Global Warming...New Report...and it ain't happy news

For years, perhaps decades, Gray has been ascribing all sorts of climate changes and hurricane cycles to fluctuations in the Thermohaline Circulation (THC), an overturning circulation in the Atlantic ocean associated with formation of deep water in the North Atlantic. None of the assertions are based on rigorous statistical associations, oceanographic observations or physically based simulations; it is all seat-of -the-pants stuff of a sort that was common in the early days of climate studies, but which is difficult to evaluate when viewed as a scientific hypothesis. The THC is undoubtedly important to climate, because it transports heat from one place to another. However it cannot do magical things. It cannot created energy out of thin air (or thick water), nor can it make energy mysteriously disappear. Thus, Gray's statement that "The average THC circulation cools the ocean by about 3 W/m2" is a scientific absurdity. In the paper Gray makes many extravagant claims about how supposed changes in the THC accounted for various 20th century climate changes ("I judge our present global ocean circulation conditions to be similar to that of the period of the early 1940s when the globe had shown great warming since 1910, and there was concern as to whether this 1910-1940 global warming would continue. But beginning about 15 years following the onset of a strong THC circulation in 1926, in the early 1940s, the warming began to abate. A weak global cooling began from the mid-1940s to the mid-1970s.") but the reader would never guess that he in fact has no direct oceanographic evidence that the THC was doing anything of the sort. These are all subjective estimates based on Gray's conception of the relation of Atlantic temperatures to the THC state. In fact, it is exceedingly difficult to directly monitor the THC, and reliable results have only recently been obtained.

We have reported recently on the "Decrease in Atlantic Circulation". For years prior to the publication of evidence that the THC was slowing down, Gray was testifying in Congress and writing widely that hurricane increases were due to Atlantic warming arising from a speed-up of the THC (see our article for some typical quotes). Confronted with evidence that the THC was in fact behaving in the opposite way to what he had been assuming, Gray did a flip-flop and came up with a new story that yields the same conclusions. There's no shame in a scientist changing his or her mind, or in seeking new theories in the face of new observations. However, if Gray's old theory was really testable, where were the tests to show that it was wrong in the years he was touting it? How is one to put any confidence in the new theory? The fact is that neither of Gray's story lines about the THC is sufficiently well formulated to allow any clear-cut test. Nonetheless, insofar as it can be understood at all, some aspects of Gray's new story line about the THC are demonstrably wrong.

The heart of the problem with Gray's new version of the THC story is that he labors under the misconception that the THC primarily upwells in the tropics, so that any reduction in the THC cools the North Atlantic but warms the tropics. This conception is at least 50 years out of date. The tropical upwelling is a shallow wind-driven cell that does not connect to the THC. It is almost impossible for cold deep water to upwell in the tropics, because it takes too much energy to bring it up; the main THC connection is with the Southern Ocean, as described by Marotzke and references therein (for more general background, see also en.wikipedia.org/wiki/Thermohaline_circulation). There are only a few very limited regions where moderately deep water can upwell in the Tropics. Simulations by Vellinga and Wood (Climatic Change, 2002) in fact show that a THC shutdown causes a cooling right into the Northern Subtropical Atlantic (the birthplace of hurricanes), and in fact only very weak warming in a few spots elsewhere in the tropics. On a longer time scale, the classic study of Manabe and Stouffer (Paleoceanography 1997) shows virtually no impact of THC shutdown in the tropics, but a considerable remote impact in the Southern Ocean. No doubt, Gray would object that these are only models, but why should we believe that Gray's drawing of circles and arrows on a map yields a better prediction than a simulation embodying the best of what we know about the underlying physics?

