Here's a neat way to understand the issue of CO2 "saturation" in the atmosphere as well as the general mechanism of the "Greenhouse effect" and whether or not water vapor has a positive or negative feedback when it comes to Global Warming. You can download the PowerPoint Show with the atmospheric science part of my presentation to the Philo Club at The Villages, FL, along with an audio narrative, here. That show with a script is here. You can also download the PowerPoint Show with my complete talk contrasting Cap&Trade with a Revenue-Neutral Carbon Tax here.The above chart shows the absorption spectrum for CO2, assuming levels from 100 ppmv (lowest level of CO2 in the ice core record) to 200 ppmv to pre-industrial levels of about 300 ppmv to current levels of around 400 ppmv and projecting up to 500 ppmv which is where we will be in around 50 years unless we curb our carbon emissions or the Earth cools a bit.
The "hot pink" area around 10μ is where the Earth's long wave infrared radiation peaks. Notice that going from 100 ppmv to 200 ppmv almost doubles the amount of absorptivity, and increasing CO2 to 300 ppmv almost triples it. However, at 300 ppmv, the 15μ band is 100% absorbed, so increasing to 400 ppmv has little additional effect as does further increase to 500 ppmv. I have never seen "CO2 saturation" presented this way. [Get an animated version with audio narration here.]
The above chart shows how the "Greenhouse Effect" works. Rays from the Sun that strike light-colored surfaces reflect the energy back to space. Rays that strike dark-colored surfaces are absorbed, warming the Earth. Warm surfaces emit all wavelengths in all directions. Some rays pass through the atmosphere back to space. Others are absorbed by CO2 gasses that re-radiate in all directions. Radiation that comes back and warms the Earth is called the “Greenhouse Effect”. [Get an animated version with audio narration here.]
The effect of water vapor in the atmosphere is controversial. IPCC models assume it has a positive feedback effect, meaning the more water vapor in the atmosphere, the more warming. Others, including me, believe the net effect of water vapor is negative, moderating warming.The above chart tells why. All clouds do warm the earth according to the "Greenhouse Effect". In fact, for night clouds, that is the only effect. However, there are fewer night clouds and the Earth is cooler at night, so the warming effect is moderated. Daylight clouds also warm the Earth a bit by the "Greenhouse Effect", but they also reflect incomming Sunlight back to space and cast a cooling umbra on the Earth. The net effect of daylight clouds is therefore cooling. Rain, snow, thunderstorms, wind, convection and so on also have a net cooling effect. AAs we all know, clouds are formed when water evaporates from the surface of the warm Earth. The "heat of vaporization" removes heat from the Earth and the warmed water vapor takes it higher up in the atmosphere. When water vapor condenses to droplets, the "heat of condensation" (equal to the "heat of vaporization") releases the heat into the clouds where some escapes by radiation to space, a net cooling effect. Some radiation comes back to Earth as "Greenhouse Effect". Thunderstorms suck warmed air from the surface to high up in the atmosphere, returning cooler air, a net cooling effect. Rain or snow cools the Earth when it falls to the surface.
Therefore, it is reasonable to believe that water vapor, the key element along with the Sun in driving weather, has a generally net cooling effect. Thus, the fact that more water is evaporated as the Earth warms, has a negative feedback, and moderates Global Warming. [Get an animated version with audio narration here.]
Ira Glickstein
31 comments:
Ira's explanation of why carbon dioxide influences the temperature of the earth is excellent, but starts in the middle of the story if one wants to understand what the fuss is all about. The beginning is the a global energy balance to determine whether or not the thermal energy of the planet is rising or falling as a function of time. Even more important to us as humans, is whether or not the thermal energy in a thin layer that includes our oceans, the lower atmosphere and the upper part of the earth crust, is rising or falling. Looked at from that point of view, one can see that inputs from the interior of the earth like lava and conduction from the radioactive core and leakage of molten material to the surface, are part of the picture. At the outer surface of the what we'll call the bio-shell, there is an radiant input from the sun and radiant radiant output from warm bodies within the shell. (Twenty-eight percent of the solar input is reflected back into space from clouds, gases in the atmosphere, the surface of the oceans and the earth crust.) The thermal radiation output from the bio-shell is quite complex, because it requires an analysis of the absorption and emission of the various components of the bio-shell including the atmosphere and its component gases. This brings us to the requirement for the analysis that Ira presented so well. To use an analogy to the mechanism of accumulation of thermal energy in greenhouses, we see that at some point one must consider the properties of the glass enclosure. Although the glass may be quite transparent to visible radiation, it is nearly opaque to the infrared radiation from the horticultural objects enclosed inside. The atmosphere is more complex than a sheet of glass, because it is thicker and non-homogeneous.
Thanks Joel for bringing up the fact that "... one can see that inputs from the interior of the earth like lava and conduction from the radioactive core and leakage of molten material to the surface, are part of the picture."
True enough, but my understanding is that warm core effects are quite a minor contributor to the total heat balance of the Earth. Of course, if we take a very long-term view, we know the core has been cooling since it was liquid some 4.5 Billion years ago, and the radioactivity will dissipate sooner or later. So, we may need more "greenhouse effect" to make up for that in the very far future.
The heat-trapping contribution of the biosphere is the dominating cause of the heat that makes life possible on Earth. Perhaps life has evolved in such a way that the biosphere has feedback mechanisms that adjust for livable temperatures.
This reminds me of the thought experiment called "Daisyworld". A planet has white and black daisys, the former thrive in warmer temperatures and the latter in cooler. Thus, when their sun gets brighter, the black daisys decline and the white take over, increasing the albedo of the planet and reflecting more sunlight back into space, thus moderating the warming. When their sun gets dimmer, the white daisys decline and the black take over, decreasing the albedo to retain more sun energy, again moderating the cooling.
