wattsupwiththat--2020-11-29--Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of A

The present paper contributes a critical commentary on the recent finding by Mann , M. E. , Steinman , B .
A. and Miller , S. K ( 2020 ) .
Absence of internal multidecadal and interdecadal oscillations in climate model simulations .
Nat .
Commun .
11 , 1–9 .
Climate oscillations are recurring large-scale fluctuations in the surface temperatures of the oceans in connection with the atmosphere .
This commentary focuses on the Pacific Decadal Oscillation ( PDO , interdecadal timescale ) and the Atlantic Multidecadal Oscillation ( AMO , multidecadal timescale ) , which have been regarded @ @ @ @ @ @ @ continents in numerous studies based on observations and paleoclimate reconstructions ( Henley , 2017 ; O ’ Reilly et al.
, 2017 ) .
In a recent paper , Michael E. Mann and colleagues ( Mann et al.
, 2020 , hereafter M20 ) fail to find a PDO signal in global measured and modeled temperatures that is statistically different from noise .
They further propose that the significant AMO-like signal is mainly due to anthropogenic aerosols in the 20th century , and to statistical artifacts before .
Therefore they doubt the intrinsic @ @ @ @ @ @ @ present paper shows that M20 ’ s results are largely artifacts themselves with issues ranging from using inadequate data and referencing improper literature on anthropogenic aerosols with regards to the AMO to inappropriately interpreting the results with regards to the PDO .
After briefly sketching the rationale and method of M20 , I will elaborate on these three points .
M20 ( p. 3 ) argue that any truly oscillatory AMO or PDO signals should generate a spatially coherent and large-scale variability pattern in the climate system with a narrowband signature in the @ @ @ @ @ @ @ signals in global ( observed and modeled ) temperature grids of different time lengths with the multi-taper method of singular value decomposition ( MTM-SVD ) , which was developed and widely applied by Mann and Park ( Mann and Park , 1994 ; Mann et al.
, 1995 ; Mann and Park , 1999 ) .
Significance tests of the test statistic LFV ( local fractional variance ) are carried out with Monte Carlo simulations generated according to the null hypothesis of colored ( red ) noise .
The method can generally be @ @ @ @ @ @ @ the spatial pattern of any potential oscillatory climate signal .
M20 examine three global sets of temperature data for oscillatory signals , all spanning a minimum length of 158 years : Control simulations ( control runs of the IPCC model ensemble CMIP5 , using pre-industrial conditions of the atmosphere without any external forcing so that “ any apparently oscillatory behavior must arise from internal variability ” ) , historical observations ( annualized global monthly average surface temperatures from the HadCRUT4 land and ocean surface temperature dataset ) , and historical simulations ( IPCC @ @ @ @ @ @ @ and natural forcing ) .
They find robust significant spectral peaks in the multidecadal AMO range ( period 40–70 years ) in the historical observations and the historical simulations , but not in the control simulations .
However , the latter data set is the only one that covers a greater length of time , with almost half of the model runs spanning 500 years or more .
The absence of robust multidecadal AMO oscillations in the control simulations stands in sharp contrast to numerous studies finding the opposite in paleoclimatic data ( @ @ @ @ @ @ @ , 2004 ; Chylek et al.
, 2011 ; Lanci and Hirt , 2015 ) .
Even with the same MTM-SVD method , the main author of M20 himself formerly identified robust and significant AMO frequencies in four independent sets of global proxy temperature data ( Mann and Park , 1994 ) .
The most obvious explanation for the discrepancy is that control runs of the CMIP5 models have little to do with reality ( Power et al.
, 2017 ) .
Since it is unclear to which extent the modeled “ internal @ @ @ @ @ @ @ control simulations can not be trusted unless their results were validated with paleoclimate data .
On the other hand , the historical observations and the historical simulations are insufficient in length in order to detect AMO frequencies with sufficient statistical power .
They cover barely two cycles of the putative oscillation , which may span 80 years and more ( Schlesinger and Ramankutty , 1994 ) and may consist of a broader band of low-frequency signals ( O ’ Reilly et al.
, 2017 ; Sutton et al.
, 2018 ) than can @ @ @ @ @ @ @ .
Furthermore , M20 leaves some confusion about the actual length of their control and historical simulations .
Although they state in the text that a minimum length of 158 years is required and fulfilled by N = 44 control runs and N = 118 historical runs of the CMIP5 models , Table 1 in their Supplement reveals that only N = 42 ( not 44 ) from the altogether N = 47 control simulations and only N = 8 ( not 118 ) from the altogether N = 164 historical simulations satisfied @ @ @ @ @ @ @ 158 years .
So even though the latter data set showed a robust significant AMO frequency around a ∼45 year period , other multidecadal frequencies might have been missed .
Having found significant AMO frequencies only in the historical observations and simulations for the industrial time , M20 suggest that this multidecadal fluctuation is due to anthropogenic aerosols rather than to an intrinsic climate oscillation .
They argue 1 ) that no multidecadal fluctuation is present under preindustrial conditions , 2 ) that in industrial times its phase is synchronized across three independent @ @ @ @ @ @ @ unlikely if it were an intrinsic oscillation , whereas 3 ) the fluctuation with positive ( warm ) peaks near 1940 and 2000 and a negative ( cool ) peak near 1980 coincides with the response of the climate system to anthropogenic sulfate aerosol emissions .
The first part of the argument is questioned above .
The second refers to the observation that three global time series , namely two specific models and the historical observations , are roughly in phase ( Figure 3 of M20 ) .
I agree with the authors @ @ @ @ @ @ @ were ( stochastically ) independent , but “ internal ” / “ intrinsic ” is not necessarily the same as “ independent ” : The same phase points to a structural relationship , but it says nothing about whether its cause is external or internal to the climate system .
For the third part of the argument , M20 refer to a recent paper by Kasoar et al .
( 2018 ) .
However , this referenced paper supports only the spatial correspondence of sulfate aerosol effects and the putative AMO signal , @ @ @ @ @ @ @ With regard to the alleged temporal correspondence , the reader is referred to Figure 3 of M20 , which not only leaves several questions open , but also ignores a substantial refutation in the literature : M20 do not provide enough detail to clearly understand what they are plotting in the time series of their Figure 3 .
Is it just one realization or an average of the two and five members that they have for the MPI-ESM-LR and HadGEM2-ES models ?
If it is the latter , they are methodologically canceling out @ @ @ @ @ @ @ .
If it is the former , on which criteria did they select the member , and do the rest behave similarly ?
Furthermore , in the MPI-ESM-LR model ( Figure 3C of M20 ) the signal amplitude and the signal-to-noize ratio appear to be very low , which is reflected in the small percentage of explained variance .
I doubt that this signal exceeds the statistical significance limit , which the authors do not comment on .
Regarding the HadGEM2-ES model , Booth et al .
showed already in 2012 that it @ @ @ @ @ @ @ sea surface temperature ( NASST ) variability in the 20th century , and claimed that aerosols caused this variability .
However , Zhang et al .
( 2013 ) refuted this claim on various methodological grounds , for example by comparing the heat content anomaly of the upper ocean in the North Atlantic with the HadGEM2-ES model with constant aerosols vs. all drivers , or by showing differences between observed and modeled spatial patterns of multi-decadal SST changes inside and outside the North Atlantic , and observed and modeled anomalies in salinity in @ @ @ @ @ @ @ the large and multivariate discrepancies in the mechanisms , Zhang et al .
concluded that the aerosol effects simulated by HadGEM2-ES can not be responsible for the multi-decadal temperature variations observed in the North Atlantic in the 20th century .
