Klimaatprofessor geeft vergissing toe

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Op maandag 15 februari 2010 09:19 schreef -Kadesh- het volgende:
Mooi, en nu inleveren afschaffen die Nobelprijs.

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Op maandag 15 februari 2010 09:24 schreef Lyrebird het volgende:
Interessant dat die ontboezemingen bij de BBC worden gedaan. Wat blijkt, die club heeft voor 8 miljard pond uit haar pensioenfonds in firma's zitten die inspelen op maatregelen die "climate change" tegen moeten gaan. Als neutrale kijker mag je dan IMHO best vraagtekens zetten bij de journalistieke onafhankelijkheid van die club.

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Op maandag 15 februari 2010 09:27 schreef RemcoDelft het volgende:

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Als het pensioen van deze journalist afhankelijk is van de hype, zou-ie dit artikel dan niet hebben weggemoffeld?

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Op maandag 15 februari 2010 09:34 schreef speknek het volgende:
Jammer dat het een Telegraafbericht is, is er een betere bron? Zapruder misschien?

(of het interview met de bbc zelf)

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Op maandag 15 februari 2010 09:34 schreef speknek het volgende:
Jammer dat het een Telegraafbericht is, is er een betere bron? Zapruder misschien?

(of het interview met de bbc zelf)

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Q&A: Professor Phil Jones

Phil Jones is director of the Climatic Research Unit (CRU) at the University of East Anglia (UEA), which has been at the centre of the row over hacked e-mails.

The BBC's environment analyst Roger Harrabin put questions to Professor Jones, including several gathered from climate sceptics. The questions were put to Professor Jones with the co-operation of UEA's press office.

A - Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

Here are the trends and significances for each period:
Period Length Trend
(Degrees C per decade) Significance
1860-1880 21 0.163 Yes
1910-1940 31 0.15 Yes
1975-1998 24 0.166 Yes
1975-2009 35 0.161 Yes

B - Do you agree that from 1995 to the present there has been no statistically-significant global warming

Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

C - Do you agree that from January 2002 to the present there has been statistically significant global cooling?

No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant.

D - Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998, and, if so, please could you specify each natural influence and express its radiative forcing over the period in Watts per square metre.

This area is slightly outside my area of expertise. When considering changes over this period we need to consider all possible factors (so human and natural influences as well as natural internal variability of the climate system). Natural influences (from volcanoes and the Sun) over this period could have contributed to the change over this period. Volcanic influences from the two large eruptions (El Chichon in 1982 and Pinatubo in 1991) would exert a negative influence. Solar influence was about flat over this period. Combining only these two natural influences, therefore, we might have expected some cooling over this period.

E - How confident are you that warming has taken place and that humans are mainly responsible?

I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity.

F - Sceptics of anthropogenic global warming (AGW) suggest that the official surface record paints a different story from the actual station records. To restore trust, should we start again with new quality control on input data in total transparency?

First, I am assuming again that you are referring to the surface record from both land and marine regions of the world, although in this answer as you specifically say "station" records, I will emphasise the land regions.

There is more than one "official" surface temperature record, based on actual land station records. There is the one we have developed in CRU, but there are also the series developed at NCDC and GISS. Although we all use very similar station datasets, we each employ different ways of assessing the quality of the individual series and different ways of developing gridded products. The GISS data and their program are freely available for people to experiment with. The agreement between the three series is very good.
Keyboard (Autocat)
Large numbers of the CRU e-mails were posted on the web

Given the web-based availability of the Global Historical Climatology Network (GHCN), which is used by both NCDC and GISS, anyone else can develop their own global temperature record from land stations.

Through the Met Office we have released (as of 29 January 2010) 80% of the station data that enters the CRU analysis (CRUTEM3).

The graphic in the link below shows that the global land temperature series from these 80% of stations (red line) replicates the analysis based on all 100% of stations (black line).

http://www.metoffice.gov.(...)ing/data-graphic.GIF

The locations of the 80% of stations are shown on the next link in red. The stations we have yet to get agreement to release are shown in grey.

http://www.metoffice.gov.(...)toring/locations.GIF

I accept that some have had their trust in science shaken and this needs the Met Office to release more of the data beyond the 80% released so far. Before all the furore broke we had begun discussions with the Met Office for an updated set of station temperatures. With any new station dataset we will make sure we will be able to release all the station temperature data and give source details for all the series.

