Guest essay by Tony Brown
Some readers might recall my recent article ‘The Long Slow Thaw?’
In this I reconstructed Central England temperature to 1538 from its current instrumental date of 1659.
I was surprised by two notable periods of warmth around 1630 and 1530. I am indebted amongst other material, to Phil Jones excellent book ‘Climate since 1500 AD’ plus such books as Le Roy Laduries’ Times of feast times of famine’ which confirm that these were indeed warm periods.
The graph below is from my article but to it has been added the official co2 levels. CET is seen by many scientists as a reasonable but by no means perfect proxy for Northern Hemisphere and Global temperatures.
Please note that the graphing package somewhat inflates the warmth in the decade around 1540, although my recent research- which will extend CET to 1498-demonstrates that the period 1500 to 1540 does indeed appear to be around as warm as the warm period in the recent CET period ending around the year 2000, characterised by the distinct hump.
Also from a graphing viewpoint it is debatable as to where the CO2 line should be placed. I chose to place it around the black trend line as the CO2 and temperature trend line probably needs to start together at the same place. This also provides clarity and context to the graphic although others might feel the CO2 line should be placed elsewhere.
However these are all nuances and the point I want to put over is that temperature is highly variable throughout the CET record -which is at variance to Dr Mann’s (global) work and the assertions of the Met office. This is despite a constant level of co2 until around 1900. The temperature decline since 2000 as the CO2 line rises ever further is especially intriguing.
Does it demonstrate that once you get to around the 300ppm level that the law of diminishing returns sets in as the logarithmic curve of CO2 versus temperatures takes effect? Does it illustrate nothing and the current downward CET slope is merely a blip that will increase sharply again as more CO2 is added?
The apparent effects of adding additional CO2 was clearly shown in an article by David Archibald several years ago,
http://wattsupwiththat.com/2010/03/08/the-logarithmic-effect-of-carbon-dioxide/
I merely present my research and findings for comment. An apparent decline perhaps as the logarithmic effect ceases to have any real world meaning? Or merely a hiatus in the ever upwards rise of temperatures since the start of the record in 1659 which may or may not be affected by CO2 and radiative physics?
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Nick Stokes says:
May 8, 2013 at 10:56 pm
But now we’ve been putting fossil C directly in the air – about 350 Gtons so far. That’s a new situation. Should we stop? We’ll have to decide. But there are plenty more Gtons to go.
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Gee, modern greenhouses have been raising CO2 levels to “unprecedented”, 1000-1500 ppm levels — never experienced by plants in MILLIONS of yrs.
Why would they do that, and what are the results?
„The curious case of rising CO2 and falling temperatures”
It’s a hoax.
http://www.volker-doormann.org/images/down3.gif
Went to the curious case of solar system:
http://www.volker-doormann.org/images/hadcrut4_minus_oni_1960a.gif
V.
Congrats to Tony Brown for the depth of his cross – referenced research
into the climate historic record…So much more reliable than climate models
with their discrepancies and ‘creative’ methodologies. certainly more reliable
than tree rings as a proxy for temperature. And its kind of reassuring to
have your farmers’ almanac records and other real world records to back
up the science too.
If you look at the variance in the Mauna Loa CO2 data and the variance in the Hadcrut temperature data, you will see that the is an excellent correlation and that temperature leads. http://www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.2/plot/hadcrut4gl/isolate:60/mean:12/from:1960
Tony
Your graph is very interesting.It shows an island region that was quite cold through the entire period since 1560. Except for 4-5 brief warm periods , the overall impression is below average temperatures most of the time . It also shows some new cold periods that I had not recognized like 1560-1630,1720-1820,1830-1880. These were not solar minimums , so ocean temperatures could be the only cause plus some major volcanic eruptions . The oceans were quite cold during this time .The temperature dips through the four solar minimums show up very clearly.
“Went to the curious case of solar system:”
http://www.volker-doormann.org/images/moberg_1530_ghi5.gif
Best
V.
‘I can respect that position, but do wish that so many scientists who push the notion of lack of variability in the past would argue the case for radiative physics instead of coming up with all sorts of studies that distort climatic history.”
Agreed.
You dont need to know anything about climate history to understand that dumping c02 at will into the atmosphere is not a wonderful risk free idea
Herkimer
I think you have made a perceptive comment in as much Britain is a pretty cold country which at various times gets less cold. These periods of brief warmth get incorporated into folk lore and are seen as the norm, think of the ‘endless’ Edwardian summer to which can be added a few brief Warm years that ended a decade ago.
