study

A revised calculation of how greenhouse gases drive up the planet’s temperature reduces the range of possible end-of-century outcomes by more than half, researchers said in the report, published in the journal Nature.

“Our study all but rules out very low and very high climate sensitivities,” said lead author Peter Cox, a professor at the University of Exeter.

But then, right at the end -

One wild card not taken into consideration by the new model is the possibility of rapid shifts in climate brought on by the planet itself. “There is indeed evidence that the climate system can undergo abrupt changes or ‘tipping points’,” Cox said.

The collapse of the gulf stream, the thawing of carbon-rich permafrost, or the melting of ice sheets on Greenland and Antarctica – any of these could quickly change the equation, and not in the Earth’s favour.

Wild card? - it is global warming that is causing the changes mentioned.

Nothing really new with regards to the science involved.  They just selectively choose which (of the many) climate models they felt are the most relevant.  All they did was dismiss those models which failed to reproduce pass temperature changes accurately.  Then added their personal opinion about a wild card.

[AbruptSLR]

As Kate Marvel has stated repeatedly, CMIP5-types of climate models that have been calibrated to the observed record, most likely underestimate ECS, as ECS increases non-linearly with global warming:

Title: "Can Climate Sensitivity be Constrained by Current Observations?"

http://www.gradadmiss.gatech.edu/hg/item/600179

Extract: "In this talk, I'll discuss the reasons the present may be dissimilar to the future in the CMIP5 models.  I'll present work in which we argue that, at least in a perfect model framework, observations are highly likely to underestimate feedbacks at equilibrium.
 
Additionally, the particular manifestation of internal variability and forced response that characterizes recent observations resulted in an even lower estimate.   Moreover, we find that not only do climate models indicate that current estimates of ECS are biased low, but models' sensitivities to observed conditions are not even predictive of their long-term sensitivities. 

Our results suggest a need for caution in any attempt to use current conditions to constrain long-term climate projections."

[Daniel B.]

Other climate scientific research has shown that the CMIP5 models are most likely over-estimating warming.

https://www.nature.com/articles/ngeo3031.epdf?referrer_access_token=xkwtnMZBWpdT39x-Wiri9NRgN0jAjWel9jnR3ZoTv0OhiLdhtid2wIzB9lmkCPRiTpKZ3UAQo2fv12-9gCU-pTXSmA81mvEIq5iu9iXO2tyw4dSYdYjuwcS7pSwhjFeC9NS-QdZLW4H8hYDxV2JKV_-qVjrERzMntwxCyN3v7bfkYAAV6Ui75h5mnpKRsb8SUrXk2rqW-o8aJvNONUEZ3i5FX3AORdqbDKuFS6Br4gS-svvpfpFgC_4xKLBlhQM4mC_fpjiUyS6aYdEPMM7287fUSBsvCBGJRco1BRfiWVqQW0dRqqIkFEiM_2QBUt4YLs_eX4DaHpPctJGIoBmytu-0PWBpLes1DCQbdCUFMv4%3D&tracking_referrer=www.washingtonpost.com

[AbruptSLR]

Other climate scientific research has shown that the CMIP5 models are most likely over-estimating warming.

You are assuming that ECS of the relatively recent past will be the same ECS of the next few decades; which is something that Marvel says is not such a good idea.

[Daniel B.]

Other climate scientific research has shown that the CMIP5 models are most likely over-estimating warming.

You are assuming that ECS of the relatively recent past will be the same ECS of the next few decades; which is something that Marvel says is not such a good idea.

I feel that the assumption of a constant ECS would be the worst case scenario.  Most chemical and physical reactions have diminishing returns.  Hence, the overestimating.

[AbruptSLR]

I feel that the assumption of a constant ECS would be the worst case scenario.  Most chemical and physical reactions have diminishing returns.  Hence, the overestimating.

