Knud Jahnke and Rasmus Benestad
After having watched a new documentary called the ‘Cloud Mystery’ – and especially the bit about the galaxy (approximately 2 – 4 minutes into the linked video clip) – we realised that a very interesting point has been missed in earlier discussions about ‘climate, galactic cosmic rays and the evolution of the Milky Way galaxy.
It is claimed in ‘The Cloud Mystery’, the book ‘The Chilling Stars’, and related articles that our solar system takes about 250 million years to circle the Milky Way galaxy and that our solar system crosses one of the spiral arms about every ~150 million years (Shaviv 2003).
But is this true? Most likely not. As we will discuss below, this claim is seriously at odds with astrophysical data.
Here is a little background on the Milky Way: The arms of spiral galaxies are not constant entities in time. They are results of gravitational instabilities in the disk or are induced by external companions. These instabilities are moving mass ‘overdensities’ containing old stars and gas, but also newly formed stars recently created from local collapse of the overdense gas.
Arms move around a spiral galaxy with a pattern speed that is defined by the mass distribution. This pattern speed differs from the motion of individual stars, just like the speed of an ocean wave differs from the movement of water particles. Estimating the pattern speed is difficult, as it is not coupled to the motion of individual stars but can only be inferred indirectly. For this reason it has not yet been reliably measured for our Milky Way – unlike for some other spiral galaxies, for which our clear and unobstructed view from the outside allows an estimate.
So how did Shaviv come up with this number?
Measuring the rotational velocity of stars in the Milky Way disk or other spiral galaxies is straightforward. The rotation is not rigid, but depends on the encircled mass inside the orbit of a star, including the Dark Matter, a yet unknown but solidly established source of gravitational attraction. It is easy and a standard technique to measure rotation curves of galaxies as a function of radius, and this is also possible for the Milky Way.
The two different rotating velocities of arms and stars have a different radial dependence – to first order the arms get preserved as entities while the stars further out have much smaller angular velocities than stars further inside – so the relative velocity of a star with respect to the nearest spiral arm will depend on its distance from the centre of the galaxy. At a certain radius, the radius of co-rotation, the two velocities are identical and a star at this radius has zero relative velocity with respect to the spiral arm pattern. It stays “forever” in the same spiral arm – or outside of it.
What are the best estimates for the relative velocity of the Sun with respect to the spiral arm pattern of the Milky Way? As mentioned, the pattern speed of the spiral arm in the Milky Way has not been firmly established.
When investigating other spiral galaxies, however, it was found that almost independently of the wide range of possible assumptions on which the pattern speed estimate was based, the radius of co-rotation follows a simple law: rcorot=r0 * (3.0 +/- 0.5), where r0 is the scale length of the exponential disk of the galaxy (the surface brightness of spiral galaxies drops very close to exponentially from the center to the outside, setting a characteristic size scale). This was measured by Kranz et al. 2003.
Since the Milky Way is a completely normal spiral galaxy, we can apply this result to it. The scale length of the Milky Way disk has recent estimates ranging from 2.6 kilo-parsec (kpc, 1pc=3.3 light years) from the SDSS survey (Juric et al. 2008), through 2.8 kpc (Ohja 2001) to 3.5 kpc (Larsen & Humphreys 2003).
We also know the Sun’s distance to the galactic center well, 7.9 +/- 0.4 kpc (Eisenhauer et al. 2003), which means that the range of values for rcorot=9.1 +/- 1.9kpc. In other words, from this calculation the co-rotation radius of the Milky Way is between 7 and 11 kpc, and at 8 kpc our Sun is close to or at the radius of co-rotation. It almost certainly is not 6 kpc further inside, as Shaviv (2003) claims.
Shaviv (2003) lists in his Table 3 a number of values for the pattern speed of the spiral arms, taking from publications ranging from 1969 to 2001, two years before his article. In these papers the derived relative motion of the Sun relative to the arms ranges from Omegarel=+13.5 km/s/kpc to -4km/s/kpc, and includes estimates that are close to zero (-4km/s/kpc < than Omegarel < +7), i.e. a location near the radius of co-rotation in the majority of the publications, and most of the more recent ones. However, he selectively disregards most of these results.
