A global temperature conundrum: Cooling or warming climate?
From the University of Wisconsin-Madison
MADISON, Wis. — When the Intergovernmental Panel on Climate Change recently requested a figure for its annual report, to show global temperature trends over the last 10,000 years, the University of Wisconsin-Madison’s Zhengyu Liu knew that was going to be a problem.
“We have been building models and there are now robust contradictions,” says Liu, a professor in the UW-Madison Center for Climatic Research. “Data from observation says global cooling. The physical model says it has to be warming.”
Writing in the journal Proceedings of the National Academy of Sciences today, Liu and colleagues from Rutgers University, the National Center for Atmospheric Research, the Alfred Wegener Institute for Polar and Marine Research, the University of Hawaii, the University of Reading, the Chinese Academy of Sciences, and the University of Albany describe a consistent global warming trend over the course of the Holocene, our current geological epoch, counter to a study published last year that described a period of global cooling before human influence.
The scientists call this problem the Holocene temperature conundrum. It has important implications for understanding climate change and evaluating climate models, as well as for the benchmarks used to create climate models for the future. It does not, the authors emphasize, change the evidence of human impact on global climate beginning in the 20th century.
“The question is, ‘Who is right?'” says Liu. “Or, maybe none of us is completely right. It could be partly a data problem, since some of the data in last year’s study contradicts itself. It could partly be a model problem because of some missing physical mechanisms.”
Over the last 10,000 years, Liu says, we know atmospheric carbon dioxide rose by 20 parts per million before the 20th century, and the massive ice sheet of the Last Glacial Maximum has been retreating. These physical changes suggest that, globally, the annual mean global temperature should have continued to warm, even as regions of the world experienced cooling, such as during the Little Ice Age in Europe between the 16th and 19th centuries.
The three models Liu and colleagues generated took two years to complete. They ran simulations of climate influences that spanned from the intensity of sunlight on Earth to global greenhouse gases, ice sheet cover and meltwater changes. Each shows global warming over the last 10,000 years.
Yet, the bio- and geo-thermometers used last year in a study in the journal Science suggest a period of global cooling beginning about 7,000 years ago and continuing until humans began to leave a mark, the so-called “hockey stick” on the current climate model graph, which reflects a profound global warming trend.
In that study, the authors looked at data collected by other scientists from ice core samples, phytoplankton sediments and more at 73 sites around the world. The data they gathered sometimes conflicted, particularly in the Northern Hemisphere.
Because interpretation of these proxies is complicated, Liu and colleagues believe they may not adequately address the bigger picture. For instance, biological samples taken from a core deposited in the summer may be different from samples at the exact same site had they been taken from a winter sediment. It’s a limitation the authors of last year’s study recognize.
“In the Northern Atlantic, there is cooling and warming data the (climate change) community hasn’t been able to figure out,” says Liu.
With their current knowledge, Liu and colleagues don’t believe any physical forces over the last 10,000 years could have been strong enough to overwhelm the warming indicated by the increase in global greenhouse gases and the melting ice sheet, nor do the physical models in the study show that it’s possible.
“The fundamental laws of physics say that as the temperature goes up, it has to get warmer,” Liu says.
Caveats in the latest study include a lack of influence from volcanic activity in the models, which could lead to cooling — though the authors point out there is no evidence to suggest significant volcanic activity during the Holocene — and no dust or vegetation contributions, which could also cause cooling.
Liu says climate scientists plan to meet this fall to discuss the conundrum.
“Both communities have to look back critically and see what is missing,” he says. “I think it is a puzzle.”
The study was supported by grants from the (U.S.) National Science Foundation, the Chinese National Science Foundation, the U.S. Department of Energy, and the Chinese Ministry of Science and Technology.
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“Both communities have to look back critically and see what is missing,” he says. “I think it is a puzzle.”
Rising CO2 levels have only been shown to follow warming trends. Or in other words, CO2 has never caused global warming.
Earth global temperature has been cooling for millions of years. This fairly recent condition of last 50 million years is called Ice house climate. Wiki: “During an icehouse earth, greenhouse gases tend to be less abundant, and temperatures tend to be cooler globally. The Earth is currently in an icehouse stage”.
