Schwartz in the news again:
Stephen Schwartz of Brookhaven National Laboratory makes our weekly roundup again this week. This time, its for a comment/reply in the latest issue of Nature concerning a previously published Nature piece “Quantifying climate change — too rosy a picture?” by Schwartz et al. In the original piece, Schwartz and co-authors argue that the IPCC Fourth Assessment Report (AR4) presents an overly confident assessment of climate sensitivity and potential future climate change. In the response by Forster et al, a number of IPCC lead authors point out that the Schwartz et al critique ignores or misinterprets several key IPCC findings.
update: if you don’t have a subscription, the original Schwartz et al Nature article is available here and the recent comment/reply is available here
update #2: It has been pointed out to us that the commentary by Stephen Schwartz and co-authors was published on the Nature Reports Climate Change website, rather than in the print journal Nature.
Re biofuels: OK David B. Benson et al, this is my last shot on this topic here: My feeling re biofuels is that the core concept is truly a carbon neutral one. From nutrients etc capture carbon from the air in organic material, burn it and release the carbon to the air. Repeat as required. OK. We are using the sun to provide the energy for the carbon capture, and extracting that energy by burning the material in air. Primitive but effective.
What I don’t believe is that all this can be accomplished using plant matter grown without any other energy inputs. For economies of scale biomass will have to be farmed intensively like any other produce. This out-of-loop energy requirement is for:
The tractors used to plant, cultivate, spray and harvest the crop;
To carry raw plant materials to the plant to extract the oil;
To power the extraction system;
To cart the plant waste back to the field to rejuvenate the soil for the next crop;
To make the fertiliser and cart the raw materials to the fertiliser plants and the fertiliser to the fields;
For the pest control sprays, and oils for the chemical base of the spray product;
To transport the workers to and from the fields;
To build and run the irrigation systems;
and finally to cart the fuel (by land and sea)to the end user where is is burned and the cycle (spiral, actually) turns again.
The comings and goings of fuel-using equipment and vehicles involved in producing a single 100,000tonne oil tanker full of usable fuel staggers the imagination. To supply even a small nation will be – I dunno.
And this ignores any inefficiencies that may be caused if the production or subsidies displace other essential food crops which then have to be grown elsewhere at higher energy cost, of if the increased demand for low quality irrigation water causes communities to have to run desalination plants for drinking water etc…
If you produce it in desert (some suggest the ideal crops dont need irrigation – ok if you dont mind it taking 10 years to harvest or a low yield) then the cartage and spoilage distances become huge, and breaking in such areas for sustained agricultural production will entail a huge effort on its own, even before we get a cup of fuel.
For biofuel to be viable it has to follow best farming practice, and that is a fuel intensive process. Until I see all the sums including those externalities Ill stick with my solar collectors and mini-hydro, thanks.
Nigel:
Biofuels can be made from waste products, for example in New Zealand we are aiming to launch a mandatory 10% ethanol petrol blend which is made from a byproduct of the milk industry. There is also talk about making biodiesel from waste scraps from slaughter houses. I get the feeling that there are many other clever ways of turning waste into energy. This can’t be a 100% substitute for today’s cheap petrol – but it shouldn’t be completely ruled out of the discussion either.
You’re right to question the total life-cycle costs of biofuels though – we need to get into the habit of asking these types of questions about all aspects of our lives. It’s going to take a while for the world to become footprint-conscious.
Yep.
“… While the past 10 years have seen a large increase in the understanding of the present-day global carbon cycle and its anthropogenic CO2 perturbation (Sabine et al., Chapter 2, this volume), scientists’ understanding of how the carbon cycle will evolve into the 21st century and how it will interact with human actions and the physical climate system is overall still poor. This chapter is intended as one step on a long road to accurately incorporating the full suite of carbon-climate-human feedbacks in numerical models….”
http://www.atmos.ucla.edu/~gruber/teaching/papers_to_read/gruber_scope_04_crc_corr.pdf
I’m not sure if this is the right place for such a post! I searched for the author of this on RC but had no luck.