Note that Gray does not merely claim that THC changes are responsible for the observed hurricane cycles. He in fact claims that the entire 20th century warming signal is due to a slowdown of the THC, and that CO2 has nothing to do with it. He claims flatly and without supporting evidence that models cannot simulate the THC properly, neglecting the fact that the models employed in the IPCC reports yield a rather wide variety of different possible THC behaviors, and none of them, including ones known to have a sensitive THC, spontaneously generate a warming of the sort Gray claims. Insofar as we can follow Gray's reasoning, he appears to think of the THC as burying heat in the deep ocean, as if the heat were some kind of solid nuclear waste. Thus, weak THC = less heat removal = warming, in Gray's world view. In reality, everything known about the physics of the THC's effect on climate suggests the opposite. For example, Vellinga and Wood find that, owing to certain nonlinearities like sea ice formation, a shutdown of the THC leads to a reduction in the Northern Hemisphere mean temperature, and very little multidecadal scale effect on the Southern Hemisphere mean temperature.

The other reasons Gray thinks that the THC could cause global warming are tied up with a number of additional misconceptions he has about the physics of climate.

Gray's grand answer to the riddle of global warming is evaporation, presumably modulated by changes in the THC. Again, Gray simply doesn't seem to understand energy conservation. Evaporation does not create heat; it does not add any heat to the climate system or take it away. It is an energy transfer that moves heat from a moist surface (like the ocean's) into the atmosphere. That severely constrains what evaporation changes can do to climate. In contrast, changes in CO2 concentration affect the top of atmosphere radiation budget directly, and change the rate at which the whole climate system loses energy.

Let's start with an atmosphere that is in equilibrium, both at the surface and top-of-atmosphere. Now reduce the evaporation (you could do it by reducing the surface wind). The surface is now receiving more energy than it loses, so it will begin to warm. However, the atmosphere is no longer receiving all the energy it used to obtain from the surface as evaporative heat transfer; hence the atmosphere will begin to cool. This adjustment will continue until balance is restored. The precise way the adjustment is divvied up between atmospheric cooling and surface warming depends on details like the net atmospheric infrared opacity, boundary layer relative humidity,and so forth. However that all shakes out, the net result is nothing at all like the observed pattern of warming, in which both troposphere and surface warm up. This reasoning can be confirmed in the simplest radiative-convective model, of the sort introduced by Manabe and Strickler in the 1960's.

A more serious problem is that Gray doesn't even understand that the greenhouse effect works primarily through the effect of greenhouse gases on the top of atmosphere radiation budget, and only very indirectly through the surface budget (as explained in A busy week for water vapor). This compromises almost all of his analysis. For example, many of the supposed changes in surface budget he describes could in fact be due indirectly to changes in greenhouse gases, via their affect on low level atmospheric temperature. By balancing a 4 W/m2 (top of atmosphere) CO2 radiative forcing against changes in evaporation, Gray concludes that the warming from doubling CO2 would be a mere two tenths of a degree C.. He ascribes the weak warming to the lack of water vapor feedback in his calculation, but in fact it is simply due to an incorrect calculation of the energy balance. Standard radiative physics based on a correct treatment of the top-of-atmosphere balance-- physics going back at least to Arrhenius-- yields a surface warming of about 1C in response to a doubling of CO2, when water vapor feedback is neglected. Gray has committed the major blunder of applying that 4 W/m2 top of atmosphere forcing at the surface. In reality, when that radiative forcing is properly applied at the top of the atmosphere, it leads to a warming of the entire atmospheric column which, at the surface, yields a far larger perturbation in the surface energy budget, as we have explained in the above-referenced article.

By the way, Gray discounts water vapor feedback, based on what seems to be a gut feeling on weather systems, plus some unspecified analysis of the NCEP reanalysis dataset (which is completely unsuitable for studying trends in mid tropospheric water vapor); more reliable satellite based studies (e.g. Soden's study described in A busy week for water vapor ) support a positive water vapor feedback, and even Lindzen seems to be no longer arguing against this feedback.