M20 make the same claim again now without mentioning this debate in the literature .
In the interdecadal time range attributed to the PDO ( 16–20 years according to the authors ) , M20 found no robust significant spectral peaks in any of the three data sets .
Again , this stands in @ @ @ @ @ @ @ literature ( for a review see e.g.
, Henley , 2017 ) , including previous work by the main author using the same MTM-SVD method ( Mann and Park , 1994 ) .
M20 explain the discrepancy by the time window being larger in their present than in their former work , rendering the present results more reliable .
However , on closer inspection the respective Supplementary Figure S2 in M20 suggests another interpretation : The moving window shows that the frequencies on the interdecadal scale are not constant over time – in @ @ @ @ @ @ @ episodic ( see Figure 1 ) .
This is fully consistent with the work of Folland et al .
( 2002 ) , which M20 themselves mention in their introductory discussion on whether the PDO has a broad or narrow frequency band .
However , with reference to their own former work ( Mann and Park , 1994 ; Mann and Park , 1999 ) they decide a priori that the PDO is confined to a narrowband 16–20 year period .
When they later find that this narrowband frequency is not robust over @ @ @ @ @ @ @ that there is no intrinsic PDO at all .
However , a more appropriate interpretation would have been that their assumption of a continuous narrowband PDO frequency was premature and should be revised .
FIGURE 1 FIGURE 1 .
Evolutionary spectra of historical observations in M20 , using a moving window of 100 years length .
The year at the horizontal axis represents the center of the 100 years moving window , with the vertical line indicating the window 1890–1990 analyzed by Mann and Park 1994 .
The colored scale depicts LVF values @ @ @ @ @ @ @ in Mann and Park , 1994 , LFV values exceeding roughly 0.53 were significant at p < 0.05 level ) .
The red arrows point to two slightly different frequencies showing up episodically significant and thereby supporting the view that the PDO is characterized by a rather broad and changing frequency band over time ( Figure adapted from Mann et al.
, 2020 , Supplementary Figure 2 .
Using the figure is permitted by the Creative Commons Attribution 4.0 International License ) .
Altogether , I conclude that the paper M20 is not @ @ @ @ @ @ @ multi- and interdecadal oscillations such as the AMO and PDO .
The author confirms being the sole contributor of this work and has approved it for publication .
The author declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .
The author would like to thank a reviewer for valuable hints concerning argumentation and literature .
Booth , B .
B. , Dunstone , N. J. , Halloran , P. R. , Andrews , T. , and @ @ @ @ @ @ @ Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability .
Nature 484 , 228–232 .
doi:10.1038/nature10946 Chylek , P. , Folland , C. K. , Dijkstra , H. A. , Lesins , G. , and Dubey , M. K. ( 2011 ) .
Ice‐core data evidence for a prominent near 20 year time‐scale of the Atlantic multidecadal oscillation .
Geophys .
Res .
Lett .
38 , L13704 .
doi:10.1029/2011GL047501 Folland , C. K. , Renwick , J .
A. , Salinger , M. J. , and Mullan , A @ @ @ @ @ @ @ Relative influences of the interdecadal Pacific oscillation and ENSO on the South Pacific convergence zone .
Geophys .
Res .
Lett .
29 , 21–24 .
doi:10.1029/2001GL014201 Gray , S. T. , Graumlich , L. J. , Betancourt , J. L. , and Pederson , G. T. ( 2004 ) .
A tree-ring based reconstruction of the Atlantic Multidecadal Oscillation since 1567 A.D. Geophys .
Res .
Lett .
31 , L12205 .
doi:10.1029/2004GL019932 Kasoar , M. , Shawki , D. , and Voulgarakis , A .
( 2018 ) .
Similar spatial @ @ @ @ @ @ @ from different regions .
Npj Clim .
Atmos .
Sci .
1 , 1–8 .
doi:10.1038/s41612-018-0022-z Lanci , L. , and Hirt , A. M. ( 2015 ) .
Evidence of Atlantic multidecadal oscillation in the magnetic properties of Alpine lakes during the last 2500 years .
Palaeogeogr .
Palaeoclimatol .
Palaeoecol .
440 , 47–52 .
doi:10.1016/j.palaeo.2015.08.040 Mann , M. E. , Park , J. , and Bradley , R. S. ( 1995 ) .
Global interdecadal and century-scale climate oscillations during the past five centuries .
Nature 378 , 266–270 .
@ @ @ @ @ @ @ Park , J .
( 1994 ) .
Global-scale modes of surface temperature variability on interannual to century timescales .
J. Geophys .
Res .
99 , 25819–25833 .
doi:10.1029/94jd02396 Mann , M. E. , Steinman , B .
A. , and Miller , S. K. ( 2020 ) .
Absence of internal multidecadal and interdecadal oscillations in climate model simulations .
Nat .
Commun .
11 , 1–9 .
doi:10.1038/s41467-019-13823-w O ’ Reilly , C. H. , Woollings , T. , and Zanna , L. ( 2017 ) .
The dynamical influence @ @ @ @ @ @ @ climate .
J. Clim .
30 , 7213–7230 .
Power , S. , Delage , F. , Wang , G. , Smith , I. , and Kociuba , G. ( 2017 ) .
Apparent limitations in the ability of CMIP5 climate models to simulate recent multi-decadal change in surface temperature : implications for global temperature projections .
Clim .
Dynam .
49 , 53–69 .
doi:10.1007/s00382-016-3326-x Schlesinger , M. E. , and Ramankutty , N. ( 1994 ) .
An oscillation in the global climate system of period 65–70 years .
Nature 367 @ @ @ @ @ @ @ T. , McCarthy , G. D. , Robson , J. , Sinha , B. , Archibald , A. T. , and Gray , L. J .
( 2018 ) .
Atlantic multidecadal variability and the U.K. ACSIS program .
Bull .
Am .
Meteorol .
Soc .
99 , 415–425 .
doi:10.1175/bams-d-16-0266.1 Zhang , R. , Delworth , T. L. , Sutton , R. , Hodson , D. L. R. , Dixon , K. W. , Held , I. M. , et al .
( 2013 ) .
Have aerosols caused the observed @ @ @ @ @ @ @ Sci .
70 , 1135–1144 .
doi:10.1175/jas-d-12-0331.1 Citation : Müller-Plath G ( 2020 ) Internal Multidecadal and Interdecadal Climate Oscillations : Absence of Evidence Is No Evidence of Absence .
Front .
Earth Sci .
8:559337. doi : 10.3389/feart.2020.559337 Copyright © 2020 Müller-Plath .
This is an open-access article distributed under the terms of the Creative Commons Attribution License ( CC BY ) .
The use , distribution or reproduction in other forums is permitted , provided the original author ( s ) and the copyright owner ( s ) are credited and @ @ @ @ @ @ @ is cited , in accordance with accepted academic practice .
No use , distribution or reproduction is permitted which does not comply with these terms .

Reposted under a Creative Commons License
Gisela Müller-Plath*
Department of Psychology and Ergonomics, Technische Universität Berlin, Berlin, Germany
Introduction
The present paper contributes a critical commentary on the recent finding by Mann, M. E., Steinman, B. A. and Miller, S. K (2020). Absence of internal multidecadal and interdecadal oscillations in climate model simulations. Nat. Commun. 11, 1–9.