Titled: LOCKWOOD AND HANSEN ARE WRONG
http://biocab.org/Solar_Irradiance_is_Actually_Increasing.html
Is an article by Nasif Nahle “Biologist”
Nahle makes a number of claims, which as a lay person, I am ill-equipped to debunk.
Note the confusion of Lean 2000 data and Lean 2001!
Quote
The following information was taken from the next page:
http://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/lean2000_irradiance.txt
In 2001, Judith Lean plotted a graph on Solar Irradiance Reconstruction from data that she and her colleagues had recolected. Graph and data were published in a paper released by ADSHAB for Public Access. However, for unknown reasons, that graph by Judith Lean disappeared from the Internet; hence I saw necessary to chart again the graph based on the data published by NOAA in 2001. I’ve attached the graph on Solar Irradiance by Lean below these paragraphs.
The graph clearly shows that the Solar Irradiance is not decreasing from 1985; on the contrary, the Solar Irradiance is increasing up to date. Mike Lockwood has declared to the press (remember that pseudoscience usually is released through Media in the first place) that the Solar Activity has decreased since 1985, while the warming is increasing since the same year, concluding that the Sun has nothing to do with the Earth’s Climate. Examine the data and the graph and figure out who’s wrong and who’s right.
Nasif Nahle
Biologist
End quote
there is a reconstructed graph – http://biocab.org/Increase_Solar_Irradiance.jpg
quote
From the actual data we conclude that the graphs from Lockwood and Frölish were flawed:
1. The methodology used by Lockwood and Frölish to smooth the lines was applied only to maxima of R (sunspot number), dismissing the TSI. This practice hides the minima, which for the issue are more important than the maxima. For example, if the minimum of TSI in 1975 was 1365.5 W/m^2, it would contrast dramatically with the minimum of TSI of 1998 that was 1366 W/m^2 (0.033% higher). That would make the Sun in 1975 “colder” than in 1998. However, if we compare minimum values with maximum values, then the Sun would be frankly “warmer” in 1998 -when the solar energy output was 1366 W/m^2- than in 1975 -when the energy output was 1366.1111 W/m^2. Today (21/07/07), the global TSI was 1367.6744 W/m^2); hence, we see that we must not smooth maxima values through movable trends because we would be hiding the minima values, which are more important because the baseline of the “cooler” or lower nuclear activity of the Sun are higher everyday. The coolest period of the Sun happened during the Maunder Minimum when the TSI was 1363.5 W/m^2. The coolest period of the Sun from 1985 to date occurred in 1996 when the TSI was 1365.6211 W/m^2. An interesting blotch is that in 1985 the TSI was 1365.6506 W/m^2 and in 2000 was 1366.6744.
2. The graph of tropospheric temperatures is Hansen’s twisted graph. Many of us for many times have demonstrated that it does not match with reality.
3. Lockwood and Frölish dismissed entirely the original work of Judith Lean et al published in 2001, which mysteriously disappeared from NOAA site. However, you can review data at NASA and below this paragraph:
End quote
Timothy Chase said…
Falafulu, can you give realistic examples of feedforward in the climate system?
Tim, if you see my message #2 at the very beginning of this thread, I simply stated:
It would be interesting if future work where by researchers in this area if they would discover that there are also feed-forward processes which are taking place at the same time as those feed-back processes.
What I stated that whether feedforward mechanism do occur in climate processes and I wouldn’t be surprised if such thing exist but have never been discovered by researchers yet. In Systems Biology, certain feedback processes were known to exist for decades, however there were certain feedforward cellular processes & mechanisms that were there all along, but they were discovered at a later time, way before feedback processes had been known to molecular & cellular biologists.
On another point: what is the consensus view on David Bellamy’s and Jack Barrett’s paper in the civil engineering journal which prophesised to show only modest warming from doubling C02? Seems to me that they forgot feedbacks…
[[I was suggesting that the solar system was the remnants of a super nova which exploded 5 billion years ago, with the sun a neutron star surrounded by debris from the supernova.]]