It thought the reason for our icehouse climate is most related to geological and/or geographical issues [where land masses, ocean basins, and mountains are located]. And the reason for periods of deep freeze of glacial periods and the warmer intergalactic periods is related to Earth orbital and it’s axis spin- or the precession of earth’s axis. So we have very roughly about 20,000 year of interglacial warmer period, and 100,000 year glacial period. One can compare that to precession period of 26,000 years. So the precession period of earth’s axis does not simply turn off and on glacial and interglacial but rather it an influences. So dominate effect is geological which causes earth to be much colder than it would be lacking these elements, in which has precession of axis affecting it- has cooling and warming effect in which warming effect can be amplified [one could look at precession another verison of a geographical effect- or if Earth was completely covered with water then precession would not have an effect- or what the sun “sees” during the 26,000 cycle is a slightly different earth because of variation of topography].
Or said differently Earth’s climate is fundamentally related to earth’s ocean temperature- average temperature. Icehouse climate has cold ocean, ocean requires thousands of years to warm it’s average temperature by 1 C, though just the surface of ocean- top 100 meter, can warm on decade to century time periods, this top layer determine global weather or is what is measured in terms of Earth average temperature, and ocean temperatures can mix at various rates [location of land masses affects this, as do many other factors]. So precession would warm average ocean temperatures, but to have a significant amount warming within a thousand year period , it has to be mostly about warming top layer of ocean. And colder ocean more significant ocean mixing and warmer ocean the mixing is less significant.
And in terms of how warm we are, the interglacial before this one, had an average ocean temperature somewhere around 2 C warmer then our oceans, and it will require thousands of year to possible become as warm at that period was.
Carefully constructing and testing complex models to confirm they don’t work appears to pay exceptionally well.
“The fundamental laws of physics say that as the temperature goes up, it has to get warmer,” Liu says.
Perhaps the fella is gunning for Captain Obvious’ job over at Hotels.com
They still say that the mediaeval warm period was just in Europe. I get the sense they are searching for reasons why the data doesn’t fit, rather than deciding to throw away the AGW hypothesis.
bh2 says, “Carefully constructing and testing complex models to confirm they don’t work appears to pay exceptionally well.”
No. They are working per specification to support the desired economic, and tax policies to drive the de-industrialization desires of the environmental Left. The GCMs do their job to warn of significant warming if mankind doesn’t stop building ever richer, more natural resource intensive economies. That the scientists are at severe reputational risk [matters] little to the environmental Left. They are simply to be casualties of the environmentalist’s war on industrialized societies by whatever means they need.
“The fundamental laws of physics say that as the temperature goes up, it has to get warmer,” Liu says.
“When more and more people are thrown out of work, unemployment results.”Calvin Coolidge
If Aesop didn’t, someone should write a childrens’ book about a character and a conundrum, where the protagonist learns in the end the conundrum did not really exist – that he has been a child (or a delusional narcissist) and that why he thought it did.
Only small minds would have a problem with concurrent global warming and cooling.
“Data from observation says global cooling. The physical model says it has to be warming.”
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Well, Liu, since you know the science is settled, you had better trust the models rather than your lying eyes; otherwise, you will suffer the ultimate punishment of forfeiting your right to comment at the Guardian, Times, BBC, etc.
A peer reviewed paper on unsettled science! My, the times are changing.
That CO2 change, and therefore human activity, does not cause global warming has been demonstrated.
Terrestrial radiation absorbed by CO2 is immediately thermalized, i.e. the energy absorbed by CO2 is transferred (in a process similar to thermal conduction) to other atmospheric molecules which outnumber CO2 molecules 2500 to 1. CO2 can only absorb terrestrial EMR that has wave length 14-16 microns out of the significant range 5-50 microns of terrestrial radiation. The absorption/thermalization quickly reduces the 14-16 micron radiation flux.
But this leaves the question of what actually does drive average global temperature change.
After some research to find out what causes climate change. . .
Two primary drivers of average global temperature have been identified. A simple equation, using only them, very accurately explains the reported up and down measurements since before 1900. The coefficient of determination, R2 is greater than 0.9 (correlation coefficient = 0.95). The equation provides credible estimates back to the low temperatures of the Little Ice Age (1610). The current trend is down.
R2 = 0.9049 considering only sunspots and ocean cycles.
R2 = 0.9061 considering sunspots, ocean cycles and CO2 change.
The tiny difference in R2, whether considering CO2 or not, corroborates that CO2 change has no significant effect on climate. All measurements, including the recent since before 2001, are within the range of historical random variation.
The coefficients of determination are a measure of how accurately the calculated average global temperatures compare with measured. R^2 greater than 0.9 is very accurate.
The calculations use data since before 1900 which are official, accepted as valid and are publicly available.
