Resisting climate hysteria
by Richard S. Lindzen on Quadrant Online
July 26, 2009
A Case Against Precipitous Climate Action
The notion of a static, unchanging climate is foreign to the history of the earth or any other planet with a fluid envelope. The fact that the developed world went into hysterics over changes in global mean temperature anomaly of a few tenths of a degree will astound future generations. Such hysteria simply represents the scientific illiteracy of much of the public, the susceptibility of the public to the substitution of repetition for truth, and the exploitation of these weaknesses by politicians, environmental promoters, and, after 20 years of media drum beating, many others as well. Climate is always changing. We have had ice ages and warmer periods when alligators were found in Spitzbergen. Ice ages have occurred in a hundred thousand year cycle for the last 700 thousand years, and there have been previous periods that appear to have been warmer than the present despite CO2 levels being lower than they are now. More recently, we have had the medieval warm period and the little ice age. During the latter, alpine glaciers advanced to the chagrin of overrun villages. Since the beginning of the 19th Century these glaciers have been retreating. Frankly, we don’t fully understand either the advance or the retreat.
excerpts:
For small changes in climate associated with tenths of a degree, there is no need for any external cause. The earth is never exactly in equilibrium. The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries. Recent work (Tsonis et al, 2007), suggests that this variability is enough to account for all climate change since the 19th Century. Supporting the notion that man has not been the cause of this unexceptional change in temperature is the fact that there is a distinct signature to greenhouse warming: surface warming should be accompanied by warming in the tropics around an altitude of about 9km that is about 2.5 times greater than at the surface. Measurements show that warming at these levels is only about 3/4 of what is seen at the surface, implying that only about a third of the surface warming is associated with the greenhouse effect, and, quite possibly, not all of even this really small warming is due to man (Lindzen, 2007, Douglass et al, 2007). This further implies that all models predicting significant warming are greatly overestimating warming. This should not be surprising (though inevitably in climate science, when data conflicts with models, a small coterie of scientists can be counted upon to modify the data. Thus, Santer, et al (2008), argue that stretching uncertainties in observations and models might marginally eliminate the inconsistency. That the data should always need correcting to agree with models is totally implausible and indicative of a certain corruption within the climate science community).
…
Climate alarmists respond that some of the hottest years on record have occurred during the past decade. Given that we are in a relatively warm period, this is not surprising, but it says nothing about trends.
Given that the evidence (and I have noted only a few of many pieces of evidence) strongly implies that anthropogenic warming has been greatly exaggerated, the basis for alarm due to such warming is similarly diminished. However, a really important point is that the case for alarm would still be weak even if anthropogenic global warming were significant. Polar bears, arctic summer sea ice, regional droughts and floods, coral bleaching, hurricanes, alpine glaciers, malaria, etc. etc. all depend not on some global average of surface temperature anomaly, but on a huge number of regional variables including temperature, humidity, cloud cover, precipitation, and direction and magnitude of wind. The state of the ocean is also often crucial. Our ability to forecast any of these over periods beyond a few days is minimal (a leading modeler refers to it as essentially guesswork). Yet, each catastrophic forecast depends on each of these being in a specific range. The odds of any specific catastrophe actually occurring are almost zero. This was equally true for earlier forecasts of famine for the 1980’s, global cooling in the 1970’s, Y2K and many others. Regionally, year to year fluctuations in temperature are over four times larger than fluctuations in the global mean.
…
In view of the above, one may reasonably ask why there is the current alarm, and, in particular, why the astounding upsurge in alarmism of the past 4 years. When an issue like global warming is around for over twenty years, numerous agendas are developed to exploit the issue. The interests of the environmental movement in acquiring more power, influence, and donations are reasonably clear. So too are the interests of bureaucrats for whom control of CO2 is a dream-come-true. After all, CO2 is a product of breathing itself. Politicians can see the possibility of taxation that will be cheerfully accepted because it is necessary for ‘saving’ the earth. Nations have seen how to exploit this issue in order to gain competitive advantages. But, by now, things have gone much further. The case of ENRON (a now bankrupt Texas energy firm) is illustrative in this respect.
…
And finally, there are the numerous well meaning individuals who have allowed propagandists to convince them that in accepting the alarmist view of anthropogenic climate change, they are displaying intelligence and virtue For them, their psychic welfare is at stake.