As I said, I believe water vapor provides a net negative feedback to global warming. Given warming of Planet Earth (due to natural and/or human causes), more water is evaporated yielding more clouds and thunderstorms, which have a net cooling effect, This tends to moderate the warming. Given cooling of Planet Earth, the opposite occurs. Fewer clouds yield a net warming influence, moderating the cooling. This seems to support the Gaia Concept and perhaps even Creation by a very Intelligent Designer.
Ira Glickstein
Ira said: This seems to support the Gaia Concept and perhaps even Creation by a very Intelligent Designer.
Joel responds: Actually, this supports Le Chatelier's Principle which is in turn is a consequence of The Second Law. If you want to call that a consequence of the Gaia Concept or an Intelligence, fine, but recognize that The Second Law exists even where planets don't exist.
You made me look up Le Chatelier's principle "Any change in status quo prompts an opposing reaction in the responding system." -- thanks Joel. But I don't see how it is a consequence of Newton's Second Law. His three Laws are:
1) In the absence of a net force, a body either is at rest or moves in a straight line with constant speed.
2) A body experiencing a force F experiences an acceleration a related to F by F = ma, where m is the mass of the body.
3) Whenever a first body exerts a force F on a second body, the second body exerts a force −F on the first body. F and −F are equal in magnitude and opposite in direction.
Perhaps you meant the Third Law, "Equal and opposite direction"?
Even that is problematic. There are many chemical reactions that, once initiated, have positive feedbacks that multiply them, such as an explosive reaction.
In the physical world of climate there are similar positive feedbacks. For example, if solar radiation input to the Earth were to increase for some reason external to our atmosphere, that would melt polar ice, exposing earth and water surfaces that have lower albedo, reflecting less solar energy and increasing surface temperatures.
It may be that cloud formation and other reactions in the biosphere are so constituted that they counteract that positive feedback with greater net negative feedack.
This negative feedback could be attributed to a lucky accident -- or, as I suggested, some kind of natural Gaia effect [that I would like to believe in] or even Design by some super-natural Intelligent Creator external to the Universe [that I do not believe in].
Ira Glickstein
PS: Most established Climate Scientists do not accept that clouds provide a net negative feedback. IPCC models, for example, assume a positive feedback, which is why I think their predictions have been in error lately.
I just read the following notes from my current issue of Science (28 May 2010):
A group of scientists visited Capital Hill this month providing answers to skeptics on climate change.
These current opinions are based largely on three detailed reports that were released last week by the National Academies' National Research Council (NRC). They had a familiar theme—the human-induced warming of the planet. This was no rehashing of the IPCC report, which has taken considerable flak of late. The new NRC reports draw on the past 5 years of peer-reviewed literature, which was published too late for inclusion in the IPCC analysis. They also reflect findings from more than a score of reports from the U.S. Global Change Research Program and earlier efforts from NAS. The membership of the three NRC panels also had little overlap with that of the IPCC's working groups.
No details were provided.
Thanks Howard for AAAS Notes on Climate Skeptics. Quotes in italics are from the linked AAAS Notes, my comments are in bold).
"...skepticism without specifics, alternate hypotheses, and facts is worthless. It does not advance the science."
Absolutely true! However, I and the skeptics and lukewarmers I read, particularly WattsUpWithThat and ClimateAudit, are full of specifics and science-based alternate hypotheses. Don't take my word for it. Look at these sites yourself. Don't lump in the wild, sometimes political- or religious-oriented deniers, whose blatherings are full of sh*t, with reasoned skeptics and lukewarmers like me.
"...arguments commonly offered by skeptics—there is no global warming, or humans are not causing it, or temperature records are inaccurate..."
EVERY skeptic I cite accepts that average surface temperature on Earth has INCREASED around 0.5ºC over the past 100 years or so. Anyone who denies that is delusional.
Any warmist or alarmist who characterizes skeptics as claiming "no global warming" is beating a "strawman". The same is true of "or humans are not causing it". SOME WARMING IS DUE TO HUMAN ACTIONS (primarily burning of fossil fuels which increases atmospheric CO2 and changes in land usage that reduce the albedo). We accept the raw temperature records as accurate (at their level of precision) but question how they have been affected by urban development and processing by the warmist-oriented climate science establishment. Many specific examples are available at the sites I linked as well as on this TVPC Blog.
"... basic physics: Increase the concentration of carbon dioxide, methane, and other greenhouse gases in the atmosphere, and the atmosphere will hold in more heat."
Absolutely true! What we question is the amount of warming (IPCC claims 0.8ºC), how the raw readings have been processed to increase apparent warming (by about 0.3ºC), the IPCC claim that over 50% (0.4ºC) is human-caused, and how the CO2 contribution to global warming has been modeled.
Here is a specific: CO2 levels have increased linearly since 1979 when they were first accurately measured. Average surface temperatures have not increased since 1998. If CO2 has a 50% effect, how can that be?
"The whole climate community has spent 30 years trying to find a way out of this. Could the Sun be doing it? Could the volcanoes be doing it?... [But] we can't explain what has happened recently without us [humans]—it has our fingerprints"
Virtually all the IPCC models are based on CO2 being the major driver and clouds having a net warming effect. Warmists and alarmists blind thenselves to science-based explanations for the moderation in warming over the past decade or more, despite steady increases in CO2.
As I showed in this Topic, CO2 increases beyond 300 ppmv have a minor effect because the primary long-wave "greenhouse" radiation in the 13-18u band gets saturated at 300 ppmv. Daytime clouds increase the Earth's albedo enough to overcome the warming effect of nightime clouds and storm clouds further cool the surface. It appears that dimethylsulfide, produced in greater quantities by algae when temperatures increase, serve as cloud condensation nuclei, increasing cloudiness and thus the albedo, partially moderating warming. In addition, it appears that longer and weaker Sunspot cycles are associated with increased cloud production associated with levels of gamma rays striking the Earth.
These are examples of alternate hypotheses that, at least for the past decade, do a better job of explaining surface temperature trends than IPCC models.