The sun is not a neutron star. It is a main sequence star. Neutron stars are composed mostly of neutronium. The sun is composed mostly of hydrogen and helium. Neutron stars are very small. The sun is very large. Neutron stars are one end product of completed stellar evolution. The sun is less than halfway through its life cycle.
re 86.
Nuetron stars, superdense remnants of Supernovae, are Pulsars, objects that spin at an incredible rate, creating the observed “lighthouse” effect.
http://casswww.ucsd.edu/physics/ph7/SN.html
More detailed:
http://www.astro.umd.edu/~miller/nstar.html
A typical neutron star has a mass between 1.35 and about 2.1 solar masses, with a corresponding radius between 20 and 10 km — 30,000 to 70,000 times smaller than the Sun. Thus, neutron stars have densities of 8×1013 to 2×1015 g/cm³, about the density of an atomic nucleus.
http://en.wikipedia.org/wiki/Neutron_star
http://heasarc.gsfc.nasa.gov/docs/xte/learning_center/ASM/ns.html
Wouldn’t the increased density have a commeasurate effect upon orbital mechanics?
“Nasif Nahle, Biologist” charts a well known estimate (note this level of precision is just a w.a.guess on a time series beginning in 1610 A.D.) — three parts in 1300. Nobody has a mechanism that would allow the slight difference, if real, to change CO2 levels or climate since 1970.
See satellite data for recent decades. You can look this stuff up.
Dr. Lean’s work is readily available, not “disappeared.”
Just one example:
http://64.233.179.104/scholar?hl=en&lr=&scoring=r&q=cache:xNIOpzpLiRcJ:w3g.gkss.de/G/Mitarbeiter/storch/pdf/CRCES.2006.summary.pdf+Judith+Lean,+Naval+Research+Laboratory
Ref 106. I am not sure if you have read the references I provided. I never said the sun was JUST a neutron star. I said it was a neutron star surrounded by the debris of the supernova. Maybe I should have added “from inside the orbit of Mercury”. I believe this discussion is similar to that which occurred with plate tectonics. The “scientific establishment” fought bitterly against this idea. In the end it was proven to be correct. I believe the same will happen with this idea.
Jim Cripwell, These guys are loons. As near as I can tell, the papers are not peer reviewed in any meaningful sense. The Sun looks like a main-sequence, average-sized star. It radiates like one. It’s spectrum looks like one. The vicinity of a neutron star surrounded by that much gas would not be a pleasant neighborhood.
However, this brings up a really good point–the papers are written by non-astrophysicists, published in non-peer-reviewed journals and espouse a notion that flies in the face of established physics. In that sense, they are like most of the denialists–e.g. Bellamy and Barrett’s work and Nasif Nahle’s self-published screeds. Folks, maybe somebody can explain to me why you would work so hard to find demonstrably-wrong crap like this when the correct science is readily available and so demonstrably correct.
I (#99) wrote:
I can give just such an example of a feed-forward (definition 2) which in fact exists within the climate system and wondered if you might spot it. However, let’s look at your response first…
Falafulu Fisi (#104) wrote:
You are right about there being feed-forward mechanisms in biology. One of the “more recent” areas in which we have discovered them is in protein networks which rather that waiting for a longer and less responsive feedback to occur, in response to a change, the network is structured in such a way that it responds to this change in a way that maintains stasis in the face of increasing demands such that the less responsive feedback need not occur, or if it does occur there will be resources for it to be more responsive.
However, there are feed-forward processes in the realm of biology which we have known about well before this. If an animal sees a predator charging in its direction, the animal doesn’t wait to for the attack, but flees. Or the squirrel which doesn’t wait until she is hungry in the winter or spring before looking for nuts but stores them either in its nest or by burying them in the ground.
In essence, what we are talking about is a form of teleological causation, and even in the case of the inanimate car which is designed with the “intelligence” to recognize the incline of a hill and throttles the engine before the car starts slowing down has a form of teleological causation to it since it was designed to recognize the incline and throttle the engine before car itself slowed down.
