I have posted on this a zillion times over here, and most of you are up to speed on this, but I posted this for my Coyote Blog readers and thought it would be good to repost over here.
Take all the psuedo-quasi-scientific stuff you read in the media about global warming. Of all that mess, it turns out there is really only one scientific question that really matters on the topic of man-made global warming: Feedback.
While the climate models are complex, and the actual climate even, err, complexer, we can shortcut the reaction of global temperatures to CO2 to a single figure called climate sensitivity. How many degrees of warming should the world expect for each doubling of CO2 concentrations (the relationship is logarithmic, so that is why sensitivity is based on doublings, rather than absolute increases — an increase of CO2 from 280 to 290 ppm should have a higher impact on temperatures than the increase from, say, 380 to 390 ppm).
The IPCC reached a climate sensitivity to CO2 of about 3C per doubling. More popular (at least in the media) catastrophic forecasts range from 5C on up to about any number you can imagine, way past any range one might consider reasonable.
But here is the key fact — Most folks, including the IPCC, believe the warming sensitivity from CO2 alone (before feedbacks) is around 1C or a bit higher (arch-alarmist Michael Mann did the research the IPCC relied on for this figure). All the rest of the sensitivity between this 1C and 3C or 5C or whatever the forecast is comes from feedbacks (e.g. hotter weather melts ice, which causes less sunlight to be reflected, which warms the world more). Feedbacks, by the way can be negative as well, acting to reduce the warming effect. In fact, most feedbacks in our physical world are negative, but alarmist climate scientists tend to assume very high positive feedbacks.
What this means is that 70-80% or more of the warming in catastrophic warming forecasts comes from feedback, not CO2 acting alone. If it turns out that feedbacks are not wildly positive, or even are negative, then the climate sensitivity is 1C or less, and we likely will see little warming over the next century due to man.
This means that the only really important question in the manmade global warming debate is the sign and magnitude of feedbacks. And how much of this have you seen in the media? About zero? Nearly 100% of what you see in the media is not only so much bullshit (like whether global warming is causing the cold weather this year) but it is also irrelevant. Entirely tangential to the core question. Its all so much magician handwaving trying to hide what is going on, or in this case not going on, with the other hand.
To this end, Dr. Roy Spencer has a nice update. Parts are a bit dense, but the first half explains this feedback question in layman’s terms. The second half shows some attempts to quantify feedback. His message is basically that no one knows even the sign and much less the magnitude of feedback, but the empirical data we are starting to see (which has admitted flaws) points to negative rather than positive feedback, at least in the short term. His analysis looks at the change in radiative heat transfer in and out of the earth as measured by satellites around transient peaks in ocean temperatures (oceans are the world’s temperature flywheel — most of the Earth’s surface heat content is in the oceans).
Read it all, but this is an interesting note:
In fact, NO ONE HAS YET FOUND A WAY WITH OBSERVATIONAL DATA TO TEST CLIMATE MODEL SENSITIVITY. This means we have no idea which of the climate models projections are more likely to come true.
This dirty little secret of the climate modeling community is seldom mentioned outside the community. Don’t tell anyone I told you.
This is why climate researchers talk about probable ranges of climate sensitivity. Whatever that means!…there is no statistical probability involved with one-of-a-kind events like global warming!
There is HUGE uncertainty on this issue. And I will continue to contend that this uncertainty is a DIRECT RESULT of researchers not distinguishing between cause and effect when analyzing data.
If you find this topic interesting, I recommend my video and/or powerpoint presentation to you.
Dear CS:
I just stumbled on to you through a Twitter lead. I am a 70 y.o. retired businessman. I have no background in science except a pretty deep understanding of weather forecasting gained when I was a Marine Pilot back in the 70’s & 80’s.
Nevertheless, I have never believed in the GW scare – from day one.
I look forward to reading your posts.
I also enjoy the area of feedbacks. I have read Andy Dessler’s paper on the cloud feedback issue. With ten years of data from EREB satellites, its giving an indication that could feedback will be mostly positive with a small chance of being negative. Which is in agreement with what the climate models are showing. If you go into realclimate there are two very good feedback articles. Several peer reviewed studies are showing mostly positive feedback.
http://www.realclimate.org/index.php/archives/2010/11/more-on-feedbacks/
What I find interesting is that in spite of the overwhelming evidence, people still doubt AGW. The evidnece is so overwhelming, scientists are considering calling this geological event the anthropocene. Humans have overwhelmed the climate.
Renewable
Positive feedbacks work on non CO2 warming too. The records were started at the end of the Little Ice Age [Maunder minimum] when the sun was quiescent. Since then it has warmed about 1/2 ° C per century with a 60 year sine wave on top of it. The cycle has occurred 3 times since records have been been kept so CO2 is unlikely to be the cause. The cycle causes no overall warming but it scares the chicken littles !
When the cycle is at it’s highest the chicken littles pass the Kyoto protocol. When it is at it’s lowest we get global cooling scares.
The real warming is the sun warming and the associated feedbacks which continue to today. Luckily for us it is very mild at 1/2 ° C per century. Dr Hansen posits feedbacks lasting hundreds of years for CO2 warming so it is unreasonable to believe sun warming acts diffeently.
The cycle follows the PDO. When the PDO is positive we have more El Nino’s than La Nina’s and of course it warms. From 1978 to 1998 the PDO was positive the whole time and of course it warmed. No CO2 needed.
From 1940 to 1978 the PDO was negative and of course it cooled. No CO2 needed.
From 1998 to present there were periods of excess El Nino’s and periods of excess La Nina’s and the temperature was flat despite tons of CO2 emissions. Thee is good reason to doubt CO2 has anything to do with warming.