Our seaside resorts are predicated on the notion of hot summers but all too frequently the tourist is disappointed at the reality. That is not to say that we don’t have good years but I remember now why my parents gave up holidaying in Britain in the early sixties, it was because the weather was often cool and unreliable and often wet.
Tonyb
herkimer says:
May 9, 2013 at 11:01 am
………..
Just to add to Tony’s comment, strongest ever sunspot cycle was SC19, 1955-1965, but then as Tony says I remember now why my parents gave up holidaying in Britain in the early sixties, it was because the weather was often cool and unreliable and often wet.
Sun is an obvious choice to explain climate change, but its direct radiative input as described and measured by the TSI (total solar iradiance) is relatively constant.
Fact that many ignore:
The CET 350 year long record shows that summer temperatures (Jun-July when the insulation is at its highest) show no perceptive long term trend rise, while it is the winters (December-January when the insulation is at lowest) which are responsible for the uptrend:
http://www.vukcevic.talktalk.net/MidSummer-MidWinter.htm
It then stands to reason that the in the long term CET trend is governed by the nearby Atlantic’s currents.
(see also my earlier comment )
vukcevic
You said
“It then stands to reason that the in the long term CET trend is governed by the nearby Atlantic’s currents.”
Ocean sst also govern in the short term . Ocean temperatures will over-ride solar effects as they did during the high solar max in 1957 . Both North and South hemisphere SST were in a declining mode 1940-1960.. Both had temperature dips in that period around 1955 and 1965. Also AO was negative much of the period .
In reply to Louis Hooffstetter:’s question May 8, 2013 at 5:35 pm, ““Nick, which is/are bettter proxies for North American temperatures, the CET record or Mann’s proxies?” Nick Stokes said:
North America? Where did that come from? Tony was talking about global.
Yes, but last time I checked, N. America and England were both in the Northern Hemisphere. If this has changed recently, please let me know. Tony was talking about global, but to make it simple for you, lets limit our discussion to the Northern Hemisphere. Now, stop dodging my question and answer it: Which are better proxies for (either North American or) Northern Hemisphere temperatures, the CET record or Mann’s proxies?:
http://www.multi-science.co.uk/mcintyre-mckitrick.pdf
Once again, if your answer is Mann’s proxies, please explain why.
tonyb
I think the role of major volcano eruptions during 1500-1800 is often under estimated. There were about 28 eruptions level 5 or over during this period including some level 6 and 7. During 1600 there were 12 . So they must have had some effect to cool global temperatures further.Things have been rather quiet recently.I wonder if they will also be more active as we get into the next cooler climate cycle between now and 2030.
Steven Mosher says:
May 9, 2013 at 11:42 am
You dont need to know anything about climate history to understand that dumping c02 at will into the atmosphere is not a wonderful risk free idea
By which you mean, the less you know about climate history, the better able you are to swallow the notion that somehow we are risking something by “dumping” C02 into the atmosphere.
Thanks, Tony.
Yes, CO2 continues to climb while temperatures don’t.
A strong indication of failure for the greenhouse warming hypothesis.
Bart says:
That was the graph that was available. Your graph still doesn’t show that much curvature over a 20 year period. And, you conveniently haven’t shown the atmospheric CO2 levels on the same graph so one can see if there is really any significant difference in the amount of curvature.
What you happened upon was a feedback that had been known about for quite some time. However, only a few of the most extreme believe-what-they-want-to-believers actually think this means the rise in CO2 levels since the industrial revolution began is not anthropogenic.
herkimer says:
“It also shows some new cold periods that I had not recognized like 1560-1630,1720-1820,1830-1880. These were not solar minimums, so ocean temperatures could be the only cause plus some major volcanic eruptions.”
It is actually possible to track most stronger CET monthly deviations from average temperatures solely from (repeatable) heliocentric planetary configurations through the whole series. In that respect, CET can be seen as a useful proxy for short term solar magnetic activity.
It’s not as if local SST’s did anything to mitigate the cold in Dec 2010 and March 2013, both very cold even by Maunder standards. That was down to the short term solar signal giving a very negative AO, at the two weakest places in the solar cycle, just after minimum and at around maximum. I think you’ll find most of it is down to where the jet stream is sitting.
The postscript in Tony’s excellent article gives very good descriptions on variabilty:
http://judithcurry.com/2011/12/01/the-long-slow-thaw/
joeldshore says:
May 9, 2013 at 6:39 pm
“Your graph still doesn’t show that much curvature over a 20 year period.”