If we add the above evidence that the radius of co-rotation lies at 9kpc distance and not further out, and convert this to relative velocities, e.g. by using the Milky Way rotation curve by Merrifield 1992, we obtain Omegarel =+3.2 km/s/kpc with an error range from -2.5 to +7.1km/s/kpc, and including zero. Shaviv’s derived “period for spiral arm crossing” of p=134 +/- 25Myr for four spiral arms is well outside the range derived from these values.
So it seems that Shaviv’s “periodicity” estimate for crossing of spiral arms by the sun does not hold up under scrutiny when using current astronomical results as the work by Kranz et al. This comes in addition to the previously shown fact that the correlation of cosmic ray flux with paleoclimatic data proposed by Shaviv and Veizer (2003) only arises “by making several arbitrary adjustments to the cosmic ray data” (Rahmstorf et al. 2004).
Note also that the question of current climate change is quite another matter from that over time scales of many millions of years – despite Shaviv’s remarkable press-release claims that “The operative significance of our research is that a significant reduction of the release of greenhouse gases will not significantly lower the global temperature”. As we repeatedly pointed out over the years: that global warming over the past decades is not linked to cosmic rays is clear from the fact that the cosmic ray measurements over the past 50 years do not show any trend (Schiermeier 2007).
Remarkably, the poor scientific basis of the galactic cosmic ray hypothesis seems to be inversely related to the amount of media backing it is getting. At least 3 documentaries (‘The Climate Conflict’, the ‘Global Warming Swindle’, and now ‘The Cloud Mystery‘) have been shown on television – all with a strong thrust of wanting to cast doubt on the human causes of global warming.
References:
Eisenhauer et al. 2003, ApJ, 597, 121; http://adsabs.harvard.edu/abs/2003ApJ…597L.121E
Kranz et al. 2003, ApJ, 586, 143; http://www.journals.uchicago.edu/doi/abs/10.1086/367551
Juric et al. 2008, ApJ, 673, 864; http://adsabs.harvard.edu/abs/2008ApJ…673..864J
Larsen & Humphreys 2003, AJ, 125,1958; http://adsabs.harvard.edu/abs/2003AJ….125.1958L
Merrifield 1992, AJ, 103, 1552; http://adsabs.harvard.edu/abs/1992AJ….103.1552M
Ohja 2001, MNRAS, 322, 426; http://adsabs.harvard.edu/abs/2001MNRAS.322..426O
Rahmstorf, S., et al., 2004: Cosmic rays, carbon dioxide and climate. Eos, 85(4), 38, 41.
Schiermeier, Q., No solar hiding place for greenhouse skeptics. Nature, 2007. 448: p. 8-9.
Shaviv, N., 2003, NewA, 8, 39; http://adsabs.harvard.edu/abs/2003NewA….8…39S
Shaviv, N. and J. Veizer, Celestial driver of Phanerozoic climate? GSA Today, 2003. 13(7): p. 4-10.
ffrancis, I don’t have time to find it again right now, but there are papers — searching Google Scholar will them — that mention the difference, look for “a regional shift with decreases at NH midlatitudes and increases at the more photochemically active subtropical and tropical latitudes.”
Hank,
I am not sure what you are suggesting. I sited other articles in another post that was not allowed for whatever reasons. But here is the article from Nature which has citations that I first alluded to. The point is there are many good scientists who have problems with current theoretical points of current cosmology. It is something that can be discussed without nuking the opposition.
http://www.nature.com/nature/journal/v452/n7184/full/452158a.html
“The Universe seems to be expanding ever faster — a phenomenon generally ascribed to the influence of ‘dark energy’. But might the observed acceleration be a trick of the light in an inhomogeneous Universe?”