Gray also made a mess of an attempt to analyze the mid-twentieth century ocean heat storage. "... the globe underwent a weak cooling between 1950 and 1975 during which CO2 amounts were rising and causing a continuous mean energy gain over this 25 year period of about 0.4 W/m2. If all of this energy went into an accumulation of temperature in the upper 100 m of the global oceans, we would see an upper mean 100 m global ocean temperature increase of 1.1oC. " We are not sure where Gray gets the 0.4 W/m2 radiative forcing figure; the total radiative forcing increase from pre-industrial times to 1975 would be more like .95 W/m2 and it is not a trivial matter to figure out how much to subtract from that to account for the part compensated by ocean warming before 1950; the CO2 radiative forcing increase between 1950 to 1975, on the other hand, would be only .45 W/m2 and the mean new forcing over the period would be about half that. Be that as it may, Gray has not even done the arithmetic right, since .4 W/m2 going into a 100m mixed layer having specific heat of 4200 J/kg and density of about 1000 kg/m3 would only yield a warming of .75C . That's far from the worst flaw in his calculation, since his two biggest blunders are the neglect of the radiative cooling due to sulfate aerosols (known to be a critical factor in the period in question) and his neglect of the many links in the chain of physical effects needed to translate a top of atmosphere radiative imbalance to a change in net surface energy flux imbalance. In fact, the calculation has been done very carefully by Hansen and co-workers, taking all factors into consideration, and when compared with observations of ocean heat storage over a period long enough for the observed changes to be reliably assessed, models and observations agree extremely well.

Okie- Here is what Mr. Kuvasz cannot rebut since most of it comes from a source he uses- THE IPCC.

Thank you, but I feel that I am the better judge of what I can and cannot do. Yet your hysterically funny, and repeatedly undeserved sense of self leads to your uncanny ability to put your foot in your mouth so often you ought to use Desenex as a tooth powder.

On the other thread I did not do as Mr. Kuvasz has done( namely, throw some indicipherable crap against the wall hoping that it will scare people off, rather, I quoted from the IPCC and Peer reviewed scientific articles and I INVITED anyone to give evidence that either radically changed or completely rebutted the scientific findings.

I am not sorry you are too scared to learn, nor at all disappointed in your inability to undestand the data. In fact, sadly it was expected. Such sudden inabilities to read often afflict Right Wingers when they are abruptly confronted with facts that undermine their dearly held positions. It is called cognitive dissonance and was why I provided references, like a good scientist does; and you did not. Apparently, it is easier for you to call the plain data indecipherable crap than it is for you to digest it, modify your position, reconstruct your argument and refute Bill Gray's debunking as an expert witness on climate change. A pity.

And I look on in fascination at why you would use as a defense for your position on climate change a document (the IPCC report) that has been attacked by the Right Wing and the ignoble and scientifically illiterate Senator from Oklahoma, Inhofe, and one which indicates climate change is real and happening due to anthropogenic reasons. Those positions were also apparently antithetical to your initial positions and you originally attempted to debunk them with the likes of Belunis and Soon, both soon to be forgotten by you as they too were debunked as charletans. Anyway, I welcome your use of a document that undermines your original position. Too bad you garbed the work of the IPCC to a useless mush.

Very clever of you, or not.

l.The IPCC indicated that water vapor feedback was the MAIN REASON why emissions of CO2 would cause a significant warming.

good, you're reading. now read more..... here

http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/


2. Scientific peer reviewed articles in sources such as "Journal of Climate" indicated that a strong water vapor feedback is NOT primarily dependent on the Surface Temperature but ESPECIALLY on the temperature in the troposphere.

See link above

3, Despite the fact that the AOCGM models( which, apparently are fed dozens of ASSUMPTIONS) PREDICT that temperatures in the troposphere increase as fast or faster than surface temperatures, the ACTUAL MEASUREMENTS MADE BY NOAA SATELLITES SHOWS THAT THIS IS NOT THE CASE.

Opps, not so. Check link. And there goes the basis for the entire argument. Too bad.

http://www.llnl.gov/PAO/news/news_releases/2005/NR-05-08-05p.html

August 11, 2005
[quote] For the first time, new climate observations and computer models provide a consistent picture of recent warming of Earth's tropical atmosphere.

Over the past decade, scientific evidence from a variety of sources has implicated human-caused increases in greenhouse gases as a major driver of recent climate change. A key argument used to rebut such findings relates to satellite records of temperature change in the troposphere - the lowest layer of Earth's atmosphere.