I feel that Brown & Caldeira (2017) make a convincing case based on satellite observations of clouds, that since 1994 the average value of ECS has been 3.7C, which is well above the mean value from CMIP5.  Furthermore, based on Friedrich et al (2016), as we approach peak Eemian conditions, ECS may increase towards 4.5C

Edit: I note that per GISS LOTI base-lined to pre-industrial, at the end of 2017 we are already at 1.153C, and thus we are rapidly approaching peak Eemian global temperatures.

[AbruptSLR]

The linked article indicates that the climate response lag time can be as long as 21 years when considering complex ocean thermal inertia influences; which when accounted for can significantly increase the true value of ECS above inferred values of ECS that assume shorter lag times (see the attached image and associated caption):

Title: "Guest post: A ‘new’ measurement of climate sensitivity?"

https://andthentheresphysics.wordpress.com/2018/01/17/guest-post-a-new-measurement-of-climate-sensitivity/

Captions: "Figure 3: Model true equilibrium climate sensitivity (True ECS) as a function of that calculated as in Figure 2, using historical-RCP8.5 temperature change with the Forster forcing and a one-box model with a 12-year lag. All of the points are above the 1:1 black dashed line, showing that the one-box model underestimates true ECS in all 18 cases. The red line is a best fit to the models, although the fit is weak."

[Daniel B.]

Some recent journals have placed the ECS around 2.7.

https://www.nature.com/articles/nature25450

2.0

https://www.researchgate.net/publication/320039513_Natural_climate_variability_part_1_Observations_versus_the_modeled_predictions

And 2.0

https://www.earth-syst-dynam-discuss.net/esd-2017-119/esd-2017-119.pdf

Of course any estimate of ECS must make certain assumptions, as depicted here:

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0482.1#/doi/full/10.1175/JCLI-D-17-0482.1

[gerontocrat]

To quote "Monty Python" - my theory that belongs to me - is that the oceans will do in all the theories and models of the atmospheric scientists.

When? he asked. Je ne sais pas. was the reply.

[Daniel B.]

lol. Sounds about right.

[AbruptSLR]

https://www.earth-syst-dynam-discuss.net/esd-2017-119/esd-2017-119.pdf

This reference quotes inferred ECS, which is about 43% lower that the true ECS.

[Csnavywx]

Actually, with ice sheets and strong ocean currents still on the planet, there's no reason to think that ECS would go down with increasing temperature. These two processes tend to retard the accumulation of surface or near-surface (MLD and intermediate water) heat over long periods of time. As they diminish, so will the brake on GMST.

You're right about diminishing returns in general, but the diminishing returns in climate come largely in the form of conditionally unstable baroclinic gradients (or eddy potential energy) and thus mixing (or eddy kinetic energy). Arctic Amplification and its effect on the polar and arctic branches of the jet stream are good examples of that. As EPTD (equator to pole temperature difference or delta-t) becomes lower, both the gradient and resultant mixing (EPE and EKE) decreases. The same happens in the horizontal with ocean temperature gradients as heterogeneous heating and the slowing wind decreases surface wind stress, which slows currents and mixing with deeper ocean layers. This feeds back into vertical ocean gradients as well, causing increased stratification (stability), also reducing mixing.

There's a real reason equable climate regimes show up repeatedly in the fossil records. They're also almost all universally considerably warmer than even the current generation of modeling can reproduce (although some recent improvement has been made). Land (continent) placement has something to do with it, but repeated episodes of equable climates with vastly different land configuration is a sign that ocean/atmosphere configuration is immensely important as well.