Here is the evidence [enjoy]:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
http://jisao.washington.edu/pdo/img/pdo_latest.jpeg
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
Here is a peer reviewed paper which explains it better than I can.
http://www.reportingclimatescience.com/news-stories/article/global-warming-temperature-rise-may-be-lower-than-predicted.html
Hi Climate Skeptic
Do you know you have made it in to the Campaign Against Climate Change – Skeptic Blogs Alerts (http://www.campaigncc.org/node/384) which I find quite amusing, hence I suppose the opposing opinion from renewable guy. I have signed up for this myself and that’s what lead me here. Renewable guy lists Real Climate – a place I do not go due to the rhetoric and got with you that one standard of posts. I think most of the studies he is referring to are modelled studies. But hey we can agree to disagree.
Just thought you should know. Will visit more often. Thank you Campaign Against Climate Change.
http://geotest.tamu.edu/userfiles/216/dessler10b.pdf
The above is based in data and observation.
The real climate article is about feedback in the climate system. Just science. For making an argument, if you wish, there is skeptical science below.
http://www.skepticalscience.com/an-even-cloudier-outlook-for-low-climate-sensitivity.html
Feedback is a critical topic but I have a feeling that climatology is about ready to get involved in a great experiment that mother nature has decided to run. The consensus view is that CO2 is like a great big thermostat, when CO2 concentrations go up the ave. global temperature goes up and if it went down, the ave. global temperature will drop. So CO2 concentrations are up more than 30% in the last 150 years and they will likely rise by 2-3 ppm per year for most of the century. So even though it may seem that we are having a lot of snow and cold in the US, Europe and parts of the far east, consensus scientists (now) say both cold and hot weather extremes are consistant with their models. In fact it seems almost any weather pattern is consistent with the model predictions except for one, cooling by a couple of tenths of a degree over a period of a decade or more.
But meteorologists who study the history of the weather and climate patterns indicated that with the PDO shifted to a cool phase, a cooling Atlantic basin and a sun cycle dropping to it lowest level of activity in a century, the historic signs are saying we are going to get cooler.
So Mother Nature and human GHG emissions are in a contest of sorts. If CO2 is the driver we should expect to see about 0.2C warming over the next 10-15 years. If historic weather cycles continue as before, coupled with a quiet sun, we might expect to see 0.2C cooling. (Joe Bastardi is already taking bets on this.)
My take is this, while I am skeptical of the consensus position, if the climate temperature trend is pushing 0.2 degrees warmer by the end of the decade, the consensus is right. If its cooled by that amount, the GHG theory is not the catastrophe it has been billed. If the trend is close to 0, well I guess we’ll just keep arguing.
The topic of man-made global warming is primarily based on the greenhouse gas theory. This theory has been the subject of so much debate, it has seriously divided the scientific community.
Scientists can debate all the global warming issues such as feedback etc etc etc, but the real question they really do need to confront is a question posed by Alan Siddons in Chapter 5 of the recently published book, ‘Slaying the Dragon: Death of The Greenhouse Gas Theory’:
“If scientists of the past had known that temperature of every planet with an atmosphere rises in direct proportion to atmospheric pressure, do you suppose they would have come up with a theory that attributed heating to the presence of certain trace gases that occupy less than 1 percent of our atmosphere?”
The honest answer has to be “NO!”
As Alan Siddons has explained in the book, the theory of the greenhouse effect was concocted for the purpose of explaining why the earth is warmer than predicted. Yet every planet is warmer than predicted.
I urge everyone to simply read what Alan Siddons outlines in the book… then, based on the laws of probability, you decide whether Alan Siddons is right or whether he is wrong.
Alan Siddons seems to be correct, in which case, it confirms that the man-made global warming concern, promoted by the IPCC, has truly been a case of ‘barking up the wrong tree’ … a very costly one indeed!
Sean
Very perceptive. I agree and what we post here means very little. The PDO has shifted negative and the sun is inactive so we should see a couple of decades of cooling. [See my last post]
In the temperature record so far there has never been warming without an excess of El Nino’s over La Nina’s, [1978 to 1998] which is another way of saying positive PDO.
The alarmists will counter that without CO2 there would have been even more cooling and like the Japanese soldiers that surrendered in the 60’s keep soldiering on.
I predict that the public will not buy it and the cooling will be the death knell of “Global Warming/Climate Change/Climate disruption”.
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In fact, NO ONE HAS YET FOUND A WAY WITH OBSERVATIONAL DATA TO TEST CLIMATE MODEL SENSITIVITY.
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http://www.skepticalscience.com/climate-sensitivity.htm
It appears they (the scientists) have done just that. Dr. Roy Spencer knows this also. Which makes him quite a bit less than honest in this matter.
Climate sensitivity from empirical observations
There have been a number of studies that calculate climate sensitivity directly from empirical observations, independent of models.
•Lorius 1990 examined Vostok ice core data and calculates a range of 3 to 4°C.
•Hoffert 1992 reconstructs two paleoclimate records (one colder, one warmer) to yield a range 1.4 to 3.2°C.
•Hansen 1993 looks at the last 20,000 years when the last ice age ended and empirically calculates a climate sensitivity of 3 ± 1°C.
•Gregory 2002 used observations of ocean heat uptake to calculate a minimum climate sensitivity of 1.5.
•Chylek 2007 examines the period from the Last Glacial Maximum to Holocene transition. They calculate a climate sensitivy range of 1.3°C and 2.3°C.
•Tung 2007 performs statistical analysis on 20th century temperature response to the solar cycle to calculate a range 2.3 to 4.1°C.
•Bender 2010 looks at the climate response to the 1991 Mount Pinatubo eruption to constrain climate sensitivity to 1.7 to 4.1°C.