Ira Glickstein
I’m not an expert here, so I just occasionally follow both sides of the arguments. Clearly there are many uncertainties, and the problem is technically complex. Consequently, I feel that one should pay more attention to experienced experts rather than to the amateur skeptics. Of course, that doesn't mean experts are always right! But the rational question is, Where should you place your bets?
Ira asks: “Average surface temperatures have not increased since 1998. If CO2 has a 50% effect, how can that be?”
One possible reason is explained here.
Ira proposes, “that dimethylsulfide, produced in greater quantities by algae when temperatures increase, serves as cloud condensation nuclei, increasing cloudiness and thus the albedo, partially moderating warming. The closest discussion I found was this.
Ira says, “It appears that longer and weaker Sunspot cycles are associated with increased cloud production associated with levels of gamma rays striking the Earth.” Here is some contrary evidence.
Thanks Howard for your quick reply. I agree it is a complex subject best left to experts.
OK, how about Prof. Phil Jones, Director of the Climatic Research Unit (CRU) at the University of East Anglia, who, in February 2010 told the BBC, according to the UK Daily Mail, "... for the past 15 years there has been no ‘statistically significant’ warming." ("Climategate" is the name given to the release of internal emails by the CRU which Jones headed.)
Jones also admits the Medieval Warm Period might have been warmer than now. That was 800-1200, way, way before large-scale industrial release of CO2.
How about Makiko Sato, PhD co-author of many academic climate research papers with James Hansen head of the Goddard Institute for Space Studies (GISS), the US equivalent of CRU? She wrote an email in 2007 (see image of email here) that shows that GISS, in July 1999 said that US annual 1934 was more than 0.5ºC WARMER than 1998! She recounts how GISS massaged the numbers seven times between 1999 and 2007 until they got 1934 and 1998 close, but 1934 was still 0.025ºC WARMER! (Her email to Hansen was legally released in January 2010 as part of a Freedom of Information Act (FOIA) query.)
Figures 2 and 3 of your second link show the Earth's albedo INCREASING over the past decade, which would explain some of the moderation in surface temperature, which was my point. It is not clear if this increased cloud cover is due to dimethyl sulfide from algae or cosmic ray reduction due to the very long Sunspot cycle that just ended, or some other possibility. Clearly, it is NOT due to any reduction of CO2!
Your third link goes back only to 1860. Why? We have reliable Sunspot observations back to 1610. Your link only mentions the length of the cycles, and not their strength (maximum Sunspot count). The Little Ice Age had a three cold periods. The first, called the Maunder minimum (1650 to 1700) with very weak, generally longer Sunspot cycles. Sunspots increased from 1750 to 1780 with stronger, generally shorter cycles. There was another dip, called the Dalton Minimum between 1800 to 1830, and yet another, less severe, dip aroung 1900. From the 1930's to about a decade ago, we had strong, short cycles.
You want experts? Here is a NASA Solar Physics link that mentions how Galileo made Sunspot observations starting in 1610 and mentions the relative lack of Sunspot activity recorded during the Little Ice Ages.
Ira Glickstein
The link to the Makiko Sato email in my previous Comment is broken. Sorry.
Here is the correct link. At the top is my graph of the seven different GISS data points that take a 0.5ºC warmer 1934 down to near parity with 1998. Scroll down until you see the Sato email near the end of the posting.
Click here to see all 215 pages of GISS emails released under the FOIA request. The email from Sato is on page 48.
You might also be interested to read what triggered Sato's email. It was a columnist's story (reproduced on page 46). See previous material (starting on page 39) about a "flaw" in the GISS analysis, which Hansen admits to, that was discovered by Steve McIntyre, a Canadian who runs the ClimateAudit skeptic (NOT denier!) blog.
Also read Hansen's and other NASA execs replies and reactions to Sato's email (after page 48).
In fairness, the flaw discovered by McIntyre (which amounted to 0.15ºC) did not apply to the 1998 or 1934 data, but only data after 2000.
Also, the 1934 vs 1998 refers to US average surface temperatures, but, IMHO, that makes it worse. If GISS can do six re-analyses on the same old US data to make a 0.5ºC difference between 1934 and 1998 go away, imagine what they can do with presumably less reliable foreign data, and tree ring or other proxy data that is based on temperatures from hundreds of years ago!
OOPS, the Medieval Warm Period just went away, despite historical records that the Norse grew grapes in Newfoundland in those days. WHOA, the Little Ice Age got smoothed over, despite historical records that the Thames was frozen so hard they could drive on it.
Please note total global warming according to the IPCC over the past 100 years or so is only 0.8ºC. A 0.5ºC adjustment would wipe out more than half of that! A 0.15ºC "flaw" is a 20% error. OY!
Why did it take the experts at NASA GISS 72 years (from 1934 to 2007) to adjust the 1934 raw temperature data downwards by 0.22ºC and 8 years (from 1998 to 2007) to adjust the raw 1998 data upwards by 0.308ºC? A great example of our US taxpayer money at work!
Ira Glickstein
Ira, you questioned the apparent lack of correlation between CO2 and temperature over the last decade. I responded with a link explaining why heating may not cause much temperature change. There are more links to refereed papers with data. You responded only by mentioning Phil Jones’ comment reported in the Daily Mail. This is a good example of my point: how not to do science. What do you think about the argument in my link?
I also gave a solar link with many more links to refereed papers. I don’t see that you have addressed the arguments given in the refereed links.
By my question, “Where should you place your bets?” on amateurs or experts, I implied that the non-expert should pay more attention to the consensus of experts. Also see Naomi Oreskes.
In fact, all accepted scientific theories at any given time are established only by the “consensus of experts.” Of course this consensus is changed over time with new data and theories. In science this consensus, for good reason, has been established by peer reviewed publications and discussions at professional meetings. Private discussions, personal correspondence, lab notes, and many other activities are obviously important, but they are not considered scientifically acceptable in forming a consensus until reviewed and published in established journals.