Climate oscillations are recurring large-scale fluctuations in the surface temperatures of the oceans in connection with the atmosphere. This commentary focuses on the Pacific Decadal Oscillation (PDO, interdecadal timescale) and the Atlantic Multidecadal Oscillation (AMO, multidecadal timescale), which have been regarded as intrinsic climate drivers on the adjacent continents in numerous studies based on observations and paleoclimate reconstructions (Henley, 2017; O’Reilly et al., 2017). In a recent paper, Michael E. Mann and colleagues (Mann et al., 2020, hereafter M20) fail to find a PDO signal in global measured and modeled temperatures that is statistically different from noise. They further propose that the significant AMO-like signal is mainly due to anthropogenic aerosols in the 20th century, and to statistical artifacts before. Therefore they doubt the intrinsic nature of the two oscillations. The present paper shows that M20’s results are largely artifacts themselves with issues ranging from using inadequate data and referencing improper literature on anthropogenic aerosols with regards to the AMO to inappropriately interpreting the results with regards to the PDO.
After briefly sketching the rationale and method of M20, I will elaborate on these three points.
M20 (p. 3) argue that any truly oscillatory AMO or PDO signals should generate a spatially coherent and large-scale variability pattern in the climate system with a narrowband signature in the frequency domain. They search for such signals in global (observed and modeled) temperature grids of different time lengths with the multi-taper method of singular value decomposition (MTM-SVD), which was developed and widely applied by Mann and Park (Mann and Park, 1994; Mann et al., 1995; Mann and Park, 1999). Significance tests of the test statistic LFV (local fractional variance) are carried out with Monte Carlo simulations generated according to the null hypothesis of colored (red) noise. The method can generally be applied to reconstruct the time course and the spatial pattern of any potential oscillatory climate signal.
Inadequate Data
M20 examine three global sets of temperature data for oscillatory signals, all spanning a minimum length of 158 years: Control simulations (control runs of the IPCC model ensemble CMIP5, using pre-industrial conditions of the atmosphere without any external forcing so that “any apparently oscillatory behavior must arise from internal variability”), historical observations (annualized global monthly average surface temperatures from the HadCRUT4 land and ocean surface temperature dataset), and historical simulations (IPCC model ensemble CMIP5, containing external anthropogenic and natural forcing). They find robust significant spectral peaks in the multidecadal AMO range (period 40–70 years) in the historical observations and the historical simulations, but not in the control simulations. However, the latter data set is the only one that covers a greater length of time, with almost half of the model runs spanning 500 years or more.
The absence of robust multidecadal AMO oscillations in the control simulations stands in sharp contrast to numerous studies finding the opposite in paleoclimatic data (Kerr, 2000; Gray et al., 2004; Chylek et al., 2011; Lanci and Hirt, 2015). Even with the same MTM-SVD method, the main author of M20 himself formerly identified robust and significant AMO frequencies in four independent sets of global proxy temperature data (Mann and Park, 1994). The most obvious explanation for the discrepancy is that control runs of the CMIP5 models have little to do with reality (Power et al., 2017). Since it is unclear to which extent the modeled “internal variability” reflects real conditions, the control simulations cannot be trusted unless their results were validated with paleoclimate data.
On the other hand, the historical observations and the historical simulations are insufficient in length in order to detect AMO frequencies with sufficient statistical power. They cover barely two cycles of the putative oscillation, which may span 80 years and more (Schlesinger and Ramankutty, 1994) and may consist of a broader band of low-frequency signals (O’Reilly et al., 2017; Sutton et al., 2018) than can be identified with the short time series. Furthermore, M20 leaves some confusion about the actual length of their control and historical simulations. Although they state in the text that a minimum length of 158 years is required and fulfilled by N = 44 control runs and N = 118 historical runs of the CMIP5 models, Table 1 in their Supplement reveals that only N = 42 (not 44) from the altogether N = 47 control simulations and only N = 8 (not 118) from the altogether N = 164 historical simulations satisfied the requirement of a minimum length of 158 years. So even though the latter data set showed a robust significant AMO frequency around a ∼45 year period, other multidecadal frequencies might have been missed.
Improper Literature Reference
Having found significant AMO frequencies only in the historical observations and simulations for the industrial time, M20 suggest that this multidecadal fluctuation is due to anthropogenic aerosols rather than to an intrinsic climate oscillation. They argue 1) that no multidecadal fluctuation is present under preindustrial conditions, 2) that in industrial times its phase is synchronized across three independent global time series, which would be unlikely if it were an intrinsic oscillation, whereas 3) the fluctuation with positive (warm) peaks near 1940 and 2000 and a negative (cool) peak near 1980 coincides with the response of the climate system to anthropogenic sulfate aerosol emissions. The first part of the argument is questioned above. The second refers to the observation that three global time series, namely two specific models and the historical observations, are roughly in phase (Figure 3 of M20). I agree with the authors that this would be unlikely if they were (stochastically) independent, but “internal”/“intrinsic” is not necessarily the same as “independent”: The same phase points to a structural relationship, but it says nothing about whether its cause is external or internal to the climate system. For the third part of the argument, M20 refer to a recent paper by Kasoar et al. (2018). However, this referenced paper supports only the spatial correspondence of sulfate aerosol effects and the putative AMO signal, both emphasizing the North Atlantic region. With regard to the alleged temporal correspondence, the reader is referred to Figure 3 of M20, which not only leaves several questions open, but also ignores a substantial refutation in the literature: M20 do not provide enough detail to clearly understand what they are plotting in the time series of their Figure 3. Is it just one realization or an average of the two and five members that they have for the MPI-ESM-LR and HadGEM2-ES models? If it is the latter, they are methodologically canceling out any internal variability the model could show. If it is the former, on which criteria did they select the member, and do the rest behave similarly? Furthermore, in the MPI-ESM-LR model (Figure 3C of M20) the signal amplitude and the signal-to-noize ratio appear to be very low, which is reflected in the small percentage of explained variance. I doubt that this signal exceeds the statistical significance limit, which the authors do not comment on. Regarding the HadGEM2-ES model, Booth et al. showed already in 2012 that it closely reproduced the AMO-like multidecadal North Atlantic sea surface temperature (NASST) variability in the 20th century, and claimed that aerosols caused this variability. However, Zhang et al. (2013) refuted this claim on various methodological grounds, for example by comparing the heat content anomaly of the upper ocean in the North Atlantic with the HadGEM2-ES model with constant aerosols vs. all drivers, or by showing differences between observed and modeled spatial patterns of multi-decadal SST changes inside and outside the North Atlantic, and observed and modeled anomalies in salinity in the subpolar North Atlantic. Due to the large and multivariate discrepancies in the mechanisms, Zhang et al. concluded that the aerosol effects simulated by HadGEM2-ES cannot be responsible for the multi-decadal temperature variations observed in the North Atlantic in the 20th century. M20 make the same claim again now without mentioning this debate in the literature.