There’s no point debate the global warming scammers. We know with certainty the global temperature will cool and we will win without having to fire a shot.
Practically everyone knows AGW is a scam.
Renewable
In the last 60 years when we have accurate records of temperature and El Nino/La Nina’s there has never been a time when it warmed without excess El Nino’s over La Nina’s.[78 to 98] The El Nino’s themselves would explain the warming. Who needs CO2?
When the reverse was true [40 to 78] it cooled. CO2 had nothing to do with it. In fact the world was at war part of that time emitting CO2 like crazy.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
As far as sensitivity is concerned it might be zero ! The observed temperature record does not show any sensitivity at all.
When I see warming without excess El Nino’s I will believe CO2 has done something.
Jack is right, he said “There’s no point debate the global warming scammers. We know with certainty the global temperature will cool and we will win without having to fire a shot.”
The number of La Nina’s is predicted to be greater than El Nino’s for the next 10 to 20 years. If the theory is correct the public will see several years of cooling and realize they have been “had”!
“Jack:
There’s no point debate the global warming scammers. We know with certainty the global temperature will cool and we will win without having to fire a shot.
Practically everyone knows AGW is a scam.”
@ a couple of you, first, yes I believe the cooling that is soon to occur will put a damp on the scare mongering for warmth. Never fire a shot and win, but in the mean time we do need to keep the truth out there so that policies are fought over and not implemented. Energy rationing and subsidies are the most dangerous, as they will lead to cronyism and other “friendly” business deals based on just making environmentalists money.
As my first sceptic blog (I have been a reader but not really a poster for a long time) I find it funny that you made the CACC list…that is indeed something.
For Steven, welcome, this is a very good blog, Warren posts very well despite being busy, but sometimes he doesn’t post for awhile. i understand that and still read quite often. If you want some good reads just post here and I can give you good links, but most of the links to the right are very good as well.
I would never tell someone to just read one side of the story, so make sure to read what realclimate and scepticscience say, and then read wattsupwiththat this site and possibly a moderate position such as Lucia’s.
Although I will say this, the alarmist or AGW sites will tend to censor all of your posts and will just tell you you are wrong if they don’t.
Keep up the good work….only a couple more years until we can win the battle for good.
Mervyn is correct. The vast majority of the greenhouse effect has NOTHING to do with CO2. Planets with thicker atmospheres have a more pronounced greenhouse effect because of the way the Maxwell Boltzmann distribution works out in a gravitational field. This is what sets the atmosphere’s lapse rate. While CO2’s absorption/emission and the lapse rate HAVE been verified, the greenhouse effect from CO2’s absorption has not. Looking to Venus with FIVE HUNDRED THOUSAND TIMES THE CO2…we find that essentially all of the greenhouse effect is explainable by the lapse rate and cloud tops being the effective radiating surface.
The piss poor correlation between CO2 and temperature in the paleoclimate data is due to the fact that there is a temperature component in CO2’s removal. In all cases the correlation works equally well both ways. Limiting it to more recent data, even if one were stupid enough to attribute 100% of the warming of the 1980-2000s warming period to CO2, the idea of powerful GHG forcing falls flat…with a max of about 2C of warming by 2100. If one instead attributes 100% of the warming since the last warm period to CO2…we’re left with an utterly unremarkable and harmless…1C total anomaly by 2100.
Hi Netdr,
You will believe what you want to believe. Here is the basic science.
Water is a condensable GHG and co2 is a stable GHG. CO2 is the driver of how much H20 is in the atmosphere. The main historical basis for understanding past climate going back through time is to get an idea of how much co2 is in the atmosphere.
You may be finding comfort amongst people of a common belief, but in the science world this is one of the pillars of understanding climate. Richard Lindzen, ROy Spencer, and even the author of this article knows that co2 is an effective GHG. Otherwise it would be iceball earth.
http://www.giss.nasa.gov/research/briefs/lacis_01/
A study by GISS climate scientists recently published in the journal Science shows that atmospheric CO2 operates as a thermostat to control the temperature of Earth.
http://www.skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm
An enhanced greenhouse effect from CO2 has been confirmed by multiple lines of empirical evidence. Satellite measurements of infrared spectra over the past 40 years observe less energy escaping to space at the wavelengths associated with CO2. Surface measurements find more downward infrared radiation warming the planet’s surface. This provides a direct, empirical causal link between CO2 and global warming.
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I don’t know where you get your information from that the conection between co2 and temperature is weak. John Tyndal established that connection back in 1862. There has been 150 years to work out the kinks. The co2 temperature link is quite strongly worked out.
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But here is the key fact — Most folks, including the IPCC, believe the warming sensitivity from CO2 alone (before feedbacks) is around 1C or a bit higher (arch-alarmist Michael Mann did the research the IPCC relied on for this figure).
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The author of this blog article supports the co2-temperature link. The issue becomes one of “what are the feedback values of the different GHG’s”
Skeptics (or deniers) take your pick, will argue that the feedback may even be negative. Richard Lindzen thinks that the feedback will be negative. Almost all the climatologists don’t agree with him.
Cloud feedback is one the unknown areas of feedback where there is uncertainty. In a previous posting on this thread I have an article by Dr.Andy Dessler with observations from satellites showing a hint at positive feedback with clouds. In his paper, the satellite observations and models are close in agreement. What this means is as the earth gets warmer, the cloud cover will decrease with temperature to allow more of the sun to heat the earth.
Jack:
There’s no point debate the global warming scammers. We know with certainty the global temperature will cool and we will win without having to fire a shot.
Practically everyone knows AGW is a scam
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I’ll talk science and you can talk scam. The word is so overused that you have worn out its meaning.