But how do such feed-forward mechanisms come into existence in the first place? Particularly in the realm of biology?
Evolution.
Efficient causation leading to a systemic process in which teleological, purposeful causation is an emergent phenomena. The tree which turns its leaves towards the sun so that it will absorb more light is just such a form of teleological causation – which comes into being as natural selection weeds out less successful competitors generation after generation until the organism is well-adapted to the environment and in one sense or another, anticipates future needs. The claws or teeth which are well-adapted to the purpose of attacking future prey – and undergo morphological development before a young predator has to fend for itself.
*
Now where can we find a feed-forward process in the climate system?
Humans.
Our actions – if we are wise – will constitute just such a feed-forward process.
We can anticipate the future effects of a Business as Usual Scenario which will result if we continue with business as usual. Whatever happens in the next forty years is essentially already locked in to the climate and largely beyond our control. But what we do now will have effects after that, effects which will be amplified by the climate system in the decades which follow, being of a greater magnitude eighty years from now and even greater by the turn of the century.
If we are wise, having concern for ourselves, our children and for future generations, we will anticipate the effects of continuing along our current path and adjust our course.
Nidel Williams(100) — All those production costs are accounted for. And indeed the biomass used is often wastes which otherwise have to be processed less efficiently. For example, the pilot biocoal facility being built in Denthe Province, The Netherlands, to which I previously posted a link to the Biopact page about it, will use forestry operation wastes to produce 75,000 tonnes of biocoal per year. Forestry operators do not want to leave the wastes just lieing around for fear of fire. So taking these to the biocoal facility encurs essentially no extra costs.
But the big promise for the future is to produce biofuels in the South: South America, sub-Sahara Africa, South Asia and Southeast Asia. There labor costs are low and having a cash crop to sell will make a big improvement in their lives. If you would follow Biopact, you would see that billions of dollars are being invested for this already.
Wind can be a useful assist for rich countries, but can never be more than about 15% of electricity production (except in Argentina). Solar is expensive and only works when the sun shines. Solar produces electricity, which is not storable. Thus solar is only another supliment.
Biofuels, on the other hand, are storable: the liquids for some time and biocoal indefinitely. Anyway, I’m sure you will agree these are preferable to fossil fuels…
Re 103 Christopher Sauvarin quoting Nasif Nahle, Biologist: “The graph clearly shows that the Solar Irradiance is not decreasing from 1985; on the contrary, the Solar Irradiance is increasing up to date.”
The graph in the link shows no such thing. The graph clearly shows an increase until solar cycle 20 ~1960, a slight decrease for the solar cycle 21 maxima ~1970 and minima ~1975, then a return to a range roughly equivalent to cycle 20 maxima and minima and there after shows no significant trend up or down for cycles 22, 23 and 24.
Nothing new to see here folks.
Re 112 David B. Benson : “Solar produces electricity, which is not storable.”
All electricity is storable. Other than batteries, examples include: pump-storage (already in wide-spread large-scale use), hot water storage, flywheels, generating hydrogen.
Jim Edgar(114) — Please not that none of the devices you mention actually store electricity, except batteries, depending.
THe do store useable energy. For example, pump-storage has an efficiency of right around 50%, which means that the solar option becomes even less attractive.
Flywheels are fine for relatively small amounts of energy.
As of yet, nobody has good methods of storing and transporting hydrogen, although some research looks promising. Still, using this as a means of generating electricity later will surely be quite a bit less than 100% efficient.
re 109
Ref 106. I am not sure if you have read the references I provided. I never said the sun was JUST a neutron star. I said it was a neutron star surrounded by the debris of the supernova.