G - There is a debate over whether the Medieval Warm Period (MWP) was global or not. If it were to be conclusively shown that it was a global phenomenon, would you accept that this would undermine the premise that mean surface atmospheric temperatures during the latter part of the 20th Century were unprecedented?

There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia. For it to be global in extent the MWP would need to be seen clearly in more records from the tropical regions and the Southern Hemisphere. There are very few palaeoclimatic records for these latter two regions.

Of course, if the MWP was shown to be global in extent and as warm or warmer than today (based on an equivalent coverage over the NH and SH) then obviously the late-20th century warmth would not be unprecedented. On the other hand, if the MWP was global, but was less warm that today, then current warmth would be unprecedented.

We know from the instrumental temperature record that the two hemispheres do not always follow one another. We cannot, therefore, make the assumption that temperatures in the global average will be similar to those in the northern hemisphere.

H - If you agree that there were similar periods of warming since 1850 to the current period, and that the MWP is under debate, what factors convince you that recent warming has been largely man-made?

The fact that we can't explain the warming from the 1950s by solar and volcanic forcing - see my answer to your question D.

I - Would it be reasonable looking at the same scientific evidence to take the view that recent warming is not predominantly manmade?

No - see again my answer to D.

J - Are there lessons to be learned for society or scientists about the way we see uncertainty and risk?

Yes - as stated by Sir John Beddington - the government chief scientist. And this doesn't just apply to climate science.

K - How much faith do you have - and should we have - in the Yamal tree ring data from Siberia? Should we trust the science behind the palaeoclimate record?

First, we would all accept that palaeoclimatic data are considerably less certain than the instrumental data. However, we must use what data are available in order to look at the last 1,000 years.

I believe that our current interpretation of the Yamal tree-ring data in Siberia is sound. Yamal is just one series that enters some of the millennial long reconstructions that are available.

My colleague Keith Briffa has responded to suggestions that there is something amiss with the Yamal tree-ring data. Here is his response:

http://www.cru.uea.ac.uk/cru/people/briffa/yamal2009/

L - Can you confirm that the IPCC rules were changed so lead authors could add references to any scientific paper which did not meet the 16 December 2005 deadline but was in press on 24 July 2006, so long as it was published in 2006? If this is the case, who made the decision and why?

This is a question for the IPCC.

M - What advice did you seek in handling FOI requests?

The university's policy and guidelines on FOI and the Environmental Information Regulations are on our website and the information policy and compliance manager (IPCM) takes responsibility for co-ordinating responses to requests within that framework. We also have colleagues in each unit and faculty who are trained in FOI to help in gathering information and assessing any possible exceptions or exemptions.

I worked with those colleagues and the IPCM to handle the requests with responses going from the IPCM. He also liaises with the Information Commissioner's Office where necessary and did so on several occasions in relation to requests made to CRU. Where appropriate he also consulted with other colleagues in the university on specific issues.

N - When scientists say "the debate on climate change is over", what exactly do they mean - and what don't they mean?

It would be supposition on my behalf to know whether all scientists who say the debate is over are saying that for the same reason. I don't believe the vast majority of climate scientists think this. This is not my view. There is still much that needs to be undertaken to reduce uncertainties, not just for the future, but for the instrumental (and especially the palaeoclimatic) past as well.

O - Can you tell us about your working life over the past decades in climate science. Paint a picture about the debate with your allies and scientific rivals etc.

I have been at CRU since November 1976. Up until 1994, my working life was almost totally in research. Since 1994, I have become more involved in teaching and student supervision both at the postgraduate and undergraduate level. I became a Professor in 1998 and the director of the Climatic Research Unit in 2004 (I was joint director from 1998).

I am most well known for being involved in the publication of a series of papers (from 1982 to 2006) that have developed a gridded dataset of land-based temperature records. These are only a part of the work I do, as I have been involved in about 270 peer-reviewed publications on many different aspects of climate research.

Over the years at scientific meetings, I've met many people and had numerous discussions with them. I work with a number of different groups of people on different subjects, and some of these groups come together to undertake collaborative pieces of work. We have lively debates about the work we're doing together.

P - The "Climategate" stolen emails were published in November. How has your life been since then?

