Tom Nelson pointed out this interesting temperature reconstruction, sourced from Katharine Hayhoe's new book. I thought it might be the Marcott paper, but a direct comparison suggests not. I wonder where it comes from?
Was just chasing the tail of this graph! It appears in her book, per Google:
http://books.google.com/books?id=iOA2n86mYtAC (search for phrase 'unnatural high'). Not so easy to find in the Amazon preview. A reference to the figure occurs in pg 63 of the paperback text.
Given that the graph shows the average temperature in deg F (not an anomaly), then we need all the warming we can get. Nov 10, 2014 at 9:26 AM Phillip Bratby
Can one of the bright sparks who reads BH please explain to this old weathered Aussie why the carbon dioxide level increased for 6,000 years, BEFORE industrialisation????
Don't these people learn? Natural proxies smooth decadal variation. Within those apparently smooth historical lines are huge peaks and troughs the equal of what we see in the instrumental record. Simply tacking the modern instrumental record on the end is DISHONEST.
So, let me see, do I read this correctly? CO2 cools temperatures for 4800 years then bingo, a new theory of physics and computer models, CO2 catastrophically increases temperatures. Makes sense to me, NOT!
Converting image to a jpg and using a couple of tools to do a reverse image search reveals a couple of things. 1. the image file but Hayhoe-last-6000-years.gif used to be on the Thinkprogress website but isn't there now 2. the above image file was used on Thinkprogress page by JOE ROMM APRIL 1, 2010 3. AUGUST 25, 2010 was used on climatechangepsychology.blogspot.co.uk/2010/08/koch-family-of-koch-industries-spends.html but dead also cos it calls the thinkprogress image file 4 Oct 2014 Christian website use uses it (scanned from book ? & relabelled) 5. www.notbluenotred.com/cycle.html cleanly, uncredited, undated ..and visted by wabyback machine November 3, 2013 - Conclusion Joe Rom was the first to use it on the web, but since the file name is Hayhoe-last-6000-years.gif I guess he got it from her work. (Is it surprising it has been used so rarely ?)
Perversely, with the small "hump" on her graph she could have labelled it "CO2 is not correlated with temperature" - until academics started measuring it.
Her graph is total rubbish. None of the warming periods are shown, the Holocene Optimum, Minoan, Roman, MWP. Just like Gores abortion. We know that the RWP and MWP wera warmer than today yet she shows a rapid increase in the past few years which is not shown in the raw data, the same period we know there has been zero temperature change with the threat of cooling in the near future.
So not an educational item rather a route to wishful thinkling by the Climateers.
This is what some people think is called science. 95% of the above graph shows a gradual reduction in temp as CO2 levels rise, and a few random departures, but the warmists dismiss all that and believe only the 5% bit at the end which they made up anyway.
More worryingly, idiots like Ed Davey will lap up this sort of nonsense.
My Guess is Joe Romm decided that the graph was too "good" to use so he removed it from that Thinkprogress page however when I search on Hayhoe-last-6000-years.gif Google throws up webpages where people had copied Romm's original2010 artlcle when the graph was labelled
"Here is a rough 6,000 year reconstruction that climate scientist Katherine Hayhoe put together from the National Climatic Data Center (NCDC) Paleoclimate archive for her new book, “A Climate for Change,” which you can see in a terrific March presentation [17]" (that goes to dead link)
The average atmospheric CO2 content over the past 500million years is 2500ppmv. So the present level is too low and higher levels would be good for plants and animals. The ice core data proves that temperature drives CO2 levels not CO2 driving temperature. CO2 is a gas that aids cooling because it is a good emitter of IR thus aiding the transfer of heat to space. Extra in the atmosphere will add mass to the atmosphere which will increase adiabatic warmiing but this small increase is covered by the cooling so overall no change.
