This is a continuation of a remarkable thread that has now received 10,000 comments running to well over a million words. Unfortunately its size has become a problem and this is the reason for the move.
The history of the New Statesman thread goes back to December 2007 when Dr David Whitehouse wrote a very influential article for that publication posing the question Has Global Warming Stopped? Later, Mark Lynas, the magazine’s environment correspondent, wrote a furious reply, Has Global Warming Really Stopped?
By the time the New Statesman closed the blogs associated with these articles they had received just over 3000 comments, many from people who had become regular contributors to a wide-ranging discussion of the evidence for anthropogenic climate change, its implications for public policy and the economy. At that stage I provided a new home for the discussion at Harmless Sky.
Comments are now closed on the old thread. If you want to refer to comments there then it is easy to do so by left-clicking on the comment number, selecting ‘Copy Link Location’ and then setting up a link in the normal way.
Here’s to the next 10,000 comments.
Useful links:
Dr David Whitehouse’s article can be found here with 1289 comments.
Mark Lynas’ attempted refutation can be found here with 1715 comments.
The original Continuation of the New Statesman Whitehouse/Lynas blogs thread is here with 10,000 comments.
PeterM
Yep. You’ve got it right. Both the NE and NW Passages have re-opened again. This has apparently happened a few times previously, base on recorded crossings, as pointed out on this thread.
“Déjà vu all over again”, as Yogi Berra would put it.
Max
TonyB
It appears that the link I posted (1847) to the Russian study on Arctic sea ice from the 1930s to today (Smolyanitsky et al.) no longer works. Here are new links to the studies showing sea ice extent in Russian Arctic is greater today than in the 1930s.
http://seaice.alaska.edu/gi/publications/mahoney/Mahoney_2008_JGR_20thC_RSI.pdf
http://icoads.noaa.gov/marcdat2/P_Vasily_Smolyanitsky.pdf
Max
Max,
I’m not sure if you’ve just not read the references you’ve quoted or rather that you’ve failed to understand them.
the first one says:
“These charts are perhaps the oldest operational sea ice data in existence and show that sea ice extent in the Russian Arctic has generally decreased since the beginning of the chart series in 1933.”
the second one is harder to understand but it does include graphs showing a decline in Arctic ice.
What makes you think it supports your case?
PeterM
You apparently glanced at the two references on Arctic sea ice trends prior to 1979, which I cited and then asked:
I did understand them very well, Peter, and
they do, indeed, confirm exactly what I have been saying, namely that the current decline in Arctic sea ice is not unprecedented.
If you look at the second reference closely (Smolyanitsky et al.), you will see that it shows trends from records starting in 1900. This shows an overall slight shrinking trend to today but with three distinctive cycles: a sharp decline from around 1910 to the mid 1940s (which coincides with a sharp increase in temperature), a partial recovery to the mid-1970s (coinciding with a general cooling in the Arctic) and a second sharp decline from around 1976 to today (also coinciding with a late 20th century temperature increase).
This confirms my point that the current decline, which is attributed by some to the impact of AGW, is not unprecedented; another equivalent period of decline occurred prior to significant CO2 emissions.
The first report cited (Mahony et al.) uses essentially the same data set but has unfortunately truncated the record prior to 1933, so these trends are not that easy to visualize, but if one looks closely at the charts, the end of the first declining trend can also be seen here.
It’s all there, Peter, if you just look.
Max
PeterM
Let’s quickly summarize our recent exchange with TonyB on Arctic sea ice.
You started the exchange by pointing out that the NE Passage had recently been crossed for the first time by a Russian tanker and posted a global temperature graph starting in 1950 as “the reason for the ice’s decline”.
Both Tony and I cited references that showed that this was not the first crossing, but that there had been earlier crossings.
You then switched to the NW Passage.
Tony replied with extensive references to earlier records of Arctic warming and crossings and I referred you to an extensive earlier exchange on this site, where your previous claim of an unprecedented opening of the NW Passage was refuted, citing several earlier closings of the NW Passage as evidence.
You then posted an NSIDC graph of end-August Arctic sea ice readings, which showed overall decline since the record started in 1979.
Both Tony and I agreed that the general trend since 1979 is one of decline. I did point out that the low point was reached at the end of summer 2007, and that the sea ice has recovered somewhat since then. I also pointed out that the trend since 1979 in Antarctic sea ice is one of net growth, roughly equivalent to the shrinking in the Arctic.
We also pointed out (with references) that the current decline in the Arctic is not unprecedented. Earlier prolonged periods of decline have occurred, notably the one from around 1910 to the mid-1940s, which coincided with a warming trend in the Arctic. This was followed by a colder period, where the ice recovered partially before starting its latest shrinking from a high point about the time as the satellite record started in 1979.
So we have the following conclusions to draw:
Believe we can end this exchange, as it risks becoming repetitive (unless you have some basically new data to bring).
Max
Max
The studies you cited to 1900 dove tail neatly into those cited in my article, where at the end I give extensive references including those by many of the agencies and individuals in your links.
