The Search for a Short Term Marker of Long Term Climate Sensitivity
By Dr. Roy Spencer. October 4th, 2009
[This is an update on research progress we have made into determining just how sensitive the climate system is to increasing atmospheric greenhouse gas concentrations.]
While published studies are beginning to suggest that net feedbacks in the climate system could be negative for year-to-year variations (e.g., our 2007 paper, and the new study by Lindzen and Choi, 2009), there remains the question of whether the same can be said of long-term climate sensitivity (and therefore, of the strength of future global warming).
Even if we find observational evidence of an insensitive climate system for year-to-year fluctuations in the climate system, it could be that the system’s long term response to more carbon dioxide is very sensitive. I’m not saying I believe that is the case – I don’t – but it is possible. This question of a potentially large difference in short-term and long-term responses of the climate system has been bothering me for many months.
Significantly, as far as I know, the climate modelers have not yet demonstrated that there is any short-term behavior in their models which is also a good predictor of how much global warming those models project for our future. It needs to be something we can measure, something we can test with real observations. Just because all of the models behave more-or-less like the real climate system does not mean the range of warming they produce encompasses the truth.
For instance, computing feedback parameters (a measure of how much the radiative balance of the Earth changes in response to a temperature change) would be the most obvious test. But I’ve diagnosed feedback parameters from 7- to 10-year subsets of the models’ long-term global warming simulations, and they have virtually no correlation with those models known long-term feedbacks. (I am quite sure I know the reason for this…which is the subject of our JGR paper now being revised…I just don’t know a good way around it).
But I refuse to give up searching. This is because the most important feedbacks in the climate system – clouds and water vapor – have inherently short time scales…minutes for individual clouds, to days or weeks for large regional cloud systems and changes in free-tropospheric water vapor. So, I still believe that there MUST be one or more short term “markers” of long term climate sensitivity.
Well, this past week I think I finally found one. I’m going to be a little evasive about exactly what that marker is because, in this case, the finding is too important to give away to another researcher who will beat me to publishing it (insert smiley here).
What I will say is that the marker ‘index’ is related to how the climate models behave during sudden warming events and the cooling that follows them. In the IPCC climate models, these warming/cooling events typically have time scales of several months, and are self-generated as ‘natural variability’ within the models. (I’m not concerned that I’ve given it away, since the marker is not obvious…as my associate Danny Braswell asked, “What made you think of that?”)
The following plot shows how this ‘mystery index’ is related to the net feedback parameters diagnosed in those 18 climate models by Forster and Taylor (2006). As can be seen, it explains 50% of the variance among the different models. The best I have been able to do up to this point is less than 10% explained variance, which for a sample size of 18 models might as well be zero.
Also plotted is the range of values of this index from 9 years of CERES satellite measurements computed in the same manner as with the models’ output. As can be seen, the satellite data support lower climate sensitivity (larger feedback parameter) than any of the climate models…but not nearly as low as the 6 Watts per sq. meter per degree found for tropical climate variations by us and others.
For a doubling of atmospheric carbon dioxide, the satellite measurements would correspond to about 1.6 to 2.0 deg. C of warming, compared to the 18 IPCC models’ range shown, which corresponds to warming of from about 2.0 to 4.2 deg. C.
The relatively short length of record of our best satellite data (9 years) appears to be the limiting factor in this analysis. The model results shown in the above figure come from 50 years of output from each of the 18 models, while the satellite range of results comes from only 9 years of CERES data (March 2000 through December 2008). The index needs to be computed from as many strong warming events as can be found, because the marker only emerges when a number of them are averaged together.
Despite this drawback, the finding of this short-term marker of long-term climate sensitivity is at least a step in the right direction. I will post progress on this issue as the evidence unfolds. Hopefully, more robust markers can be found that show even a stronger relationship to long-term warming in the models, and which will produce greater confidence when tested with relatively short periods of satellite data.
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2 TO 10 INCHES OF EARLY OCTOBER SNOW hits the Lake Tahoe region
http://www.snowforecast.com/index.php?option=com_content&task=view&id=43&Itemid=2
http://www.snowforecast.com/
I sometimes have trouble with all of the concern over the doubling of CO2 when it is not really something we can accomplish. If it is going to happen naturally, then it is more of an academic exercise in predicting the changes to which we must adapt.
