In a new GRL paper, Svensmark et al., claim that liquid water content in low clouds is reduced after Forbush decreases (FD), and for the most influential FD events, the liquid water content in the oceanic atmosphere can diminish by as much as 7%. In particular, they argue that there is a substantial decline in liquid water clouds, apparently tracking a declining flux of galactic cosmic rays (GCR), reaching a minimum days after the drop in GCR levels. The implication would be that GCR can affect climate through modulating the low-level cloudiness. The analysis is based on various remote sensing products.
The hypothesis is this: a rapid reduction in GCR, due to FD, results in reduced ionization of the atmosphere, and hence less cloud drops and liquid water in low clouds. Their analysis of various remote sensing products suggest that the opacitiy (measured in terms of the Angstrom exponent) due to aerosols reaches a minimum ~5 days after FD, and that there is a minimum in the cloud liquid water content (CWC) minimum occurring ~7 days later than the FD. They also observe that the CWC minimum takes place ~4 days after the fine aerosol minimum (the numbers here don’t seem to add up).
The paper is based on a small selection of events and specific choice of events and bandwidths. The paper doesn’t provide any proof that GCR affect the low clouds– at best -, but can at most only give support to this hypothesis. There are still a lot of hurdles that remain before one can call it a proof.
One requirement for successful scientific progress in general, is that new explanations or proposed mechanisms must fit within the big picture, as well as being consistent with other observations. They must also be able to explain other relevant aspects. A thorough understanding of the broader subject is therefore often necessary to put the new pieces in the larger context. It’s typical of non-experts not to place their ideas in the context of the bigger picture.
If we look at the big picture, one immediate question is why it should take days for the alleged minimum in CWC to be visible? The lifetime of clouds is usually thought to be on the order of hours, and it is likely that most of the CWC has precipitated out or re-evaporated within a day after the cloud has formed.
In this context, the FD is supposed to suppress the formation of new cloud condensation nuclei (CCN), and the time lag of the response must reflect the life time of the clouds and the time it takes for new ultra-fine molecule clusters (tiny aerosols) to grow to CCN.
Next question is then, why the process, through which ultra-fine molecule clusters grow by an order of ~1000 to become CCN, takes place over several days while the clouds themselves have a shorter life time?
There is also a recent study in GRL (also a comment on May 1st, 2009 in Science) by Pierce and Adams on modeling CCN, which is directly relevant to Svensmark et al.‘s hypothesis, but not cited in their paper.
Pierce and Adams argue that the theory is not able to explain the growth from tiny molecule clusters to CCN. Thus, the work by Svensmark et al. is not very convincing if they do not discuss these issues, on which their hypothesis hinges, even if the paper by Pierce and Adams was too recent for being included in this paper.
But Svensmark et al. also fail to make reference to another relevant paper by Erlykin et al. (published January 2009), which argues that any effect on climate is more likely to be directly from solar activity rather than GCR, because the variations in GCR lag variations in temperature.
Furthermore, there are two recent papers in the Philosophical Transactions A of the Royal Society, ‘Enhancement of cloud formation by droplet charging‘ and ‘Discrimination between cosmic ray and solar irradiance effects on clouds, and evidence for geophysical modulation of cloud thickness‘, that are relevant for this study. Both support the notion that GCR may affect the cloudiness, but in different aspects to the way Svensmark et al. propose. The first of these studies focuses on time scales on the order of minutes and hours, rather than days. It is difficult to explain how the changes in the current densities taking place minutes to hours after solar storms may have a lasting effect of 4-9 days.
There are many micro-physical processes known to be involved in the low clouds, each affecting the cloud droplet spectra, CWC and the cloud life times. Such processes include collision & coalescence, mixing processes, winds, phase changes, heat transfer (e.g., diffusive and radiative), chemical reactions, precipitation, and effects from temperature. The ambient temperature determines the balance between the amount of liquid water and that of water vapour.
On a more technical side, the paper did not communicate well why 340 nm and 440 nm should the magic numbers for the remote sensing data and the Angstrom exponents, calculated from the Aerosol Robotic Network (AERONET). There are also measurements for other wavelengths, and Svensmark et al. do not explain why these particular choices are best for the type of aerosols they want to study.
For a real effect, one would expect to see a response in the whole chain of the CCN-formation, from the smallest to the largest aerosols. So, what about the particles of other sizes (or different Angstrom exponents) than those Svensmark et al. have examined? Are they affected in the same way, or is there a reason to believe that the particles grow in jumps and spurts?
If one looks long enough at a large set of data, it is often possible to discern patterns just by chance. For instance, ancient scholars thought they found meaningful patterns in the constellations of the stars on the sky. Svensmark et al. selected a smaller number of FDs than Kristjansson et al. (published in 2008) who found no clear effect of GCR on cloudiness.
Also, statistics based on only 26 data points or only 5 events as presented in the paper is bound to involve a great deal of uncertainty, especially in a noisy environment such as the atmosphere. It is important to ask: Could the similarities arise from pure coincidence?
Applying filtering to the data can sometimes bias the results. Svensmark et al. applied a Gaussian smooth with a width of 2 days and max 10 days to reduce fluctuations. But did it reduce the ‘right’ fluctuations? If the aerosols need days to form CCNs and hence clouds, wouldn’t there be an inherent time scale of several days? And is this accounted for in the Monte-Carlo simulations they carried out to investigate the confidence limits? By limiting the minimum to take place in the interval 0-20 days after FD, and defining the base reference to 15 to 5 days before FD, a lot is already given. How sensitive are the results to these choices? The paper does not explore this.