=================
I understand. Perhaps you might wish to take your own advice. Miller discusses accreating Neutron Stars here:
http://www.astro.umd.edu/~miller/nstar.html
What you aren’t answering are the varied problems for the hypothesis the Sun is a Neutron star Miller and other provide, such as the incredible rate of spin, the manner in which accreation actually happens (as opposed to the understood models of accreation re Stellar Evolution), the gravitational mass of a Neutron Star that far exceeds that of what is measured for the sun (thus suggesting our planet should not be orbiting as it does), as well as x-ray and gamma bursts far in excess of what we see emitted from the sun, to the best of my understanding. Also, and I’m speculating here, the blast of a supernovae pretty much expels all matter from around the star.
The understood model of why and how Neutron Stars exist seem, on their face, to contradict the hypothesis the Sun is a Neutron Star. Before the idea goes any further, perhaps these problems need to be reconciled.
Can you?
Re 115 David B. Benson
As of yet, no one has devised a method of generating or storing electricity with anything even approaching 100% efficiency, and to expect that anyone will is preposterous. Same for fuels that will be burned, bio or fossil.
Re 116. Superconducting magnetic energy storage (SMES) comes quite close to 100% storage efficiency for electricity. Sorry to be preposterous.
I haven’t been following this thread that closely, but where did the “our Sun is a dirty neutron star” come from???
Correcting #90 — The world’s ocean vessel fleet, assuming it produces 99,000 billion tonne-km per year, consums 230 million tonnes of diesel fuel per year which contributes 0.1725 Gt of the yearly anthropogenic carbon load of about 8 Gt.
This sees far more reasonable, so probably is not too far off. Anyway, that’s about 2584 tonnes of diesel fuel per vessel per year. How many automobiles worth is that?
re: #103 Christopher
I suggest you explore Nasif Nahle’s entire biocab website, and come back with your assessment of his credibility. At that point, if you need some more help, many people here can help you learn more about helping laymen figure things out.
Since this thread is accumulating loonie items…
We need a subspecies of Maxwell’s Daemons, called MaCOO’s Demons, but even smarter.
They stand on diagonal screens. When they see a CO2 molecule, they rip it apart and drop the C into a bin, and let the O2 go on. If enough can be hired, it’s easy retrofits for power plants.
re 118
Rhetorical question: Isn’t a biologist disproving AGW much like an engineer disproving Evolution?
1500-year cycles, yadda yadda yadda:
http://www.earthtimes.org/articles/show/news_press_release,176495.shtml
You may not want to read that particular biologist’s theory about evolution. Oh, my eyes ….
Re #118: [Superconducting magnetic energy storage (SMES) comes quite close to 100% storage efficiency for electricity.]
If one doesn’t consider the amount of energy used to keep the superconductors cooled below the point at which they cease to be superconducting :-)
I suppose capacitors could be considered to be very efficient energy storage devices. And to be picky, a battery of course doesn’t store energy as electricity: it uses the electricity to cause reversable chemical changes in the battery; reversing the changes creates electricity again.
Here is Dr. Schwartz’ homepage at Brookhaven –
http://www.ecd.bnl.gov/steve/schwartz.html
His publications link has copies of the 2 recent articles and associated presentations, for some additional insight into how the final conclusions were obtained.
In another category, he shows several Popular Presentations on climate change. These show melting glaciers, the effects of sea level rise on Long Island. It isn’t typical skeptic fare. For example –
http://www.ecd.bnl.gov/steve/pop/greensmenW.pdf
Makes about as much sense as trying to replace all the physics incorporated into a global climate model with a clean-slate neural network in need of “training.”
Re #126: Of course I accounted for the electricity needed to cool the superconductor in a SMES, and still the storage efficiency is close to 100%.
And regarding your pickiness: I wasn’t referring to batteries; in a superconductor the electricity is actually being stored as electricity, albeit DC.
Jim Edgar: The efficiency of modern pumped storage is around 85% – See: http://en.wikipedia.org/wiki/Pumped_storage
Apparently Norway already has enough that it could act as a battery for all of Europe for days – hence the recent talk of a Europe wide HVDC network. The 15% wind penetration is a myth – ask Denmark!