You’re probably looking at the top graph. That is the rate of emissions. It is greater than linear. That integrates to total accumulated emissions in the bottom graph to greater than quadratic. That’s lots of curvature.
Unfortunately, it only goes to 2006. I do not have a source for updated data. The CDIAC site seems not to provide it anymore. But, I have seen the plots, and the emissions rates have not decreased at all in the last 5 years. Quite the contrary, they have increased worldwide. Measured CO2 rate has completely stalled and the appears to be turning down in lock step with the temperatures. The divergence is getting to be very pronounced.
“What you happened upon was a feedback that had been known about for quite some time.”
Nice try. It isn’t a feedback. It is the basic relationship. And, there is no room in it for significant anthropogenic contributions.
What happened to my post? I asked Tony about his sentence: ‘ CET is seen by many scientists as a reasonable but by no means perfect proxy for Northern Hemisphere and Global temperatures.’ Since Southern Hemisphere temps seem to be a degree or two lower, is it the rise and fall that makes CET a good proxy? Anyway, what does he think about the other hemisphere?
Oops! I saw it on the third run-through…
Don Atkin
Sorry for not replying to your post. I should have done a fresh read through after my morning coffee.
Yes, it is the direction of travel that makes CET useful. I am sorry for quoting him again but Lamb summed up the problems with virtually all temperature data sets and especially historic reconstructions when he said ‘we can understand the tendancy but not the precision.’
The world has many climates and the Southern Hemisphere and Northern Hemisphere do not ALWAYS march to the same tune, so direction of travel, generally (but not always) yes, precision , no.
The southern Hemisphere few hisatoric records (ie pre 1850) either instrumental or anecdotal so whilst the ideal would be to construct its own temperature narrative that would be difficult to do.
Tonyb
Tony
You say:
‘Yes, it is the direction of travel that makes CET useful. I am sorry for quoting him again but Lamb summed up the problems with virtually all temperature data sets and especially historic reconstructions when he said ‘we can understand the tendency but not the precision.’
The world has many climates and the Southern Hemisphere and Northern Hemisphere do not ALWAYS march to the same tune, so direction of travel, generally (but not always) yes, precision , no.’
Your article is about the link between atmospheric carbon dioxide and land surface temperature i.e. climate sensitivity over land for which you claim that the CET record is a reasonable proxy. The IPCC gave a global value in AR4 with a mean of 3 oC which has since been lowered by several IPCC scientists to a mean of 1.6 oC. Both of these values depend on a positive feedback from water vapour but Lindzen and Spencer among others have presented empirical data showing this is net negative and as a result find a climate sensitivity of 0.3 to 0.7 oC. These values, however, depend on latitude with the low values in the tropics.
http://bishophill.squarespace.com/blog/2013/4/25/climate-sensitivity-in-ar5.html
http://wattsupwiththat.com/2011/07/25/loehle-and-scafetta-calculate-0-66%C2%B0ccentury-for-agw/#more-44052
Schmittner found differences in climate sensitivity by zone: Arctic, North Temperate, Tropics, South Temperate, and Antarctic, with a large difference between the Arctic and Antarctic. In fact the graphic in his poster shows that there are multiple climate sensitivities – five for oceans and two for land. This means that there is no mean value as claimed by the IPCC, it is local and changes with ocean heat flux and cloud cover:
http://wattsupwiththat.com/2011/12/18/co2-sensitivity-is-multi-modal-all-bets-are-off/
Data presented at Columbia University show distinct zonal differences in the patterns of ocean temperature anomalies by latitude: Arctic, NH Mid, Tropical, SH Mid and Antarctic ocean areas http://www.columbia.edu/~mhs119/Temperature/T_moreFigs/zonalT.pdf
And these fit with zonal differences that show up in UAH temperature anomalies:
http://wattsupwiththat.com/2013/05/04/uah-global-temperature-down-significantly/#more-85587
These zonal differences are reflected in differing warming/cooling patterns in ocean basins
http://wattsupwiththat.com/2013/03/11/is-ocean-heat-content-data-all-its-stacked-up-to-be/#more-81892
And the disparity in heat content in the oceans of the SH and NH:
http://wattsupwiththat.com/2011/09/18/tisdale-on-ocean-heat-content-anomalies/#more-47656
http://wattsupwiththat.com/2013/05/03/ocean-heat-content-0-to-2000-meters-why-arent-northern-hemisphere-oceans-warming-during-the-argo-era/#more-85514
Clive Best has slinked these differences in sensitivity over land to surface humidity:
http://clivebest.com/blog/?p=3258
As has Byrne in this reference given recently by Mosher at ClimateEtc.