As CO2 partitions 50 to 1 between water and air, we would have to add 51 times the CO2 to the atmosphere (as it is soaked up by the oceans) needed to physically double the CO2 in the atmosphere. There is not enough available carbon to do this. One estimate is that, if we burned everything, we might raise it by 20%.
Thus, it would seem that the climate sensitivity discussion is more of an academic exercise, doubling being not a realistic expectation and, particularly so, as it would not be our fault and not something we should act upon with the idea that we could alter developments. As CO2 has been much higher in the recent past (even 50-90% higher than now at times) and we cooled very nicely, assuming an ongoing effect might be premature.
Where in these discussions is the inclusion of the tie between temperature and CO2 levels in which CO2 does not drive the temperature, but follows the temperature? Records from ice cores, albeit not quantitative, clearly show that temperature repeatedly collapses while CO2 is high or still rising. The question of sensitivity becomes vague when the linkage is so weak. I stand confused.
Basically, it would appear that CO2 and temperature do not correlate over the long term as otherwise it would have been steadily climbing since the Little Ice Age and it has not – it has fluctuated widely.
Just some thoughts amidst so much discussion.
OK,
This is a long post , but take the time to read it.
Here is some basic math – check it out & see if it makes sense.
I have done this basic math before & what I find interesting is that it supports Dr. Spencer’s idea above. Dr Spencer, please comment on this validity of what follows :
1) I think they key conclusion you have above is :
“For a doubling of atmospheric carbon dioxide, the satellite measurements would correspond to about 1.6 to 2.0 deg. C of warming”
2) From multiple sources, CO2 concetrations in 1880 were about 290 PPM
So, a doubling of CO2 from that would be 580 PPM & that should correspond to net increase of 1.6 to 2.0 deg C warming according to the Spencer hypothesis.
3) Temperature & CO2 concentrations are logarithmic function in theory, so we can use the two points above to construct a logarithmic funtion to predict warming from 1880 to 2000.
4) CO2 concentration in 2000 was 369 PPM from Mauna Loa data
5) Case 1 : 1.6 deg F increase per doubling
A) data points : 290 ppm, 13.72 deg C (from graph at top of post)
580 ppm, 15.32 deg C (= 13.72 deg C + 1.6)
B) Curve fit : (where F(x) = temp & x = CO2 ppm
F(x) = 2.308313*ln(x)+0.63214
C) Solve for 2000 Temp (at 369 PPM)
= 14.28 deg C
D) Increase in Temp
= 0.56 deg C (=14.28-13.72
6) Case 2 : 2.0 deg F increase per doubling
A) data points : 290 ppm, 13.72 deg C (from graph at top of post)
580 ppm, 15.72 deg C (= 13.72 deg C + 2.0)
B) Curve fit : (where F(x) = temp & x = CO2 ppm
F(x) = 2.885390*ln(x)-2.6399818
C) Solve for 2000 Temp (at 369 PPM)
= 14.42 deg C
D) Increase in Temp
= 0.70 deg C (=14.42-13.72)
7) So based on the initial statement, we should expect to have seen between 0.56 and 0.70 deg C warming between 1880 & 2000.
8) Based on the graph at the top of the post, the temp anom in 1880 was about -0.2 deg C and the temp anom in 2000 was about + 0.45 deg C (both 5 year running average).
9) This is a difference of 0.65 deg C and right in the expected range of 0.56 to 0.70 deg C , thus it would appear to me that the observed data is right in line with the Spencer hypothesis of 1.6 – 2.0 deg C per doubling.
10) I have done this calculation before by doing a logarithmic curve fit to the observed temperature data , then using the resultant least squares fit formula to calculate the temperature change per doubling & always came up with a similar number – which is substantially less than the IPCC #’s – yet another reason I have been skeptical.
Dr Spencer (& others) – what do you think?