[Csnavywx]

Other climate scientific research has shown that the CMIP5 models are most likely over-estimating warming.

https://www.nature.com/articles/ngeo3031.epdf?referrer_access_token=xkwtnMZBWpdT39x-Wiri9NRgN0jAjWel9jnR3ZoTv0OhiLdhtid2wIzB9lmkCPRiTpKZ3UAQo2fv12-9gCU-pTXSmA81mvEIq5iu9iXO2tyw4dSYdYjuwcS7pSwhjFeC9NS-QdZLW4H8hYDxV2JKV_-qVjrERzMntwxCyN3v7bfkYAAV6Ui75h5mnpKRsb8SUrXk2rqW-o8aJvNONUEZ3i5FX3AORdqbDKuFS6Br4gS-svvpfpFgC_4xKLBlhQM4mC_fpjiUyS6aYdEPMM7287fUSBsvCBGJRco1BRfiWVqQW0dRqqIkFEiM_2QBUt4YLs_eX4DaHpPctJGIoBmytu-0PWBpLes1DCQbdCUFMv4%3D&tracking_referrer=www.washingtonpost.com

Colored another way:

https://twitter.com/ClimateOfGavin/status/954684105953824769



Millar et al uses HADCrut, which is cooler than the other surface datasets due to the way they handle data-sparse areas. (There was a loooooong discussion on this in the pre-Nino years when the "hiatus" was still going on -- Cowtan and Way came up with a good method to solve the issue though GISS handles it well enough).

ECS's of 2C (lamda of 0.5) are pretty darn unlikely unless you believe cloud feedbacks are zero to negative (plenty of evidence to suggest otherwise, actually). Base CO2+water vapor radiative forcing effects get you to 2C easily all by themselves. Dressler had a great lecture on this last year.

Speaking of these papers, there's a good post up today on ...and Then There's Physics discussing just this issue:

https://andthentheresphysics.wordpress.com/2018/01/20/narrowing-the-climate-sensitivity-range/#comment-110246

... complete with a comment by Dressler at the bottom with their own emergent constraint-type paper to be published soon.

[oren]

I feel that the assumption of a constant ECS would be the worst case scenario.  Most chemical and physical reactions have diminishing returns.  Hence, the overestimating.

You seem to forget that ECS is not defined as the linear response to CO₂ growth, but as a logarithmic response to the doubling of CO₂. So your diminishing returns are already baked into the definition.

[Neven]

It looks like Daniel B. has come to the end of the line of climate risk denial (climate sensitivity). Congratulations. 

[Daniel B.]

I feel that the assumption of a constant ECS would be the worst case scenario.  Most chemical and physical reactions have diminishing returns.  Hence, the overestimating.

You seem to forget that ECS is not defined as the linear response to CO₂ growth, but as a logarithmic response to the doubling of CO₂. So your diminishing returns are already baked into the definition.

Of course.  That is a given.  The issue is whether the ECS is avconstant value for CO2 doubling.

[mitch]

ECS was developed as a model metric in the 1970's, to compare responses of different climate models to the same forcing. It then began to be applied to the world in general when it appeared that humans would potentially double CO2 in the atmosphere. It is state dependent, since the feedbacks are state dependent. It is not useful to think of it as a constant, and it is useful to realize that the total earth system response will probably be more than the purely physical responses that make up ECS--in other words, Earth System Sensitivity. 

[Daniel B.]

ECS was developed as a model metric in the 1970's, to compare responses of different climate models to the same forcing. It then began to be applied to the world in general when it appeared that humans would potentially double CO2 in the atmosphere. It is state dependent, since the feedbacks are state dependent. It is not useful to think of it as a constant, and it is useful to realize that the total earth system response will probably be more than the purely physical responses that make up ECS--in other words, Earth System Sensitivity.

Yes.  The ECS has a certain value for this current state.  Future changes will alter that value.  Exactly how, is not known, just as a precise value is not known.  In all likelihood, it will decrease as positive influences increase.

[GeoffBeacon]

The Oxford Martin School

I think this is the right thread to point out that Millar and fellow author Myles Allen are at the Oxford Martin School.  One of Oxford  Martin's latest is New principles to guide corporate investment towards climate goals

Investors will play a major role, whether active or passive, in climate change mitigation. To enable prudent decision-making, we propose three physically based engagement principles that could be used to assess whether an investment is consistent with a long-term climate goal.