Gusbob, There are good theoretical reasons for assuming the laws of physics are constant throughout the Universe. Everyone realizes that this could not be the case, but even introducing putative dark matter (for which there’s lots of evidence) and dark energy (which is purely hypothetical at thid point), cosmology is simpler if the laws of physics stay the same. Such a model has been seen to have considerable predictive power–and predictive power is more important than explanatory power. There have been models where the laws of physics varied–for instance, introducing a field with varying phase throughout the Universe, but this really complicates the model. And while there may be many cosmologists who find the current situation unsatisfying (after all cosmology is well under a century old), you will notice they don’t use the discrepancies to advocate for their own pet theories.
Ray I don’t understand your problem. It is the nature of a scientific discrepancy. When there are discrepancies, people will look at how to modify the current pet model to make a better fit. Or look elsewhere to make a better fit. Regards dark matter there are several scientists arguing for modified gravity instead of dark matter.
I first remarked that I find to much circular thinking with dark matter. I am more than willing to leave my pet theory aside and simply look at dark matter proofs. For example the bullet cluster has been offered as proof of dark matter.
http://space.newscientist.com/data/images/ns/cms/dn9809/dn9809-1_250.jpg
One argument of this “proof” goes that due to the estimated center of gravity within the two clusters we can see dark matter (which they color in as if real). But the associated gas nebula seem to be lagging behind. So the interpretation is the bullet cluster is the result of a collision in which two masses of dark matter passed through each other. The lagging gas clouds is due to their entanglement due to electrostatic interactions so that the gas overcame the attraction of the dark matter gravity. They are stating that electrostatic forces are more powerful attractants than dark matter.
So explain how this powerful dark matter, with 6 or so times more gravitational force than normal gravity just passes through each other. No accretions? The proof just seems so contrived.
And why no dark matter in the solar system other than the fact it is not needed theoretically where normal gravity does just fine. Such inhomogeneities seem counter big bang.
An interesting read:
http://www.iop.org/EJ/article/1748-9326/3/2/024001/erl8_2_024001.html
Abstract. A decrease in the globally averaged low level cloud cover,
deduced from the ISCCP infrared data, as the cosmic ray intensity
decreased during the solar cycle 22 was observed by two groups. The
groups went on to hypothesize that the decrease in ionization due to
cosmic rays causes the decrease in cloud cover, thereby explaining a
large part of the currently observed global warming. We have examined
this hypothesis to look for evidence to corroborate it. None has been
found and so our conclusions are to doubt it. From the absence of
corroborative evidence, we estimate that less than 23%, at the 95%
confidence level, of the 11 year cycle change in the globally averaged
cloud cover observed in solar cycle 22 is due to the change in the
rate of ionization from the solar modulation of cosmic rays.
Gusbob, it is a much bigger deal to postulate variable gravity than it is to sat there could be matter we don’t see. For one thing, for matter not to be seen, it only has to be nonradiating. For another thing, there are plenty of candidates for such matter–mini-black-holes, supersymmetric particles,… Postulating that gravity is variable would imply, for example, that the gauge particles that transmit gravity are massive and therefore self-interacting. And first, we do not know for certain that there is no dark matter in the solar system. Second, there are plenty of candidates that would be expected to cluster. Third, you do expect residual inhomogeneities left over from the Big Bang (that is one of the things that WMAP was meant to map).
The thing that seems to escape you is that science is really a pretty conservative enterprise: If you have a theory that is working pretty well, but does not explain everything perfectly, you try to modify it slightly to explain the problematic observations. This often leads to new discoveries. What you do not do is say, “Well the theory must be wrong,” toss it out and start from scratch with a new theory that has no supporting evidence. It is only when the modifications to a theory render it unrecognizable that it gets thrown out. Case in point: Special relativity is not really revolutionary at all, but rather represents a synthesis between mechanics and electromagnetism. General relativity is much more revolutionary, but even here Newtonian gravity is a limiting case. Bohr’s Correspondence Principle is a formal recognition of this trait of science.