With all this at stake, one can readily suspect that there might be a sense of urgency provoked by the possibility that warming may have ceased and that the case for such warming as was seen being due in significant measure to man, disintegrating. For those committed to the more venal agendas, the need to act soon, before the public appreciates the situation, is real indeed. However, for more serious leaders, the need to courageously resist hysteria is clear. Wasting resources on symbolically fighting ever present climate change is no substitute for prudence. Nor is the assumption that the earth’s climate reached a point of perfection in the middle of the twentieth century a sign of intelligence.
Read the complete essay with references at Quadrant Online
Richard S. Lindzen is the Alfred P. Sloan Professor of Atmospheric Sciences at Massachusetts Institute of Technology
h/t to Bob Carter
Steve Fitzpatrick (07:22:42) :
said,
“Joel Shore:
One final point before I must do some real work: If you discount the very uncertain (according to the IPCC) aerosol effects that are used in GCM’s to substantially reduce net forcing, then the mid-1800’s to present temperature history is predicted almost perfectly by the historical record of greenhouse gas concentrations, converted to expected (IPCC again) radiative forcing, multiplied by Swartz’s “discredited” constant of ~0.3 C/watt/M^2.
Does this not give you even a bit of doubt about the GCM’s? If not, then I really do not understand how you evaluate data.”
It is clear that part of the effect of anti pollution efforts in the 1970’s is the reduction of aerosals. This is evident in the ice cores taken in the Peruvian Andes .
http://www.pbs.org/wgbh/nova/sciencenow/0405/04.html
It is clear from such measurements that significant reductions in sulfate aerosals need to be taken into account in understanding climate change.
It is also clear that the industrialization of China and India may have increased the sulfate pollution in the last decade and could be responsible for moderation of the rate of temperature increase. None of this is as ridiculous and suspicious as you seem to believe.
Eric:
Albert Enistein had no advanced training in physics, and before changing everyone’s understanding of the world, made a living reviewing patent applications. I guess that made him an amateur. Francis Crick was trained in physics, but helped revolutionize biology.
I have worked with, worked for, and had work for me both brilliant (really insightful) BS level engineers and incredibly incompetent PHDs, including one PHD who is pretty well known. My personal experience is that credentials and position are at best weakly correlated with technical competence. When I was young, I would never have believed this.
Graeme Rodaughan: I think your question about falsification criteria is an overly simplified, binary way of looking at things. I know of no complex modern theory in science whereby one can come up with a single falsification criterion. Moreover, what you speak of are not really independent theories but part of the larger rubric of our current understanding of climate.
The normal way that science proceeds in the real world is that when there is observation data that seems to conflict with a theory that already has a significant body of evidence supporting it, then people try to reconcile them by looking at both the data and theory. If they can’t be reconciled and enough such problems exist, then people start to abandon the theory for other theories that provide a better explanation.
There are many tests that AGW has already passed on the way to becoming part of the accepted current theoretical understanding of climate. For example, when it was first proposed by Arrhenius, many scientists doubted that CO2 would actually accumulate in the atmosphere from our emissions (because they thought the oceans would just absorb it) and it wasn’t until the 1950s when both Keeling’s data and Revelle’s theoretical analysis showed that the CO2 was and is expected to accumulate. A more recent example is the water vapor feedback … i.e., some questioned whether the water vapor, especially in the upper troposphere would increase with warming as the models predicted. Again, the evidence from satellite data has now shown that it indeed does. Another example is the satellite and radiosonde data showing that the stratosphere is cooling while the troposphere warms this data (unlike the data regarding tropical tropospheric amplification on multidecadal timescales) is unambiguous enough that the signal seen is much greater than the measurement uncertainties.
Future things to watch:
(1) The debate over cloud feedbacks…If it becomes clear from multiple studies (that scientists in the field have had time to consider and respond to) that the cloud feedback is negative, then this would cause a major modification to the current theoretical understanding.
(2) If there is a negative temperature trend maintained for enough years that it is clearly statistically significant then that would require a major rethinking of the current theoretical understanding.
(3) Paleoclimate: If there was new evidence from paleoclimate data that significant altered our estimates of climate sensitivity based on past climatic events, then that would require modification of our theoretical understanding.
I am sure that one can think of several more. Despite protestations of some skeptical, mainstream scientists are all the time devising various tests of our current understanding of the climate system.