Of course, the other fun calculation to do is to plug into this equation the potential temp. decrease from “global carbon governance”. Here’s a quick take on that :
1) IPCC thinks we are heading towrds 600 PPM (+/-) by the year 2100 (although there are some who certainly question that number, but that is a whole different discussion).
2) That is 230 PPM above where we are at now.
3) Let’s say we can do a 20% reduction – which would be painful to say the least – consider that we have had about a 6% reduction (I believe – might need that # checked) from the current economic downturn – so at a 20% reduction, we are talking a 3 fold decrease in energy consumption compared to what we have seen the last year – even with alternative energy replacements, this would be painful.
4) 20% of 230 PPM is 46 PPM – so look at the cases of 554 PPM vs 600 PPM
5) In running the equations above, you will find that the net effect will be between 0.19 deg C and 0.23 deg C reduction from where we would go with no action at all
6) Folks, that’s 0.3 to 0.4 deg F over the next 100 years. The fact that we are even having this discussion on considering strangling the world’s economy – and restricting energy sources that have brought more prosperity, more longevity & higher quality of life to humanity in the last 100 years than in the entire world’s history before it – is simply astounding. And for what – a 0.3 to 0.4 deg decrease in temperature. We have adapted to a 0.8 deg F change over the last 100 years without the blink of an eye. I am not worried in the slightest that we can adapt to another 0.3 to 0.4 deg F over the next 100 years. I am highly concerned about what the policy makers of this world could do though- they are far more dangerous to the well being of this planet & it’s citizens than CO2 will ever be.
Off topic…
Here the definitive article on how insolation correlates to treering growth:
http://www.biocab.org/Insolation_Treerings_Growth.html
A graph from raw data in the article and a short comment in the section Conclusions about how the mechanism of photorespiration works in C3 plants, that is, in Siberian Larch trees, bristlecone pines, Canadian pines, etc.,
were added.
Someone in this thread said that trolls never think they’re trolls. If that’s true, it’s because they’re stupid. That might seem too obvious to bother stating, but what I mean is that they seem genuinely to believe that their thought processes about financial interests, someone’s religion, etc., and their own superficial knowledge of scientific findings are somewhere near being as good as it gets. This is either the first or one of the very few times I’ve ever posted here, and there’s a good reason for it: Relatively speaking, I don’t know what I’m talking about, even though I know far more than people I interact with in society. The troll’s knowledge doesn’t even rise to that standard.
Jeff L (12:55:26) :
Maths works for me but you need to clarify why you are mixing your Fs and Cs
Took a little extra time as I was puzzled by the mixture
william (12:32:25),
What you believe about the source of the rise in CO2 isn’t true. Yes, human activity has contributed to CO2 levels. But most of the increase is natural.
Please refute Jeff L’s post @12:55:26, if you can. But if it stands, your comment is conjecture. Lots of people repeat what they hear in the media 24/7.
I think you need some perspective: click. Note the very small human CO2 contribution, compared with the enormous natural CO2 emissions.
For every CO2 molecule emitted by human activity, about 34 are emitted by the planet naturally. The year to year fluctuations in natural CO2 emissions can be greater than the human contribution, so how could anyone measure the human impact on climate from one molecule out of 34?
In fact, they don’t actually measure it; it is too small. What they do is program computer models, which give results based on the programming. But models fail to take into account factors such as clouds and an expanding biosphere, which feeds on the extra CO2. There is a natural delay as the biosphere expands, but there is no problem caused by human CO2 emissions. Certainly, agricultural productivity is enhanced.
Models are notoriously unable to predict the climate. But it is the models that the AGW hypothesis is based on, not the real world.
And based on this computer model speculation, the UN/IPCC intends to tax the air we breathe.
Glad you’re here, learning the truth. This site is constantly converting people who learn misinformation into scientific skeptics. If someone tells you something, make them convince you. Don’t just assume they’re right. Organizations, including the media, have ulterior motives. And they are not your friends.
William,
“CO2 increases in the past did not trigger tipping points because the increase in CO2 took place very gradually over hundreds of years.”