My life has been awful since that time, but I have discussed this once (in the Sunday Times) and have no wish to go over it again. I am trying to continue my research and supervise the CRU staff and students who I am responsible for.

Q - Let's talk about the e-mails now: In the e-mails you refer to a "trick" which your critics say suggests you conspired to trick the public? You also mentioned "hiding the decline" (in temperatures). Why did you say these things?

This remark has nothing to do with any "decline" in observed instrumental temperatures. The remark referred to a well-known observation, in a particular set of tree-ring data, that I had used in a figure to represent large-scale summer temperature changes over the last 600 years.

The phrase 'hide the decline' was shorthand for providing a composite representation of long-term temperature changes made up of recent instrumental data and earlier tree-ring based evidence, where it was absolutely necessary to remove the incorrect impression given by the tree rings that temperatures between about 1960 and 1999 (when the email was written) were not rising, as our instrumental data clearly showed they were.

This "divergence" is well known in the tree-ring literature and "trick" did not refer to any intention to deceive - but rather "a convenient way of achieving something", in this case joining the earlier valid part of the tree-ring record with the recent, more reliable instrumental record.

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Op maandag 15 februari 2010 09:18 schreef Deprater het volgende:
Ook geeft de vroegere alarmist toe dat het in de vroege middeleeuwen mogelijk net zo warm is geweest als nu.

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Of course, if the MWP was shown to be global in extent and as warm or warmer than today (based on an equivalent coverage over the NH and SH) then obviously the late-20th century warmth would not be unprecedented. On the other hand, if the MWP was global, but was less warm that today, then current warmth would be unprecedented.

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Op maandag 15 februari 2010 09:52 schreef Sjaakz het volgende:
Waaruit blijkt die enorme 'omslag' in het denken van Professor Phil Jones nou?

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The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

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Op maandag 15 februari 2010 10:02 schreef Deprater het volgende:
Hij zegt dus dat er wel een opwarming is nu, maar dat die in vorige eeuwen ook voorkwam in meerdere of mindere mate

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Op maandag 15 februari 2010 10:01 schreef Monolith het volgende:

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Het artikeltje uit de OP komt vol trots aanzetten met een 'bekentenis' dat de opwarming sinds 1995 niet significant zou zijn, maar laat daar bij het volgende voor het gemak maar even weg:
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The positive trend is quite close to the significance level.

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Op maandag 15 februari 2010 10:02 schreef Deprater het volgende:
Hij zegt dus dat er wel een opwarming is nu, maar dat die in vorige eeuwen ook voorkwam in meerdere of mindere mate.

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So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

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Op maandag 15 februari 2010 10:08 schreef RemcoDelft het volgende:
Les 1 in de statistiek: iets is OF significant, OF niet significant. Het kan niet "een beetje" of "bijna" significant zijn.

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Op maandag 15 februari 2010 10:12 schreef damian5700 het volgende:

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De suggestie die professor Phil Jones neerlegt is op zijn zachts gezegd niet bepaald ten faveure voor het aanzien van de theorie.

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Op maandag 15 februari 2010 10:10 schreef gelly het volgende:

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Misschien kan je beter zelf wat scholing volgen :
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Die grens is dus helemaal niet zo arbitrair als jij dat stelt.

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Op maandag 15 februari 2010 10:20 schreef RemcoDelft het volgende:

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Over het algemeen wordt een 95% grens aangehouden voor "significant". Als je op 93% uitkomt, heet dat dus "niet-significant" en niet "bijna significant" want dan zou je 96% ook "net niet niet significant" kunnen noemen.
Onzin dus, grenzen kies je, en ga je niet daarna aanpassen omdat dat beter uitkomt.

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Op maandag 15 februari 2010 10:35 schreef ethiraseth het volgende:

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Hoe is dat nou, in zon zwart-wit wereld leven?