Steve Fitzpatrick:
I think that you were responding to eric here, not me. But, I would just add that I don’t think it is really correct to say that the exercise depends on the accuracy of the climate models. What the climate models are being used for is just a testbed whereby one can see how well an analytical technique is able to diagnose the climate sensitivity. The advantage of looking at this in the models is one knows what the “right answer” is, again within the model. I suppose it is conceivable that a technique that does not diagnose the sensitivity well in the models could do a better job in the real world, but that seems rather unlikely…If anything, it seems to usually work the other way around (i.e., that the real world is more complicated than one’s models, so a technique that works for the models does not work as well in the real world).
Eric:
Yes, published estimates of aerosols (including satellite based) suggest a significant worldwide decline from the 1980’s to present, including the post 2000 period of relatively flat temperatures and post 2003 period of flat ocean heat content. I know of no credible data (real data, not model projections) which suggests China’s increased use of coal (which began ramping up in the early 1990’s) has reversed this worldwide trend in apparent brightening. The estimates of continuing brightening until the present, if anything, increase the apparent discrepancy between modeled temperature increases and recent surface temperature and ocean heat content data.
Have you noticed that RSS’s TLS trend (/www.remss.com/msu/msu_data_description.html) graphic is very similar to the satellite based estimated trend in aerosols (en.wikipedia.org/wiki/File:Aerosol_dimming.jpg)? Could a significant portion of the of the falling TLS trend actually be due to globally falling sulfate aerosols? If so, could the negative slope in the TLS tend (a commonly sighted proof high climate sensitivity from greenhouse gases) in fact be partially due to falling sulfate aerosols rather than 100% from greenhouse driven warming in the lower troposphere?
My point is that none of the claims of high climate sensitivity are so clear, neat, and certain as you suggest. GCM Modelers ought lower the hubris level and increase the level of caution.
eric:
And some of us think that the assumption that rising CO2 can only be from human emissions is “saying stupid stuff”.
Yes, we’re emitting CO2, and the planet is perfectly able to absorb many times what we are emitting. And if I pee in the ocean, is that the cause of it rising? Wouldn’t it be childishly naive to assume so?
Joel Shore (12:07:56) : ”
(1) The debate over cloud feedbacks…If it becomes clear from multiple studies (that scientists in the field have had time to consider and respond to) that the cloud feedback is negative, then this would cause a major modification to the current theoretical understanding.
(2) If there is a negative temperature trend maintained for enough years that it is clearly statistically significant then that would require a major rethinking of the current theoretical understanding.
(3) Paleoclimate: If there was new evidence from paleoclimate data that significant altered our estimates of climate sensitivity based on past climatic events, then that would require modification of our theoretical understanding.
”
I just want to applaud the effort to shoot down AGW. It is the mark of a good scientist to be his own severist critic. The pro-AGW scientists should be the first to think of ways they could be wrong and list those possibilities in public.
Steve Fitzpatrick (09:59:33) :
“Eric:
Albert Enistein had no advanced training in physics, and before changing everyone’s understanding of the world, made a living reviewing patent applications. I guess that made him an amateur. Francis Crick was trained in physics, but helped revolutionize biology.”
The idea that Einstein was an amateur whose primary job in the patent office is a canard, that I have heard from other climate sceptics, when I mention the fact the few professional research climatologists dissent form support of AGW.
Einstein’s job at the patent office paid the bills while he was studying for his doctorate. He was seeking a job teaching physics to pay the bills but anti-Semitism prevented him from getting such employment. He would normally take his physics to work, and work on it whenever his supervisor wasn’t looking.
Crick was also no amateur biologist.
http://en.wikipedia.org/wiki/Francis_Crick
After World War II, in 1947, Crick began studying biology and became part of an important migration of physical scientists into biology research. This migration was made possible by the newly won influence of physicists such as Sir John Randall, who had helped win the war with inventions such as radar. Crick had to adjust from the “elegance and deep simplicity” of physics to the “elaborate chemical mechanisms that natural selection had evolved over billions of years.” He described this transition as, “almost as if one had to be born again.” According to Crick, the experience of learning physics had taught him something important—hubris—and the conviction that since physics was already a success, great advances should also be possible in other sciences such as biology. Crick felt that this attitude encouraged him to be more daring than typical biologists who tended to concern themselves with the daunting problems of biology and not the past successes of physics.