I think Climategate demonstrates that science is not advanced when the discussions become popular topics either in the media, on open Internet blogs, or as political agenda. Obsession with Climategate has distorted the broad scientific issues and unfortunately reduced the public interest in warming, but it has had little effect on the scientific consensus.
Your first link claims that there has been warming over the past decade in the oceans and atmosphere that does not show up in the official temperature data published by IPCC sources (CRU and GISS).
If true, that is another reason to disbelieve CRU and GISS scientists who have, according to any fair reading of their internal emails, been biasing the data as far as science will allow (if not more so).
As for the lack of published papers by climate scientists who buck the consensus, the CRU emails detail how the "team" biased the peer-review process and punished a journal editor who dared print an opposing view.
As for the specifics of your link, look closely at the graph - it ends in 2003 even though the paper was published in 2009 using 2008source data. Sea ice extent has increased since at least 2007.
Your consensus of experts only repeats the obvious which I and all responsible skeptics accept: 1) Global Warming is real and average surface temperatures have increased over the past 100 or so years and 2) Humans are partially responsible (fossil fuel CO2 and land use affects on albedo).
The problem with the survey is they did not say what they meant by "significant" when they ask, in Q2, if "human activity is a significant contributing factor". I think 10% is significant and I would have answered YES to Q2. 97% of respondants who said they were published climatologists also answered YES to Q2. Does that mean they agree with the IPCC that over 50% of the warming is due to human activities? Why did Q2 not specify a percentage instead of using the meaninglessly vague "significant".
Your Naomi Oreskes link adds little except to document the IPCC conclusion that "Human activities ... are modifying the concentration of atmospheric constituents ... that absorb or scatter radiant energy. ... [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations". That is where I get my "over 50%" number.
I try to look at the larger picture. Although CRU and GISS claim to be independent conglomerators of worldwide temperature data, it is clear they use the same sources and the emails show how they coordinate results and use similar analysis schemes. The "consensus" is based on those data. When independent analysts like Steve McIntyre find significant errors, GISS tars him as an amateur and a former mining executive. When GISS finally admits their mistake, they minimize it as a "flaw" and that US data only affects 2% of the Earth surface.
It is clear we have different views about the value of Climategate. What if the internal emails were from some corporation, cooking their books to inflate their sales results and profitability? Are scientists who depend on continued government funding likely to admit their alarmist panic was mistaken and lose the funding? I'd like to think that scientists are more honest that accountants, and, overall, they probably are. But, there are always exceptions - especially when government contracts are at stake.
Ira Glickstein
Ira, I am not objecting to most of your thoughtful analyses of climate models. They have motivated me to look at more sources and actually learn a little about the problem. I still feel that to be on solid ground one must test one’s opinions against the experts who know vastly more about climate models, and that do not depend on amateur Internet blogs. There is really no short cut to becoming an expert.
What I find counterproductive is the culture of Climategate that dominates the media and the Internet. The noisiest voices know the least, and most of them have a general anti science, political, or conspiratorial bias. I think you recognize this.
There are now about a dozen independent professional investigations that have reviewed the issues and agreed that while the data problems are serious, here were no evil-doers, and the overall conclusions of the scientific models have not been changed. Read Wikipedia’s review of the Climategate controversy and see if you agree.
Howard, I read your Wikipedia Climategate link and you will not be surprised to hear that I think it is biased. Note that, unlike most Wikipedia items, this one is locked to prevent editing. Some specifics:
1) The first paragraph says the CRU emails were obtained by hacking the server, implying it was done from outside. Based on the "read me Harry" comments embedded in the files, it is more likely this was an inside "whistleblower" who was aware of files compiled for a FOIA response. He or she released them when official permission was withheld.
2) The second paragraph says "The scientific consensus that global warming is happening and that it is induced by human activity was determined not to be challenged by the emails." As I have said before, skeptics accept that part of the consensus, so the claim is a "strawman" point repeated by warmists to cover up the real question: HOW MUCH warming has occurred and HOW MUCH is due to human activities.
3) In section 1, para. 2, The Air Vent and WattsUpWithThat websites are identified as "skeptic", but RealClimate is not identified as a "warmist" site.
4) The paragraph about "hide the decline" and the "trick" by Michael Mann is totally one-sided. If recent tree-ring data is "known to be erroneous" based on comparison with contemporary thermometer readings, what scientific justification is there for utilizing the earlier parts of it to flatten out the Medieval Warm Period (800-1200AD) known to have occurred based on historical records?
5) Although this Wikipedia piece is strongly biased, it does confirm that the CRU: a) blocked access to scientific data that was generated and analysed using public money, b) did not respond properly to valid FOIA requests, and c) the UK Information Commissioners Office could not prosecute because of the statute of limitations.
Ira Glickstein
There are too many uncertainties to make detailed arguments useful. One point about the relation of data to models I do understand from my physics and systems science background is that the quality of the model itself can be more persuasive than the data. Measurements are inherently only approximations. Data always have some uncertainly. Consequently there is always more than one model that will fit the data.
As Hansen et al. conclude: “The match of simulated and observed global temperature curves is not an indication that knowledge of climate sensitivity and the mechanisms causing climate change is as accurate as suggested by that fit. An equally good match to observations probably could be obtained from a model with larger sensitivity (than 2.9_C for doubled CO2) and smaller net forcing, or a model with smaller sensitivity and larger forcing” (See page 691).
Of course the weaker the data, the more numerous are the models that fit, and the more violent the controversies over the models. Climategate is a good example where there is currently unresolvable uncertainty. These climate models are very complex as indicated by the GISS ModelE (see link above) and involve many specialists.
Complex dynamical models like this have domains of instability and chaos. Such systems can’t be handled analytically and must be run on computers. Modelers look for instabilities (“tipping points”) because they are where the dynamics is the most sensitive to perturbation or forcings. This means that predictions are always only statistical distributions. In a chaotic domain, by definition, no datum can be accurate enough for a deterministic solution. The choice of model then depends less on data and more on subjective qualities like conceptual simplicity, explanatory value, and robustness, all of which depend on experienced judgment.