Inappropriate Interpretation
In the interdecadal time range attributed to the PDO (16–20 years according to the authors), M20 found no robust significant spectral peaks in any of the three data sets. Again, this stands in sharp contrast to a large body of literature (for a review see e.g., Henley, 2017), including previous work by the main author using the same MTM-SVD method (Mann and Park, 1994). M20 explain the discrepancy by the time window being larger in their present than in their former work, rendering the present results more reliable. However, on closer inspection the respective Supplementary Figure S2 in M20 suggests another interpretation: The moving window shows that the frequencies on the interdecadal scale are not constant over time – in other words, narrowband PDO oscillations are episodic (see Figure 1). This is fully consistent with the work of Folland et al. (2002), which M20 themselves mention in their introductory discussion on whether the PDO has a broad or narrow frequency band. However, with reference to their own former work (Mann and Park, 1994; Mann and Park, 1999) they decide a priori that the PDO is confined to a narrowband 16–20 year period. When they later find that this narrowband frequency is not robust over a larger time window, they conclude that there is no intrinsic PDO at all. However, a more appropriate interpretation would have been that their assumption of a continuous narrowband PDO frequency was premature and should be revised. FIGURE 1
FIGURE 1. Evolutionary spectra of historical observations in M20, using a moving window of 100 years length. The year at the horizontal axis represents the center of the 100 years moving window, with the vertical line indicating the window 1890–1990 analyzed by Mann and Park 1994. The colored scale depicts LVF values (In the 100 years time series in Mann and Park, 1994, LFV values exceeding roughly 0.53 were significant at p < 0.05 level). The red arrows point to two slightly different frequencies showing up episodically significant and thereby supporting the view that the PDO is characterized by a rather broad and changing frequency band over time (Figure adapted from Mann et al., 2020, Supplementary Figure 2. Using the figure is permitted by the Creative Commons Attribution 4.0 International License).
Conclusion
Altogether, I conclude that the paper M20 is not advancing our understanding of the nature of multi- and interdecadal oscillations such as the AMO and PDO.
Author Contributions
The author confirms being the sole contributor of this work and has approved it for publication.
Conflict of Interest
The author declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Acknowledgments
The author would like to thank a reviewer for valuable hints concerning argumentation and literature.
References
Booth, B. B., Dunstone, N. J., Halloran, P. R., Andrews, T., and Bellouin, N. (2012). Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability. Nature 484, 228–232. doi:10.1038/nature10946
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CrossRef Full Text | Google Scholar
Keywords: Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, sulfate aerosols, climate oscillations, multi-taper method of singular value decomposition spectral analysis (MTM-SVD), CMIP5 model simulation
Citation: Müller-Plath G (2020) Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence. Front. Earth Sci. 8:559337. doi: 10.3389/feart.2020.559337
Edited by:Jing-Jia Luo, Bureau of Meteorology, Australia
Reviewed by:Elsa Mohino, Complutense University of Madrid, Spain
Copyright © 2020 Müller-Plath. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
AUTHOR=Müller-Plath Gisela
TITLE=Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence
JOURNAL=Frontiers in Earth Science
VOLUME=8
YEAR=2020
PAGES=580
URL=https://www.frontiersin.org/article/10.3389/feart.2020.559337
DOI=10.3389/feart.2020.559337
ISSN=2296-6463
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wattsupwiththat--2020-11-29--Coal Outperforms Wind Power During UK Wind Week!

Reposted from NOT A LOT OF PEOPLE KNOW THAT With an impeccable sense of timing , some bright spark decided @ @ @ @ @ Week .
Perhaps they should have called it UK NO Wind Week !
Sat under @ @ @ @ @ s contribution from wind power since yesterday has been less than 1GW , around 2 @ @ @ @ @ generated .
This situation is expected to last a few more days yet .
As @ @ @ @ @ fuels which have come to the rescue , with gas currently supplying 60 % of @ @ @ @ @ , and even coal , which has been fired up to give 7 % .
@ @ @ @ @ day we have had more power from coal than from wind .
Thirteen years ago @ @ @ @ @ us that wind power could be powering every home by this year .
( I @ @ @ @ @ that lately ! )
And we were supposed to run out of gas by now @ @ @ @ @ supplies !
We are governed by idiots .

Reposted from NOT A LOT OF PEOPLE KNOW THAT
NOVEMBER 27, 2020tags: Electricity
By Paul Homewood
h/t Joe Public
With an impeccable sense of timing, some bright spark decided to make this UK Wind Week.
Perhaps they should have called it UK NO Wind Week!
https://gridwatch.co.uk/Wind
Sat under an anticyclone, Britain’s contribution from wind power since yesterday has been less than 1GW, around 2% of the total electricity generated. This situation is expected to last a few more days yet.
As ever, it is fossil fuels which have come to the rescue, with gas currently supplying 60% of the nation’s power, and even coal, which has been fired up to give 7%.
Indeed, in the last day we have had more power from coal than from wind.
Thirteen years ago, the Labour government promised us that wind power could be powering every home by this year. (I wonder where I have heard that lately!)
And we were supposed to run out of gas by now, because of disruption to supplies!
We are governed by idiots.
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wattsupwiththat--2020-11-29--Guardian: Rein in Advertising to Save the World from Climate Change

According to a think tank report , excessive advertising is driving materialist consumerism which is contributing to the destruction of the world through global warming .
But in my opinion this is a thinly disguised attack on free speech .
Rein in advertising to help tackle climate crisis , report urges Industry promotes materialism and lifts sales of climate-harming products , study says Advertising needs to be controlled and changed to reduce its impact on the climate , according to a report released as consumers prepare to spend billions on Black Friday .
The report by the New Weather Institute @ @ @ @ @ @ @ examines how advertising indirectly contributes to climate change and the ecological emergency .
The report says the advertising industry has so far escaped scrutiny about its role in contributing to climate change .
Tim Kasser , an emeritus professor of psychology at Knox College in Illinois , who co-authored the report , said there was a body of evidence to show that in order to make progress in addressing and reversing climate and ecological degradation , it would be prudent to rein in and change the practices of the advertising industry .
“ @ @ @ @ @ @ @ evidence exists to support the conclusion that the advertising industry indirectly contributes to climate and ecological degradation through its encouragement of materialistic values and goals , the consumption-driving work and spend cycle , and the consumption of two illustrative products , namely beef and tobacco , ” Kasser wrote .
The executive summary of the report ; Many industries have been recognized as directly and indirectly causing climate and ecological degradation .
So far , however , the advertising industry has largely escaped accountability .
This report attempts to remedy the omission by @ @ @ @ @ @ @ causes such harm .
Specifically , it reviews scientific literature showing that materialistic values and goals , the consumption-driving work & spend cycle , and the consumption of two illustrative products ( namely beef and tobacco ) are each a ) encouraged by advertising and b ) implicated in causing various forms of environmental damage .
It seems likely that similar dynamics occur for other products , services , and experiences .
This body of empirical evidence therefore supports the conclusion that if humanity hopes to make progress in addressing and reversing climate @ @ @ @ @ @ @ prudent to rein in and change the practices of the advertising industry .
The author Tim Kasser is Emeritus Professor of Psychology at Knox College , US , author of several books including Hypercapitalism ( 2018 ) and The High Price of Materialism ( 2002 ) , and co-editor of Psychology and Consumer Culture ( 2004 ) .
He is a research advisor to the Badvertising campaign .
Although reining in advertising might seem like a great idea , especially as we all endure the frenzy of Christmas marketing , I see this @ @ @ @ @ @ @ on free speech .
I ’ m not disputing the harm tobacco causes , but once you have laws which regulate what people are allowed to advertise on the basis of the nebulous climate harm the products allegedly cause , its no big stretch to abuse those laws to regulate other forms of speech , such as advocacy for political opposition to renewable energy , on the grounds that the speaker is “ advertising ” activities or ideas which are harmful .

Polish steak advertisement circa 1928, modified. link
Guest essay by Eric Worrall
According to a think tank report, excessive advertising is driving materialist consumerism which is contributing to the destruction of the world through global warming. But in my opinion this is a thinly disguised attack on free speech.