I often get an uneasy feeling when seeing  work associated with this stable. e.g.

Why I think we're wasting billions on global warming, by top British climate scientist

Guest post: Bioenergy ‘flaw’ under EU renewable target could raise emissions

Often it is considerable effort to argue against what they say. e.g. Where the importance of methane is de-emphasised in the paper New use of global warming potentials to compare cumulative and short-lived climate pollutants. It's clever technical stuff.

I get a "conservative scientist" impression from that paper - and from watching Myles Allen's presentation in Save the planet: invest in fossil fuels?)

A decade or so ago, I lobbied John Hutton, Secretary of State for the relevant UK Government Department (as they change names so often I can't remember what it was called) to go ahead with the experimental CCS project at Peterhead and I still think we ought to be putting large sums into research and pilot schemes.

HOWEVER,  CO2 capture may be our only option for stabilising temperatures - we need to find out the costs, fast worries me. I think it's because I suspect the Oxford  Martin ethos embeds a vision of a corporative growth model that refuses to accept we must radically change the way we live:

A global ban on fossil fuels is neither affordable nor enforceable, so capture and disposal of CO2 is the only option. Assuming we don’t want to turn the world over to cultivating biofuels and resort to eating insects, then there will always be some uses of fossil fuels for which there is no effective non-fossil substitute, much as environmentalists hate to admit it.

I suspect their ethos avoids anything too radical in changing the lifestyles of the affluent.

Am I wrong?

[AbruptSLR]

ECS was developed as a model metric in the 1970's, to compare responses of different climate models to the same forcing. It then began to be applied to the world in general when it appeared that humans would potentially double CO2 in the atmosphere. It is state dependent, since the feedbacks are state dependent. It is not useful to think of it as a constant, and it is useful to realize that the total earth system response will probably be more than the purely physical responses that make up ECS--in other words, Earth System Sensitivity.

Yes.  The ECS has a certain value for this current state.  Future changes will alter that value.  Exactly how, is not known, just as a precise value is not known.  In all likelihood, it will decrease as positive influences increase.

Co-dependents facilitate addicts' denial of reality; which drags both themselves, and those around them, into chaos.

[Csnavywx]

ECS was developed as a model metric in the 1970's, to compare responses of different climate models to the same forcing. It then began to be applied to the world in general when it appeared that humans would potentially double CO2 in the atmosphere. It is state dependent, since the feedbacks are state dependent. It is not useful to think of it as a constant, and it is useful to realize that the total earth system response will probably be more than the purely physical responses that make up ECS--in other words, Earth System Sensitivity.

Yes.  The ECS has a certain value for this current state.  Future changes will alter that value.  Exactly how, is not known, just as a precise value is not known. In all likelihood, it will decrease as positive influences increase.

Agreed with the italicized. You really need to support the bolded. Otherwise, it's supposition. There's plenty of reason and evidence to suggest otherwise (whether that be through cloud behavior or paleoclimate).

[Daniel B.]

ECS was developed as a model metric in the 1970's, to compare responses of different climate models to the same forcing. It then began to be applied to the world in general when it appeared that humans would potentially double CO2 in the atmosphere. It is state dependent, since the feedbacks are state dependent. It is not useful to think of it as a constant, and it is useful to realize that the total earth system response will probably be more than the purely physical responses that make up ECS--in other words, Earth System Sensitivity.

Yes.  The ECS has a certain value for this current state.  Future changes will alter that value.  Exactly how, is not known, just as a precise value is not known.  In all likelihood, it will decrease as positive influences increase.

Co-dependents facilitate addicts' denial of reality; which drags both themselves, and those around them, into chaos.

I have been giving you the benefit of the doubt on your past posts.  Perhaps I should just heed your advice, lest you drag me down into your chaos.