Until recently, climate modelers compared their simulations with temperatures from a single satellite dataset, which showed slight cooling of the tropical troposphere since 1979. This region of the atmosphere is predicted to warm in climate model simulations that include observed increases in greenhouse gases. The discrepancy in tropical temperature trends has been used to cast doubt on the reliability of computer models, and on their usefulness for predicting future climate changes.[/i]

Three papers published in today's edition of Science Express shed light on this debate. The first two studies revisit temperature data obtained from satellites and weather balloons, and provide compelling evidence that the tropical troposphere has warmed since 1979. The third study, led by scientists at Lawrence Livermore National Laboratory, finds that these new observational estimates of temperature change are consistent with results from state-of-the-art climate models.

The computer models analyzed in the Livermore study show that in the deep tropics, temperature changes in the troposphere are larger than at the surface. This "amplification" effect is caused by the release of heat when moist tropical air rises and condenses into clouds. The size of the amplification effect is very similar in nearly 50 simulations performed with 19 different models.

The new satellite and weather balloon data described in the first two Science Express papers have amplification behavior that is in agreement with the model results and with basic physical theory.

"This strongly suggests that there is no longer any fundamental discrepancy between modeled and observed temperature trends in the tropical atmosphere," said Benjamin Santer, lead author of the Livermore-led Science Express paper and a scientist in LLNL's Program for Climate Model Diagnosis and Intercomparison. "The new observational data helps to remove a major stumbling block in our understanding of the nature and causes of climate change. Our work illustrates that progress toward an improved understanding of the climate system requires a combination of observations, theory and models."

Okie- Here is what Mr. Kuvasz cannot rebut since most of it comes from a source he uses- THE IPCC.

Thank you, but I feel that I am the better judge of what I can and cannot do. Yet your hysterically funny, and repeatedly undeserved sense of self leads to your uncanny ability to put your foot in your mouth so often you ought to use Desenex as a tooth powder.

On the other thread I did not do as Mr. Kuvasz has done( namely, throw some indicipherable crap against the wall hoping that it will scare people off, rather, I quoted from the IPCC and Peer reviewed scientific articles and I INVITED anyone to give evidence that either radically changed or completely rebutted the scientific findings.

I am not sorry you are too scared to learn, nor at all disappointed in your inability to undestand the data. In fact, sadly it was expected. Such sudden inabilities to read often afflict Right Wingers when they are abruptly confronted with facts that undermine their dearly held positions. It is called cognitive dissonance and was why I provided references, like a good scientist does; and you did not. Apparently, it is easier for you to call the plain data indecipherable crap than it is for you to digest it, modify your position, reconstruct your argument and refute Bill Gray's debunking as an expert witness on climate change. A pity.

And I look on in fascination at why you would use as a defense for your position on climate change a document (the IPCC report) that has been attacked by the Right Wing and the ignoble and scientifically illiterate Senator from Oklahoma, Inhofe, and one which indicates climate change is real and happening due to anthropogenic reasons. Those positions were also apparently antithetical to your initial positions and you originally attempted to debunk them with the likes of Belunis and Soon, both soon to be forgotten by you as they too were debunked as charletans. Anyway, I welcome your use of a document that undermines your original position. Too bad you garbed the work of the IPCC to a useless mush.

Very clever of you, or not.

l.The IPCC indicated that water vapor feedback was the MAIN REASON why emissions of CO2 would cause a significant warming.

good, you're reading. now read more..... here

http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/


2. Scientific peer reviewed articles in sources such as "Journal of Climate" indicated that a strong water vapor feedback is NOT primarily dependent on the Surface Temperature but ESPECIALLY on the temperature in the troposphere.

See link above

3, Despite the fact that the AOCGM models( which, apparently are fed dozens of ASSUMPTIONS) PREDICT that temperatures in the troposphere increase as fast or faster than surface temperatures, the ACTUAL MEASUREMENTS MADE BY NOAA SATELLITES SHOWS THAT THIS IS NOT THE CASE.