So? This has always been the rallying cry of alarmists, but the models impute a postive feedback to the CO2 forcing based on the absolute level, not on how quickly or slowly it gets there. It is based around forcing F = 5.35 * Ln (ratio of CO2 change). If you go back to the mesozoic era, CO2 levels were around 2000 ppm yet some would have us believe that levels of a mere 450 ppm will trigger tipping points with catastrophic consequences.
You have to show why the laws of physics that drive radiative forcing act differently for CO2 levels that take a thousand years to reach 450 ppm compared to taking a mere century.
Steve (Paris) (13:24:29) :
Jeff L (12:55:26) :
Maths works for me but you need to clarify why you are mixing your Fs and Cs
…opps a little typo – cases should be 1.6 deg C & 2.0 deg C per doubling ,tying to Dr Spencer’s #’s -Sorry for the confusion
JL
Re: jorgekafkazar (11:52:46) :
“I feel like I’m participating on a moot debate about how many angels can dance the kazatsky on a PhD’s pate.”
Now there’s a sane voice amidst a cacophony of tail-chasing dogs!
OT but CA is hitting big time media see andy revkin’s dot earth blog
RR Kampen (05:50:56) :
First temperature rises due to long term Milankovitch (and such) effects. Vegetation and sea start releasing CO2 with a lag.
I haven’t the time to read all the comments, so if someone addressed this, forgive me. But I going to need a citation for vegetation releasing CO2 with rising temperatures if I’m going to consider it, please. Someone else can address the sea part. Being a landlubber, I don’t like oceans.
Jeff L
Nice math, but AGW/CO2 is not about science it is about political control.
Looks like september was the hottest on record, according to UAH AMSU Daily Temps: http://discover.itsc.uah.edu/amsutemps/
Completely OT, but is this graph legitimate or might there be some capture/input errors? (I know others have asked about this; please accept my apologies if it’s already been addressed in another thread.)
http://ocean.dmi.dk/arctic/meant80n.uk.php
Leif Svalgaard (05:08:51) : I generally think it is a bad idea to conduct science by press releases or hints or teasers. ..This is Vaporware. .. A blog can serve as a sounding board for new ideas .. But this way [giving us a teaser] does not serve that purpose.
What is the way then Leif to garner new ideas? People do not release the ideas they are researching generally before they have finished.
Leif Svalgaard (05:32:33) :
kim (05:12:51) : Maybe he’s looking for further pointers, as do you, Leif.
At least I lay out my train of thought and what I’ve got. Not just just in blogs, but ..
So you do also Leif.
Keith Minto (23:17:59) :
Graeme Rodaughan (23:04:08) :
Good points that you make, but, in another world I inhabit we say “Don’t feed the Troll”
Thanks Keith – posted before I saw the signs…
Cheers G
Michael (23:33:03) :
I like to use the price of a carbon credit as my marker. Money talks, bullshit walks. Just my 10 cents.
10 Cents or 2 Cents – Isn’t that what a tonne of Carbon is worth these days…
What a bubble!
wws (06:06:32) : “WUWT won this year’s “Best Science” category in the Weblog Awards. Click on their icon on the upper right of the page. Compare the results to RealClimate. ~dbs, mod.]”
I did just that, hadn’t before, and it was very informative. I had never heard of the site that got the second highest vote total (I won’t name names, interested people can find out for themselves) so I looked to see what it was about. I was quite surprised to find that (at least at this time) it had articles about meetings and parties, favorite wines, people they didn’t like, and t-shirt sales, but not a *single* article currently on the site that was actually about Science.
wws – what on earth are you talking about? The second highest vote was got by Pharyngula, which is by PZ Myers, a biologist and associate professor at the University of Minnesota, Morris and all about science and none of the stuff you are talking about.
I had really hoped for something more. Disapointing, but a further confirmation that WUWT stands head and shoulders above all of its competitors as the place where REAL science is discussed.
That sarcasm is based on an obviously delusional visit to some hallucinationatory site.
I’m getting a bit tired of trying to repair peoples cognitive dissonance. Some peoples belief systems are so ingrained that when presented with the irrefutable facts, they still cannot bring themselves to believing the scientific truth.