Solar cycle duration or magnitude, considered separately, fail to correlate but their combination, expressed as the time-integral of sunspot number anomalies, gives excellent correlation. A sunspot number anomaly is the difference between the sunspot number for a year and an average sunspot number for many years.
Everything not explicitly considered (such as the 0.09 K s.d. random uncertainty in reported annual measured temperature anomalies, aerosols, CO2, other non-condensing ghg, volcanoes, ice change, etc.) must find room in the unexplained 9.51%.
The method, equation, data sources, history (hind cast to 1610) and predictions (through 2037) are provided at http://agwunveiled.blogspot.com and references.
Yet, the bio- and geo-thermometers used last year in a study in the journal Science suggest a period of global cooling beginning about 7,000 years ago and continuing until humans began to leave a mark, the so-called “hockey stick” on the current climate model graph, which reflects a profound global warming trend.
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dunno….looks perfectly normal to me
Lots of little hockey sticks…and the overall trend is still down……….and not a single one of them is because of CO2
http://www.foresight.org/nanodot/wp-content/uploads/2009/12/histo3.png
http://wattsupwiththat.com/2009/12/09/hockey-stick-observed-in-noaa-ice-core-data/
Damnit! How many times do I have to tell you? THIS IS SETTLED SCIENCE!!!!!!!
Andrew N says:
“Data from observation says the sun is at the centre of the solar system. The Bible says it circles the Earth”
—
And a Pulitzer prize and Nobel winning author, Ernest Hemingway, titled one of his books, “The Sun Also Rises.” Everyone knows the sun does not rise; the Earth turns. But we still talk about “sun sets” and “sun rises” as if we were ignorant of the science. Or perhaps it’s perfectly acceptable to speak from one’s perspective in conversation when not speaking in scientific terms. The Bible never claims to be a scientific dissertation but speaks in the language and perspective of the writers of the time.
“Both communities have to look back critically and see what is missing,” he says. “I think it is a puzzle.”
If they assign CO2 as a cause of cooling instead of warming then the puzzle is solved. I wonder if that thought ever occurred to them …
Over the last 10,000 years, Liu says, we know atmospheric carbon dioxide rose by 20 parts per million before the 20th century, and the massive ice sheet of the Last Glacial Maximum has been retreating. These physical changes suggest that, globally, the annual mean global temperature should have continued to warm, even as regions of the world experienced cooling, such as during the Little Ice Age in Europe between the 16th and 19th centuries.
Dare I point out that it can be warm enough to cause the ice sheets to shrink without actually getting warmer. How complicated is that?
If you don’t think it was a lot warmer 5000 or so years ago, you might try reading the article in the recent National Geographic about the recently discovered ruins of a rich maritime civilization based on the Orkney Islands north of Scotland (yes, those Orkney Islands, extremely cold and barely habitable today). Back then there seems to have been a prolific agricultural society lasting for about a thousand years or so and rich enough to support perhaps ten thousand or more people — a lot for megalithic Europe. No one had discovered these ruins before — even though they were right there underneath the surface — perhaps because it seemed “obvious” that no large megalithic civilization could exist so far north in such a rotten climate. Clearly it wasn’t such a rotten climate back then. When even the archaeologists are saying temperatures were much warmer during the holocene optimum, I think the debate is over!
Sounds to me like a few CAGW proponents are starting to get cold feet and formulating strategies on how to jump from the consensus train before it plummets into the canyon.
D. Cohen says:
August 11, 2014 at 7:14 pm
(Orkney Islands) “barely habitable today”
“Orkney has a cool temperate climate that is remarkably mild and steady for such a northerly latitude, due to the influence of the Gulf Stream. The average temperature for the year is 8 °C (46 °F); for winter 4 °C (39 °F) and for summer 12 °C (54 °F)”
“The soil of Orkney is generally very fertile and most of the land is taken up by farms, agriculture being by far the most important sector of the economy and providing employment for a quarter of the workforce. More than 90% of agricultural land is used for grazing for sheep and cattle, with cereal production utilising about 4% (4,200 hectares (10,000 acres)) and woodland occupying only 134 hectares (330 acres)”
YEAR POPULATION
1941 21,688
1951 21,275
1961 19,125
1971 16,976
1981 18,418
1991 19,570
2001 19,245
2011 21,349
Interestingly, this is exactly what one would expect if the warming effect from CO2 was saturated. The effect of increased CO2 at higher altitudes is one of cooling. So, if the low altitude warming effect were saturated then the overall effect would be cooling.
If the data says cooling, maybe the models are wrong?