I would like to add it to the list of exhibits that one day will be in museums of science around the world to show sloppy shoddy spinning 'science' in climate alarmism. Oh how the visitors will laugh and sigh and be outraged! Schoolchildren doing projects on the corruption of science will compete to find egregious examples. They will be appalled at the wasted decades, wasted lives, wasted spirits, wasted resources, wasted opportunities of the Great CO2 Scare Scandal.
Hey Bish Tom Nelson covered this story in Jan 2012 along with more shocking slides He also gave the same link Joe Romm gave to the original presentation PDF ( to REP members via conference call on March 9, 2010), it's dead Hayhoe_Climate.pdf the original must be out there somewhere. - I have tried to track it down but Google can't find a version before 2012 (they don't have the graph). It's horrible having to read docs titled "A Climate for Change: Global Warming Facts for Faith-Based Decisions" ... Does Hayhoe have Evangelical faith as well as Green faith ?
Additionally Hayhoe is peddling her alarmism as a religious movement. And she pushes her enterprise with her preacher hubby to make certain the loot stays all in the family: http://www.amazon.com/Climate-Change-Warming-Faith-Based-Decisions/dp/B005EP273O She and her hubby are out selling the book as a study series to gullible Christians and are bringing the book back out in a coordinated marketing scheme.
@Shub ....Well found link to pdf (I missed checking it on Wayback, cos Joe Romm had actually linked to the html page ..I hadn't checked wayback for the pdf link itself) - REP.org Republicans for Environmental Protection have changed name to conservamerica.org and the file hasn't been carried over
@Shub it would be funny, but junk like that has already gone into the education system and brainwashed kids ..and the fact that Joe Romm moved it off his page without a note looks like revisionism
This is from Creation Care, a blog in the 'Evangelical Environmental Network' using Hayhoe's graph. Quoting at length (emphasis mine):
Another misuse of the evidence made by Dr. Biesner's on Moody Radio, "There is no correlation between rising carbon dioxide levels and the increase in the earth temperature." The graph on the left taken from the National Academy of Sciences Climate Change Website clearly shows the relationship over time. Carbon Dioxide levels and temperature track identically. Now look at temperature and carbon dioxide record from Biblical times to the present (referring to Hayhoe's graph). Notice the unprecedented rapid temperature rise in the last 150 years. With the beginning of the industrial age, we started burning more and more fossil fuels and thus changing the delicate balance God created for sustaining life on His creation.
[Fig]
Without the normal 285 ppm of carbon dioxide in our atmosphere, our earth would be a chilly place with an average 70oF colder climate. One of the true miracles of creation is the greenhouse gas effects that make this earth habitable for humanity. [...] Small amounts of carbon dioxide make a difference. Dr. Biesner often states that changes in CO2 couldn't have a significant impact on temperature. [...] Perhaps an easy way to understand that small amounts of gas are deadly requires a quick look at carbon monoxide. At levels below 100 ppm, carbon monoxide causes headaches, dizziness, and nausea but at exposure of 150-200 ppm for approximately one hour may be deadly.[1] At concentration levels less than half the current carbon dioxide levels, carbon monoxide kills.
Steadily, for the past 4000 years, and without gaps for wars, famines, and other events, 'scientists' (I use the term loosely) have been consulting their Stephenson screens, CO2 monitors and satellite data, to compile this graph..
@Shub I looked at that PDF of Katharine Hayhoe's presentation. Can we assume that people like Richard Betts approve of those kind of lousy graphs, since they never stood up to say they are misleading ?
A scientist not understanding anything about resolution in time reconstructions? can't wait for her colleagues to organise protest letters against this travesty!!