Ref 119 “I haven’t been following this thread that closely, but where did the “our Sun is a dirty neutron star” come from???” I raised the issue. There is a fundamental question. Does the sun affect climate? The proponents of AGW believe the answer is a definite NO. The deniers are not so sure. The answer must depend on what the sun consists of. There is a new hypothesis that the solar system is the remnants of a
Ref 119 “I haven’t been following this thread that closely, but where did the “our Sun is a dirty neutron star” come from???” I raised the issue. There is a fuindamental question viz does the sun affect climate? The proponents of AGW know the answer is no; the deniers are not so sure. The answer depends on what the sun consists of. There is a new hypothesis that the solar system is the remnants of a supernova that exploded 5 billion years age. Under this idea, the sun is a neutron star surrounded by the debris from the supernova inside the orbit of Mercury. Not a popular idea on RC, but my email address is b f 9 0 6 @ n c f . c a
Re 130, Thanks for the link, Greg. Pumped storage is anything but new technology (as the wiki article says, the first installations went into service over a century ago), but I am continually surprised by how few people even know about it. The Ontario example in the wiki refers to the Niagara installation down river from the Falls, but there is one on the NY side of the river as well, and there are many others in the US (see list at bottom of the wiki). The bugaboo of inconsistent solar and wind output can be easily mitigated, if not completely solved, using pumped storage.
[[Wouldn’t the increased density have a commeasurate effect upon orbital mechanics?]]
Not usually, no. In general you can treat any spherical object as a point source where gravity is concerned, and most celestial mechanics makes that assumption.
[[Ref 106. I am not sure if you have read the references I provided. I never said the sun was JUST a neutron star. I said it was a neutron star surrounded by the debris of the supernova. Maybe I should have added “from inside the orbit of Mercury”. I believe this discussion is similar to that which occurred with plate tectonics. The “scientific establishment” fought bitterly against this idea. In the end it was proven to be correct. I believe the same will happen with this idea.]]
I’m sorry, but I don’t think so. To believe it would require pretty much all of modern stellar evolution theory to be wrong, and there’s just too much evidence backing that theory up.
We can tell from a discipline called “helioseismology,” which uses radar to explore the depths of the sun, what the density structure of the sun is. It does not have a neutronium core. The core of the sun is dense, but it is orders of magnitude less dense than neutronium.
One stillborn pumped storage installation proposed by ConEd in the late 1960s-early 1970s was the Storm King project, which would have used off-peak power, primarily from ConEd’s Indian Point nuke station, to pump water from the Hudson River to a proposed reservoir on the northwest flank of Storm King mountain,~55 miles north of the southern tip of Manhattan. The site for the pump-generator plant was cleared and blasted out of the base of the mountain, and work on the bores was started before the project was halted by public opposition due to potential for the heavily polluted river water to contaminate ground water. The site is also just within the boundry of significant ocean salinity intrusion. Now that the river is very much cleaner, and a fair portion of the work has been done, I wonder if this project could be revived, especially since the summit of Storm King may be a prime site for wind generation.
There are also wind and coal power plants that are using excess electricity to store compressed air.
> I accounted for the electricity needed to cool the superconductor
> in a SMES, and still the storage efficiency is close to 100%.
I’d appreciate a cite to that work, I’m curious about the assumptions (what superconductor material, what temperature, what refrigeration)?
Everything I find is in reference to superconducting magnetic bearings for flywheel storage so far.
From Nahle quote (#128):
“A great percentage of that heat is radiated to the cold space (radiation); from there, the heat is transferred to the gravity field.”
Heat radiation converts to gravitational force… I suppose I should be writing this stuff down. Now I know why the freezer levitates when the compressor is running.
J. Althauser (#127) wrote:
Schwartz isn’t your typical skeptic – he is worried that things could get much worse than the IPCC projects once the effects of aerosols are removed…
What he doesn’t seem to realize is that we have a good handle on the forcing due to greenhouse gases. We are able to arrive at these independently of any estimates regarding the effects of aerosols. And although it is based upon the paleoclimate record rather than first principles, we are also fairly confident regarding the climate sensitivity to CO2 doubling (~3 C).