Perhaps the only way to fix them is with reincarnation as an amoeba should that be a viable option. Start all over and learn everything you should have after your current go round on Earth.
Richard (14:58:41) :
People do not release the ideas they are researching generally before they have finished.
Worse, they seem to release their results before they have finished…
hunter (06:12:45) :
The AGW true believers are hoping that by moving the goal posts, from ice extent to volume, they can distract people from the fact that
1 – ice volume was never an issue in earlier years
2- that measuring ice volume is very dubious
3- that ice volume is irrelevant to floating ice.
The AGW hysteria was always about ice pack extent, until ice pack extent began to grow. This is typical AGW community behavior, as we have seen regarding sea levels, temperatures, tropical cyclones, etc.
The Arctic ice pack acts to insulate the water and reflect sunlight.
But this is not about ice. It is about AGW true believer’s inability to deal with inconvenient facts.
They attack a man of proven integrity, like Dr. Spencer, by mixing his religious beliefs with his science, and ignorantly judging both.
No one who is a serious student of science is ever going to conclude that being a theist disqualifies someone from being a scientist.
Dr. Spencer ahs proven himself over many decades to be a capable ethical scientist, operating transparently and with integrity. As contrasted to, say, Briffa, Hansen, Schmidt, Mann, et al.
Agreed: Shifting Goal post once nature does not comply with the Official Consensus is a proven tactic… In Australia the official line has moved from measuring atmospheric temps (since they are going down) to Ocean Temps… (at least until 2005).
REF: http://www.onlineopinion.com.au/view.asp?article=9075&page=0
Richard 14:58:41
Yes, and the process is all good. Call it ‘Distributed Intuition’.
====================================
Richard, wws’s assessment of “Pharyngula” exactly matched mine.
In fact, I was so disgusted by the raw hatred and partisan politics exhibited there when I looked around last year that I’ve never had any reason to go back.
Science? At “Pharyngula”? Yep, that’d be an obviously delusional visit to some hallucinationatory site.
Back to the article – here are my thoughts:
The “SENSITIVITY’ of the climate to CO2 is the crucial question. In laymans terms what will happen to the Global Temperature of you double the quantity of CO2 in the atmosphere.
High sensitivity – it will shoot up by ~ 4.5C,
Low Sensitivity ~ 1C,
Insensitive ~ 0 (It wont matter much, other natural causes such as the Suns’ irradiance, albedo etc will completely swamp any effects of CO2)
Current Observational Evidence – Low sensitivity to insensitive: Over a century when the Earth has recovered from the Little Ice Age the temperatures have climbed by a scant 0.6C while CO2 climbed by over 30%. In the past 10 years temperatures have declined slightly while CO2 risen by ~ 5%.
Question – Will this continue or is this just a pause, a prelude to runaway global warming which will suddenly catch up, as predicted by Hansen, the MIT climate playstation modeling dartplaying wonderboys etc.?
Can the info from current roll of dice be plugged into the playstaion modeling game to crack the code and beat the house?
Dr Spencer is excited – he thinks maybe he has got it. Best of luck Dr Spencer. I wish you all success. Let us know when you have done it.
In the meantime here is my two penny worth on the outcome. (High Sensitivity, Low Sensitivity, Insensitive). I lean towards Low Sensitivity to Insensitive, why? –
Because I believe that the Earth’s Climatic system, is highly homeostatic, like almost all systems we see in nature. The stars form and live long stable lives. The Earth’s temperatures rise but then they fall again.
From a radiative balance system, and arguing from first principles, this also makes sense. Assuming the suns radiation and everything else remains constant, if we just heat up the earth by more “greenhouse effect” of CO2, then more will radiate out than before bringing things in balance again.
Then there is also the question- will things remain totally in balance if the Earth heats up slightly? Probably not. Other things like water vapour and clouds will act to dampen the effects. Also the Earth’s biosphere is a considerable player in the temperature climate game. This biosphere (of which we are only a part) also acts to try and keep status quo.
The same cannot be said for cooling. If the incoming radiative heat gets less over time, as it seems to be gradually doing, then the Earth will cool (gradually) over time.