OMG her book is really a Climate Change guide for evangelical christians Not only that : it is used to brainwash kids... You know the NCSE
The National Centre for Science Education, on its website, requests donations of items for its library and resources, including this book "A Climate for Change: Global Warming Facts for Faith-Based Decisions"
that 3 star reviewer then lists the erors she found in the book
"UPDATE! Our book is currently out of print because we requested and received our rights back from our publisher so we could update and release a second edition. We'll be fixing pesky errors, updating data and figures, and adding more discussion on both the theology and the practical actions we can take to address this important issue. be back online and in print by early 2015"
That's on Amazon.com yet it is available on Amazon.co.uk
* Katharine Hayhoe was the star of BBC Horizon: Global Weirding (handpicked picked cherrypicked for her extreme message ?) * "TIME Magazine Names Evangelical Scientist, Dr. Katharine Hayhoe, to 100 Most Influential List"
I loved this line that Shub quotes (which I accept is not Hayhoe):
"One of the true miracles of creation is the greenhouse gas effects that make this earth habitable for humanity."
Well, if the miracle of creation determined what the CO2 level should be then we have nothing to worry about: our creator will ensure it remains at a level to make the Earth habitable for humanity. Of course, it could be that there is no creator...It could also be that there is nothing to worry about anyway.
Shub - Small amounts of a gas can indeed be deadly, but not necessarily in the way they think. If I remember correctly, at LESS than around 200ppm of CO2 life on earth is unsustainable.
If the paleo data is reliable there seem to be four stable climate states for the Earth.
Hothouse earths are 5C warmer than the present, with CO2 up to 1000ppm.
Interglacial tend to resemble current temperatures with 280ppm
Glacial periods tend to be 5C cooler with 200ppm
Snowball earths were 10C cooler than us, with CO2 below 100ppm and glaciation down to the tropics.
The last identifiable snowball earth was 600 million years ago. The last hothouse earth was 2 million years ago. Since then we have had 90% glacial, 10% interglacial in 100,000 year cycles.
In the spirit of the ongoing #GamerGate revolt and boycott against “Social Justice Warriors“ (SJWs) mated with the latest Bill McKibben “climate justice“ red banner Marxist protest in NYC I like to promote the term “Climate Justice Warrior” (CJW) as something a younger generation of cynics can grok as being cultishly fanatical.
“A sustainable society will require fairness (equity) and justice locally and globally, both within this generation and between our generation and future generations.” – John Cook and Hadyn Washington (“Climate Change Denial: Heads in the Sand,” 2011).
“Preventing the collapse of human civilization requires nothing less than a wholesale transformation of dominant consumer culture.” – John Cook and Hadyn Washington (“Climate Change Denial: Heads in the Sand,” 2011).
Marcott 2013 never was retracted due to a few weasel words in the paper and the bizarre issuance of FAQ on the notorious Fenton/EMS PR firm owned site RealClimate.org that disowned the blade completely but then illegally welded on the high resolution thermometer record (apples) to the terribly low resolution 12K year long proxy record (oranges). Not only would that no longer even pass power review in corrupt climate “science” but without the pure artifact and totally non-temperature related blade, the paper wouldn't have been publishable in top journal Science in the first place.
Here is Marcott 2013 still being used on an NOAA web site, and not a single news site has corrected their reports of how Mann was validated by it:
Remember, ever since Climategate, Obama & Co. have been actively protecting climate “science” from an Enron worthy investigation. In two years, after the worst of purposefully deceptive Obamacare kicks in and so many lose employee benefits, a fully right wing government will finally establish the equivalent of “Climateaudit.gov”.
Toorightmate asked: Can one of the bright sparks who reads BH please explain to this old weathered Aussie why the carbon dioxide level increased for 6,000 years, BEFORE industrialisation????
CO2 is less soluble in warm water than cold water. As the ocean warmed after the last ice age, CO2 rose almost 100 ppm. On this graph, you are looking at only the last 6000 years and about 15 ppm of this "outgassing". Since exchange of heat between the deep ocean and the surface is takes many millennia, outgassing was still proceeding when the Industrial Revolution occurred.