For a claimed ‘FD strength of 100 %’ (whatever that means) the change in cloud fraction was found to be on the order 4% +-2% which, they argue, is ‘slightly larger than the changes observed during a solar cycle’ of ~2%. This is not a very precise statement. And when the FD only is given in percentage, it’s difficult to check the consistency of the numbers. E.g. is there any consistency between the changes in the level of GCR between solar min and max and cloud fraction and during FD? And how does cloud fraction relate with CWC?
Svensmark et al. used the south pole neutron monitor to define the FD, with a cut-off rigidity at 0.06GV that also is sensitive to the low-energy particles from space. Higher energies are necessary for GCR to reach the lower latitudes on Earth, and the flux tends to diminish with higher energy. Hence, the south pole monitor is not necessarily a good indicator for higher-energy GCR that potentially may influence stratiform clouds in the low latitudes.
In their first figure, they show a composite of the 5 strongest FD events. But how robust are these results? Does an inclusion of the 13 strongest FD events or only the 3 leading events alter the picture?
Svensmark et al. claim that the results are statistically significant at the 5%-level, but for the quantitative comparison (their 2nd figure) of effect of the FD magnitude in each of the four data sets studied, it is clear that there is a strong scatter and that the data points do not lie neatly on a line. Thus, it looks as if the statistical test was biased, because the fit is not very impressive.
The GRL paper claims to focus on maritime clouds, but it is reasonable to question if this is true as the air moves some distance in 4-9 days (the time between the FD and the minimum in CWC) due to the winds. This may suggest that the initial ionization probably takes place over other regions than where the CWC minima are located 4—9 days afterward. It would be more convincing if the study accounted for the geographical patterns and the advection by the winds.
Does the width of the minimum peak reveal time scales associated with the clouds? The shape of the minimum suggests that some reduction starts shortly after the FD, which then reaches a minimum after several days. For some data, however, the reduction phase is slower, for others the recovery phase is slower. The width of the minimum is 7-12 days. Do these variations exhibit part of the uncertainty of the analysis, or is there some real information there?
The paper does not discuss the lack of trend in the GCR of moderate energy levels or which role GCR plays for climate change. They have done that before (see previous posts here, here, and here), and it’s wise to leave out statements which do not have scientific support. But it seems they look for ways to back up their older claim, and news report and the press release on their paper make the outrageous claim that GCR have been demonstrated to play an important role in recent global warming.
A recent analysis carried out by myself and Gavin, and published in JGR, compares the response to solar forcing between the GISS GCM (ER) and the observations. Our analysis suggests that the GCM provides a realistic response in terms of the global mean temperature – well within the bounds of uncertainty, as uncertainties are large when applying linear methods to analyse chaotic systems. The model does not include the GCR mechanism, and the general agreement between model and observations therefore is consistent with the effect of GCR on clouds being minor in terms of global warming.
As an aside to this issue, there has been some new developements regarding GCR, galaxy dynamics and our climate (see the commentary environmentalresearchweb.org) – discussed previously here.
Rene #286
What I said was: “I would be surprised if the “trend” doesn’t point skywards with a vengeance by 2015”. This is what statistical analysis is telling me.
However, I would not be surprised if it kicks in earlier – I am assuming you know that natural variations are masking the AGW component.
Now, can you please answer my question to you:
Do you really think an “upward trend hypothesis (is) programmed into the models”?
Good online textbook series: http://www.learner.org/courses/envsci/unit/text.php?unit=2...
Adding to David B Beson’s post # 298:
http://geosci.uchicago.edu/~rtp1/ClimateBook/ClimateWorkbook.pdf
which I found from links from the guest post from Spencer Weart here at RC back in 2007.
Thank you for your various responses to my posting #262. I had not expected to stir up such a hornet’s nest. I cannot address all the responses in one post, but I will happily take them in order:
#265 Tamino If you have a point to make on the science, I will address it. All of the main temperature datasets show a post 2001 cooling trend. [edit]
#266 Patrick 027 You wrote: “GCMs do not assume approximate relative humidity, etc. – those are results of GCMS. Water vapor does seem to be increasing in the upper troposphere.” I believe that you are wrong on both counts. Can I suggest that you read Chapter 8 of IPCC AR4 WG1 “Report Climate Models and Their Evaluation” pp 629-633? And also take a look at the data from NASA here: http://earthobservatory.nasa.gov/IOTD/view.php?id=4312
There are better presented sources of this data, but it does indicate, as NASA states, that the amount of water vapour entering the atmosphere is less than that predicted in GCMs, and that relative humidity is decreasing in the critical mid-upper troposphere.
#267 Patrick 027: You also wrote: “And I should point out that the greenhouse gas absorption spectrum’s effect on Earth’s radiation to space can be directly observed with satellites.” That was exactly my point when I stated that if one compares the outgoing longwave radiation measured by ERBE with GCM outputs, the GCMs systematically show lower OLW than actually measured. Conclusion is that the GCMs are somehow overestimating the cooling effect of GHGs or adding in positive feedback when it should be negative.