Rein in advertising to help tackle climate crisis, report urges Industry promotes materialism and lifts sales of climate-harming products, study says Sandra Laville
Fri 27 Nov 2020 17.00 AEDT Advertising needs to be controlled and changed to reduce its impact on the climate, according to a report released as consumers prepare to spend billions on Black Friday. The report by the New Weather Institute thinktank and the charity We are Possible examines how advertising indirectly contributes to climate change and the ecological emergency. … The report says the advertising industry has so far escaped scrutiny about its role in contributing to climate change. Tim Kasser, an emeritus professor of psychology at Knox College in Illinois, who co-authored the report, said there was a body of evidence to show that in order to make progress in addressing and reversing climate and ecological degradation, it would be prudent to rein in and change the practices of the advertising industry. “This report argues that enough sound empirical evidence exists to support the conclusion that the advertising industry indirectly contributes to climate and ecological degradation through its encouragement of materialistic values and goals, the consumption-driving work and spend cycle, and the consumption of two illustrative products, namely beef and tobacco,” Kasser wrote. … Read more: https://www.theguardian.com/environment/2020/nov/27/rein-in-advertising-to-help-tackle-climate-crisis-report-urges
The executive summary of the report;
Advertising’s Role in Climate and Ecological Degradation Many industries have been recognized as directly and indirectly causing climate and ecological degradation. So far, however, the advertising industry has largely escaped accountability. This report attempts to remedy the omission by looking at four ways that advertising indirectly causes such harm. Specifically, it reviews scientific literature showing that materialistic values and goals, the consumption-driving work & spend cycle, and the consumption of two illustrative products (namely beef and tobacco) are each a) encouraged by advertising and b) implicated in causing various forms of environmental damage. It seems likely that similar dynamics occur for other products, services, and experiences. This body of empirical evidence therefore supports the conclusion that if humanity hopes to make progress in addressing and reversing climate and ecological degradation, it would be prudent to rein in and change the practices of the advertising industry. Read more: https://www.badverts.org/reports-and-publications
The author Tim Kasser is Emeritus Professor of Psychology at Knox College, US, author of several books including Hypercapitalism (2018) and The High Price of Materialism (2002), and co-editor of Psychology and Consumer Culture (2004). He is a research advisor to the Badvertising campaign.
Although reining in advertising might seem like a great idea, especially as we all endure the frenzy of Christmas marketing, I see this whole idea as a thinly disguised attack on free speech.
I’m not disputing the harm tobacco causes, but once you have laws which regulate what people are allowed to advertise on the basis of the nebulous climate harm the products allegedly cause, its no big stretch to abuse those laws to regulate other forms of speech, such as advocacy for political opposition to renewable energy, on the grounds that the speaker is “advertising” activities or ideas which are harmful.
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wattsupwiththat--2020-11-29--Measuring Old Corals & Coral Reefs (Part 1)

Fundamental to science is measurement .
It is a way of objectively assessing something , anything , even the state of a coral reef , even of an individual coral .
Historically coral growth rates were measured by coring the really old massive Porites .
Like tree rings in temperate forests , the massive old Porites can be cored to see the banding and from this it is possible to calculate coral calcification rates which are a measure of the growth rate of individual corals .
Peter Ridd has been asking for some quality assurance of so many of the @ @ @ @ @ @ @ , including coral growth rates .
Key Australian institutions have responded by stonewalling , and in the case of James Cook University , actually sacking him .
After two rounds in the federal courts his appeal against his dismissal is finally going to the High Court of Australia , with the next hearing probably in February 2021 .
While the lawyers are preoccupied with Peter ’ s rights , or otherwise , to academic freedom and freedom of speech , my concern is whether Peter is actually telling the truth when he says @ @ @ @ @ @ @ and definitely not dying from coral bleaching , though there is a problem with the integrity of the science .
Most media reports , based on extensive aerial surveys by his one-time colleague Terry Hughes , conclude that the reef is variously 50 % or 60 % dead from coral bleaching as a direct consequence of global warming .
These media reports do not consider coral growth rates , but rather the area of coral that Professor Hughes has measured to be bleached , with an inference being that this will all die @ @ @ @ @ @ @ ’ t both be right .
How can they have come to such different conclusions regarding the health of the Great Barrier Reef ?
Is the reef really half dead , or not ?
My working hypothesis is that Terry Hughes ’ claims the reef is half dead , are not objective because there is a flaw with his particular survey method .
This method is detailed in the technical literature , specifically his paper in Ecology published in 2018 entitled ‘ Large-scale bleaching of corals on the Great Barrier Reef ’ .
@ @ @ @ @ @ @ is a way of getting to the truth via some method or other that often involves measurement .
Sometimes scientists get the method wrong , and so they come up with answers that are also wrong .
Sometimes the wrong answer pleases because it is politically correct .
Could it be that in surveying by looking out the window of an aeroplane at such a high altitude ( 150 metres ) , and then ground truthing only with respect to a particular reef habitat-type known as the ‘ reef crescent ’ , Professor @ @ @ @ @ @ @ ?
Could he be avoiding , even in denial , when it comes to all the corals in the reef lagoon ?
Marine scientists , and anyone with experience diving coral reefs , knows that there are distinct ecological zones at coral reefs .
The reef crest , as the name suggests , is the highest part with corals in this habitat often exposed at low tides , sometimes rained-on , and during storms and cyclones this is the part of the reef that will be most likely smashed by big waves .
@ @ @ @ @ @ @ reef may be totally devoid of live coral or the coral may be more stunted , and sparse .
At the same reef there may be healthy corals in the lagoon and back reef to the leeward side of the crest , and also corals growing down the front slope , even around the perimeter of the crest if it is a flat-topped platform .
So , in only surveying the crest , the scientist/Terry Hughes could come away with the impression the reef is dead , when it is actually teeming with @ @ @ @ @ @ @ crest .
Professor Hughes specifically states in his 2018 article that underwater surveys were conducted to assess the accuracy of aerial surveys using five 10 x 1m belt transects placed on the reef crest .
There is no suggestion that he distinguished between the different reef habitats .
He only surveys the reef crest .
He surveyed the area that probably had the ‘ worst ’ and ‘ least ’ coral .
I tested my hypothesis that Professor Hughes ’ s methodology is flawed at Pixie Reef just two days ago ( 25th @ @ @ @ @ @ @ Skido into the air and took photographs at 5 , 10 , 20 , 40 , 100 and 120 metres of altitude at the reef crest , reef lagoon and reef front slope .
Following are photographs just at 5 and 120 metres and just from the crest and lagoon at Pixie Reef .
( If I can get a large collection of these type of photographs together from different reefs , they could form the basis of a note for publication about measurement and the importance of measuring different habitat types at @ @ @ @ @ @ @ to understand the health of the entire reef ecosystem , not just the reef crest . )
A photograph taken at 120 metres altitude of the reef crest is quite different from a photograph of the reef lagoon taken at exactly the same altitude .
At 120 metres altitude parts of the reef crest looks rather barren , perhaps bleached .
Hughes has mostly concluded that the Great Barrier Reef is 60 % bleached from 150 metres looking out a plane window at the reef crest .
The rather large circular boulders in @ @ @ @ @ @ @ are massive Porites corals .
The type of coral that Peter Ridd would like AIMS to core , so we had an objective measure of coral growth rates back 100s of years .
The photograph of the reef crest from 120 metres altitude was taken with the drone ( Skido of course ) lifted vertically from 5 metres to 120 metres .
This is what the same reef looked like at just 5 metres above the crest .