A 10% rise in CO2 is 1/7 of a doubling - or 1.1^7 = 2. If you believe climate sensitivity is 3 degC for 2XCO2, then a 10% increase in CO2 is equivalent to about 0.43 degC. The change in CO2 on this graph before the industrial revolution appears to be less than 10%. Scientists say that CO2 is both a forcing (directly changing the radiation imbalance and thereby temperature) and a feedback (a change in response to temperature change that amplified or suppresses temperature change).
However, when you look at temperature change over more than a few thousand years, changes in the earth's orbit become important to climate. Right now, the earth is closest to the sun in January and receives about 7% more solar radiation January than in July. About 20,000 years ago, the opposite was true. The extra radiation arriving in the Northern Hemisphere (where the ice sheets were located) at that time supposedly was responsible for ending the last ice age. A warm period called the Holocene Climate Optimum followed when the Arctic was much warming than today. Even though TOTAL solar radiation doesn't change appreciably due to changes in the earth's orbit, regional changes in where that solar radiation can have a big impact on temperature. The slow fall of temperature seen on this graph may represent our slow descent towards the next ice age - that a small natural increase in CO2 forcing is incapable of countering.
Proxies such as ice cores are the result of processes operating over large area. The CET is a record of one small area. This makes it much more sensitive to local weather.
To what extent do you think this explains the greater variability of the CET?
Reader Comments (64)
Given that the graph shows the average temperature in deg F (not an anomaly), then we need all the warming we can get.
Was just chasing the tail of this graph! It appears in her book, per Google:
http://books.google.com/books?id=iOA2n86mYtAC (search for phrase 'unnatural high'). Not so easy to find in the Amazon preview. A reference to the figure occurs in pg 63 of the paperback text.
[self-snipped]
I'd hate to be thought of as rude.
> I wonder where it comes from?
From her red crayon?
Given that the graph shows the average temperature in deg F (not an anomaly), then we need all the warming we can get.
Nov 10, 2014 at 9:26 AM Phillip Bratby
Hee hee.
She drew the graph freehand with a blue crayon in her left hand and a red one in her right. That is as much analysis as the graph deserves.
Compare her figure with this from IPCC AR5 chapter 5.
Can one of the bright sparks who reads BH please explain to this old weathered Aussie why the carbon dioxide level increased for 6,000 years, BEFORE industrialisation????
Don't these people learn? Natural proxies smooth decadal variation. Within those apparently smooth historical lines are huge peaks and troughs the equal of what we see in the instrumental record. Simply tacking the modern instrumental record on the end is DISHONEST.
I don't know what data she is using, but she is definitely using the Marcott method.
toorightmate: and why temperature went down as CO2 went up.
So, let me see, do I read this correctly? CO2 cools temperatures for 4800 years then bingo, a new theory of physics and computer models, CO2 catastrophically increases temperatures. Makes sense to me, NOT!
Converting image to a jpg and using a couple of tools to do a reverse image search reveals a couple of things.
1. the image file but Hayhoe-last-6000-years.gif used to be on the Thinkprogress website but isn't there now
2. the above image file was used on Thinkprogress page by JOE ROMM APRIL 1, 2010
3. AUGUST 25, 2010 was used on climatechangepsychology.blogspot.co.uk/2010/08/koch-family-of-koch-industries-spends.html but dead also cos it calls the thinkprogress image file
4 Oct 2014 Christian website use uses it (scanned from book ? & relabelled)
5. www.notbluenotred.com/cycle.html cleanly, uncredited, undated ..and visted by wabyback machine November 3, 2013
- Conclusion Joe Rom was the first to use it on the web, but since the file name is Hayhoe-last-6000-years.gif I guess he got it from her work.
(Is it surprising it has been used so rarely ?)
Perversely, with the small "hump" on her graph she could have labelled it "CO2 is not correlated with temperature" - until academics started measuring it.
The first thing that man learns from History is that man never learns from History.