#268 Jacob Mack: You wrote: “There is no “cooling trend,” post 2001, as this is not a long enough time period to constitute a climate trend.Relative humidity is not just an “assumption,” as water vapor levels do tend towards equilibrium, so while it is true that air can “hold” (not exactly true, as it is not holding per se; see here:hyperphysics.phy-astr.gsu.edu/HBASE/Kinetic/relhum.html)more water vapor, this does not equate to either an immediate “run away” effect, or an equilibration that leads to zero net warmign effect either.” Thank you for your response, Jacob. Firstly, if you check my posting, I did not mention a climate trend. I merely pointed out a cooling trend. With respect to relative humidity, my answer to your comment is similar to my answer to Patrick 027, namely that (a) constant relative humidity IS an assumption built into the GCMs as part of the governing equations. Variation in SH is part of a calculation procedure based on this assumption. My point on this issue is simply that the results of the models do not match observations in the mid- to upper troposphere. It does not matter whether this is a failure in the assumptions, the governing equations, the characterisation or numerical error. The fact remains that this calls into question the validity of any “extrapolated deduction” from the solid observation that CO2 is an effective absorber of LW. I don’t understand your reference to a “runaway effect”, which doesn’t appear to be related to anything I wrote. More to follow…
Paul, there is no cooling trend, and this is my point; the time period for the warming pause has not been long enough to diminish the warming trend which is ling enough to call climate according to the World Meteological Association, and many climatologists. Also the past decade is still the hottest deacde on the instrumental record. Okay, regarding constant relative humidity, it is actually a fact of physics/physical chemistry in the system and empirical observations, that relative humidity remains almost constant and when it ia averaged, it actually is constant, so the GCM’s input this factual data to consider such aspect fo water vapor levels.
As far as observations of the mid to upper trposphere; there are several well documented observations of this, but I did find some abstracts and preliminary papers regarding alternate methods to observe RH in these atmospheric regions and every paper I found stated the method should be used with great “caution.” (their word not mine) The ongoing papers go on to make mention of greater uncertainties that may distort the findings altogether.
I made reference to runaway effect, as many skeptics make mention that such events should have taken place based upn so called RH “assumptions, so I was merely stating the fallacy in such logic before you may make mention of it. If you take the time to read the references I gave you before replying again, you will see why I made mention of it.
I have these papers and other references, but I suggest you start with the references I gave you in addition to what other posters gave you as well.
David Benson also made mention of Spencer Weart as well, and I suggest you read those references which explains the physics of C02 in the upper atmosphere clearly.
Paul, it’s not hornets, it’s wannabe reference librarians.
Did you look up anything since that 2004 NASA page, which has been very popular with people who find it at Warwick Hughes’s website?
What do you make of, for example, this paper:
http://www.atmos-meas-tech.net/2/379/2009/amt-2-379-2009.pdf
“… 6.2 Precision validation
The results of our simplified 2-analysis seem a bit ambiguous. ….”
Re 304. Paul, you still do not understand the difference between “assumption” and “result”. Go away and read some more, and come back once you understand this distinction. Until then, everything you say will be ignored.
Re: #304 (Paul)
As I said, when it comes to trends you’re clueless.
NONE of the main temperature datasets show a post-2001 cooling trend. Example: for UAH TLT data, the trend estimate since 2001 is -0.013 +/- 0.039 deg.C/yr. Note the “+/-” part. That means the trend could be as low as -0.052 or as high as +0.026 (95% confidence). And that means: there’s no evidence of a cooling *trend*, in fact there’s no reliable evidence that the trend is any different than it has been throughout the entire UAH TLT record. Really: the *only* thing we can learn from UAH TLT data post-2001 is that 9 years isn’t nearly long enough to discern what the real *trend* is. Exactly the same condition applies to RSS TLT, NASA GISS, and HadCRUT3v data.
It’s obvious to everybody except yourself that you really don’t know what a trend is and what it isn’t. It’s equally evident that you still feel entitled to come here and spin an elaborate yarn about the mistaken nature of global warming.
If you really want to know about global warming, you must first accept the fact that at the moment you’re in WAY over your head. Somehow I don’t expect that to happen.
Gavin, CTG, and others, it’s always good to check what people will find if they put the question into ordinary Google in a naive way. Have a look:
http://www.google.com/search?q=difference+between+%E2%80%9Cassumption%E2%80%9D+and+%E2%80%9Cresult%E2%80%9D+climate+model
and the image search:
http://images.google.com/images?q=difference between “assumption” and “result” climate mode
May I suggest a pointer to an explanation from a journal or reliable source would be appropriate, to reduce the cloudiness of Google’s result?
Urk. I’ve been quotewhacked. Again:
http://www.google.com/search?q=difference+between+assumption+and+result+climate+model
For those who are here to learn, here’s an illustration of what’s going on.
When someone posts an old paper and makes a factual claim — as with humidity from the old 2004 page above — keep looking. Post questions if you think your question might tempt a working scientist into taking a few minutes to explain. Remember, most blogs aren’t worth the trouble, they’re overrun by people blathering and driving away anyone waiting quietly to learn.
So, humidity, what’s going on out there? Well, I went poking with Scholar and eventually came across a site that pays a lot of attention to what can be learned about humidity from satellite work — clearly they don’t assume, they’re working out how to measure it. That’s the site for the European Centre for Medium-Range Weather Forecasts. I’m sure there are many others; this is just the one I stumbled upon.
Who are they? http://www.ecmwf.int/
“We are an international organisation supported by 31 States. We provide operational medium- and extended-range forecasts and a state-of-the-art super-computing facility for scientific research. We pursue scientific and technical collaboration with satellite agencies and with the European Commission.”
And what kind of instruments are they using?
All of them.
And what are they able to say about humidity in the atmosphere?
There’s a huge database there, many bulletins and summaries.
But just to make the point that humidity is a question being answered, in detail, improving over time — not a fixed assumption — here’s a little bit from a recent report on their site. Again it’s just an example of people working in areas I didn’t know existed.
http://www.ecmwf.int/about/special_projects/interim_reports_2009/UK_ONeill_SP-GBDARC_interim_report_2009.pdf
Reporting year
July 2008 to June 2009
Project Title: Assimilation of retrieved products from EOS MLS
They’re talking about new instruments coming available and how they take the new information and bring it into useful form along with the previous information, and what they can do with it.