For the better part of two years, Crick worked on the physical properties of cytoplasm at Cambridge’s Strangeways Laboratory, headed by Honor Bridget Fell, with a Medical Research Council studentship, until he joined Max Perutz and John Kendrew at the Cavendish Laboratory. The Cavendish Laboratory at Cambridge was under the general direction of Sir Lawrence Bragg, who won the Nobel Prize in 1915 at the age of 25. Bragg was influential in the effort to beat a leading American chemist, Linus Pauling, to the discovery of DNA’s structure (after having been ‘pipped-at-the-post’ by Pauling’s success in determining the alpha helix structure of proteins). At the same time Bragg’s Cavendish Laboratory was also effectively competing with King’s College London, whose Biophysics department was under the direction of Sir John Randall. (Randall had turned down Francis Crick from working at King’s College.) Francis Crick and Maurice Wilkins of King’s College were personal friends, which influenced subsequent scientific events as much as the close friendship between Crick and James Watson. Crick and Wilkins first met at King’s College and not, as erroneously recorded by two authors, at the Admiralty during World War II.
“I have worked with, worked for, and had work for me both brilliant (really insightful) BS level engineers and incredibly incompetent PHDs, including one PHD who is pretty well known. My personal experience is that credentials and position are at best weakly correlated with technical competence. When I was young, I would never have believed this.”
I don’t care what degrees people have. If they are doing work in the discipline at a professional level, and publishing in respected peer reviewed journals, they have more credibility than an amateur.
rephelan (19:44:22) : “Ahhh, the eternal, burning question of the 20th century, carried over into the 21st: Pepe’s or Sallie’s? Sallie’s or Pepe’s? Why choose? Both are distinctive, tasty and better than anything made anywhere else. After all, American Pizza was invented in New Haven.”
Pepe’s, always was, always will be.
http://thepauperedchef.com/2007/09/new-haven-pizza.html
Steve Fitzpatrick,
You asked for evidence that the ocean heat data since 2003 is still under active consideration. Check out the final page of this article published Nov 2008.
http://earthobservatory.nasa.gov/Features/OceanCooling/page1.php
“In this analysis, we focused on 1961-2003 because it is the time period highlighted as being an important, unresolved issue in the last IPCC report [Intergovernmental Panel on Climate Change Fourth Assessment Report],” said Domingues, “but also because the problems with the newest Argo data—the problems that Josh Willis found as well as other problems we have identified—haven’t been totally solved. For the most recent years [2003-2007], the sea level budget once again does not close. Our team is still working on that problem.”
Steve,
I do not have the background material and data behind this report, but apparently there are some scientists who claim Asian Brown Clouds are masking the Greenhouse effect. See bullet 5 on page 18 of this report.
http://www.unep.org/pdf/ABCSummaryFinal.pdf
The report says 20 to 80% of GHG induced warming is canceled by ABC’s.
Eric,
With regard to the accuracy of Argo and closure of the sea level budget: http://etienne.berthier.free.fr/download/Cazenave_et_al_GPC_2009.pdf show clearly that the sea level budget for 2003 to 2008 does close, and there is little reason to doubt the Argo based calculation of total ocean heat changes. In their conclusions they wrote:
“From the results presented in this study, we see that confronting
independent estimates of ocean and land contributions to sea level
with altimetry results leads to a rather coherent picture for recent
years variations. This can be summarized as follows: since 2003, sea
level has continued to rise but with a rate (of 2.5 +/−0.4 mm/yr)
somewhat reduced compared to the 1993–2003 decade (3.1+/
−0.4 mm/yr). Over 2003–2008, the GRACE-based ocean mass has
increased at an average rate of ∼1.9 mm/yr (if we take the upper range
of possible GIA corrections as recommended by Peltier, submitted for
publication). Such a rate agrees well with the sum of land ice plus land
water contributions (i.e., GRACE-based ice sheet mass balance
estimated in this study, GRACE-based land waters plus recently
published estimates for the current glacier contribution). These results
in turn offer constraints on the ocean mass GIA correction, as well as
on the glacier melting contribution.
The steric sea level estimated from the difference between
altimetric (total) sea level and ocean mass displays increase over
2003–2006 and decrease since 2006. On average over the 5 year
period (2003–2008), the steric contribution has been small (on the
order of 0.3+/−0.15 mm/yr), confirming recent Argo results (this study
and Willis et al., 2008).”