http://www.mit.edu/~pog/src/byrne_land_ocean_warming_contrast_2013.pdf
“Surface temperatures increase at a greater rate over land than ocean in simulations and observations of global warming. It has previously been proposed that this land-ocean warming contrast is related to different changes in lapse rates over land and ocean because of limited moisture availability over land. A simple theory of the land-ocean warming contrast is developed here in which lapse rates are determined by an assumption of convective quasi-equilibrium. The theory predicts that the difference between land and ocean temperatures increases monotonically as the climate warms or as the land becomes more arid. However, the ratio of differential warming over land and ocean varies non-monotonically with temperature for constant relative humidities and reaches a maximum at roughly 293K.”
And Mosher also pointed to studies showing differences between land and sea in this reference from Rowan e al.
http://onlinelibrary.wiley.com/doi/10.1029/2006GL028164/abstract
Given these data, can we really say that the CET record is a useful proxy for global climate sensitivity, albeit it gives useful information about past temperatures in the UK and some surrounding areas that disputes the hockey stick claims of Mann, Marcott and Pages2K.
It is not whether warming and cooling occurs, it does in regular cycles. Rather, it is where it occurs and the consequences. A large increase in temperature in the Arctic zone in winter, as proposed by Arrhenius, where the temperatures are – 30 oC, has little consequence for the bulk of mankind (personkind!). But a drop in temperature of a few degrees in Europe, the USA and Canada has real consequences – as we see this year in the late start to the grain growing season. We need to monitor the changes in the boundaries of these zones since, in the NH, a 1 oC reduction in temperature causes a retreat south by about 170 km in the areas where grains can be produced – for which CET is probably useful for Europe but what about the N America and China and the SH. This is the reason I consider climate science should concentrate on climate zones rather than regional or global evaluations.
@climatereason.
I can understand reports from the time can give an idea of the rough temperature but this is no way accurate. London’s UHI effect is far higher now than in the 14-1600’s for instance. CO2 concentrations from ice cores are not as accurate as hoped as recent research has shown due to contamination. (An internet search should source this. I have seen it but have no record of it now). CO2 concentrations from Victorian times were measured, using the same chemical methods as today, at up to 500ppmv in various places round Europe, Germany, Italy, England. CO2 concentrations are difficult to average given the changes diurnally, seasonally and hemispherically.
Peter said
“This is the reason I consider climate science should concentrate on climate zones rather than regional or global evaluations.”
I agree. Average Global temperatures obscure the fact that some places warm whilst others are cooling or static. We have the same example for average ‘global’ sea level rise which in some places is dropping whilst in others it is rising sharply whilst it is static in the third example.
The futility of trying to get everything into a convenient ‘average global’ straightjacket is nowhere better illustrated than the ‘global economic growth rate’. Those countries seeing a huge contraction in their economies would find the idea that average global growth was 3% to be completely meaningless.
As I mentioned upthread trying to sort places into climate zones and assesing the temperature trends would be an interesting exercise, but one that needs to be done by a research team with the proper resources.
tonyb
JohnMarshall
I use ‘official’ co2 concentrations through the centuries in order that this aspect is uncontroversial to those who believe co2 has a serious affect on our temperatures.
I referenced earlier the article I wrote on ‘historic variations in co2’. I think the subject warrants further examination and an audit of the pre 1958 co2 measurements which would sort out the controversy one way or the other. I remain to be convinced either way as to whether past co2 variability was greater than currently officially believed.
tonyb
One part of Maunder minimum period that I found interesting is that the reconstructed North Atlantic SST Anomaly shows a steady warming from about 1600 to about 1690 which was the latter 45 years of the 90 years of warming through the early part of the Maunder Minimum and then dropping after 1690 until about 1720. This was happening as the solar cycle in terms of sunspot activity was dropping to zero from 1600 to 1645. So the solar minimum was not affecting the Ocean sst.The reconstructed CET was rising from1620 to1650 and then dropped [ even while North Atlantic SST was still warming] and stayed below average until 1720. It perhaps showed another period when solar cycles and ocean sst cycles seemed out of sync like during 1940-1960. I think it may have also been the 10 major volcanic eruptions between 1640 and 1680 that may have partly caused CET to start dropping before the North ATlantic SST started to drop unless the solar minimum which was fully underway by 1645 was the prime cause?
http://bobtisdale.blogspot.ca/2008/07/sst-reconstructions.html