—— Brief excerpt follows ——
The Kalpana VHRR (Very High Resolution Radiometer) water vapour channel is very similar to the water vapour channel of MVIRI (Meteosat Visible and Infrared Radiation Imager) on Meteosat-7 and both satellites observe the Indian subcontinent. Thus it is possible to compare the performance of
VHRR and MVIRI in NWP models. … Using Kalpana WV radiances instead of observations from Meteosat-7 improves the fit of radiosonde data; in particular … low-middle level moisture. ….
In the future, a sounder with several additional channels in the visible, infrared, and water vapour bands will become available on the Indian INSAT-3D satellite, to be launched by ISRO. The information of three humidity and more than seven temperature sounding channels of the INSAT-3D
sounder will provide more vertical information – useful for the definition of the humidity and temperature fields. …
—– end excerpt —–
Ya know, when someone tells you that some assumption is built into the models rather than being a result from research being looked at by the scientists, and improved as the tools get better, you ought to ask — persistently — where they are getting their bad information.
And, of course, you can look it up. Make the effort.
Again, I post this kind of stuff just to show what an utter amateur can turn up in a few minutes’ time.
The site raises _lots_ of interesting questions, because “medium to long-range weather” research is certainly accumulating a lot of information at a level of detail more than could be just poured into a climate model.
Perhaps hearing from some folks like that would be an interesting topic?
Paul –
H2O feedback: aside from the date on your source, you might be mixing up specific and relative humidity. If the climate model results are constant relative humidity (PS obviously there are regional variations from that, of course), and the actual result is a decrease in relative humidity, what kind of error is that? If it is a small decline, the change in specific humidity may still be an increase, and it may not be so far off from the model results.
LW emission to space seen by satellites – I don’t know offhand what the error is for climate models, but you seem to be suggesting that any overestimate of the greenhouse effect makes the greenhouse effect much weaker than we think. Suppose the climate model result is off by 10 % (I’m not saying this is true or false). This does not mean that any change in the greenhouse effect that is less than 10 % cannot be simulated well by a model. What is suggests is that perhaps the model’s simulated changes due to some addition of CO2 is off by 10 % and then perhaps the temperature changes might also be off by 10 % (in addition to or cancelation of other sources of error), starting with an assumption of linearity of error in proportion to value – which could be wrong, but likely not by a lot with that kind of thing.
The satelite measurements clear show that CO2, water vapor, and clouds (and smaller contributions from CH4, O3, …) take sizable chunks out of what would otherwise be the LW radiation from the surface to space.
PS by the way, it’s not like we’re trying to use GCM’s + paleoclimate, etc to land on the moon. Even if climate model ensembles were shown to be off by 30 %, there would still be useful information, and the implication would be similar – adding CO2 will have an effect 70 % or 130 % of what we thought it would. Consider what this might mean for policy – in the case of reduced warming, that we could allow ourselves to emit a little more CO2 + etc, or we could justify a reduced emissions tax, or that we have a little more time to build some aqueducts and move some people and things(although some greater regional precision+accuracy in climate models would be helpful for such infrastructure projects) and develop new crops, etc, or we could still use the policies we were going to use and be happy that the resulting climate change is even less, or some combination of those…
David B. Benson #298 says:
“Barton Paul Levenson:
1. CO2 is a greenhouse gas (Tyndall 1859).
2. CO2 is rising (Keeling et al. 1958).
3. The new CO2 is mainly from burning fossil fuels (Suess 1955).
4. Temperature is rising (NASA GISS, Hadley CRU, UAH, RSS, etc.).
5. The increase in temperature correlates with the increase in CO2 (60–76% for temp. anomaly and ln CO2 for 1880-2007).”
1. No dispute
2. No dispute
3. There is no substantial work that has unequivocally shown this to be true. It is a hypothetical. There is no empirical evidence that expressly verifies it (including stable isotope and radioactive isotope work).
4. True but not necessarily in synchronisation with GHGs. And not necessarily in a linear fashion.
5. That is a correlation which is NOT cause and effect.
By the way. Do you get a commission from Weart? I have seen you recommend his book at least 20 times over the course of the last year.
re: 301 (DavidK)
I am assuming you know that natural variations are masking the AGW component.
I am aware that the claimed AGW component is small relative to natural variation, yes. That still does not mean the claimed AGW component is as large as alarmists say it is (which is presumably what is programmed into the models, to answer your other question).
Now, can you please answer my question to you:
Do you really think an “upward trend hypothesis (is) programmed into the models”?
Comment by DavidK — 10 August 2009 @ 5:32 PM
“Petro (290), how on earth could I be able to verify someone else’s sources?
Comment by Rod B”
The same way you check the sources of, say, Hank here.
Checking the sources.
Or myself: google search and check the results, checking for sources of what I say.
Simple.
Richard Steckis writes:
It is a theory, not a hypothesis. Tyndall showed CO2 was a greenhouse gas back in 1859. CO2 is rising (38% since the Industrial Revolution began). Temperature should be rising as a result, and it is. The temperature increase correlates closely with the CO2 increase (r = 0.87 for 1880-2007). No other major inputs have changed significantly for 50 years. What more do you want?
A 38% increase is not “small.”
Empirical evidence shows the water-vapor feedback is happening and is positive:
Brown, S., Desai, S., Keihm, S., and C. Ruf, 2007. “Ocean water vapor and cloud burden trends derived from the topex microwave radiometer.” Geoscience and Remote Sensing Symposium. Barcelona, Spain: IGARSS 2007, pp. 886-889.
Dessler AE, Zhang Z, Yang P 2008. “Water-Vapor Climate Feedback Inferred from Climate Variations.” Geophys. Res. Lett. 35, L20704.
Philipona, R., B. Dürr, A. Ohmura, and C. Ruckstuhl 2005. “Anthropogenic greenhouse forcing and strong water vapor feedback increase temperature in Europe.” Geophys. Res. Lett., 32, L19809.