There are live corals but no massive Porites or even red Gorgonians , though both @ @ @ @ @ @ @ been excluded from a 10 metre belt transect across the reef crest and from an aerial survey of the crest , because they exist in a different habitat type .
A photograph taken at 5 metres from above a section of reef lagoon shows plate corals , presenting as toadstools when photographed from under-the-water , which seems most appropriate given this is Pixie reef .
I didn ’ t find any pixies though .
So much thanks to Stuart Ireland for taking me to Pixie Reef , and for taking all the photographs @ @ @ @ @ @ @ .
All the photographs ( except the shutterstock of the coring ) , were taken at Pixie reef on 25th November 2020 .
Pixie reef is just to the north east of Cairns in Far North Queensland .
**** The image at the very top of this blog post is of me/Jen swimming over the top of a 7 metre wide Porites at Pixie Reef on 25th November 2020 .
This is the type and size of coral that Peter Ridd would like to think was still being cored by the Australian Institute @ @ @ @ @ @ @ as an objective measure of coral growth rates .
AIMS used to core these old corals , to get an idea of climate change back hundreds of years .
This coral could be more than 400 years old , with annual bands that can be measured at the scale of one year , year on year perhaps back 300 or 400 years to calculate an annual growth rate .
So , from the one coral we could ( if they cored it ) see if growth rates have increased or decreased year on @ @ @ @

Reposting from Jennifer Marohasy’s Blog
November 27, 2020 By jennifer
Fundamental to science is measurement. It is a way of objectively assessing something, anything, even the state of a coral reef, even of an individual coral. Historically coral growth rates were measured by coring the really old massive Porites.
Like tree rings in temperate forests, the massive old Porites can be cored to see the banding and from this it is possible to calculate coral calcification rates which are a measure of the growth rate of individual corals.
Peter Ridd has been asking for some quality assurance of so many of the measurements relating to Great Barrier Reef health, including coral growth rates. Key Australian institutions have responded by stonewalling, and in the case of James Cook University, actually sacking him. After two rounds in the federal courts his appeal against his dismissal is finally going to the High Court of Australia, with the next hearing probably in February 2021. While the lawyers are preoccupied with Peter’s rights, or otherwise, to academic freedom and freedom of speech, my concern is whether Peter is actually telling the truth when he says that the Great Barrier Reef is resilient and definitely not dying from coral bleaching, though there is a problem with the integrity of the science.
Most media reports, based on extensive aerial surveys by his one-time colleague Terry Hughes, conclude that the reef is variously 50% or 60% dead from coral bleaching as a direct consequence of global warming.
These media reports do not consider coral growth rates, but rather the area of coral that Professor Hughes has measured to be bleached, with an inference being that this will all die.
Terry Hughes and Peter Ridd can’t both be right.
How can they have come to such different conclusions regarding the health of the Great Barrier Reef? Is the reef really half dead, or not?
Jen/me the other side of a red Gorgonian coral, just two days ago at Pixie Reef.
My working hypothesis is that Terry Hughes’ claims the reef is half dead, are not objective because there is a flaw with his particular survey method. This method is detailed in the technical literature, specifically his paper in Ecology published in 2018 entitled ‘Large-scale bleaching of corals on the Great Barrier Reef’.
Science is not a truth. It is a way of getting to the truth via some method or other that often involves measurement. Sometimes scientists get the method wrong, and so they come up with answers that are also wrong. Sometimes the wrong answer pleases because it is politically correct.
Could it be that in surveying by looking out the window of an aeroplane at such a high altitude (150 metres), and then ground truthing only with respect to a particular reef habitat-type known as the ‘reef crescent’, Professor Hughes has inadvertently recorded a wrong answer? Could he be avoiding, even in denial, when it comes to all the corals in the reef lagoon?
Marine scientists, and anyone with experience diving coral reefs, knows that there are distinct ecological zones at coral reefs. The reef crest, as the name suggests, is the highest part with corals in this habitat often exposed at low tides, sometimes rained-on, and during storms and cyclones this is the part of the reef that will be most likely smashed by big waves. Not surprisingly this habitat/area of a coral reef may be totally devoid of live coral or the coral may be more stunted, and sparse. At the same reef there may be healthy corals in the lagoon and back reef to the leeward side of the crest, and also corals growing down the front slope, even around the perimeter of the crest if it is a flat-topped platform. So, in only surveying the crest, the scientist/Terry Hughes could come away with the impression the reef is dead, when it is actually teeming with life – just not at the reef crest.
Pixie reef from about 100 metres altitude (thanks to my drone Skido). In the foreground (with our boat) is what is known as the reef lagoon. Then there is the reef crest which is mostly showing as beige in colour. Beyond the crest is the front of the reef that slopes more steeply to a greater depth. The types of coral vary so much with these three different habitat types.
A lower altitude picture more clearly showing a delineation between the reef lagoon and reef crest, at the one reef, Pixie Reef not far from the city of Cairns in Far North Queensland.
Professor Hughes specifically states in his 2018 article that underwater surveys were conducted to assess the accuracy of aerial surveys using five 10 x 1m belt transects placed on the reef crest. There is no suggestion that he distinguished between the different reef habitats. He only surveys the reef crest. He surveyed the area that probably had the ‘worst’ and ‘least’ coral.
I tested my hypothesis that Professor Hughes’s methodology is flawed at Pixie Reef just two days ago (25th November). We put my drone Skido into the air and took photographs at 5, 10, 20, 40, 100 and 120 metres of altitude at the reef crest, reef lagoon and reef front slope. Following are photographs just at 5 and 120 metres and just from the crest and lagoon at Pixie Reef. (If I can get a large collection of these type of photographs together from different reefs, they could form the basis of a note for publication about measurement and the importance of measuring different habitat types at the same reef if the idea is to understand the health of the entire reef ecosystem, not just the reef crest.)
A photograph taken at 120 metres altitude of the reef crest is quite different from a photograph of the reef lagoon taken at exactly the same altitude. At 120 metres altitude parts of the reef crest looks rather barren, perhaps bleached. Hughes has mostly concluded that the Great Barrier Reef is 60% bleached from 150 metres looking out a plane window at the reef crest.
The reef crest at Pixie Reef looking down from 120 metres.
The reef lagoon at Pixie Reef looking down from 120 metres. Photograph taken on 25th November with Skido.
The rather large circular boulders in the lagoon photograph from 120 metres up are massive Porites corals. The type of coral that Peter Ridd would like AIMS to core, so we had an objective measure of coral growth rates back 100s of years.
Jen/me laying a tape measure to know that this Porites is about 1.2 metres in height and 1.8 metres wide. These are external measurements. I wonder how old this coral is? It would be possible to know its age through coring (an internal measure), and then by counting the annual growth rings.
This is a close-up of the same Porites showing its golden-coloured tentacles. When the tentacles are retracted, I wonder if the coral is pale pink in colour, rather than golden?
The photograph of the reef crest from 120 metres altitude was taken with the drone (Skido of course) lifted vertically from 5 metres to 120 metres. This is what the same reef looked like at just 5 metres above the crest. There are live corals but no massive Porites or even red Gorgonians, though both exist at Pixie reef but would have been excluded from a 10 metre belt transect across the reef crest and from an aerial survey of the crest, because they exist in a different habitat type.
The reef crest at just 5 metre’s altitude.
A photograph taken at 5 metres from above a section of reef lagoon shows plate corals, presenting as toadstools when photographed from under-the-water, which seems most appropriate given this is Pixie reef. I didn’t find any pixies though.