Hudson Bay Co records (to 1750) and other records demonstrate that there was another period of major warming around 1820-1870 (and lesser ones before that)
The high spot for ice around 1900 in your studies matches with the high spots noted after the end of the warming in 1870.
So we have a well documented warming around 1820-1870
Another well documemted warming around 1922 to 1940’s (noted in newspapers of the time and Pathe news reel)
A high spot for ice around the end of the 1970’s when satellite observation started and another decline since that date.
This is without even mentioning the well documented warming periods during the Vikings 1000 years ago and the Ipiatuk 2000 years ago.
Seems that Peter himself is a ‘denier’ of facts and labours (deliberately?)under the impression that the arctic has always been frozen solid until man came along and caused devastation from 1979.
tonyb
Max,
You quote: “….. a sharp decline [in Arctic Sea Ice] from around 1910 to the mid 1940s (which coincides with a sharp increase in temperature), a partial recovery to the mid-1970s (coinciding with a general cooling in the Arctic) and a second sharp decline from around 1976 to today (also coinciding with a late 20th century temperature increase).”
Yes I’d go along with that.
Incidentally, isn’t 1910 approximately when Mann’s hockey stick shows its sharp upturn? I’m sure that Michael will be pleased to learn that one of his erstwhile severist critics is now providing supporting evidence for his graph :-)
PeterM
Let’s leave Mann’s discredited hockeystick out of it (1859). We have flogged that dead horse ad nauseam, and the whole saga is covered in blow-by-blow detail in Montford’s book, which I am sure you have read.
The early 20th century global warming cycle from 1910 to 1944 (to which you refer) has been covered by IPCC AR4 WG1 and several others [most notably Delworth & Knudsen (2002)]. It resulted in linear warming (HadCRUT) of 0.53C over the 35-year period, prior to any significant human CO2 emissions. IPCC concedes that there is “more uncertainty regarding the causes of early 20th century warming than the recent warming”[IPCC AR4 WG1 Ch. 9, p.691], although possible forcing from changes in solar activity is mentioned. This is curious, because solar forcing has been estimated by IPCC to have been essentially negligible since 1750 [IPCC AR4 WG1 SPM, p. 4].
This compares with the recent late 20th century warming cycle starting in 1976, which IPCC refers to as “a time when global mean temperatures began a discernable upward trend that has been at least partly attributed to increases in greenhouse gas concentrations in the atmosphere” [IPCC AR4 WG1 Ch.3, p.120], adding “climate simulations are consistent in showing that the global mean warming observed since 1970 can only be reproduced when models are forced with combinations of external forcings that include anthropogenic forcings” [Ch. 9, p.685]. The HadCRUT record shows that this period resulted in a linear warming of around 0.40C, or slightly less than the earlier period.
As Robin has pointed out to you earlier on this thread, the IPCC logic appears to go as follows:
1. Our models cannot explain the early 20th century warming
2. We know that the slightly smaller late 20th century warming was caused by AGW.
3. How do we know this?
4. Because our models cannot explain it otherwise.
In addition to being an “argument from ignorance”, the flaw in the above logic is easy to spot by anyone, whether this is a rational skeptic of “dangerous AGW” or not.
A dilemma, but I’m sure you can spot the flaw.
Max
Peter
If you want to see a genuinely sharp increase in temperature I suggest you look at the period from 1698 until the 1730’s of which I have spoken before.
http://booty.org.uk/booty.weather/climate/cet_ewp.htm
We also have a sharp increase in the 1400’s
tonyb
Surprise: Peer reviewed study says current Arctic sea ice is more extensive than most of the past 9000 years
http://wattsupwiththat.com/2010/09/23/surprise-peer-reviewed-study-says-current-arctic-sea-ice-is-more-extensive-than-most-of-the-past-9000-years/#more-25249
Brute,
No it doesn’t! Just read the actual paper.
Max,
Mann’s hockey stick discredited? I was just starting to think that but your recent post convinced me he was right after all :-)
Tony B,
1698? You claim that 20th century records were unreliable, but they were so much better then?
PeterM
Re Mann’s discredited hockeystick. Have you read Montford’s book? It tells it all.
Max
Peter
As you well know I state that global temperature figures are nonsensical.
Individual records need to be treated with caution, however CET is the most examined instrumental record in the world and consists of some 650,000 data ponts.
The upward swing-with fits and starts- started in 1698 and continues to this day.
tonyb
Sorry Pete, you’re wrong again………
Brute,
I do wonder about the American education system. You just wouldn’t be able to manage without overseas trained doctors, nurses, engineers and scientist.
When I was at school we used to do comprehension tests and by the age of 10 or 11 we were expected to understand the difference in the meanings of:
1)… there have been times when sea-ice cover was less extensive than at the end of the 20th century.
and
2)current Arctic sea ice is more extensive than most of the past 9000 years
Have I read Montford’s book? I think I read enough of that sort of drivel on this blog, for free, without having to pay for the priveledge
too ;-)
However, if you can convince me that Andrew Montford is motivated by a genuine desire for scientific understanding rather than concerns that effective action to reduce GHG emissions might clash with his ultra right-wing libertarian political opinions, I’ll give it a go.