Her graph is total rubbish. None of the warming periods are shown, the Holocene Optimum, Minoan, Roman, MWP. Just like Gores abortion. We know that the RWP and MWP wera warmer than today yet she shows a rapid increase in the past few years which is not shown in the raw data, the same period we know there has been zero temperature change with the threat of cooling in the near future.
So not an educational item rather a route to wishful thinkling by the Climateers.
This is what some people think is called science. 95% of the above graph shows a gradual reduction in temp as CO2 levels rise, and a few random departures, but the warmists dismiss all that and believe only the 5% bit at the end which they made up anyway.
More worryingly, idiots like Ed Davey will lap up this sort of nonsense.
My Guess is Joe Romm decided that the graph was too "good" to use so he removed it from that Thinkprogress page however when I search on Hayhoe-last-6000-years.gif Google throws up webpages where people had copied Romm's original2010 artlcle when the graph was labelled
And I failed to mention CO2.
The average atmospheric CO2 content over the past 500million years is 2500ppmv. So the present level is too low and higher levels would be good for plants and animals. The ice core data proves that temperature drives CO2 levels not CO2 driving temperature. CO2 is a gas that aids cooling because it is a good emitter of IR thus aiding the transfer of heat to space. Extra in the atmosphere will add mass to the atmosphere which will increase adiabatic warmiing but this small increase is covered by the cooling so overall no change.
Here are 9000 years worth of North Atlantic isotope records from Knudsen et al:-
http://www.nature.com/ncomms/journal/v2/n2/fig_tab/ncomms1186_F4.html
They all show cooling with some multidecadal and multicentennial, variation. Impossible to abstract Hayhoe's interpretation of temperature variation.
does it matter, at this stage, where it comes from?
you angry white males are solo judgemental, arrgh
I would like to add it to the list of exhibits that one day will be in museums of science around the world to show sloppy shoddy spinning 'science' in climate alarmism. Oh how the visitors will laugh and sigh and be outraged! Schoolchildren doing projects on the corruption of science will compete to find egregious examples. They will be appalled at the wasted decades, wasted lives, wasted spirits, wasted resources, wasted opportunities of the Great CO2 Scare Scandal.
I guess it demonstrates that science was never Katharine Hayhoe's strong subject when she was at school.
Hey Bish Tom Nelson covered this story in Jan 2012 along with more shocking slides
He also gave the same link Joe Romm gave to the original presentation PDF ( to REP members via conference call on March 9, 2010), it's dead
Hayhoe_Climate.pdf the original must be out there somewhere. - I have tried to track it down but Google can't find a version before 2012 (they don't have the graph).
It's horrible having to read docs titled "A Climate for Change: Global Warming Facts for Faith-Based Decisions" ... Does Hayhoe have Evangelical faith as well as Green faith ?
Additionally Hayhoe is peddling her alarmism as a religious movement. And she pushes her enterprise with her preacher hubby to make certain the loot stays all in the family:
http://www.amazon.com/Climate-Change-Warming-Faith-Based-Decisions/dp/B005EP273O
She and her hubby are out selling the book as a study series to gullible Christians and are bringing the book back out in a coordinated marketing scheme.
Stew
The presentation is here:
http://web.archive.org/web/20111105185137/http://www.rep.org/Hayhoe_Climate.pdf
It's a flood of nonsense. Check out page 7 for example. "It’s happening faster and faster"
Sigh. One more.
Soon they'll have a cord of hockey sticks.
@Shub ....Well found link to pdf
(I missed checking it on Wayback, cos Joe Romm had actually linked to the html page ..I hadn't checked wayback for the pdf link itself)
- REP.org Republicans for Environmental Protection have changed name to conservamerica.org and the file hasn't been carried over
@Shub it would be funny, but junk like that has already gone into the education system and brainwashed kids
..and the fact that Joe Romm moved it off his page without a note looks like revisionism
This is from Creation Care, a blog in the 'Evangelical Environmental Network' using Hayhoe's graph. Quoting at length (emphasis mine):
http://creationcare.org/view.php?id=716
Well - I'm amazed...