This is not to say that an outsider can’t contribute to the issues. One example is Professor Bernard Elkin, now Emeritus, an aerodynamics expert. (His team saved the near disastrous Appolo 13 flight.) Elkin’s Phase Space graph of CO2 and temperature anomaly is striking, and appears in lots of discussions.
Elkins phase space graph shows a strong positive correlation between temperature and CO2 based on several hundred thousand years of Ice Core data. This is well accepted by skeptics. But note that, according to that same Ice Core data, temperature rises sharply about 800 years before CO2 rises. Both stay at high levels for a few thousand years. Then temperature drops, followed, 1000 or more years later, by CO2 decreases. We therefore come to the only reasonable conclusion: the direction of causation is rising temperature (due to some cause other than CO2) driving higher CO2 levels, and dropping temperature (due to some cause other than CO2) driving lower CO2 levels.
I went into the evidence that temperature drives CO2 on this Blog back in 2007.
Elkins also shows that current CO2 levels are at unprecedented levels, which is also well accepted by skeptics and clearly shown in the illustration that heads this Blog Topic. Historical levels are, over hundreds of thousands of years, around 200-300 ppmv, while the current levels are approaching 400 ppmv and are likely (IMHO) to reach 500 ppmv within 50-100 years. Even if we skeptics are correct that CO2 sensitivity has been grossly overestimated, this unprecedented rise concerns me, which is why I favor a Carbon Tax.
Of course you are correct that many different models can fit a given set of data. Given that uncertainty, and the failure of IPCC models to predict the current stabilization of average surface temperatures, it would be imprudent to spend trillions and wreck the economies of industrial nations on the mistaken notion we are anywhere near a "tipping point" where rising CO2 will lead to uncontrollable global warming.
Ira Glickstein
Ira, I don’t see that your comment is relevant. You say, “We therefore come to the only reasonable conclusion: the direction of causation is rising temperature (due to some cause other than CO2) driving higher CO2 levels, and dropping temperature (due to some cause other than CO2) driving lower CO2 levels.” That is OK, but because an initial rise of temperature is not caused by CO2, that does not imply that CO2 does not cause the temperature to rise further. The dispute is about how much?
See Skeptical Scientist. Of course this is complicated and the details are still not fully understood.
Now we are getting somewhere Howard! The graph in your link to Skeptical Science is the best one I have seen that illustrates my point!
Your link correctly states it is the Milankovitch effect due to cyclic changes in the eccentricity [~21K years], obliquity [~41K years], and precession [~26K years] of the Earth's orbit that causes the initial warming at the end of each Ice Age [~120K years]. I've mentioned Milankovitch before on this Blog as one of the longer natural cyclic effects on global temperatures.
There are shorter, multi-decadal, natural cycles that are of more relevance to human lifetimes. These include variations in ocean currents and changes in the lengths and strengths of Sunspot cycles.
For example, over the past 50 years or so, we have had a stretch of shorter, stronger Sunspot cycles that, through interaction with cosmic rays and cloud formation, have most likely caused most of the warming over the past century. Fortunately, Solar cycle #23, which just ended, turned out to be longer than normal and cycle #24 looks to be weaker than normal, which is probably the main cause of the stabilization in global temperatures over the past decade.
Cyclic ocean currents (El Nino Southern Oscillation, Pacific Decadal Oscillation, and others) are largely responsible for the warming that started in the late 1970's and extended until the late 1990's.
OK, so according to your Skeptical Science link, the initial effect is the increase in temperatures which, about 1000 YEARS later, causes CO2 to increase. OK, we all agree!
You say "...because an initial rise of temperature is not caused by CO2, that does not imply that CO2 does not cause the temperature to rise further. The dispute is about how much?" EXACTLY! And I have the answer and it is "not that much".
For the proof, Howard, please take a good look at the wonderful graph in your link, particularly the period from about 130K to 110K years ago. Notice how the CO2 (blue) stays high for ~20K years as the temperature (red) plummets to a low value and only then does the CO2 follow suit. A similar, but less pronounced situation occurs for the other two Ice Age cycles on the graph. So the final effect is the decrease in temperatures which, ~5-20K YEARS later, causes CO2 to decrease. Do you agree?
Now, I accept that the greenhouse effect of higher CO2 levels causes some additional warming. But, it cannot be a major cause because the temperature plummets precisely during the 5-20K YEAR period where CO2 remains at its maximum!
The only tenable counter-argument the warmists have is that the current increase in CO2 levels is unprecedented in amount and cause. As I noted, we are headed for 400 ppmv on the way to 500 ppmv in the lifetimes of my grandchildren. Also, a major cause is human burning of fossil fuels and land use changes. That is a strong argument for energy conservation and a Carbon Tax to encourage alternative carbon-free or carbon-neutral energy sources.
Ira, you argue that sunspots “caused most of the warming over the past century.” Where do you get that? The Skeptical Scientist gives a dozen references that say otherwise.
What I said Howard was: ".. stronger Sunspot cycles that, through interaction with cosmic rays and cloud formation, have most likely caused most of the warming over the past century. [Emphasis added, this is theory, not yet proven or disproven.]
As we all know, correlation is not (necessarily) causation. So, scientists must postulate a causal link to back up their theory. First, I will provide the correlation history and then the best science-based causal link I know.
In the case of Sunspots, which have been accurately observed and recorded since 1610 - see graphic, there is strong historical correlation between stretches of long, weak cycles and global cooling (Maunder and Dalton minimums of the Little Ice Ages) and short, strong cycles and global warming (Modern Maximum of 1960's through 1990's).