@Peter
Perhaps your local library has a copy you could borrow?
Or are you simply throwing up barriers because you’re concerned that the contents of the book might force you to reconsider your own preconceived notions of the truth.
Has anyone else come across these little marvels of engineering? At first glance they seem to have considerably more potential than the currently ridiculous electric cars.
http://www.insideline.com/mdi/airpod/2010/2010-mdi-airpod-first-drive.html
Peter
You accuse Brute of lack of comprehension. Did your teachers tell you off for making snap judgements without reading the work you were given-a trait you seem to continue to this day on a variety of topics from sea levels, to sea ice to temperatures? :)
Your response to Andrew Montfords book-making an ad hom attack on the way- does you no credit as the information within it relies on authenticated detail not wild speculation.
The very detailed report Brute referred to makes the points we have been trying to make to you, that sea ice cover varies enormously, something you do not want to believe. You refuse to look at the examples given to you concerning the notable warming in the 1820’s and 1920’s period even though the latter is accompanied by Pathe news reel and accounts in newspapers.
Some extracts from the paper;
“Since the early Holocene, sea-ice cover exhibits a general decreasing trend.”
“Paleoceanographic studies also indicate that sea-ice cover in the western Arctic has varied throughout the Holocene (de Vernal et al. 2005a, 2008; Ledu et al.2008).”
“The changes in relative abundance of these taxa nevertheless suggest variations in sea-surface conditions throughout the Holocene. In particular, the increase of P. dalei relative to the decrease of I. minutum at about 5500 years BP may reflect a warming in surface waters, as suggested by the modern distribution of both taxa.”
“In the Holocene record of core HLY0501-05, sea-ice cover has ranged between 5.5 and 9 months/year, summer SSS has varied between 22 and 30, and summer SST has ranged from 3 to 7.5 8C (Fig. 7)”.
“It is important to note that the amplitude of these millennial-scale changes in sea-surface conditions far exceed those observed at the end of the 20th century.”
Tonyb
PeterM
I have read Hansen’s various testimonies before US Congress plus many of his studies and PR releases, even though I am convinced that he is an eco-activist, rather than a serious, objective scientist. It’s all part of knowing the full picture.
You now decline to read the most comprehensive summary of the Mann hockeystick saga because you have personal doubt (1868) that
Sounds to me like you are a) prejudging Montford’s objectives based on his perceived political leanings and (worse yet) b) depriving yourself of some basic information (which may not agree with your own personal viewpoint).
You have to know all sides of the story to make a rational, objective choice, Peter.
Of course, if “dangerous AGW” is more like a religious belief for you, then I understand why you would shun writings that you would deem heretical of your belief.
Max
Barelysane
The article on the MDI AIRPod air-driven automobile is very interesting.
As with electrical or hydrogen-driven cars the primary power source needs to come from somewhere, but compressed air may be a more efficient method to store this energy than electrical batteries or compressed hydrogen from electrolysis (with all its safety complications).
If the basic power source is from fossil fuels, then I doubt that using compressed air as an intermediate would be more energy efficient than the internal combustion engine. But if the basic source is nuclear power (as would be the case in France, for example), I could see how this could be an improvement over either battery-operated electrical or hydrogen-driven cars.
It will be interesting to see how this develops.
Max
PeterM and Brute
The study, which Brute cited, concluded
For what it’s worth, the chart showing Arctic sea ice trends over the past 9,000 years shows the months per year during which sea ice had an extent of greater than 50% of the maximum value.
Today’s value appears to be around 9 months at >50% of the maximum. This is confirmed by the latest NSIDC data, which show that 3 months (August, September and October) are the only months at <50% of the maximum.
Over the 9,000 years, it appears that most of the years had fewer than 9 months at >50% of the maximum (generally between 6 and 8 months), so the statement is confirmed by the chart.
Sorry, Peter, you may disagree with the statistical approach used in the study, but that’s what the study shows, so Brute is right in this case.
Max
PeterM
Regarding the study on Arctic ice extent over the past 9,000 years, you berated Brute with:
In this case it turns out (see 1874) that the cited study shows that BOTH statements are correct (as Brute claimed).
Max
Look, 9000 years ago the Earth was in a glacial maximum. The polar ice caps extended well down into Northern Europe and Northern America.
http://en.wikipedia.org/wiki/Ice_age
To say that the “current Arctic sea ice is more extensive than most of the past 9000 years” is just nonsense.
PeterM
You are stating your personal opinion when you write:
Call it what you want to, this is what the study cited by Brute concludes. It is also what the graph in the study shows. Assuming the data shown on the graph are correct, it is also confirmed by the current NSIDC data for today’s value.
Until this study can be scientifically refuted by another study citing actual data it stands, whether you happen to like the conclusions reached or not.
It’s that simple, Peter.
Max