Santer, B. D, C. Mears, F. J. Wentz, K. E. Taylor, P. J. Gleckler, T. M. L. Wigley, T. P. Barnett, J. S. Boyle, W. Bruggemann, N. P. Gillett, S. A. Klein, G. A. Meehl, T. Nozawa, D. W. Pierce, P. A. Stott, W. M. Washington, M. F. Wehner, 2007. “Identification of human-induced changes in atmospheric moisture content.” Proc. Natl. Acad. Sci., 104, 15248-15253.
“3. There is no substantial work that has unequivocally shown this to be true.”
Fossil fuels have a different isotopic signature.
It shows that point 3 is unequivocally true.
“4. True but not necessarily in synchronisation with GHGs.”
Why would it be in lock-step? That would only be true if CO2 was the ONE AND ONLY cause of temperature increase. Only denialists like yourself use that idea and then as a strawman to “prove” AGW is wrong.
“5. That is a correlation which is NOT cause and effect.”
But it shows that the causation is having the effect. Remember (of course you won’t), that not only does there appear a correlation the magnitude of the change is within the realm of valid attribution to CO2.
It is also a supporter of points 1-4 before it, not the whole point in and of itself.
Else the planets have no orbit because that was just correlation with a theory that the planets have elliptical orbits…
Steckis (314):
3. The new CO2 is mainly from burning fossil fuels (Suess 1955). Your response:
See Nitrogen and Water Requirements of C3 Plants Grown at Glacial to Present Carbon Dioxide Concentrations, H.W. Polley, H.B. Johnson and H.S. Mayeux, Functional Ecology, Vol. 9, No. 1 (Feb. 1995) pp. 86-96. Here is a quote from their paper:
If you have access to JStor, you can view this paper. Regarding C-14, do you dispute that fossil fuels are low in C-14, or do you dispute that burning them will dilute C-14 in the atmosphere? I really don’t understand what your objection is, because this seems self-explanatory.
5. The increase in temperature correlates with the increase in CO2 (60–76% for temp. anomaly and ln CO2 for 1880-2007).” Your answer:
Radiation physics provides a cause and an effect. Look up Beer’s Law.
Last of all, Spencer Weart has spent years researching the history of global warming, and has compiled this information in a freely available book, written in a style that is easy to comprehend. To suggest that Gavin gets a commission from Weart is insulting, to say the least.
#291- Hello John it’s been awhile. Quite a plate, but let’s give it a whirl.
I base my sea ice info on some of the following sources:
Sea Ice:
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
http://nsidc.org/data/seaice_index/daily.html
http://arctic.atmos.uiuc.edu/cryosphere/
Arctic temp:
http://ocean.dmi.dk/arctic/meant80n.uk.php
coupled with a longer term perspective as seen in paper “Arctic Long Term Ice Data” by Smolyanitsky, etc.. Taking into account the opinion that the sea ice data can have a error of +/- 10-20%, depending on who you believe. Add to the mix ocean currents, the analysis is not necessarily hard, but it is tedious. And that is just surface are. To get ice mass, you have to know the volume and density, which is a big guess Let’s just go with sea ice area, at least we are on firmer ground. Looking at Smolyanitsky’s work and current sea ice surface area, I’ll go with:
Prior to 2000, TOTAL sea ice are was flat. There was a trend down in total sea ice from 2000-2007 years, but now looks like a upturn recently. The interesting item in Smolyanitsky etc.’s work is that it shows those pesky ~50 cycles that showed up in my posts, this spring. Here I used the 1659-2008 central England data, and Fourier analysis.
Glacier Changes:
From the limited reading I’ve done on glaciers, a lot depends on who you read and believe. Some glaciers advance, others retreat. Here is a recent item on those in the Himalayan.
http://www.ias.ac.in/currsci/aug102009/309.pdf
that states that glacier change is not due to “global warming”. My opinion in this area is, I don’t know enough to comment.
Temperature Change:
John you say 1.2 F. rise. I’m not sure from when to when. However is we look at some of the longest records from;
East Anglia 1659-2008 – Up ~1.2 C.
http://rimfrost.no/
Uppsala 1722-2008 – Up ~1.5 C (1770-2008)
Minneapolis-St. Paul 1819-2006 – Up ~1 C.
Paris 1757-2009 – Up ~1 C.
Berlin 1761-2009 – Flat
From these long term records their average increase is about 1 C., over a span of over 200 years. So I don’t see human involvement in the process. No major changes, except for Uppsala from 1984-2008, which is contradicted by the Stockholm-GML 1756-2005 as far as a recent rise.
“Let’s just go with sea ice area, at least we are on firmer ground.”
No, let’s not, since that doesn’t tell you what ground you’re standing on.
Sea ice extent depends on how much sunlight there is much more than the temperature. And it is more variable because of that to boot.
But the thickness depends on the rate of melting vs the rate of creation which is more dependent on the average temperatures.
“From these long term records their average increase is about 1 C., over a span of over 200 years. So I don’t see human involvement in the process.”
So what has changed over the last 200 years enough to explain the differences?
Pixie dust?
J. Bob says “Some glaciers advance, others retreat.” Nope, not even close. Most glaciers are retreating and/or losing mass.
http://www.nichols.edu/departments/glacier/cum%20bn.jpg
from http://www.nichols.edu/departments/glacier/global%20glacier%20mass%20balance.htm
“The World Glacier Monitoring Service annually compiles the mass balance measurements from around the world. From 2002-2006, continuous data is available for only 7 glaciers in the southern hemisphere and 76 glaciers in the Northern Hemisphere. The mean balance of these glaciers was its most negative in any year for 2005/06. [1] The similarity of response of glaciers in western North America indicates the large scale nature of the driving climate change.”
from one publication, Ice and Climate, the WCRP/SCAR Climate and Cryosphere Newsletter Number 9, June 2007:
“…the ongoing rapid and perhaps accelerating trend of worldwide glacier shrinkage, on the century time-scale, is of a nonperiodical nature and may lead to the deglaciation of large parts of many mountain ranges within the coming decades…” Worldwide Glacier Monitoring – Present State and Current Challenges, Zemp et.al.