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What this means is that 70-80% or more of the warming in catastrophic warming forecasts comes from feedback, not CO2 acting alone. If it turns out that feedbacks are not wildly positive, or even are negative, then the climate sensitivity is 1C or less, and we likely will see little warming over the next century due to man.
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If you to follow the same level of validation that science goes through, then your statement rests at the very low level of opinion.
http://www.skepticalscience.com/detailed-look-at-climate-sensitivity.html
The scientists have done their homework on this. Why not read and learn about what you doubt?
Everything “Renewable Guy” has posted so far has amounted to saying “is so!”. Every one of the cited “empirical” based studies was either computer model based, or a speculative proxy. That’s NOT empirical data.
There’s no evidence, as opposed to a mountain of computer modeling, that CO2 is some kind of “global thermostat” at the levels of sensitivity AGW involves.
The Jury’s still out on AGW, as a Scientific Theory (no need to diverge into the areas of policy formation and economics, which don’t really involve Science at all)…and simply believing it is won’t make it so.
In fact, if it weren’t for the attachment of non-Scientific policy, political and economic factors to an otherwise unremarkable area of Scientific work, this circumstance wouldn’t be an issue of any significant argument, except perhaps to the extent of a bit of internecine bickering over a bit of grant money or academic posting of no real interest beyond those involved.
But the onset of the ‘popular movement’ (or maybe new religion) of ‘Environmentalism’ combined with its adaption to political agendas, drags the Science into the gutter with all the priests, politicians and pundits.
The role of CO2 in long-term climate, especially with respect to human emissions, will probably not be well understood for decades (as many as are needed to really develop that empirical data the commentator cites, erroneously). In the meantime, thankfully, the statistics of available empirical data strongly indicates that catastrophic predictions of impacts from climate change are wrong. Actual observations appear unexceptional and well withing the range of normal variation, and historic rates of change over time. As normal adaptive behavior has managed even greater volatility in the historic past, even without benefit of current technologies, it’s vanishingly unlikely there’s anything to fear from human induced Greenhouse gas driven Climate Change…even were it left completely unbridled.
ADiff:
Everything “Renewable Guy” has posted so far has amounted to saying “is so!”. Every one of the cited “empirical” based studies was either computer model based, or a speculative proxy. That’s NOT empirical data.
There’s no evidence, as opposed to a mountain of computer modeling, that CO2 is some kind of “global thermostat” at the levels of sensitivity AGW involves.
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http://www.skepticalscience.com/climate-models-intermediate.htm
There are various difficulties in predicting future climate. The behaviour of the sun is difficult to predict. Short-term disturbances like El Nino or volcanic eruptions are difficult to model. Nevertheless, the major forcings that drive climate are well understood. In 1988, James Hansen projected future temperature trends (Hansen 1988). Those initial projections show good agreement with subsequent observations (Hansen 2006).
Hansen got it right over 20 years ago. Documented and on paper. James Hansen has been out front in climate modeling.
http://en.wikipedia.org/wiki/James_Hansen#Responsibility_for_climate_change
Hansen notes that in determining responsibility for climate change, the effect of greenhouse gas emissions on climate is not determined by current emissions, but by accumulated emissions over the lifetime of greenhouse gases in the atmosphere. By this measure the U.K. is still the largest single cause of climate change, followed by the U.S. and Germany, even though its current emissions are surpassed by the Peoples Republic of China.[52]
But that’s nothing but yet more rhetorical fluff Renewable Guy.
Based on earlier predictions (Hansen, Gore, et al.) the world should be flooded, dried up, and wasted by now.
But none of that has happened, and doesn’t appear to be happening.
What can I say about a theory whose predictions don’t pan out?
The debate about the (yet undetermined) magnitude and sign of sensitivity to CO2 is a tempest in a tea-pot.
It’s the claims of pending disaster that have proven AGW so much ‘hot air’. Is the climate changing? Almost certainly, just as it always has. Are humans a factor? Again, almost certainly, although how, ahd how much, are still not clearly understood. But one thing is becoming extremely clear: there is no ‘Emergency’, no ‘Crisis’…and no reason to act as if there were. There’s no imperative for ‘action’, moral or otherwise, and certainly nothing to spend a fortune on or get particularly upset about one way or another.
Once it becomes generally accepted that Emperor has no clothes, all the ‘heat’ will go out of the discussion, and it can get back to real Science again.
ADiff:
But that’s nothing but yet more rhetorical fluff Renewable Guy.
Based on earlier predictions (Hansen, Gore, et al.) the world should be flooded, dried up, and wasted by now.
But none of that has happened, and doesn’t appear to be happening.
What can I say about a theory whose predictions don’t pan out?
The debate about the (yet undetermined) magnitude and sign of sensitivity to CO2 is a tempest in a tea-pot.
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Your point of view differs with the observations coming in from the science community. Below is a pictoral of a summary of what is being observed.
Wish all you want, co2 will help the earth get warmer. Which shifts life on the planet forcing adaptation. Past changes in climate are accounted for in energy.
http://www.skepticalscience.com/graphics/Warming_Indicators_1024.jpg
Possibly you would like to join a good discussion on TES “the environemnt site”. There are interesting talent on both sides of the argument there that you might enjoy.
Renewable Guy,
We’ve been over this ground on this site before, Hansen’s 1988 predictions where not at all right. They completely missed the flattening out, or even decreasing, temperature trend from 1998-pressent. Unless, well, you want to use his “scenario C” with greatly reduced CO2 emissions that didn’t happen….
Line up this with his predictions and just tell me what your eyeballs see: http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_Dec_102.gif. Even looking at the “warmer” GISS temps, one has to give a lot of weight to only a few recent higher temp records just to get to the middle ground between scenario C and B. And as any good statistician would know, we tend to make too much out of the end points on our data, expecting a continuation of a recent trend, when more likely we’ll see a regression to the mean (which we’ve already seen).