Since Cazenave, Willis has confirmed (both through publication and informally) that while further unknown errors in Argo data may exist, the currently accepted Argo data yields a best estimate range for change in heat content between very slightly positive to slightly negative over the past 5+ years. At least one other group has independently published satellite based ocean mass/altimeter confirmation of the Cazennave conclusions.
The NASA website story about Willis’ discovery of the problem with Argo data relates events that took place well before Cazenave et al, Willis (2008), or other recent publications… yet it is still being used by many to cast doubt on the Argo data, even though the problem it refers to was resolved. I am surprised that NASA does not update this web page to reflect the whole story (that the Argo problem was identified and suspect data discarded). The best available data, reported in multiple peer reviewed publications, shows little or no increase in heat content in the last 5+ years, and NASA ought to convey that information to the public, rather than suggest that ocean heat content is very uncertain (and so may still be increasing). NASA is clearly misrepresenting of the state of the field. It is simply not accurate to suggest, as you seem to with your reference to the NASA story, that current Argo based ocean heat content data lacks credibility.
With regard to the Asian Brown Cloud, you appear to have completely missed the point of my earlier comment. Of course there are regions where aerosol effects have increased due to increased burning of fossil fuels, especially coal. These regional “brown clouds” for certain have significant regional effects. Acid rain in the northeastern USA and Canada, before SO2 emissions from power plants were regulated, is one example of such a regional effect. However, the existing data suggest that worldwide total aerosol effects began to decline in the 1980’s and have continued to do so. Reduced worldwide aerosols and consequent “brightening of the sun” have been suggested by some climate scientists to have contributed significantly to the increase in the rate warming in the 1990’s. Fair enough, but then the continued fall in aerosols (and continued brightening) after 2000 makes the recently flat average temperature and ocean heat content more surprising. This is the point that I hoped you would address.
It is clear to most everyone that greenhouse gases cause radiative forcing, and it is clear that this forcing must cause some increase in the Earth’s average temperature. What I and many others doubt is that the historical temperature data, greenhouse gas data (including ice core concentrations), and other relevant climate measures are consistent with very high climate sensitivity and the resulting projections of large temperature increases (eg 1.8C to >5C) over the next 100 years (and of course I also doubt the associated projections of melting of Greenland, widespread death of corals, catastrophic “tipping points”, rapid sea level rises, etc.).
What the existing data do support is a likely range of 1.0 and 1.2 C for a doubling of CO2, if you assume that greenhouse gases have caused all warming since ~1800. This is nowhere near the IPCC range. It may be that reductions in emissions of CO2 (and other greenhouse gases, which are much less costly to reduce per watt heating avoided) is a prudent course of public action, even for a climate sensitivity of 1.2C. But whatever action is taken ought to be based on realistic estimates of both costs and benefits. Grossly exaggerated estimates of future warming, which inflate the apparent benefits of rapidly reduced CO2 emissions, and so justify the high costs involved, ought not be the basis for making important policy decisions.
Or as I said earlier in this thread: The perceived urgency for action depends on the perceived climate sensitivity.
It seems that the anomalous changes were explained by melting ice which introduces cooler water to the ocean. Since this is fresh water and fresh water is lighter than salt water, could this be a sign that the sea surface is getting cooler, because the heating is concentrated at the poles and melting ice.
In the conclusions part the paper says:
“Fig4 Compares for the 2003–2008 period, the observed (from T/P
and Jason-1 altimetry) sea level curve (from Ablain et al., submitted
for publication) to GRACE-based ocean mass change (with a GIA
correction of 2 mm/yr) and total land ice plus land waters contribution
discussed above. We note that land ice plus land waters has
contributed for 75%–85% to recent sea level rise, i.e., significantly
more than during the decade 1993–2003 (Bindoff et al., 2007)”
As far as the ABC’s are concerned, I understand what conclusions you draw from the graph, but I interpret the statement of the effect of ABC’s on forcing as a global statement, not a regional one. Taken in that light there must be some data behind it, which must conflict with the graph that you show.
I don’t believe that this is a hoax. I admit that I haven’t looked at the full report to find the data.
Steve Fitzpatrick (07:31:24) : Thanks for that nice summary WRT Argo. It’s funny that when we get more accurate measurements from newer tech that does not agree with the hysterical interpretation of data, it gets buried or distorted. Public entities need be held responsible for the obfuscation and misrepresentations they continue to promulgate.