On a shorter time scale, where good thermometer data is generally available (since 1850), see the second graphic in this Topic. I annotated that graph to highlight weak Sunspot cycles (peak below 80 shown in green) and strong ones (peak above 110 in pink). Note how the weak cycles come before dips in smoothed global surface temperatures and how strong cycles come just ahead of rises. (Back in Jan 2009 I predicted cycle #24 would peak at 80. The experts at NASA originally predicted it would peak at 156, then revised downward to 134. When I predicted 80 their prediction was down to 104. Their latest prediction is 90 - so who is the expert? :^)
So what is the causal link? In 2007, a Danish climate scientist Henrik Svensmark showed that charged particles caused by cosmic rays from deep space tend to seed cloud formation. When Solar activity is at a maximum, the strong magnetic activity of the Sun deflects these cosmic rays from the Earth, fewer clouds are formed, and Earth heats up. When Solar activity is at a minimum, the cosmic rays are not deflected from the Earth, they cause more clouds, and the Earth is cooled, or at least not heated up as much.
While this is just a theory, it explains why Earth has been both much warmer and much cooler than now, prior to large-scale human activities. High CO2 sensitivity only explains current warming and only for the period of large-scale human burning of fossil fuels and changes in land use.
By the way, after reading my last Comment, do you think the Ice Core proxy data, showing correlation between rising Temperature being followed, centuries later, by rising CO2 and dropping Temperature being followed, millenia later, by dropping CO2, have any applicability to the theory that MOST of the recent global warming is due to human-caused CO2?
Ira Glickstein
There are too many time scales in all these arguments. Rapidly increasing human CO2 production occurred within the last century. Whatever explanation of the correlation of T and CO2 over 400,000 years has nothing to do with humans. 1000-year phase shifts must have to do with the ocean’s mixing times.
From the few papers I have read, the controversial scientific/policy issue is over how effective is the added “forcing” of human CO2 in increasing temperature over less-than-century time scales.
The problem, then, is to (1) measure the T sensitivity to CO2 and (2) measure all other possible causes of temperature change. This is what the majority of argument is about. According to the references in Skeptical Scientist there is good evidence that human CO2 is significantly raising the T. How much is obviously uncertain.
I was complaining earlier about “amateur blogs” replacing expert refereed publications. But I just referred you to the Skeptical Scientist which is an amateur blog. So to follow my own advice I recommend that you actually read the Knutti and Heger review from the Institute for Atmospheric and Climate Science at ETH.
I still feel that to be on solid ground one must test one’s opinions against the experts who know vastly more about climate models.
Generally I would join you Howard in your distrust of "amateur" scientists and put my faith in the "experts". But the human CO2/global warming panic is different because it has been political since James Hansen briefed Congress and former VP Al Gore, an amateur when it comes to science, popularized it in his An Inconvenient Truth movie.
In your last two postings you make two key points: "[1.] Whatever explanation of the correlation of T and CO2 over 400,000 years has nothing to do with humans. [and 2.] 1000-year phase shifts must have to do with the ocean’s mixing times."
The most dramatic moment in Gore's presentation is when he shows the 400,000 year Ice Core graphs, calls attention to the obvious correlation between CO2 and Temperature, and then mounts a lift that raises him high above the stage where he extends the CO2 to current and future levels, implying that global temperatures will triple and soar uncontrollably over the next few decades. As you say in your point [1.], the 400,000 year Ice Core record has nothing to do with humans! So, why did Gore show it? And why did he use a version where the CO2 graph and the Temperature graphs were on separate axes so it was difficult to see the multi-decadal and multi-milennial lags of the CO2 trace behind the Temperature trace?
Your point [2.] seems to be an attempt to explain the 1000 year lags as due to ocean mixing times. But, major human burning of fossil fuels and CO2 increases have taken place over only the past 100 or 200 years, and accellerated only over the past 50 years. The alarmists and warmists plot the extreme warming between the 1960's and 1990's against the CO2 rise without any delay to account for ocean mixing times. They cannot have it both ways!
Over my long and mostly successful career as a System Engineer I discovered that mathematical analysts, more often than they admit, compute results that, while arithmetically impeccable, are exactly and totally wrong, due to bad assumptions. The analysts I dealt with were totally honest and very competent in their expertise but were unable to step back and look at the common sense factors.
Please step back a moment from the highly technical peer-reviewed papers with impressive equations and curves and apply your common sense.
The great graphic in your Skeptical Science shows Temperature dropping by 7°C while CO2 remains around 270 ppmv for 20,000 years afterward. How can CO2 sensitivity be as high as 2–4.5°C or more (for doubling of CO2) as claimed by the IPCC and in the Knutti paper you linked in your last Comment?
Ira Glickstein
Howard, I've done some simple math related to your last posting and would appreciate your comments on it.
The IPCC and your linked paper say climate sensitivity to CO2 is 2 to 4.5°C. Climate sensitivity is generally defined as the temperature rise due to a doubling of CO2 levels, and, presumably, temperature drop due to halvings of CO2 levels.
According to GISS and CRU, average surface temperature has risen by about 0.8°C since 1850. If climate sentitivity is at the low end of the range, namely 2°C for doubling from pre-industrial CO2 levels of 280 ppmv, that would amount to about 280 x 0.8/2 = 112 ppmv rise in CO2. Actual rise is about 110 ppmv, so the low end of the CO2 sensitivity assumes about 100% of the warming since 1850 is due to CO2. OK mathematically, but I think it is more like 10%. But let us move on.
If we assume the high end from your linked paper, 4.5°C for doubling, that would amount to 280 x 0.8/4.5 = 50 ppmv of CO2 to get the 0.8°C warming we have experienced. But we have had about 110 ppmv rise, so the 4.5°C sensitivity is high by over a factor of two for the measured temperature and CO2 increases we have actually experienced so far.
Summary: 1) The low end of the climate sensitivity to CO2 given by your linked paper, 2°C, matches our experiences over the past 150 years, assuming ALL the warming is due to CO2. 2) The high end would predict warming more than twice of what we have experienced over the past 150 years. Therefore it must be too high and any models based on it will over-estimate future global warming due to CO2 by more than a factor of two!