We also have to remember that predictions turning out to be (sort of) right, does not prove that your method for predicting that thing will actually continue to work (see Washington Redskins games predicting presidential elections). This is the basic problem with models. You have to validate them through experimentation, otherwise they are little more than guess work that may or may not be right for a while and then turn out to be greatly flawed.
“Renewable Guy:” referring to the Dessler et al paper. This one has been debunked and can be done so by anyone knowing fundamental error analysis. Dessler have used too few data to draw any valid conclusions on the sign of the feedback. In fact within the 95 % probability intervall there is even room for a negative one!
One of many sources:
http://landshape.org/enm/dessler-zhang-and-yang-fail-significance-tests/#
There is still no valid observation that can confirm the assumed feedback data in the models much as you would like that or as much as the various propaganda sites state this. Results from running computer models are only seen as evidence in climate science. Nowhere else in science – I am aware of.
Wally:
Renewable Guy,
We’ve been over this ground on this site before, Hansen’s 1988 predictions where not at all right. They completely missed the flattening out, or even decreasing, temperature trend from 1998-pressent. Unless, well, you want to use his “scenario C” with greatly reduced CO2 emissions that didn’t happen….
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What’s really expected of the projection is to get the general temperature correct. Today’s models come closer to the detail you are calling out for. Keep in mind he was guessing at what future GHG emissions would be. No model can predict that.
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http://www.skepticalscience.com/news.php?n=380&p=3http://www.skepticalscience.com/news.php?n=380&p=3
Misrepresentations of Hansen’s Projections
The ‘Hansen was wrong’ myth originated from testimony by scientist Pat Michaels before US House of Representatives in which he claimed “Ground-based temperatures from the IPCC show a rise of 0.11°C, or more than four times less than Hansen predicted….The forecast made in 1988 was an astounding failure.”
This is an astonishingly false statement to make, particularly before the US Congress. It was also reproduced in Michael Crichton’s science fiction novel State of Fear, which featured a scientist claiming that Hansen’s 1988 projections were “overestimated by 300 percent.”
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The article I chose goes into a great deal of detail supporting Hansen’s 1988 paper. It appears that Patrick Micheals erased Hansen’s b and c scenario, leaving the agressive A scenario of CO2 emissions. This is a very common tactic amongst professional lobbyists to make their points. Hansen’s B scenario comes the closest to the actual CO2 emissions. But this is not about guessing co2 emissions. Its about projecting what the possible temperature outcome might be.
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Total Scenario B greenhouse gas radiative forcing from 1984 to 2010 = 1.1 W/m2
The actual greenhouse gas forcing from 1984 to 2010 was approximately 1.06 W/m2 (NASA GISS). Thus the greenhouse gas radiative forcing in Scenario B was too high by about 5%.
http://www.skepticalscience.com/news.php?n=380&p=3
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Being off by 5% in scenario B is astoundingly good.
Which means Hansen understands feedbacks very well along with the warming caused by the CO2 itself.
Jan Lindstrom
Below is the beginning of his paper. This was published in 2010. My apologies for not posting the link. In this paper he talks about that it is to soon to come to a solid conclusion about positive feedback from clouds. But the conclusion is that it hints at what the models have been showing all along. He did this with 10 years of satellite data. 30 years of satellite data will be the more appropriate amount.
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http://geotest.tamu.edu/userfiles/216/dessler10b.pdf
A Determination of the Cloud
Feedback from Climate Variations
over the Past Decade
A. E. Dessler
Estimates of Earth’s climate sensitivity are uncertain, largely because of uncertainty in the
long-term cloud feedback. I estimated the magnitude of the cloud feedback in response to short-term
climate variations by analyzing the top-of-atmosphere radiation budget from March 2000 to February
2010. Over this period, the short-term cloud feedback had a magnitude of 0.54 T 0.74 (2s) watts
per square meter per kelvin, meaning that it is likely positive. A small negative feedback is possible,
but one large enough to cancel the climate’s positive feedbacks is not supported by these observations.
Both long- and short-wave components of short-term cloud feedback are also likely positive.
Calculations of short-term cloud feedback in climate models yield a similar feedback. I find no
correlation in the models between the short- and long-term cloud feedbacks.
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Renewable guy
Hansen is a crackpot that fails time and time again. And where the heck do you get 5% from for scenario B? That projection is off by about 25% BUT it was for a period in which warming should have been expected. The 1980-present warming was unremarkable and nearly identical to the warming period from about 1913-1943. http://woodfortrees.org/plot/hadcrut3vgl/mean:60
As I said, Hansen is a crackpot and hasn’t a darn clue what he’s talking about…because HIS projection assumes that CO2 is the source of most of the warming.
Poitsplace:
As I said, Hansen is a crackpot and hasn’t a darn clue what he’s talking about…because HIS projection assumes that CO2 is the source of most of the warming.
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Gavin Schmidt helpfully provides the annual atmospheric concentration of these and other compounds in Hansen’s Scenarios. The projected concentrations in 1984 and 2010 in Scenario B (in parts per million or billion by volume [ppmv and ppbv]) are shown in Table 1.
Table 1: Scenario B greenhouse gas (GHG) concentration in 1984, as projected by Hansen’s Scenario B in 2010, and actual concentration in 2010
http://www.skepticalscience.com/news.php?n=380&p=3
GHG 1984 Scen B 2010 actual 2010
CO2 344 ppmv 389 ppmv 392 ppmv
N2O 304 ppbv 329 ppbv 323 ppbv
CH4 1750 ppbv 2220 ppbv 1788 ppbv
CCl3F 0.22 ppbv 0.54 ppbv 0.24 ppbv
CCl2F2 .038 ppbv 0.94 ppbv 0.54 ppbv
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Again, remember that the model isn’t about knowing what the future emissions are. Its about guessing future emissions and then projecting the different climate conditions. His guess of future emissions in scenario B was very close to actual emissions. The math is worked for you in the link.
http://en.wikipedia.org/wiki/James_Hansen
James Hansen has won several awards in science. You get those awards because you are right about the science in an impressive way.