Orbital and tilt and seasonal variations in solar energy? Once again the sun is under-estimated. They prefer 20ppm co2, which is 0.00002%.
thingadonta says:
August 11, 2014 at 7:45 pm
.
“20ppm ”
20 / 1,000,000 = 0.002%
philjourdan says:
August 11, 2014 at 5:13 pm
Ok, I am no Feynman. But do you need to be? When your models do not agree with the data, there is nothing wrong with the data! Your models suck!
The ignorance of climate scientists is mind boggling.
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Feynman – nice touch.
Actually, I’ve suspected for some time that most of the real CAGW scientists (excludes, among others, psychologists, historians, economists and railroad engineers) actually understand they’ve lost the battle with Mother Nature’s data. They’re simply hoping the funding lasts until retirement.
I could be wrong – they could actually be that stupid.
An excellent post by rgbatduke at August 11, 2014 at 4:21 pm.
“The last time temperatures were this low, atmospheric CO_2 was roughly 4000-5000 ppm — over ten times what it is today. Well over 95% of the last half-billion years has been spent with temperatures higher than they have been on average (including interglacials) in the Pleistocene ice age.”
That should tell you something: the planet is rather cold, and life in general would like it considerably warmer than it is today, and hey, it appears that even 4000 to 5000ppm of CO2 does little to maiintain/drive temperatures.
When the authors say “We have been building models and there are now robust contradictions,” they mean that the divergence between models and observational data is now so stark, it cannot be concealed any longer. The jig is up.
As the pause continues, this will become even more obvious and problematic. If the pause continues through to 2019 (and many warmist suggest that there will not be a resumption to warming for at least a decade), all the models will be outside the 95% confidence bounds. As I have often commented, if the pause continues through to 2019 (and assuming no significant volcanos), it is difficult to see how there can be an AR6. The IPCC will be forced to acknowledge that their model projections are way off target, and not reliable. More and more papers will be coming in with ever lower figures for climate sensitivity such that there will no longer be scary cAGW. Human nature is that it does not like admitting that it was wrong, and would sooner cut and run, and for that reason I do not expect to see an AR6.
Liu says “climate scientists plan to meet this fall to discuss the conundrum.” Of course they may discuss massaging the data, but whilst that might ‘help’ the hindcasting, the problem is that it will do nothing to address the looming problem with the forward projections should the pause continue. They are in a lose lose situation, because we do not understand enough about climate and its drivers, and even the little that we do know, is not well modelled. The models are fundamentally flawed as rgbatduke frequently points out and it is time that this is acknowledged. At this stage, I do not see the point of keeping any of the models; our knowledge is just too incomplete to make them worthwhile. .
It does appear that we are fast reaching a point where the inconvenient truth cannot be concealed any longer, and it is time to hit the reset, and get back to the basics. A good place to start is to properly acknowledge the paleo record, accept the Holocene Optimum, the Minoan, Roman and Viking Warm Periods, the LIA are real and to accept that none of those can be explained by CO2 alone and that something else drove the climate in those eras. Let us acknowledge the wide bands of natural variation and let us try and get a proper handle on natural variation and what drives it. Also a reexamination of whether CO2 is simply a response to warming (outgassing from a warmer ocean), as opposed to being the driver of temperature change.
When hitting the reset button, Personnaly, I would ditch the land based thermometer record. It is now too basterdised to be of much use. The main climate driver is the oceans, and that is where we should concentrate our efforts.
Edward Richardson says:
August 11, 2014 at 7:23 pm
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Edward sets out some details on the climate of the Orkney Isles. Average temperature is 8degC.
Personally, I consider that it is difficult to see how the Vikings managed to settle and farm their settlements in Greenland given the primative tools available (no mechanical diggers, no tractors to distribute food, rescue distressed animals, no running water etc) unless the climate at their settlements were on a par with the Orkney Islands. A couple of years ago, the UK had a harsh winter and this took an extreme toll on hillside farming in Scotland and Wales, and many small hillside farms were wiped out. The conditions in Greenland, at the time of the Viking settlements, must have been quite benign since just one or two harsh winters would have killed off the community.
Greenland’s climate data can be found at http://www.greenland.climatemps.com/
Personally, I consider that we under-estimate how much warmer Northern Europe/North Western Europe must have been during the Viking Warm Period. I consider that for the Viking sttlements to have flourished (given their primative farming technology) the temperatures around South Western Greenland must have been about 4 to 8 deg warmer than today. To what extent that was local, say being influenced by a very warm gulf stream, I do not know, but I do consider it probable that South Western Greenland was very much warmer than it is today