J.C.H. wrote: “There are also wind and coal power plants that are using excess electricity to store compressed air.”
There is also a car that has been developed in Europe that uses compressed air drive — “The Air Car”. It can be charged either by directly pumping compressed air into its storage tank from an external compressor at an appropriately equipped filling station (in several minutes) or with an electric internal compressor that runs off of house current (in several hours). The designer claims it has a range of 200-300 Km per charge or about double that of “the most advanced electric car”. Another advantage over battery-powered electric cars is that the toxic materials, relatively short service life, and high replacement cost of batteries are eliminated.
There are so many promising technologies for clean renewable generation of electricity, and safe, economical and clean storage of electricity that can directly replace the use of fossil fuels. It is just a matter of implementing them.
Read about a great break-thru in battery-like device tech. If it pans out, it’s green lights ahead for EVs & the death knell for ICEs:
http://www.cnn.com/2007/TECH/09/07/electric.car.batteries.ap/
If this is a real advance, I do hope this is not bought up by the car-oil industry and shelved.
Re 131 Jim Cripwell: “There is a fundamental question. Does the sun affect climate? The proponents of AGW believe the answer is a definite NO.”
This is a fundamental untruth.
Greg(130) — Thank you for the update and link.
In Austin those could be mushroom-powered batteries – harnessing and storing slacker power.
I don’t know how much air a windmill could compress to 12,000ish PSI for the air car. It seems like that would take a little fossil-fuel umph.
I want to compress air with draught animals to run air-powered farm machinery. There you would not have to worry that much about range. The big horses have the umph to compress air to just about any imaginable PSI – the hard working kind. It’s simple existent technology. Horses would be converting marginal plants to compressed air, and compressed air would be producing quality food.
In comment #19 to “Ozone impacts on climate change” (Jul 26), Tamino says that “global warming has shown statistically significant acceleration”, and quotes figures of .018C p.a. from 1977.0-2007.0 and .020C p.a. from 2000.0-2007.0, using HadCRUT3, compared with .016C from 1970.0-2000.0.
In my #189 I said that I would study these figures more closely. I felt that 7 years was a bit short, and 30 a bit long, so I chose 20 years, which is roughly one full solar cycle (including polarity). It is the only length period I chose, and only 1987.0-2007.0, so I hope I will not be accused of cherry-picking.
I used the data:
.178 .174 .109 .247 .203 .070 .104 .169 .270 .138
.347 .526 .302 .277 .406 .455 .465 .444 .475 .422
A linear regression on these gives a slope of .0197+/-.0033 Cpa, which is consistent with #19’s estimate for the last 7 years, yet cannot truly be described as “statistically significant acceleration”. Let us call this hypothesis H0, and note that the sum of error squares is 0.1360.
To study the possibility of acceleration within these figures I decided to split them into two, and regress separately. I got .00018 +/- .00794 for the first set (1987.0-1997.0) and .00970 +/- .00954 for the second (1997.0-2007.0). This shows that in neither period was there a statistically significant trend in temperature, but that there was a substantial jump between the two periods. Fitting a flat model in each of the two decades gives .168 for the first and .416 for the second, a jump of .248C. The sum of error squares for this hypothesis H1, which has 18 degrees of freedom just like the linear one, is 0.1094, quite a lot less than 0.1360.
Is this difference so significant that we should prefer the latter model of a temperature jump around 1997? When error sums of squares have different degrees of freedom, an F statistic can be made from them and the difference between them. When the d.o.f are the same, this is not possible; I can think of three approaches to this.
a. If e0 = .1360 and e1 = .1094, with ratio 1.243, P[E0/E1 > 1.243] = P[E0-1.243*E1>0] is the probability that a derivable quadratic form in normal variates is greater than 0. The Durbin-Watson test is another example where such a probability needs to be calculated. It just so happens that my 1978 thesis was on this subject, and I used methods of Pan Jie-Jian and Imhof to calculate such probabilities. Unfortunately, I no longer have the code available! It would be a lot of work to reproduce this, but possibly someone knows of some package where it is already implemented.
b. I conjecture that the significance must be at least as much as if e1 actually had 1 fewer degrees of freedom. In that instance, the F_1,17 statistic would be 17(e0-e1)/e1 = 4.13, which is close to (but just outside) 5% significance.
c. The maximum likelihood ratio, or Bayes factor in favour of H1 over H0, is (e0/e1)^(20/2) = 8.8.