The reef lagoon at just 5 metres altitude. To really know the corals it is necessary to go under the water, of course.
This is what a plate coral looks like under the water. Of course, at Pixie reef it may look more like a toadstool.
So much thanks to Stuart Ireland for taking me to Pixie Reef, and for taking all the photographs under-the-water, and he also flew Skido. All the photographs (except the shutterstock of the coring), were taken at Pixie reef on 25th November 2020. Pixie reef is just to the north east of Cairns in Far North Queensland.
****
The image at the very top of this blog post is of me/Jen swimming over the top of a 7 metre wide Porites at Pixie Reef on 25th November 2020. This is the type and size of coral that Peter Ridd would like to think was still being cored by the Australian Institute of Marine Science (AIMS), as an objective measure of coral growth rates. AIMS used to core these old corals, to get an idea of climate change back hundreds of years. This coral could be more than 400 years old, with annual bands that can be measured at the scale of one year, year on year perhaps back 300 or 400 years to calculate an annual growth rate. So, from the one coral we could (if they cored it) see if growth rates have increased or decreased year on year, or not.ShareTweetShare
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wattsupwiththat--2020-11-30--Polar bear habitat update for late November

Sea ice formation is ahead of usual in some regions and behind in others but overall , sea ice habitat is abundant enough for this time of year for virtually all polar bears across the Arctic to be back out on the sea ice hunting seals .
Overall , there was more sea ice at 24 November 2020 than there was on the same date in 2016 , which was the last year that a number of polar bear subpopulations were surveyed , including Western and Southern Hudson Bay , Southern Beaufort , Chukchi Sea ( Crockford 2019 , 2020 @ @ @ @ @ @ @ Masie : UPDATE 27 November 2020 : Problem bear report published today ( for week 13 , Nov. 16-22 ) has been added below .
Ice is forming rapidly over Hudson Bay a bit earlier than usual but Davis Strait off southern Baffin Island still has little ice cover .
The pattern of ice formation over Hudson Bay has been a bit unusual this year because winds blew a big chunk of ice offshore part-way through the freeze-up process .
Also , freeze-up came earlier than normal .
Aside from noting that one @ @ @ @ @ @ @ the ice at 16 November , polar bear researcher Andrew Derocher has been silent as to the locations of the rest of his collared bears until this morning , when he published a chart dated 23 November showing that half of the eight bears that are likely not pregnant females are on the ice ( see below ) .
The other four will stay onshore in dens to have their cubs later this year .
Of course , knowing these bears are all offshore now doesn ’ t tell us when they actually @ @ @ @ @ @ @ know , they went on the ice 17 November ( the day after Derocher ’ s first announcement ) .
Regardless , Derocher falsely implied in his tweet this morning that the situation at 23 November supported his claim that this was “ not an early freeze-up.
” Except that by all independent measures , including ice charts , reports from eyes-on-the-ground , and photos of bears hunting on the ice , freezeup this year was early even for the 1970s and 1980s ( Castro de la Guardia et al .
2017 ; @ @ @ @ @ @ @ Many bears ( but not all ) were out on the ice hunting by the first few days of November ( see chart below ) , which would have been earlier than usual in the 1980s ( when the average date for bears to leave was 16 November ) .
A few stragglers stayed behind , including Derocher ’ s collared bears , apparently in no obvious hurry to get on the ice .
The Canadian Ice Service chart of ‘ departure from normal ’ for Hudson Bay shows there is a lot @ @ @ @ @ @ @ of the bay and south into James Bay ( all that blue ! )
.
In contrast , there is much less ice than usual in northern Hudson Bay and Davis Strait ( off southern Baffin Island ) , shown in red and pink .
A study by Castro de la Guardia and colleagues ( 2017 : Figure 3 ) determined that the earliest freeze-up dates since 1979 for Western Hudson Bay came on 6 November in 1991 and 1993 .
As the ice charts from CIS archives ( below ) show , @ @ @ @ @ @ @ the shore of Western Hudson Bay in 1991 for the first week of November as there was this year ( chart above ) .
In other words , Derocher saying this wasn ’ t an early freeze-up year does not make it so .
In 1993 ( below ) , there was much more ice in the north of Hudson Bay than this year in early November but not any more along the west coast , where polar bears congregate waiting for the ice to form : Two weeks later , the amount @ @ @ @ @ @ @ impressive for this time of year , according to ice present for the week of 23 November ( below ) – this chart shows the actual amount of ice cover rather than the anomaly .
The ice is forming quickly .
So , I ’ d say it ’ s no wonder polar bear experts have not published ‘ official ’ breakup/freezeup dates for polar bears since 2015 ( Castro de la Guardia et al .
2017 ) – freezeup has been average ( 2017 ) or earlier than average ( 2018-2020 ) @ @ @ @ @ @ @ a row .
Although in 2016 freeze-up was very late , we know that occasionally a very late freezeup year happened , as it did in 1983 , even before claims were made that man-made climate change was the regulator of all Arctic ice ( Ramsay and Stirling 1988 ) .
The latest two reports from the Polar Bear Alert Program in Churchill ( for weeks 11 and 12 , November 2-8 and 9-15 ) were finally published online today but neither of them mention the state of the ice .
But given @ @ @ @ @ @ @ this week and the low number of incidents in week 12 ( 4 ‘ occurrences ’ ) and the number of bears in the holding facility ( PBHF ) at the end of last week ( 0 ) , it looks like the report for 9-15 November ( below ) was the last of the season .
: Problem bear report published today ( for week 13 , Nov. 16-22 ) is added below , indicating a few bears still have not left for the ice despite its abundance .
FOR COMPARISON TO @ @ @ @ @ @ @ BEAR REPORT FOR 2017 ( BELOW ) : The Beaufort Sea has been largely ice-covered since the third week in October ( in contrast , in 2012 this didn ’ t happen until mid-November ) .
Currently , shorefast ice is forming rapidly along the shores of the Bering Sea but ice from the Chukchi Sea has not yet moved south through the Bering Strait .
Wrangel Island , where many Chukchi polar bear females have their cubs , was reached by the advancing ice pack by 11 November .
On the Russian @ @ @ @ @ @ @ Seas have been completely ice covered in ice since early November ( below ) after rapidly forming shorefast ice met up with slowly advancing the pack ice this fall .
Franz Josef Land in the eastern Barents Sea has now got substantial ice cover after a slow return of the Arctic ice pack .
However , the Svalbard archipelago in the western Barents is still ice-free , as it has been for many years now at this point in the fall ( except last year ) .
As a consequence , most Barents @ @ @ @ @ @ @ to make their maternity dens on the mobile pack ice to the north or on one of the islands of Franz Josef Land .
There is little ice in eastern Kara Sea at this point in the season , especially around Novaya Zemlya , but that has been the case for this region since the late 1990s at least .
A graph of ice cover over the Kara Sea for the last five years ( NSIDC Masie , below ) , shows that 2020 was only the second lowest in recent years after @ @ @ @ @ @ @ .
The Polar Bear Catastrophe That Never Happened .
Global Warming Policy Foundation , London .
Available in paperback and ebook formats .
Crockford , S.J .
2020 .
State of the Polar Bear Report 2019 .
Global Warming Policy Foundation Report 39 , London .
pdf here .
Ramsay , M.A .
and Stirling , I .
1988 .
Reproductive biology and ecology of female polar bears ( Ursus maritimus ) .