Ira Glickstein.
PS: Given climate sensitivity of 2°C for doubling, would mean that the drop in temperature during the last Ice Age of 7°C would be expected to decrease CO2 by more than two halvings. So, it should have gone down from 270 to less than 60. Yet, over around 20,000 years, it did not drop at all! So much for climate sensitivity to CO2. I believe the true CO2 sensitivity is in the range of 0.1°C to 0.5°C at most.
Ira, if you are simply going to claim that your “long and successful career” and Gore’s “amateur” science means that your arguments outweigh all the technical peer-reviewed papers, then I will have to check you off as simply anti-science. Do you really expect me to ignore peer reviewed evidence?
You come up with arguments claiming to support your view like, “the only reasonable conclusion: the direction of causation is rising temperature (due to some cause other than CO2) driving higher CO2 levels, and dropping temperature (due to some cause other than CO2) driving lower CO2 levels.”
Ira, that conclusion was reached by experts 20 years ago! None of the experts claim that greenhouse gases are the cause of initiating or terminating the ice ages. No credible scientist has argued that position. It is also true that no expert doubts that rising CO2 causes immediate heating of the Earth.
It is illogical for you to argue that because CO2 does not initiate the first thousand years or so of warming, nor the first thousand years of cooling, that it is not crucial for the amount of warming and cooling. There is a rich literature on this topic beginning with Lorius, et al.. A review with links is at Real Climate. Anyway, the phase relations of old ice cores are not that reliable.
The greenhouse gases play two roles. Over millennia they are a biogeochemical feedback on warming initiated by the orbital variations. They amplify the warming once it is already underway. The lag of CO2 of about 1000 years on warming corresponds rather closely to the time it would take to extract excess CO2 out of the deep ocean by natural ocean currents. The same delay argument holds for dissolving CO2 in the cooling ocean. These lags are explained by models of CO2 acting only as a feedback, not as an initiator.
The phase state graph clearly shows the difference between CO2 (1) acting only as delayed amplification in a millennial complex dynamics that is noisy but that has stayed within a stable regime for 400,000 years, and (2) acting as well-understood direct forcing that has removed the climate from this stable regime. Your calculation assumes that T and CO2 are directly functionally related, but we know that history and other variables play a role. I don’t see how you can reasonably ignore the Knutti & Heger evidence that shows a consensus on climate sensitivity.
I'm sorry Howard that you "... have to check [Ira] off as simply anti-science."
As a System Science PhD, I know the technical peer-review process is absolutely esssential. Science journal publications are correct a very high percentage of the time - but nothing is 100%
As Chairman of my PhD committee you taught me by example that skepticism is necessary in science. You were correct in your skepticism of the then reigning experts published in peer-reviewed Artificial Intelligence and Artificial Life journals. I was caught up in that mass delusion and you saved me!
I'd appreciate it if you would look into just two issues that trouble me about established climate science:
1) CO2 SENSITIVITY: Virtually all published climate scientists accept that a doubling of CO2 levels of 270 ppmv from pre-industrial times will result in a 2°C to 4.5°C rise in average surface temperatures. Over the past 150 years, according to GISS, temperatures have risen about 0.8°C while CO2 levels have gone up about 110 ppmv, which agrees with the low end estimate, assuming 100% of recent warming is due to CO2. But, since the minimum sensitivity explains all the actual data, how can the high end, more than twice as much, be explained?
2) ALTERING OFFICIAL TEMPERATURE DATA: One of the GISS emails, (released under a FOIA request) dated 14 Aug 2007, to GISS Director James Hansen from his co-author on peer-reviewed papers Mikiko Sato (PhD in Physics) details seven different revised GISS estimates of US surface temperatures for 1934 and 1998. An initial difference of over 0.5°C between 1934 and 1998 is reduced to virtually zero. What is the scientific explanation for the same group of climate scientists coming up with as large a difference as 0.5°C using the same old raw data records?
Ira Glickstein
Ira, you are right that I should not be complaining about your skepticism. That is the only position to take. But there are good skeptics and bad skeptics. There is a big difference between a detached, objective skeptic who can forcefully argue both sides, and an emotional crusading skeptic who has settled in his own mind which side he is on.
For some reason, when the theories and data are uncertain the skeptics tend to pick one side or the other, rather than keep an open mind. Climategate made the situation even worse. In any case, the two issues you raise, CO2 sensitivity and the use or misuse of data should certainly be questioned.
I think there is another type of bias here between theory and data. The hard scientists like physicists tend to be led by theory rather than data. In physics with very few exceptions (like discovery of X rays) theory is responsible for progress. The experiments to get data are few and are chosen by the theory. In softer sciences, there is much more data collection, and theory is often dependent on statistical analysis of large amounts of data.
I’m also thinking that hard-nosed realist C-minds tend to pay more attention to data, the “hard facts,” rather than to some abstract theory, which was thought up by fuzzy L-minded idealists!
My L-mind, on the other hand, tends to pay attention to the basic physical theory that says if you put enough extra CO2 in the atmosphere it will warm up. Anyway, the data are so uncertain and noisy that I’m not going to give up my theory because of some discrepancies in data.
Climate is a very complex chaotic system. It has multiple feedback mechanisms. Theory and math models do not have a very large role in understanding climate at the detailed level, but they do play a role in the larger picture. I know you, Howard, are very well aware of how a tiny change in initial conditions can result in immense differences in specific behaviors, yet, chaos theory permits prediction of certain common patterns.
At IBM/Lockheed Martin, I relied on experts in mathematical analysis. They had all kinds of wonderful tools like MatLab and Mathematica and used them to make estimates of data bus loading, performance of Doppler-inertial navigation, Kalman filters, and such.