An unbiassed observer would clearly prefer H1 over H0 as an explanation of the data, apart from concerns about the physical meaning. What could cause a jump of about 0.25C +/- 0.11C over a fairly short space of time?
Here are 6 possibilities, though some are more serious than others :-). Some I am pretty sure are not true, and others I hope are not true.
a. Gaia was suddenly angered by the USA not signing the Kyoto Agreement.
b. A La Nina (cooling) followed by an El Nino (warming) masked a steadier increase from CO2 warming.
c. The change to solar cycle 23 in 1996.5 was somehow implicated. If so, another bump in temperatures is possible when cycle 24 takes hold, probably around 2009/10. But it may not be as great as a repeat 0.25C since cycle 24’s delayed onset suggests it could be a lot weaker than cycle 23
d. It is just another of those funny climate things that are hard to explain, like the downturn in global temperatures after the early 1940’s even though solar activity was seen to be increasing up until about 1953 (see Lockwood & Frohlich figure 4).
e. A large-scale change in the type or placement of thermometers occurred and any attempted corrections failed.
f. It is a statistical fluke, and a straight line fit is actually correct.
For most of those possibilities I would expect the rise over the next 10 years to be less than the +0.25C jump observed in the last 10. This contradicts the Hadley Centre’s forecast on meto.gov.uk (press release 10/8/07) of +0.3C by 2014 (and at that rate +0.4C by 2017 unless they have also noticed it will be late cycle 24 by then). With their powerful Japanese computers and intricate models, you may decide to prefer their forecast to my rather simple analysis – but at least you can understand the latter. As a matter of some interest, does anyone know how their +0.3C breaks down in terms of contributions from various effects (presumably the models can be run with various effects turned on and off)?
To conclude, the straightforward linear model H0 for the last 20 years gives a linear trend of .020+/-.003 Cpa, which could be used for the usual extrapolation, but it does not fit anywhere near as well as the model H1 of two flat lines with a jump. Extrapolating H1 is problematic because one needs to know whether conditions will be suitable for a similar jump in the next few years, if indeed we could identify what those conditions were. The next few years are a critical time for the magnitude of warming implicated by the AGW hypothesis. After the flat figures of 2002-2007 will we see another big jump or some steady increase?
Aw come on Jim 143, give them some credit! AGWrs never say the sun doesnt affect climate, they may even suggest that perhaps the sun is the butterfly flap that started this current climatic excursion, but they do say convincingly that the sun is NOT the major forcing behind the climate state we are now enjoying, we Anthroponuts are. Cheesh!
Re 132. Jim Cripwell, on the contrary, your little hypothesis is very popular here. I haven’t laughed so hard since I heard somebody say he was going to vote for Dubya over Kerry because of his war record. Jim, do you know what happens when you have a neutron star surrounded by a plasma? One of 2 things: If the plasma has enough angular momentum, it spirals around the neutron star emitting x-rays, generating hellacious magnetic fields and generally raisin’ hell. Otherwise it smashes into the neutron star and is itself turned into neutrons, generating gamma rays and generally raisin’ hell. So, Jim, where are all those x-rays?
As to your little straw man, again, thanks for the laugh. The thing is I can’t figure out whether you know your straw man is a straw man or if you really think it’s an accurate appraisal of climate science. Either way, Jim, learn some science. We’ll all be glad you did.
Re 142. Lynn, An interesting possibility, but there are a lot of unsolved problems (high-voltage among the most significant). The Wikipedia article below mentions the EEstor technology.
http://en.wikipedia.org/wiki/Supercapacitor