Eric,
What paper are you quoting? As far as I can see, you gave no reference.
I am quoting the paper you referenced which said the data since 2003 checks out.
It checks out because more glacial ice melted than was expected from previous years, and this explains the gap between ocean expansion and temperature.
Steve Fitzpatrick,
As I understand it, your main thesis is that climate sensitivity is much less than the IPCC says, and the variations we are seeing in climate is primarily due to natural variations. This variation is significant.
There is an inconsistency in your position as Swanson, coauthor of the recent paper by Tsonis and Swanson, on natural variation of the earth’s climate, points out in his RealClimate blogpost:
http://www.realclimate.org/index.php/archives/2009/07/warminginterrupted-much-ado-about-natural-variability/#more-686
“A climate that is highly sensitive to radiative forcing (i.e., responds very strongly to increasing greenhouse gas forcing) by definition will be unable to quickly dissipate global mean temperature anomalies arising from either purely natural dynamical processes or stochastic radiative forcing, and hence will have significant internal variability. The opposite also holds. It’s painfully easy to paint oneself logically into a corner by arguing that either (i) vigorous natural variability caused 20th century climate change, but the climate is insensitive to radiative forcing by greenhouse gases; or (ii) the climate is very sensitive to greenhouse gases, but we still are able to attribute details of inter-decadal wiggles in the global mean temperature to a specific forcing cause. Of course, both could be wrong if the climate is not behaving as a linear forced (stochastic + GHG) system.”
eric,
You do know that quoting realclimate is like trying to make a point about a question of astronomy by quoting an astrologer.
Oy Smokey don’t be rude about astrologers.
Remember the great Tycho Brae was astrologer and astronomer to the King of Denmark.
And his pupil one J Kepler worked out the motions of the neavenly bodies well before I. Newton, physics I invented it, was born.
There is nothing wrong with a good set of Tarot cards, they will predict the future climate far better than these computer models. Cheaper too, just cross my palm with silver.
PS No money refunded.
Kindest Regards
Smokey,
I am quoting one of the authors of the paper:
“Has the Climate Really Shifted”
http://www.uwm.edu/~
kswanson/publications/2008GL037022_all.pdf
His paper is often quoted by skeptics.
He was given a guest slot at RealClimate
eric:
Fig4 Compares for the 2003–2008 period, the observed (from T/P
and Jason-1 altimetry) sea level curve (from Ablain et al., submitted
for publication) to GRACE-based ocean mass change (with a GIA
correction of 2 mm/yr) and total land ice plus land waters contribution
discussed above. We note that land ice plus land waters has
contributed for 75%–85% to recent sea level rise, i.e., significantly
more than during the decade 1993–2003 (Bindoff et al., 2007)”
I did not even look at the text at first because you said it was form the “conclusions” section, which it clearly was not, so I assumed it was from a different paper. Now that I have read it, I honestly do not see any connection between what they said in the above paragraph (that is, most of the observed ocean level change came from increases in fresh water added to the ocean rather than from ocean expansion, consistent with independent measurements of glacial mass) and your comment:
“It seems that the anomalous changes were explained by melting ice which introduces cooler water to the ocean. Since this is fresh water and fresh water is lighter than salt water, could this be a sign that the sea surface is getting cooler, because the heating is concentrated at the poles and melting ice.”
I have no idea what you are trying to say above. Really, not a clue. What the authors did say was very clear:
‘On average over the 5 year period (2003–2008), the steric contribution has been small (on the order of 0.3+/−0.15 mm/yr), confirming recent Argo results (this study and Willis et al., 2008).’
Where of course “steric contribution” means expansion due to warming. Are you suggesting that the authors did not mean by the above statement that the thermal expansion was very small, or are you just suggesting that they are wrong? If you think they are wrong, please explain why.
With regard to: “The report says 20 to 80% of GHG induced warming is canceled by ABC’s.” Yes the report does say that, but it is a global reference, not specific to the cloud from Chinese emissions. The bulk of the report focuses on regional effects. The same (more or less) statement about “canceling” of greenhouse warming by aerosols is made in the most recent IPCC report, and earlier IPCC reports as well. This “canceled” global warming is the only thing that can account for the relatively modest warming (about 0.8C) that has actually taken place since 1850 if the IPCC estimates of high climate sensitivity.