Although they knew much more than me about statistics and math models, they sometimes missed the mark by a mile due to lack of a "feel" for physical systems. Therefore, I always did a "quick and dirty, back of the envelope calculation" (in those days I actually used a pencil and scrap paper :^) to get my own estimates of the answers. If they were within a factor of two of my numbers, I would go with their results. If not, I would ask them to describe their model assumptions to me again. Sometimes I would turn out to be the one who was mistaken. Other times, they turned out to have missed some critical issue. I call the latter kind of error "precicely wrong" - perfect arithmetic, precise to the eighth decimal place, but missing the target by a mile.
You say your "L-mind ... tends to pay attention to the basic physical theory that says if you put enough extra CO2 in the atmosphere it will warm up." Absolutely true, and a good physical-based model. CO2 is undoubtedly an important greenhouse gas (GHG) and GHGs are the reason the Earth is warm enough to support biological life. Humanity is on its way to doubling atmospheric CO2 from pre-industrial levels of 270 ppmv up to 540 ppmv within 100 years at the rate we are going. I am very concerned about this because it is unprecedented. OK so far?
Please have a look at this graph of peer-reviewed data published in the journal of the Royal Meteorological Society and of the Institute of Radio Engineers way back in the 1950's, when CO2 was 310 ppmv, around 80 ppmv less than it is now. Notice that the absorptivity for CO2, H2O and resultant Total Atmosphere is 1.0 in the long-wave bands (5 to 20 microns) where these GHGs absorb.
As a rough analogy, we can think of GHGs as forming a shade (or blanket) that prevents long-wave radiation in the affected bands from escaping. As I show in my first figure in this Topic (based on the above-linked peer-reviewed data), 100 ppmv of CO2 is like a thin blanket that blocks about 1/3 of the greenhouse radiation from escaping. Increasing to 200 ppmv blocks about 2/3 and 300 ppmv blocks virtually all the radiation in the affected bands.
Thus, increases beyond 300 ppmv will have little effect. Once you have piled on three blankets, the fourth or fifth has little to no further warming effect.
The BBC asked CRU Director Prof. Phil Jones "Do you agree that from 1995 to the present there has been no statistically-significant global warming?" His answer: "Yes, but only just."
CO2 levels have increased at the same high rate over the past 15 years and IPCC models, using high CO2 sensitivity assumptions, predict continued warming. They have been shown to be wrong, at least for the past 15 years. That indicates, to me at least, that their models over-emphasize the effects of CO2 beyond around 300 ppmv due to saturation of GHGs in the affected long-wave bands, and because their models do not recognize that clouds, on net, have a cooling effect.
Ira Glickstein
Since we've been talking about the importance of peer-review Howard, I'd appreciate your reaction to the May 27 2010 US Dept. of the Interior report about safety measures for oil drilling in deep water.
The Interior Department report says (page 37) "... draft recommendations were peer reviewed by seven experts identified by the National Academy of Engineering.".
But, according to the New Orleans Times-Picayune "Members of a panel of experts brought in to advise the Obama administration on how to address offshore drilling safety after the Deepwater Horizon disaster now say Interior Secretary Ken Salazar falsely implied they supported a six-month drilling moratorium they actually oppose."
The expert's joint letter said, "We broadly agree with the detailed recommendations in the report and compliment the Department of Interior for its efforts, ... However, we do not agree with the six-month blanket moratorium on floating drilling. A moratorium was added after the final review and was never agreed to by the contributors."
According to the Times-Picaune "An Interior Department spokeswoman agreed that the experts had not given their blessing for a moratorium, and said the department did not mean to leave the impression they had."
Ira Glickstein
Ira, here is one answer I found to your saturation analogy. It is at RealClimate.
I think we will have to wait 10 years before there is strong enough data to result in action.
I haven't grasped the significance of your last post.
As you probably know, Howard, RealClimate is a warmist Blog, run by GISS climate researchers. I have been following it for a few years to stay up with that end of the spectrum on Global Warming. I read the Weart/Pierrhumbert material when it came out and also the rebuttal on skeptic sites.
Here is a counter view that emphasizes the logarithmic effect of additional CO2 concentration.
The graphs in the above link show how every additional 20 ppmv of CO2 has a smaller and smaller effect on greenhouse effect warming, even if the saturation argument is a simplification due to the high altitude issues mentioned by Weart/Pierrehumbert.
CO2 sensitivity is expressed by everybody (including the Weart/Pierrehumbert RealClimate link you provided) as the temperature rise due to CO2 doubling. Thus, the temperature increase going from, say 10 to 20 ppmv, or 100 to 200 ppmv, will be about the same as going from 280 ppmv to 560 ppmv.
I agree with you that "we will have to wait 10 years before there is strong enough data to result in action." Indeed, if the stabilization of temperature over the past decade and a half persists for another decade, in the face of steady CO2 increases, the warmists will have lots of 'splaining to do. On the other hand, if we see a statistically significant increase in temperature of 0.1°C I will admit the warmists were correct.
Of course, that assumes climate scientists can accurately measure average global temperatures to that level of precision. The fact that GISS analysts were able to make a 0.5°C difference in average US surface temperatures between 1934 and 1998 disappear in seven re-analyses of the same raw data makes me doubt that assumption (see my Comment June 13, 2010 12:25 PM).
I am ready to take action now with an across the board Carbon Tax levied at well, mine, and port that is relatively simple to implement and hard to cheat on. The alternative, Cap and Trade, will not work and is loaded with political favoritism and opportunities to cheat. Indeed, that is one area where GISS Director James Hansen and I are in total agreement.
Ira Glickstein
PS: We've been discussing the importance of the "peer review" process and my concern that it has been distorted in the climate science domain for ideological and political reasons. I mentioned the oil spill experts recommended by the National Academy of Engineering because it shows how political operatives make a big deal about "peer review" by experts and then go ahead and imply that these experts supported all the recommendations. In fact, the experts were never shown the two most critical recommendations in the official report and, when the report came out the experts opposed them and the Interior Department had to apologize.
Post a Comment