[Csnavywx]

To further my earlier post:

[AbruptSLR]

To further my earlier post:

Dessler provides a comment at the linked website, where he confirms what he states in the video, and he notes that Kyle Armour and Kate Marvel presented analyses at the AGU that indicated that low estimates of ECS based surface temperature patterns over the past few decades are not correct:

https://andthentheresphysics.wordpress.com/2018/01/20/narrowing-the-climate-sensitivity-range/#comment-110246

Extract: "We have another paper that is basically ready to submit that has a more rigorous ECS range (likely 2.4-4.5 K) based on our revised energy balance framework."

And while an ECS range of 2.4 to 4.5C has a mean value of 3.45C, I cannot help but to believe that Hansen's ice-climate feedback will result in still higher estimates of future values of ECS if ice mass loss from the WAIS continues to accelerate.

[AbruptSLR]

Actually, with ice sheets and strong ocean currents still on the planet, there's no reason to think that ECS would go down with increasing temperature. These two processes tend to retard the accumulation of surface or near-surface (MLD and intermediate water) heat over long periods of time. As they diminish, so will the brake on GMST.

The linked article indicates that the continuing decrease of Arctic sea-ice extent will continue to slow the AMOC; which, as Csnavywx notes, will increase the rate of global warming:

Florian Sévellec, Alexey V. Fedorov & Wei Liu (2017), "Arctic sea-ice decline weakens the Atlantic Meridional Overturning Circulation", Nature Climate Change 7, 604–610, doi:10.1038/nclimate3353

https://www.nature.com/articles/nclimate3353

Abstract: "anomalous surface heat and freshwater fluxes, resulting in positive buoyancy anomalies that can affect ocean circulation. In this study, we use an optimal flux perturbation framework and comprehensive climate model simulations to estimate the sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to such buoyancy forcing over the Arctic and globally, and more generally to sea-ice decline. It is found that on decadal timescales, flux anomalies over the subpolar North Atlantic have the largest impact on the AMOC, while on multi-decadal timescales (longer than 20 years), flux anomalies in the Arctic become more important. These positive buoyancy anomalies spread to the North Atlantic, weakening the AMOC and its poleward heat transport. Therefore, the Arctic sea-ice decline may explain the suggested slow-down of the AMOC and the ‘Warming Hole’ persisting in the subpolar North Atlantic."

[Daniel B.]

Dessler has opined that he can rule out a low ECS (<2.0), but also a high ECS (>4.5).  That seems reasonable, but I would not rule them out quite yet.  Interestingly, the Dessler paper to which you refer states, "We calculate ECS in each ensemble member using energy balance, yielding values ranging from 2.1 to 3.9 K."

https://www.atmos-chem-phys-discuss.net/acp-2017-1236/

Additional recent estimates from other editorials in your linked sites include, 2.1, which they state, "is maybe still a bit lower than other estimates, but still seems reasonable."

https://andthentheresphysics.wordpress.com/2017/12/14/more-about-equilibrium-climate-sensitivity/

Another recent analysis states a range of 2.0-3.0, with a nest guess estimate of 2.5.

http://clivebest.com/blog/?p=8146

Dessler advocate for using paleoclimate data instead of observation data, but a recent paper using such showed a lower estimate of 1.87.

Earlier, Peter CO, et.al. published a paper with a range of 2.2-3.4, with a central estimate of 2.8.

https://www.nature.com/articles/nature25450
https://link.springer.com/article/10.1007/s00382-017-3744-4

I find your claims of an ECS in the mid to upper 3 range as being highly questionable, and running counter to the most recently published scientific research.