“Recent studies indicate that 67% of Himalayan glaciers are retreating, presumably because of climate change, although other factors may be involved” Climate Change and Water Resources in the Himalaya
Haritashya et. al.
“Mass balance measurements in Western North America from 1984-2005 indicate a declining trend in glacier mass balance: all of the glaciers are out of balance, and some will disappear.
Western North American Glacier Mass Balance 1984-2005, Equilibrium or Disequilibrium Response? Mauri S. Pelto
“In the shorter term (2000-2003) our repeat DGPS surveys show the glacier terminus has retreated on average 63 m. Average surface lowering was 3.3 m a-1 below 400 m a.s.l, and nearly 2.0 m a-1 above 600 m a.s.l., equating to a continuing glacier-wide surface ice loss of 8.0 ± 1.3 x 106 m3a-1, or more than double the 1947-2003 average rate.” Glacier Response to Climate Change on Heard Island, Southern Indian Ocean Thost & Truffer
“…a recent study (Chinn et al., submitted) estimates a net ice volume loss of 17% over the period 1977-2005, mainly due to calving into forming proglacial lakes…” Glacier Changes and Monitoring in New Zealand, Hoelzle et al
A few glaciers have positive mass balance “Surprisingly, the results of repeated airborne altimetry (Bamber et al., 2004) indicates a growth of the Austfonna ice cap (centred at 79.7Ў N -24.0Ў E) in NE-Svalbard. Previous estimates (Hagen et al., 2003; Pinglot et al., 2001) indicated that Austfonna was in equilibrium, whereas most other Svalbard glaciers were retreating.” Austfonna (Svalbard, Norway) during IPY, Schuler et al, but that occurrence is so rare as to be noteworthy.
Richard Steckis (314) — I’ll assume you were attempting to be humorous, but to be definite, no, there is no commission. By the way, have you read it? First link in the science section of the sidebar.
First, regarding point 3. It is settled science as if it wasn’t perfectly obvious that people are burning fossil carbon. More information may be obtained from the Carbon Dioxide Information Analysis Center at ORNL.
But most important, there is a fundamental point about the scientfic method which seems to escape you. John Tyndall’s experiments, refined later by others, establish beyond the shadow of a doubt that CO2 is a global warming (so-called greenhouse) gas. It is even known what amount of warming CO2 alone would provide. But what is not so certain, because of feedbacks, how much warming CO2 in the atmosphere provides. First look at the dacadal averages from the HadCRUTv3 global temperature product:
http://tamino.files.wordpress.com/2008/04/10yave.jpg
By eye or with a transparent straightedge, estimate an overall trend line. It goes up with wobbles both above and below the trend. Too a modest approximation that is the global warming gas forced temperature increase effect.
But we can do more (without substantial effort) and BPL did it; determine the correlation between ln(CO2) and temperature anomaly. Since we already know causation exists, this just indicates how much of the data variation from a flat line is explained. As BPL shows, at least 60%; the rest is the wobbles above and below the trend line.
To be clear, this is a completely reasonable thing to do given we know causation exists. Of coure, to be more precise one needs some form of AOGCM and better attribution methods. But just to show the approximate magnitude these simplier methods suffice.
319 Geoff Says:
“Photosynthesis by enclosed plants depleted the CO2 and increased the ratio of 13CO2 to 12CO2 in air as it was moved by a blower from the air intake to the outlet of the chamber.”
This describes the behaviour of photosynthetic use of co2 by plants and the effect on delta 13C in a growth chamber. What we are talking about is not photosynthesis but potential respiration, decomposition and other carbon releasing processes whereby the carbon produced thereby is depleted in 13C. All biogenic carbon is depleted in 13C.
also:
“If you have access to JStor, you can view this paper. Regarding C-14, do you dispute that fossil fuels are low in C-14, or do you dispute that burning them will dilute C-14 in the atmosphere? I really don’t understand what your objection is, because this seems self-explanatory.”
No. I do not dispute that 14C is depleted or non-existent in fossil fuels. What I am saying is that atmospheric 14C can be quite variable due to the influences of solar activity and GCRs. The origin of 14C in the atmosphere is primarily from cosmic processes. The flux of 14C in the atmosphere is also heavily influenced by those processses. You do not need fossil fuel burning to register significant declines in atmospheric 14C.
319 Geoff also says:
“5. The increase in temperature correlates with the increase in CO2 (60–76% for temp. anomaly and ln CO2 for 1880-2007).” Your answer:
That is a correlation which is NOT cause and effect.
Radiation physics provides a cause and an effect. Look up Beer’s Law. ”
I am familiar with the Beer-Lambert’s Law. The relationship between radiative absorption of co2 and gas concentration is logarithmic and not linear. Beer-Lambert’s law in no way contradicts what is said about correlation not being cause and effect.
As to the comment re: Weart’s book, that was directed at David Benson, not Gavin and was with jocular intent. Any offence is regretted.
Noting the ten or so years of of non-increasing temperatures, I earlier asked how many more years of this would be needed before people begin to start questioning AGW.
The only answer was DavidK’s, who said by 2015. Am I to take it this means everyone else will cling to it no matter what?