You see, all the model projections depend on the least well defined and most uncertain of the radiative forcing factors: aerosol dimming that cancels much or most of the radiative warming from greenhouse gases. Even the IPCC says they are very uncertain (look at the uncertainty bars on the aerosol effects http://en.wikipedia.org/wiki/File:Radiative-forcings.svg). Take away most of the assumed aerosol dimming and the historical temperature data is only consistent with much lower climate sensitivity, which is only consistent with much shorter thermal lags in the ocean. The amazing thing to me is that even the well documented rapid stop in accumulation of ocean heat in 2003, which fairly well screams that the ocean lag period can’t be long (30+ years), and suggests again that climate sensitivity must be fairly low, is either completely ignored by modelers, or if they address it, they suggest the ocean heat data is not reliable (like the misleading NASA story on Josh Willis finding errors in Argo data… which the story neglects to note have long since been resolved). For modelers, anything which indicates low sensitivity just HAS to be wrong, because if it is NOT wrong then their models are. Sad really.
I have no idea where the issue short term variability (aka weather) came from, and I don’t see how it is relevant to the discussion that has taken place up to this point.
Steve Fitzpatrick,
What I am saying is the addition of cold water to the oceans, as a result of melting ice, has a net cooling effect on the oceans. The latent heat of fusion is being absorbed from the incoming energy flux without causing an increase in ocean temperatures. I expect that this would cause an underestimate of climate sensitivity if this is not recognized.
Since I am not an expert on aerosals, I can’t make a definitive judgment about where in the range of the aerosal forcings, the real forcing effect lies.
I suspect very few non specialists in the field have the knowledge to really discuss this intelligently. Judging from the discussion and the maps, adding up the regional effects to determine the net effect on the earth’s climate is a daunting enterprise.
http://www-ramanathan.ucsd.edu/on_global_dimming_files/ICNAA%20Plenary%20Lecture.pdf
eric (16:00:44) : The paper in question has two authors-and one has a, shall we say, different view?
http://www.wisn.com/weather/18935841/detail.html
From timetochooseagain: http://www.wisn.com/weather/18935841/detail.html
Good lnk – some real science at last I think.
Couple of interesting paragraphs –
“In climate, when this happens, the climate state changes. You go from a cooling regime to a warming regime or a warming regime to a cooling regime. This way we were able to explain all the fluctuations in the global temperature trend in the past century,’ Tsonis said. ‘The research team has found the warming trend of the past 30 years has stopped and in fact global temperatures have leveled off since 2001.’
“The most recent climate shift probably occurred at about the year 2000. Now the question is how has warming slowed and how much influence does human activity have? ‘But if we don’t understand what is natural, I don’t think we can say much about what the humans are doing. So our interest is to understand — first the natural variability of climate — and then take it from there. So we were very excited when we realized a lot of changes in the past century from warmer to cooler and then back to warmer were all natural,’ Tsonis said. Tsonis said he thinks the current trend of steady or even cooling earth temps may last a couple of decades or until the next climate shift occurs.”
Tenuc and timetochooseagain,
You are indulging in the classic cherry picking method to make an argument.
It is clear that both Tsonis and Swanson agree that natural variation is masking a longer term trend.
http://conservativemeanderings.wordpress.com/2009/03/04/senators-debate-global-warming-policy-despite-global-cooling-evidence/
““The temperature has flattened and is actually going down,” Tsonis told CNSNews.com. “We are seeing a new shift towards cooler temperatures that will last for probably about three decades.”
But Tsonis also said that neither he nor Swanson think their study undermines arguments for global warming caused by human activity.
“We are not saying there is not warming due to human activity,” Tsonis told CNSNews.com. ‘We are saying that there are natural shifts on top of that. But, for now, it looks like it is going to cool.”
Tsonis said that currently the natural cycles, which occur in part because of the way oceans interact, are stronger than the influence human activity has on the environment. But when the earth begins to warm again in several decades, he said, the globe could be in trouble because natural warming and man-made warming will occur simultaneously
“At this point it [natural variation] at least balances, or may be stronger, than the human influence,” said Tsonis. “But if temperatures shift again as we believe they will, then warming will be dramatic. It will be natural warming on top of human warming.””
On the other hand it is possible that aerosals are part of the story of the reduction in temperature increase in recent years.