[AbruptSLR]

The two linked articles explain how scientist have previously underestimated the impact of geothermal heat flux on future ice mass loss from the Greenland Ice Sheet:

Title: "Heat loss from the Earth triggers ice sheet slide towards the sea"

https://phys.org/news/2018-01-loss-earth-triggers-ice-sheet.html

Extract: "Today, in the esteemed journal Scientific Reports, researchers from the Arctic Research Centre, Aarhus University, and the Greenland Institute of Natural Resources present results that, for the first time, show that the deep bottom water of the north-eastern Greenland fjords is being warmed up by heat gradually lost from the Earth's interior. And the researchers point out that this heat loss triggers the sliding of glaciers from the ice sheet towards the sea."

&

Title: "Machine learning predicts new details of geothermal heat flux beneath the Greenland Ice Sheet"

https://phys.org/news/2018-01-machine-geothermal-flux-beneath-greenland.html

[AbruptSLR]

Dessler has opined that he can rule out a low ECS (<2.0), but also a high ECS (>4.5).  That seems reasonable, but I would not rule them out quite yet.  Interestingly, the Dessler paper to which you refer states, "We calculate ECS in each ensemble member using energy balance, yielding values ranging from 2.1 to 3.9 K."

https://www.atmos-chem-phys-discuss.net/acp-2017-1236/

Additional recent estimates from other editorials in your linked sites include, 2.1, which they state, "is maybe still a bit lower than other estimates, but still seems reasonable."

https://andthentheresphysics.wordpress.com/2017/12/14/more-about-equilibrium-climate-sensitivity/

Another recent analysis states a range of 2.0-3.0, with a nest guess estimate of 2.5.

http://clivebest.com/blog/?p=8146

Dessler advocate for using paleoclimate data instead of observation data, but a recent paper using such showed a lower estimate of 1.87.

Earlier, Peter CO, et.al. published a paper with a range of 2.2-3.4, with a central estimate of 2.8.

https://www.nature.com/articles/nature25450
https://link.springer.com/article/10.1007/s00382-017-3744-4

I find your claims of an ECS in the mid to upper 3 range as being highly questionable, and running counter to the most recently published scientific research.

As you must have read, Dessler clearly explained that the 2.1 to 3.9 K range for ECS was just a worked example of the energy balance method, and was not calibrated to the best observational data; and Dessler explained that when calibrated this method resulted in a 2.4 to 4.5C range for ECS.

Furthermore, Dessler indicates that it will likely take at least a year before other consensus scientists stop referencing values of ECS below 2.4C.

[Daniel B.]

Dessler has opined that he can rule out a low ECS (<2.0), but also a high ECS (>4.5).  That seems reasonable, but I would not rule them out quite yet.  Interestingly, the Dessler paper to which you refer states, "We calculate ECS in each ensemble member using energy balance, yielding values ranging from 2.1 to 3.9 K."

https://www.atmos-chem-phys-discuss.net/acp-2017-1236/

Additional recent estimates from other editorials in your linked sites include, 2.1, which they state, "is maybe still a bit lower than other estimates, but still seems reasonable."

https://andthentheresphysics.wordpress.com/2017/12/14/more-about-equilibrium-climate-sensitivity/

Another recent analysis states a range of 2.0-3.0, with a nest guess estimate of 2.5.

http://clivebest.com/blog/?p=8146

Dessler advocate for using paleoclimate data instead of observation data, but a recent paper using such showed a lower estimate of 1.87.

Earlier, Peter CO, et.al. published a paper with a range of 2.2-3.4, with a central estimate of 2.8.

https://www.nature.com/articles/nature25450
https://link.springer.com/article/10.1007/s00382-017-3744-4

I find your claims of an ECS in the mid to upper 3 range as being highly questionable, and running counter to the most recently published scientific research.

As you must have read, Dessler clearly explained that the 2.1 to 3.9 K range for ECS was just a worked example of the energy balance method, and was not calibrated to the best observational data; and Dessler explained that when calibrated this method resulted in a 2.4 to 4.5C range for ECS.

Furthermore, Dessler indicates that it will likely take at least a year before other consensus scientists stop referencing values of ECS below 2.4C.

We will see.  That is one opinion against many.