You are entitled to your opinion about Hansen. The professional scientists as a whole disagree with you.
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The 1980-present warming was unremarkable and nearly identical to the warming period from about 1913-1943. http://woodfortrees.org/plot/hadcrut3vgl/mean:60
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Climate change varies. But it is consistently upwards as is your graph. Climate change shows up in long term averages. I’m actually surprised by the pick of your graph to prove your point.
Warren Meyer,
The impact of feedbacks is worse than you thought. It may account for 70%-80% of the predicted temperature rise, but this is not what is important. Is the catastrophic consequences that follow. These rise exponentially with temperature, so without the feedbacks > 95% of the catastrophe does not happen. Take a look at the Climate Impacts on page 10 of the UNIPCC Summary for policy makers, accessed from this page. http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms1.html
Renewable Guy,
Can you help?
1. Why in criticizing Spencer’s comment “NO ONE HAS YET FOUND A WAY WITH OBSERVATIONAL DATA TO TEST CLIMATE MODEL SENSITIVITY “, you direct us first to a posting that discusses measuring feedbacks using equations?
2. You quote six studies of observational tests of climate sensitivity. The first is a 1990 study of Vostock Ice Core Samples. At that time, it was believed that the co-incidence of CO2 to temperature rises showed a strong influence of CO2 on temperature. Al Gore’s Inconvenient Truth movie has a nice graph of this. Problem is that more recent studies show that CO2 rises lagged temperature rises by hundreds of years. So what looked to be a confirmation of positive feedback was no such thing.
3. When you say “Hansen got it right over 20 years ago” do you mean the same Dr Hansen that said in 1986 that temperatures would be 3 to 4 degrees (fahrenheit?) higher in 2010 to 2020?
http://hauntingthelibrary.wordpress.com/2011/01/06/james-hansen-1986-within-15-years-temps-will-be-hotter-than-past-100000-years/
Hansen’s model’s of 1989 were correct in predicting CO2 levels and temperature would rise. However, CO2 levels have risen faster than his highest forecast and temperature rise undershot. http://wattsupwiththat.com/2010/08/13/is-jim-hansens-global-temperature-skillful/
This suggests to me that Hansen’s models strongly over-estimated feedback. The other explanation to this lack of warming – of the aerosols – is weak, as explained in Warren’s presentation at around 61 minutes (slide 62).
Renewable Guy perhaps you might want to read this about your favorite website (skepticalscience.com)
http://motls.blogspot.com/2010/03/john-cook-skeptical-science.html
And as for Cook’s empirical evidence section that you gave to earlier, I suggest you read this (point 2)
http://joannenova.com.au/2010/07/the-unskeptical-guide-to-the-skeptics-handbook/
and this
http://www.climateviews.com/Climate_Views/Download_Articles_files/CookRebuttalb.pdf
and this
http://www.americanthinker.com/printpage/?url=http://www.americanthinker.com/2010/02/the_agw_smoking_gun.html
And read this about Desslers paper
http://joannenova.com.au/2010/11/dessler-2010-how-to-call-vast-amounts-of-data-spurious/
And here are some more articles about skeptical science that you might be interested in
http://joannenova.com.au/2010/06/how-john-cook-unskeptically-believes-in-a-hotspot-that-thermometers-cant-find/
http://joannenova.com.au/2010/07/the-unskeptical-guide-to-the-skeptics-handbook/
http://stevengoddard.wordpress.com/2010/10/03/as-usual-john-cook-doesnt-get-it/
Renewable Guy,
“Today’s models come closer to the detail you are calling out for.”
Today’s models that can’t be tested for 30 years, at minimum?
“Keep in mind he was guessing at what future GHG emissions would be. No model can predict that.”
This is immaterial to testing the model after the fact (which we of course can’t actually do, but climatologists seem to wish they can). Just plug in the recorded CO2 concentrations and be done with it.
“Being off by 5% in scenario B is astoundingly good.”
Remember this is calculated radiative forcing from CO2 and other gases, not temps.
http://theinconvenientskeptic.com/2010/12/mass-accumulation-of-greenlands-ice-sheets/
http://theinconvenientskeptic.com/2011/01/understanding-scientific-bias-part-2/
And here’s a fact about John Cook, which I think you should know
wattsupwiththat.com/2010/09/27/skeptical-science-john-cook-embarrassing-himself/#comment-493050
I have never seen an answer to a question I have had in my mind for years: Why is CO2 necessary for runaway temperature increase?
If, for any reason, there is a slight increase in ocean temperature, H2O partial pressure increases. This puts more IR absorbing material in the atmosphere. This causes more warming, increasing H2O partial pressure even more. Thus, temperature should run away even without CO2, but it doesn’t. There must be some mechanism that offsets this effect. Could it be that the H2O gives a negative feed back, as many have suggested? Is there some other stabilizing mechanism that has been postulated?
Adam:
Renewable Guy perhaps you might want to read this about your favorite website (skepticalscience.com)
http://motls.blogspot.com/2010/03/john-cook-skeptical-science.html
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Pick any topic you want from the long list there. I will enjoy the discussion. I have seen this blogger before.