Journal of Zoology London 214:601-624. http : //onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1988.tb03762.x/abstract Stirling I , Jonkel C , Smith P , Robertson R , @ @ @ @ @ @ @ the polar bear ( Ursus maritimus ) along the western coast of Hudson Bay .
Canadian Wildlife Service Occasional Paper No .
33. pdf here .

Reposted from Polar Bear Science
Posted on November 25, 2020 |
Sea ice formation is ahead of usual in some regions and behind in others but overall, sea ice habitat is abundant enough for this time of year for virtually all polar bears across the Arctic to be back out on the sea ice hunting seals.
Overall, there was more sea ice at 24 November 2020 than there was on the same date in 2016, which was the last year that a number of polar bear subpopulations were surveyed, including Western and Southern Hudson Bay, Southern Beaufort, Chukchi Sea (Crockford 2019, 2020), see graph below from NSIDC Masie:
Northern Hemisphere sea ice at 24 November, 2016-2020.
Northern Hemisphere sea ice at 24 November, 2016-2020.
UPDATE 27 November 2020: Problem bear report published today (for week 13, Nov. 16-22) has been added below.
EASTERN CANADIAN ARCTIC
Ice is forming rapidly over Hudson Bay a bit earlier than usual but Davis Strait off southern Baffin Island still has little ice cover.
The pattern of ice formation over Hudson Bay has been a bit unusual this year because winds blew a big chunk of ice offshore part-way through the freeze-up process. Also, freeze-up came earlier than normal. Aside from noting that one bear with a tracking collar was on the ice at 16 November, polar bear researcher Andrew Derocher has been silent as to the locations of the rest of his collared bears until this morning, when he published a chart dated 23 November showing that half of the eight bears that are likely not pregnant females are on the ice (see below). The other four will stay onshore in dens to have their cubs later this year.
Of course, knowing these bears are all offshore now doesn’t tell us when they actually left shore – as far as we know, they went on the ice 17 November (the day after Derocher’s first announcement). Regardless, Derocher falsely implied in his tweet this morning that the situation at 23 November supported his claim that this was “not an early freeze-up.”
Except that by all independent measures, including ice charts, reports from eyes-on-the-ground, and photos of bears hunting on the ice, freezeup this year was early even for the 1970s and 1980s (Castro de la Guardia et al. 2017; Stirling et al. 1977). Many bears (but not all) were out on the ice hunting by the first few days of November (see chart below), which would have been earlier than usual in the 1980s (when the average date for bears to leave was 16 November). A few stragglers stayed behind, including Derocher’s collared bears, apparently in no obvious hurry to get on the ice.
The Canadian Ice Service chart of ‘departure from normal’ for Hudson Bay shows there is a lot more ice than usual in the middle of the bay and south into James Bay (all that blue!). In contrast, there is much less ice than usual in northern Hudson Bay and Davis Strait (off southern Baffin Island), shown in red and pink.
A study by Castro de la Guardia and colleagues (2017: Figure 3) determined that the earliest freeze-up dates since 1979 for Western Hudson Bay came on 6 November in 1991 and 1993. As the ice charts from CIS archives (below) show, there was about as much ice off the shore of Western Hudson Bay in 1991 for the first week of November as there was this year (chart above). In other words, Derocher saying this wasn’t an early freeze-up year does not make it so.
In 1993 (below), there was much more ice in the north of Hudson Bay than this year in early November but not any more along the west coast, where polar bears congregate waiting for the ice to form:
Two weeks later, the amount of ice cover over Hudson Bay is impressive for this time of year, according to ice present for the week of 23 November (below) – this chart shows the actual amount of ice cover rather than the anomaly. The ice is forming quickly.
So, I’d say it’s no wonder polar bear experts have not published ‘official’ breakup/freezeup dates for polar bears since 2015 (Castro de la Guardia et al. 2017) – freezeup has been average (2017) or earlier than average (2018-2020), for the last four years in a row. Although in 2016 freeze-up was very late, we know that occasionally a very late freezeup year happened, as it did in 1983, even before claims were made that man-made climate change was the regulator of all Arctic ice (Ramsay and Stirling 1988).
The latest two reports from the Polar Bear Alert Program in Churchill (for weeks 11 and 12, November 2-8 and 9-15) were finally published online today but neither of them mention the state of the ice. But given no report appears to have been published this week and the low number of incidents in week 12 (4 ‘occurrences’) and the number of bears in the holding facility (PBHF) at the end of last week (0), it looks like the report for 9-15 November (below) was the last of the season.
UPDATE 27 November 2020 : Problem bear report published today (for week 13, Nov. 16-22) is added below, indicating a few bears still have not left for the ice despite its abundance.
FOR COMPARISON TO THE ABOVE, SEE THE LAST PROBLEM BEAR REPORT FOR 2017 (BELOW):
WESTERN ARCTIC INCLUDING RUSSIAN FAR EAST
The Beaufort Sea has been largely ice-covered since the third week in October (in contrast, in 2012 this didn’t happen until mid-November). Currently, shorefast ice is forming rapidly along the shores of the Bering Sea but ice from the Chukchi Sea has not yet moved south through the Bering Strait. Wrangel Island, where many Chukchi polar bear females have their cubs, was reached by the advancing ice pack by 11 November.
Chukchi Bering Sea, NSIDC Masie ice chart for 24 November 2020 (Day 329).
CENTRAL RUSSIAN COAST
On the Russian coast, the Laptev and East Siberian Seas have been completely ice covered in ice since early November (below) after rapidly forming shorefast ice met up with slowly advancing the pack ice this fall.
Russian Arctic, NSIDC Masie 4 November 2020.
BARENTS AND KARA SEAS
Franz Josef Land in the eastern Barents Sea has now got substantial ice cover after a slow return of the Arctic ice pack. However, the Svalbard archipelago in the western Barents is still ice-free, as it has been for many years now at this point in the fall (except last year). As a consequence, most Barents Sea pregnant female polar bears will choose to make their maternity dens on the mobile pack ice to the north or on one of the islands of Franz Josef Land.
Barents and Kara Seas, NSIDC Masie, 24 November 2020 (Day 329).
There is little ice in eastern Kara Sea at this point in the season, especially around Novaya Zemlya, but that has been the case for this region since the late 1990s at least. A graph of ice cover over the Kara Sea for the last five years (NSIDC Masie, below), shows that 2020 was only the second lowest in recent years after 2016.
Kara Sea sea ice at 24 November, 2016-2020, NSIDC Masie.
REFERENCES
Castro de la Guardia, L., Myers, P.G., Derocher, A.E., Lunn, N.J., Terwisscha van Scheltinga, A.D. 2017. Sea ice cycle in western Hudson Bay, Canada, from a polar bear perspective. Marine Ecology Progress Series 564: 225–233. http://www.int-res.com/abstracts/meps/v564/p225-233/
Crockford, S.J. 2019. The Polar Bear Catastrophe That Never Happened. Global Warming Policy Foundation, London. Available in paperback and ebook formats.
Crockford, S.J. 2020. State of the Polar Bear Report 2019. Global Warming Policy Foundation Report 39, London. pdf here.
Ramsay, M.A. and Stirling, I. 1988. Reproductive biology and ecology of female polar bears (Ursus maritimus). Journal of Zoology London 214:601-624.
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1988.tb03762.x/abstract
Stirling I, Jonkel C, Smith P, Robertson R, Cross D. 1977. The ecology of the polar bear (Ursus maritimus) along the western coast of Hudson Bay. Canadian Wildlife Service Occasional Paper No. 33. pdf here.
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