Richard Steckis writes:
Suess, H.E. 1955. “Radiocarbon Concentration in Modern Wood.” Sci. 122, 415-417.
Revelle, R. and H.E. Suess 1957. “Carbon Dioxide Exchange between Atmosphere and Ocean and the Question of an Increase of Atmospheric CO2 During the Past Decades.” Tellus 9, 18-27.
“Noting the ten or so years of of non-increasing temperatures…”
Except that there HAS been an increase in temperature over that time.
So when it STARTS going down, THEN you can start asking “for how long will this have to happen?”.
M’kay?
“Beer-Lambert’s law in no way contradicts what is said about correlation not being cause and effect.”
And F=ma was proven by noting the time taken to pass marked points of an air puck going down an inclined slope.
However, you would argue that F=ma is NOT proven since this is merely correlation and not causation.
Richard Steckis writes @314: “By the way. Do you get a commission from Weart? I have seen you recommend his book at least 20 times over the course of the last year.”
He keeps recommending it in the vain hope that you might actually read it and familiarize yourself wit the ~200 years of climate science already in the bag.
Here’s the deal Steckis: This is science. Science is about explaining the world around us. Climate scientists have found that they can explain an astounding amount of climate, but only if CO2 is a significant contributor to warming. There is lots of empirical data that support this contention. An unfortunate consequence of this is that it means we are changing the planets climate in ways that will have severe adverse consequences. If you disagree, great. Find some evidence. Construct a theory that accounts for as much of Earth’s climate as the consensus model but has a low CO2 sensitivity. If you do, you’ll be famous. Until you do, you aren’t doing science.
This isn’t the first time or place that Richard Steckis has questioned the fact that the rise in atmospheric CO2 is due to burning fossil fuels.
He did so on my blog. He even attempted to support the idea by referring to a post by Roy Spencer on WUWT. It was child’s play to show how Roy Spencer’s post is so foolish, it isn’t even wrong.
This is a test. The idea that increased atmospheric CO2 isn’t due to burning fossil fuels is dumber than a bag of hammers. Those who believes this aren’t skeptics. They’re crackpots.
> It’s at this point that his analysis goes horribly wrong.
> He detrends the CO2 and 13CO2 data, then estimates their rate of change ….
That sounds like something I’ve heard somewhere else recently.
#321, 322 – Mark, if you’re into Pixie dust, go for it. Sea ice depends on more then just the sun. It’s an interaction between the sea and air temp, along with the energy from the sun AND energy radiated back into the sky (atmosphere). Other factors include ocean currents and wind.
Tamino says:
“This isn’t the first time or place that Richard Steckis has questioned the fact that the rise in atmospheric CO2 is due to burning fossil fuels.”
And it won’t be the last time or place. And Tamino. Questioning is good. Questioning is how science is done.
Ray Ladbury says:
“Here’s the deal Steckis: This is science. Science is about explaining the world around us. Climate scientists have found that they can explain an astounding amount of climate, but only if CO2 is a significant contributor to warming.”
[edit of irrelevant strawman – focus on the actual question you have raised]
I know a bit about science Ray. Done a bit and will do more.
Tamino,
What is really dumber that a bag of hammers is to not question and to just follow a putative consensus. I would rather question conventional wisdom and be wrong than have a closed mind to possible alternatives.
“There is no substantial work that has unequivocally shown this to be true.” “unequivocally” means so bleeding obvious that all denialists are forced to accept it. Some denialists don’t accept that the isotopic signature proves that the rise in CO2 comes from fossil fuel burning. Therefore, “There is no substantial work that has unequivocally shown this to be true.” QED
I wonder how many fifth graders can see the silliness in this argument?
“I wonder how many fifth graders can see the silliness in this argument?
Comment by Brian Dodge ”
Not unequivocally…
:-P
“I would rather question conventional wisdom and be wrong than have a closed mind to possible alternatives.
Comment by Richard Steckis”
Why would you want to WASTE TIME arguing conventional wisdom is wrong?
This would be like responding with “what salt?” when someone asks you to pass the salt.
Your mouthings are no noble cause.
Your mind is so open, your brains have fallen out.
“Sea ice depends on more then just the sun.
Comment by J. Bob ”
Read again and take your blinkers off:
“Sea ice extent depends on how much sunlight there is much more than the temperature.”
How is that saying that it ONLY depends on the sunlight?
Bring out your straw!
Now, how does the wind or current depend highly on temperature, therefore making the sea ice EXTENT a good analogue for temperature like you want to make it?
It DOES NOT.
Hence the point: No. Let’s not use sea ice extent.
Using it is no firmer ground, just an easier value to measure which hardly makes it a BETTER measure.
Richard Steckis wrote:
No, we are talking about carbon isotope fractionation as a result of photosynthesis. The Suess effect has been documented by sampling cellulose matter in juniper and pinyon trees, matter that is created through C3 photosynthesis. Decreased respiration as a result of closed stomata during drought conditions will cause the cellulose to become isotopically heavier (less negative del C13 values), which trends in the opposite direction from the Suess effect. Thus, pinyon and juniper del C13 values may be viewed as a minimum estimate of the Suess effect. For reference, del C-13 values range from -19.5 (minimum) to -18.5 (maximum) during 1700 to 1750, and for a similar 50 year span, from -21.8 (minimum in 1985) to -19.9 (maximum in 1935). I encourage you to plot Leavitt’s tree ring data yourself http://www.ltrr.arizona.edu/~sleavitt/SWPinyon-d13C.htm.
Regarding your comments on C-14, I am not aware of any process that produces a monotonically decreasing C-14 signature in the atmosphere as a result of decreased cosmic ray flux. Sure, cosmic ray abundance will vary with the solar cycle, but this is cyclical. Do you have a reference for a cosmic ray flux that decreases with time?