Adam:
And read this about Desslers paper
http://joannenova.com.au/2010/11/dessler-2010-how-to-call-vast-amounts-of-data-spurious/
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Interesting paper on a blog. If she really has something going as to a legitimate critcism, she should publish a rebuttal in a reputable science journal. Jo Nova writes this for the skeptics and not for the science community.
I invite you to discuss the details of what she is talking about.
Wally
Today’s models that can’t be tested for 30 years, at minimum?
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The models are also tested with hindcasting.
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Remember this is calculated radiative forcing from CO2 and other gases, not temps.
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There is relationship of radiative forcing to temperature.
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http://www.skepticalscience.com/climate-sensitivity-advanced.htm
Climate sensitivity is the amount the planet will warm when accounting for the various feedbacks affecting the global climate. The relevant formula is:
dT = λ*dF
Where ‘dT’ is the change in the Earth’s average surface temperature, ‘λ’ is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W m-2]), and ‘dF’ is the radiative forcing, which is discussed in further detail in the Advanced rebuttal to the ‘CO2 effect is weak’ argument.
Wally,
http://theinconvenientskeptic.com/2010/12/mass-accumulation-of-greenlands-ice-sheets/
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All indicators are positive that the temperature of the surface of the earth is increasing. With that ice melts. The GRACE satellite measurements show that. You have a tough argument to make that if the temperature rises the ice won’t melt. If co2 increases the temperature won’t increase? Go for it.
http://www.skepticalscience.com/Latest-GRACE-data-record-ice-loss-in-2010.html
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http://theinconvenientskeptic.com/2011/01/understanding-scientific-bias-part-2/
Scientists aren’t a court of “a scientist can do no wrong”. There are certain behaviours of scientists, that they are out for life. The fossil fuel lobbyists make an entire life of dishonesty.
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And here’s a fact about John Cook, which I think you should know
wattsupwiththat.com/2010/09/27/skeptical-science-john-cook-embarrassing-himself/#comment-493050
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The term “denier skeptic” is what the whole thing is about. So Anthony holds himself in high regard and now he is injured. Its time for him to get over himself. He chose to come into a an arena of rough and tumble discussion. If he is that sensitive, then what is doing here to begin with. You have to have thick skin to play this game.
Sorry I didn’t mean Wally on the last one, I should have put Adam.
Ted Rado
I wouldn’t know this in detail. Venus which is very hot, does not really have runaway warming, but a very high radiation balance. Venus is 95% CO2.
There does seem to be a radiative limit when all factors are taken into account.
I have read that Mars has 95 % CO2 but is very cold.
“Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%). The average pressure on the surface of Mars is only about 7 millibars (less than 1% of Earth’s)”
Martian surface temperatures range widely from as little as 140 K (-133 C, -207 F) at the winter pole to almost 300 K (27 C, 80 F) on the day side during summer.
http://nineplanets.org/mars.html
Venus has a very dense atmosphere. If you measure at the altitude where it is 1 earth atmosphere the temperature is Earth like. The surface is like being at a super low death valley.
“The pressure of Venus’ atmosphere at the surface is 90 atmospheres (about the same as the pressure at a depth of 1 km in Earth’s oceans). It is composed mostly of carbon dioxide.”
Nineplanets.org [now 8 planets?]
The point is that CO2 seems to be over rated as a GHG. Most of the warming on earth, comes from water vapor which reacts to any warming even solar. The sign and magnitude of this reaction is unknown.
“Pick any topic you want from the long list there. I will enjoy the discussion. I have seen this blogger before.”
Renewable guy, if you want perhaps you could go through and show where Lubos is wrong. I’m sure he’d be happy to reply.
As for your one point I choose this one
http://www.skepticalscience.com/Arctic-sea-ice-melt-natural-or-man-made-intermediate.htm
Cook is attempting to refute the argument that Arctic ice melt is natural.
His arguments are pretty flawed. He doesn’t provide any observations to support hos claim that Arctic melt is anthropogenic. What he merely says is that its melting faster than the models predict, so therefore it must be man made.
Now Renewable Guy, Cook does not provide any evidence whatsoever that the Arctic warming is unprecedented or unusual. He provides no papers, that provide actual empiracal evidence for a link between co2 and the arctic climate. He also fails to mention that we only have 30 years of satellite data on arctic sea ice, so that will limit our knowledge.
And notice how Cook cherry picks the end year of his graph as 2007. Because if he included the next few years people would have seen that the 2007 ice loss grew right back.
http://www.skepticalscience.com/images/arctic_seaice.gif
Renewable Guy Cook’s article is just a weak simple strawman argument, just like pretty much everything else on his website.
Now, here are some papers, which Cook didn’t reference in his article
“Greenland warming of 1920–1930 and 1995–2005”
http://www.joelschwartz.com/pdfs/Chylek.pdf
Abstract
“We provide an analysis of Greenland temperature
records to compare the current (1995– 2005) warming
period with the previous (1920 – 1930) Greenland warming.
We find that the current Greenland warming is not
unprecedented in recent Greenland history. Temperature
increases in the two warming periods are of a similar
magnitude, however, the rate of warming in 1920 – 1930
was about 50% higher than that in 1995 – 2005.”
Conclusion
“An important question is to what extent can the
current (1995 – 2005) temperature increase in Greenland
coastal regions be interpreted as evidence of man-induced
global warming? Although there has been a considerable
temperature increase during the last decade (1995 to 2005) a
similar increase and at a faster rate occurred during the early
part of the 20th century (1920 to 1930) when carbon dioxide
or other greenhouse gases could not be a cause. The
Greenland warming of 1920 to 1930 demonstrates that a
high concentration of carbon dioxide and other greenhouse
gases is not a necessary condition for period of warming to
arise. The observed 1995 – 2005 temperature increase seems
to be within a natural variability of Greenland climate.
….