Opps, not so. Check link. And there goes the basis for the entire argument. Too bad.

http://www.llnl.gov/PAO/news/news_releases/2005/NR-05-08-05p.html

August 11, 2005
[quote] For the first time, new climate observations and computer models provide a consistent picture of recent warming of Earth's tropical atmosphere.

Over the past decade, scientific evidence from a variety of sources has implicated human-caused increases in greenhouse gases as a major driver of recent climate change. A key argument used to rebut such findings relates to satellite records of temperature change in the troposphere - the lowest layer of Earth's atmosphere.

Until recently, climate modelers compared their simulations with temperatures from a single satellite dataset, which showed slight cooling of the tropical troposphere since 1979. This region of the atmosphere is predicted to warm in climate model simulations that include observed increases in greenhouse gases. The discrepancy in tropical temperature trends has been used to cast doubt on the reliability of computer models, and on their usefulness for predicting future climate changes.[/i]

Three papers published in today's edition of Science Express shed light on this debate. The first two studies revisit temperature data obtained from satellites and weather balloons, and provide compelling evidence that the tropical troposphere has warmed since 1979. The third study, led by scientists at Lawrence Livermore National Laboratory, finds that these new observational estimates of temperature change are consistent with results from state-of-the-art climate models.

The computer models analyzed in the Livermore study show that in the deep tropics, temperature changes in the troposphere are larger than at the surface. This "amplification" effect is caused by the release of heat when moist tropical air rises and condenses into clouds. The size of the amplification effect is very similar in nearly 50 simulations performed with 19 different models.

The new satellite and weather balloon data described in the first two Science Express papers have amplification behavior that is in agreement with the model results and with basic physical theory.

"This strongly suggests that there is no longer any fundamental discrepancy between modeled and observed temperature trends in the tropical atmosphere," said Benjamin Santer, lead author of the Livermore-led Science Express paper and a scientist in LLNL's Program for Climate Model Diagnosis and Intercomparison. "The new observational data helps to remove a major stumbling block in our understanding of the nature and causes of climate change. Our work illustrates that progress toward an improved understanding of the climate system requires a combination of observations, theory and models."

Aroused from my comfortable sleep by the ignorant mouthings of peckerheads once more.

If the temps were cycling down right now, the sky is falling crowd would be just as animated over the coming ice age. In fact, they were just 35 years or so ago.

okie wrote:

If the temps were cycling down right now, the sky is falling crowd would be just as animated over the coming ice age. In fact, they were just 35 years or so ago.

Repeating the myth about the scientific consensus was about an ice age 35 years ago still doesn't make that myth true. There was no scientific consensus about an ice age. There were a couple of papers that were well publicized. The majority of science discounted it.

Do you understand how trends work okie? You can't pick 2 dates only to figure a trend.

You certainly can't pick the anomalies you want to and decide that disproves the trend. It shows you really don't care about science when you do that.

Parados, it appears lost on okie that the gif he linked to support his Luddite view was the errorneously reported and uncorrected data on atmospheric temperatures that was later recalibrated in the several studies I linked to that removed background noise and showed the validity of the data with theory.

That is so incredibly and astonishingly clueless as to be funny.

In essence, it is akin to looking at an old map of the Hudson Bay from the time of Sebastian Cabot and insisting that there is a Northwest Passage, and remarkably as global warming persists, he may well get his wish.

kuvasz wrote:

Parados, it appears lost on okie that the gif he linked to support his Luddite view was the errorneously reported and uncorrected data on atmospheric temperatures that was later recalibrated in the several studies I linked to that removed background noise and showed the validity of the data with theory.

That is so incredibly and astonishingly clueless as to be funny.

In essence, it is akin to looking at an old map of the Hudson Bay from the time of Sebastian Cabot and insisting that there is a Northwest Passage, and remarkably as global warming persists, he may well get his wish.

I believe it was from one of your links you posted, kuvasz. If you don't like it, then quit posting it. You post the stuff, I cite something from it, then I'm told its worthless. Go figure.