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Op maandag 15 februari 2010 10:58 schreef SeLang het volgende:
Goldman Sachs zal hier wel weer achter zitten

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Op maandag 15 februari 2010 11:26 schreef Deprater het volgende:
iedereen en terecht lijkt me, niet significant , betekend "van geringe betekenis"

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Op maandag 15 februari 2010 11:26 schreef Deprater het volgende:

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iedereen en terecht lijkt me, niet significant , betekend "van geringe betekenis"
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Op maandag 15 februari 2010 13:17 schreef Deprater het volgende:

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Er waren vroeger ook ijstijden van honderden jaren, wie zegt dat we nu kouder worden of warmer en wat is normaal??
Wat was de oorzaak dat de ijstijd overging in een subtropische tijd, de Amersfoortse kei is ook hierheen gerold door het kruiend ijs, tenslotte

Iedere beschaving komt eens aan het einde,

De aarde is 4 miljard jaar oud en ieder 25 miljoen jaar ontstond er een nieuwe populatie op aarde, of wel 10 populaties geleden lag Europa onder de evenaar en was afrika een onderdeel van zuid-amerika.

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Op maandag 15 februari 2010 11:49 schreef Iblis het volgende:
Waar dat niet bijzonder vandaan komt is me nog niet helemaal duidelijk. Waarschijnlijk omdat er in het verleden ook opwarming heeft plaatsgehad (maar dat betwist niemand, maar soms doet men alsof dit een eye-opener is, het gaat echter om de verklaring van die opwarming).

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Op maandag 15 februari 2010 13:17 schreef Deprater het volgende:

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Er waren vroeger ook ijstijden van honderden jaren, wie zegt dat we nu kouder worden of warmer en wat is normaal??
Wat was de oorzaak dat de ijstijd overging in een subtropische tijd, de Amersfoortse kei is ook hierheen gerold door het kruiend ijs, tenslotte

Iedere beschaving komt eens aan het einde,

De aarde is 4 miljard jaar oud en ieder 25 miljoen jaar ontstond er een nieuwe populatie op aarde, of wel 10 populaties geleden lag Europa onder de evenaar en was afrika een onderdeel van zuid-amerika.

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Op maandag 15 februari 2010 13:35 schreef speknek het volgende:

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Ik denk overigens dat ze met het feit dat de slope van de opwarming niet significant verschillend is gedurende de laatste eeuw, aan willen tonen dat er geen hockeystick is, waar je die wel zou verwachten als ceteris paribus de mens meer CO2 de lucht in pompt. Dat in zichzelf is best een interessante, en misschien zelfs schokkende, ommekeer van Jones. Alleen, is hij er zelf snel genoeg bij om te zeggen dat hij niet denkt dat het ceteris paribus is, maar dat bij de eerdere opwarmingen er belangrijke natuurlijke factoren meespeelden, die nu niet meespelen.

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Op maandag 15 februari 2010 10:51 schreef Iblis het volgende:
Hoeveel lezers zullen de opmerking “De opwarming is wetenschappelijk gezien niet significant” ongeveer lezen als “De opwarming is onbeduidend qua omvang”?

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Op maandag 15 februari 2010 13:35 schreef speknek het volgende:

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Ik denk overigens dat ze met het feit dat de slope van de opwarming niet significant verschillend is gedurende de laatste eeuw, aan willen tonen dat er geen hockeystick is, waar je die wel zou verwachten als ceteris paribus de mens meer CO2 de lucht in pompt. Dat in zichzelf is best een interessante, en misschien zelfs schokkende, ommekeer van Jones. Alleen, is hij er zelf snel genoeg bij om te zeggen dat hij niet denkt dat het ceteris paribus is, maar dat bij de eerdere opwarmingen er belangrijke natuurlijke factoren meespeelden, die nu niet meespelen.

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Op maandag 15 februari 2010 14:01 schreef Montov het volgende:

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De 3/4 periodes zijn ook niet gelijk aan elkaar qua lengte, en zijn uiteraard arbitrair gekozen. Het zijn opwarmingsperiodes, 21 jaar in de 19 eeuw en 31 jaar begin vorige eeuw en 35 jaar eind vorige eeuw. Het is niet representatief, niet gelijk en met verschillende intervallen er tussen. Conclusies over de hockeystick zijn er niet mee te maken.

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Op maandag 15 februari 2010 14:20 schreef Deprater het volgende:

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Nee, dat vind ik een andere zaak, de wetenschap kan heel nuttig zijn, (vliegtuigen, plastics, waterzuivering, noem maar op) maar heeft ook de atoombom uitgevonden

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Op maandag 15 februari 2010 10:51 schreef Iblis het volgende:
Hoeveel lezers zullen de opmerking “De opwarming is wetenschappelijk gezien niet significant” ongeveer lezen als “De opwarming is onbeduidend qua omvang”?