To summarize, we find no direct evidence to support
the claims that the Greenland ice sheet is melting due to
increased temperature caused by increased atmospheric
concentration of carbon dioxide. The rate of warming from
1995 to 2005 was in fact lower than the warming that
occurred from 1920 to 1930.”
“Variable solar irradiance as a plausible agent for multidecadal variations in the Arctic-wide surface air temperature record of the past 130 years”
http://www.cfa.harvard.edu/%7Ewsoon/myownPapers-d/Soon05-SolarArcticTempGRLfinal.pdf
Abstract
“This letter offers new evidence motivating a more
serious consideration of the potential Arctic temperature
responses as a consequence of the decadal, multidecadal
and longer-term persistent forcing by the ever-changing
solar irradiance both in terms of total solar irradiance (TSI,
i.e., integrated over all wavelengths) and the related UV
irradiance. The support for such a solar modulator can be
minimally derived from the large (>75%) explained
variance for the decadally-smoothed Arctic surface air
temperatures (SATs) by TSI and from the time-frequency
structures of the TSI and Arctic SAT variability as examined
by wavelet analyses. ”
Conclusion
“(1) Solar forcing explains well over 75% of the
variance for the decadally-smoothed Arctic annual-mean
or spring SATs, and
[18] (2) Time-frequency characteristics for the annual-
mean or seasonally-averaged Arctic SATs are consistent
with similar wavelet structures derived for the TSI forcing.
[19] In contrast, a CO2-dominated forcing of Arctic SATs
is inconsistent with both the large multidecadal warming
and cooling signals and the similar amplitude of warming
trends between cold (winter) and relatively warmer (spring
and autumn) seasons found in the Arctic-wide SAT records.”
“Observationally based assessment of polar amplification of global warming”
http://www.cfa.harvard.edu/%7Ewsoon/MattCronin-Mar21-07-d/Polyakovetal02-PolarWarmingGRL.pdf
The abstract
“Arctic variability is dominated by multi-decadal
fluctuations. Incomplete sampling of these fluctuations
results in highly variable arctic surface-air temperature
(SAT) trends. Modulated by multi-decadal variability, SAT
trends are often amplified relative to northern-hemispheric
trends, but over the 125-year record we identify periods
when arctic SAT trends were smaller or of opposite sign
than northern-hemispheric trends. Arctic and northern-
hemispheric air-temperature trends during the 20th century
(when multi-decadal variablity had little net effect on
computed trends) are similar, and do not support the
predicted polar amplification of global warming.”
conclusion
“Arctic and northern-hemispheric air-temperature trends over
the 20th century, when multidecadal variability had little net
effect on computed trends, are similar and do not support the
hypothesis of the polar amplification of global warming
simulated by GCMs. It has been hypothesized that this may
be due to the moderating role of arctic ice. Evaluation of fast-
ice melt required to compensate for the two-fold enhance-
ment of polar warming simulated by GCMs shows that the
equired ice-decay rate would be statistically indistinguish-
able from zero, given the substantial intrinsic variability
observed in the data. Observed long-term trends in arctic air
temperature and ice cover are actually smaller than expected,
and may be indicative of complex positive and negative
feedbacks in the arctic climate system. In summary, if we
accept that long-term SAT trends are a reasonable measure of
climate change, then we conclude that the data do not
support the hypothesized polar amplification of global
warming.”
“Arctic air temperature change amplification and the Atlantic Multidecadal Oscillation”
http://www.lanl.gov/source/orgs/ees/ees14/pdfs/09Chlylek.pdf
The abstract
“Understanding Arctic temperature variability is essential
for assessing possible future melting of the Greenland ice
sheet, Arctic sea ice and Arctic permafrost. Temperature trend
reversals in 1940 and 1970 separate two Arctic warming
periods (1910–1940 and 1970–2008) by a significant 1940–
1970 cooling period. Analyzing temperature records of the
Arctic meteorological stations we find that (a) the Arctic
amplification (ratio of the Arctic to global temperature trends)
is not a constant but varies in time on a multi-decadal time
scale, (b) the Arctic warming from 1910 – 1940 proceeded
at a significantly faster rate than the current 1970 – 2008
warming, and (c) the Arctic temperature changes are highly
correlated with the Atlantic Multi-decadal Oscillation
(AMO) suggesting the Atlantic Ocean thermohaline
circulation is linked to the Arctic temperature variability on
a multi-decadal time scale. ”
The conclusion
“The Arctic region did
warm considerably faster during the 1910– 1940 warming
compared to the current 1970 – 2008 warming rate (Table 1).
During the cooling from 1940 – 1970 the Arctic amplifica-
tion was extremely high, between 9 and 13. The Atlantic
Ocean thermohaline circulation multi-decadal variability is
suggested as a major cause of Arctic temperature variation”
Renewable Guy, John Cook’s very unskeptical website is not a reliable source of information.
I suggest that you actually do your own proper research on the subject, rather than just accept anything off Cook’s website like it’s the word of God.
It may shock you; but skepticalscience.com is not the complete and total centre of the universe.
Renewable guy, just a minor question.
what is the normal temperature of the earth?
Are we above or below that normal temperature?
I mean you can reasonably claim there is a problem without this baseline piece of data. After all if the normal temperature is supposed to be warmer than it is now then we should be worried that it is to cold and not warming fast enough. After all from the historical and geological record we know the earth has been much warmer at various times in the past. So the current temperature may well be to cold for normal.
On the other hand the earth has also had long periods of being much colder so maybe we are to warm no and should be worried, but of course to reach that conclusion we would have to know that the temperature should be colder than it is currently.
So were is the published data showing us what the normal temperature of the earth is? Without that the entire AGW crisis is just so much smoke and mirrors.