Steadily, for the past 4000 years, and without gaps for wars, famines, and other events, 'scientists' (I use the term loosely) have been consulting their Stephenson screens, CO2 monitors and satellite data, to compile this graph..
You live and learn, don't you..?
Re : revisionism ..I find it ironic that Joe Romm used that dubious graph on a webpage he wrote which says that it was a whitewash when the ombudsman found a PBS program about Climate change innocent of bias that Romm shouts at "It's funded by Koch"
..and now that Romm seems to have withdrawn that graph ..the page titled PBS ombudsman Getler whitewashes the Koch-funded greenwashing episode of Nova that whitewashes the threat of human-caused climate change has a big empty space in the middle
@Shub I looked at that PDF of Katharine Hayhoe's presentation. Can we assume that people like Richard Betts approve of those kind of lousy graphs, since they never stood up to say they are misleading ?
A scientist not understanding anything about resolution in time reconstructions? can't wait for her colleagues to organise protest letters against this travesty!!
...oh, wait...
Shun
Entropic man says Creationists know naff all about science.
From the caption: "Natural Thermometers"
LOL
Andrew
PAGES2K?
http://sunshinehours.wordpress.com/2014/10/30/whatever-happened-around-1750-saved-humanity/
OMG her book is really a Climate Change guide for evangelical christians
that 3 star reviewer then lists the erors she found in the bookNot only that : it is used to brainwash kids... You know the NCSE
- A 1 star reviewer does an extensive debunk and has 12 commenter s shouting at him for it
- Bish says new ..it was published 29 Oct 2009
and the errors are only pesky !
That's on Amazon.com yet it is available on Amazon.co.uk* Katharine Hayhoe was the star of BBC Horizon: Global Weirding (handpicked picked cherrypicked for her extreme message ?)
* "TIME Magazine Names Evangelical Scientist, Dr. Katharine Hayhoe, to 100 Most Influential List"
I loved this line that Shub quotes (which I accept is not Hayhoe):
Well, if the miracle of creation determined what the CO2 level should be then we have nothing to worry about: our creator will ensure it remains at a level to make the Earth habitable for humanity. Of course, it could be that there is no creator...It could also be that there is nothing to worry about anyway.Didn't know this - Katharine Hayhoe is not a PhD.
Edit: She *is* a PhD. It's not listed in some places.
"So why do we even exist? That's because a lot of the data doesn't quite give you what you need -- yet. We do."
Mission statement from CEO Katharine Hayhoe's Atmos Research & Consulting....an all female organization apparently.
http://www.atmos-research.com/#!services/ca4p
Shub - Small amounts of a gas can indeed be deadly, but not necessarily in the way they think. If I remember correctly, at LESS than around 200ppm of CO2 life on earth is unsustainable.
So human influence on the climate has reversed a long-term decline in temperatures, thus delaying, or possibly even preventing, the next glaciation?
Thanks for making that clear, Katherine......
I can't see where it comes from, its' too dark there.
Cumbrian lad
If the paleo data is reliable there seem to be four stable climate states for the Earth.
Hothouse earths are 5C warmer than the present, with CO2 up to 1000ppm.
Interglacial tend to resemble current temperatures with 280ppm
Glacial periods tend to be 5C cooler with 200ppm
Snowball earths were 10C cooler than us, with CO2 below 100ppm and glaciation down to the tropics.
The last identifiable snowball earth was 600 million years ago. The last hothouse earth was 2 million years ago. Since then we have had 90% glacial, 10% interglacial in 100,000 year cycles.
John Cook is also an Evangelical Christian.
In the spirit of the ongoing #GamerGate revolt and boycott against “Social Justice Warriors“ (SJWs) mated with the latest Bill McKibben “climate justice“ red banner Marxist protest in NYC I like to promote the term “Climate Justice Warrior” (CJW) as something a younger generation of cynics can grok as being cultishly fanatical.