I’m sorry I got on my high horse regarding Weart’s article. As someone who teaches Physics, I rather enjoy Spencer’s writing style — perhaps I am being a bit protective!
#320 J. Bob
Do you know what the term ‘cherry pick’ means?
As to .7C I was referring to the GMT assessment from the IPCC (I did not look it up but I believe it is referring to the period from 1880 through around now.
Did you ever look at the NCAR chart and the multiple attribution analysis. you think 1C is not a major change? But the attribution is very clear in the analysis?
I am having a hard time understanding why you have not looked at the global meant temp and connected analysis and continue to cherry pick your data from hear, or there as you deem fit.
Mark in #322 has nailed it actually, something had to change. We were around thermal equilibrium before the industrial age and now we are experiencing a positive forcing.
We are past perihelion on the obliquity cycle, so we should be on the long slow path of cooling and knitting sweaters for the next ice age, if we were in the natural cycle, in the next 15-20k yrs. Unless of course you have actually figured out the alternative reason for the forcing and associated temperature trend change?
Stock delineation of pink snapper and tailor from Western Australia by analysis of stable …
JS Edmonds, RA Steckis, MJ Moran, N Caputi, … – Journal of fish biology, 1999
… The 18 O/ 16 O and 13 C/ 12 C ratios in the otolith carbonate of pink snapper …
#336 Richard Steckis
Are you saying that the additional Co2 is not from burning fossil fuels, even though it does not have the same C 14 signature?
“I know a bit about science Ray. Done a bit and will do more.”
That is essentially irrelevant re: CO2,fossil fuels and AGW. You are not a climate scientist. The idea that you somehow know something about climate science that literally thousands of climate scientists around the world and every major climate science professional society agrees upon through conferences and published literature is the height of arrogance.
#320 J. Bob
Regarding the error of 10 to 20%
Please, please, please, with sugar on top, read this comment by Walt Meier from the National Snow and Ice Data Center:
https://www.realclimate.org/index.php/archives/2009/07/summer-sea-ice-round-up/comment-page-10/#comment-132627
and for extra credit
https://www.realclimate.org/index.php/archives/2009/07/summer-sea-ice-round-up/comment-page-11/#comment-132804
And please, please, please, try not to forget that ice extent ins hardly as important as ice mass loss when discussing things and as always, context is Key.
Richard Steckis – “You do not need fossil fuel burning to register significant declines in atmospheric 14C.”
Generally speaking, up to a point, yes – C-14 dates are calibrated by tree rings to convert to calendar dates to correct for C-14 variability (presumably a function of both cosmic rays and variations in the C cycle (less CO2 in the air would lead to a higher C-14 abundance as a fraction of atmospheric C).
HOWEVER
The half life of C-14 is over 5000 years. Supporting evidence of anthropogenic fossil fuel contributions to the C cycle largely pertain to the last two hundred years, mostly more recently than that.
If the atmosphere were an isolated system, even if C-14 production went to zero, there would be little change in C-14/C ratio over a century or two. Allowing some C input from biomass – well, most of that just came out of the atmosphere recently. What is the C-14 abundance of the upper ocean, and the C-14 ratio of CO2 released from upwelling deep water? These things matter a lot to measuring the ages of deep sea creatures, but I don’t think they would allow atmospheric C-14 to sharply decline so much in a century (but I haven’t gone through all the math – maybe I’m wrong – but then again, maybe the studies that verify anthropogenic fossil fuel contributions take these things into account).
(What I remember from a diagram about C fluxes, the upper ocean (1000 Gt C) would exchange most of it’s C with the atmosphere on a time scale of ~10 years (annual fluxes back and forth around 90 Gt C). Of course, this should keep the C-14 age of the upper ocean relatively young. If the ocean cycles through the upper ocean every 1500 years (or is it 10,000 years -?), and there is ~ 40,000 Gt C in the deep ocean, that’s about 13 Gt per year, which could age the atmosphere toward 1500 year C-14 age on a time scale of around 50 years, if C-14 production actually ceased. That’s still slower than the rate of C-14 aging by fossil C emissions.
Furthermore, with C increasing in the ocean, atmosphere, and biomass (except for deforestation …), where else is C being depleted to make up for this, except for anthropogenic emissions?
“That’s still slower than the rate of C-14 aging by fossil C emissions.”
Oops, I forgot to account for C-14 aging by fossil C mixing into the ocean and biomass (so fossil C alone would not age the atmosphere so fast, but it would age the biomass and ocean as well as the atmosphere). But presumably these things have also been studied, so no fatal flaw here. It’s just really hard to conclude otherwise than anthropogenic emissions have caused almost all the CO2 increase in the last two centuries.
A sincere thanks to – Patrick 027, Jacob Mack, CTG, Ray Ladbury – for pointing out my error in stating that “constant relative humidity is an assumption”. I foolishly took this from my working notes on the IPCC AR4 WG1 report, instead of opening the 6mb to check the source. I posted the response to Patrick 027 without seeing the later responses, so I will also accept the head banging from CTG #307. My statement was inaccurate. I should have said “GCM assumptions lead to a constant relative humidity to a first approximation”.
Re 342 – not to be too nitpicky, but:
1. there is no perihelion of the obliquity cycle (but it’s obvious what you meant from context).
2. Timing of the next ice age – maybe 30,000 years from now, maybe 50,000 years from now, without AGW. With AGW, maybe not for 100,000 years (?). See my comment here: http://www.skepticalscience.com/news.php?p=2&t=69&&n=36#2768 (in the meantime, the precession cycle will continue to affect low-latitude monsoons, but with reduced effect in the next _0,000 years from reduced eccentricity relative to the most recent past).