“A sustainable society will require fairness (equity) and justice locally and globally, both within this generation and between our generation and future generations.” – John Cook and Hadyn Washington (“Climate Change Denial: Heads in the Sand,” 2011).
“Preventing the collapse of human civilization requires nothing less than a wholesale transformation of dominant consumer culture.” – John Cook and Hadyn Washington (“Climate Change Denial: Heads in the Sand,” 2011).
HH Lamb found that there have been many sharp and significant ups and downs in temperature in the last few thousand years.
These have all been miraculously smoothed away by Hayhoe
http://notalotofpeopleknowthat.wordpress.com/2014/11/10/katharine-disappears-the-mwp/
Marcott 2013 never was retracted due to a few weasel words in the paper and the bizarre issuance of FAQ on the notorious Fenton/EMS PR firm owned site RealClimate.org that disowned the blade completely but then illegally welded on the high resolution thermometer record (apples) to the terribly low resolution 12K year long proxy record (oranges). Not only would that no longer even pass power review in corrupt climate “science” but without the pure artifact and totally non-temperature related blade, the paper wouldn't have been publishable in top journal Science in the first place.
Here is Marcott 2013 still being used on an NOAA web site, and not a single news site has corrected their reports of how Mann was validated by it:
http://climate.gov/news-features/climate-qa/what%E2%80%99s-hottest-earth-has-been-%E2%80%9Clately%E2%80%9D
Remember, ever since Climategate, Obama & Co. have been actively protecting climate “science” from an Enron worthy investigation. In two years, after the worst of purposefully deceptive Obamacare kicks in and so many lose employee benefits, a fully right wing government will finally establish the equivalent of “Climateaudit.gov”.
Toorightmate asked: Can one of the bright sparks who reads BH please explain to this old weathered Aussie why the carbon dioxide level increased for 6,000 years, BEFORE industrialisation????
CO2 is less soluble in warm water than cold water. As the ocean warmed after the last ice age, CO2 rose almost 100 ppm. On this graph, you are looking at only the last 6000 years and about 15 ppm of this "outgassing". Since exchange of heat between the deep ocean and the surface is takes many millennia, outgassing was still proceeding when the Industrial Revolution occurred.
A 10% rise in CO2 is 1/7 of a doubling - or 1.1^7 = 2. If you believe climate sensitivity is 3 degC for 2XCO2, then a 10% increase in CO2 is equivalent to about 0.43 degC. The change in CO2 on this graph before the industrial revolution appears to be less than 10%. Scientists say that CO2 is both a forcing (directly changing the radiation imbalance and thereby temperature) and a feedback (a change in response to temperature change that amplified or suppresses temperature change).
However, when you look at temperature change over more than a few thousand years, changes in the earth's orbit become important to climate. Right now, the earth is closest to the sun in January and receives about 7% more solar radiation January than in July. About 20,000 years ago, the opposite was true. The extra radiation arriving in the Northern Hemisphere (where the ice sheets were located) at that time supposedly was responsible for ending the last ice age. A warm period called the Holocene Climate Optimum followed when the Arctic was much warming than today. Even though TOTAL solar radiation doesn't change appreciably due to changes in the earth's orbit, regional changes in where that solar radiation can have a big impact on temperature. The slow fall of temperature seen on this graph may represent our slow descent towards the next ice age - that a small natural increase in CO2 forcing is incapable of countering.
The big yin is correct
Comparing apples-proxies- with oranges-instrumental records- hugely distorts the record.
Here is CET superimposed over a variety of paleo proxy reconstructions from my recent article
http://curryja.files.wordpress.com/2013/06/fig.jpg
Tonyb
Tonyb
Proxies such as ice cores are the result of processes operating over large area. The CET is a record of one small area. This makes it much more sensitive to local weather.
To what extent do you think this explains the greater variability of the CET?