I understand that variable gravity is a much bigger deal and I am not at all in favor of that notion either. The point is simply there are some big theoretical holes that very respectable scientists are trying to fill in a variety of wars. I have no trouble with dark baryonic matter. I do have trouble with WIMPs and the like. What is very curious is that you find the creation of WIMPS as “conservative science” but a electromagnetic ideas as far fetched.
Gus, I think the problem is that — unless you reject the notion that CO2 and warming are related — you don’t have an observation that’s not explainable by current science that calls for coming up with a new theory. Does that make sense to you?
The reason WIMPs are the more conservative option is that we have seen weakly interacting particles. We also have some theoretical reasons for positing a supersymmetric set of particles. OTOH, the “electromagnetic” ideas have no evidentiary or theoretical support. The mechanisms aren’t even worked out and the theories they are meant to displace work very well. Why throw out a working theory when it can be saved by positing some plausible additions and those additions are (eventually) empirically verifiable?
Hank Roberts Says: “Gus, I think the problem is that — unless you reject the notion that CO2 and warming are related — you don’t have an observation that’s not explainable by current science that calls for coming up with a new theory.”
We have all experienced the creation of the right explanation that turns out to be for the wrong reasons. Explanations explain because they are created for that sole reason. It is the exceptions that need to be addressed and these exceptions become the crucible for the explanations validity. And there are lots of exceptions. I listed several that went un-addressed like FG Sagittae. There are lots of variable stars that defy the standard stellar life cycles,V838 Monocerotis is another. Human nature tends to accept the flimsiest and suspect explanations if those explanations help conserve old theories around which we have built so much.
I have always believed it is wise to have a few working hypotheses. And I have not advocated throwing out any current theory. I just pointed out their shortcomings and offered some alternatives.
I don’t reject that CO2 and warming are related. I do however question to what extent. On the contrary it appears most people here are quick to reject that the sun’s variability and warming are related even though many paleoclimatic studies suggest a very strong link. Why is that? The quick explanation is that the past 25 years of satellite data have shown little solar variability. And for those who want to save the theory of CO2 being the dominant driver, that was good enough. I say give it another 25 years.
The sun is very quiet right now. How does the standard solar fusion theory that expects a steady state balance between gravity and thermal pressure explain the simple observation of varying sun spot cycles and cycle minimums, and alternating magnetic fields?
gusbobb writes:
What part of “the sun has been steady for 50 years but global warming has turned sharply upwards in the last 30” do you not understand?
Gus, if you insist on claiming there is a
> standard solar fusion theory that expects a steady state
> balance between gravity and thermal pressure
please cite your source for this belief.
Gusbob, you don’t understand the current theories sufficiently to point out shortcomings–and what is worse, you don’t even realize how little you understand.
Hank responds”> standard solar fusion theory that expects a steady state> balance between gravity and thermal pressure
please cite your source for this belief.”
Come on Hank, that is the standard in every astronomy text book. Below is a quick link from Duke stating what is in every text book. There are amazingly still a lot of astronomers who like to talk of the “solar constant” as if it is a real and tested attribute.
BPL says “What part of “the sun has been steady for 50 years but global warming has turned sharply upwards in the last 30″ do you not understand?”
BPL check out the link to the graph from NOAA showing a the tight correlation with rising ocean temperatures and sunspot activity. The sun’s activity has increased very much the last 100 years. The solar magnetic field has doubled. And why isn’t the ocean a “wild card” that absorbs heat and releases a various time such that temperatures and sun activity might not always be exactly linear.This wild card is evoked to explain why the Antarctic isn’t showing a linear correlation with CO2 increases. Do we just pick and choose as we wish when to explain away nonlinearities. We have more recently seen that solar activity has plateaued and seems to be decreasing. I Understand that the last ten years we also coincidentally have no upward trend in global temperatures.
http://www.oar.noaa.gov/spotlite/archive/images/sunclimate_3b.gif
And Ray, why do yo consistently confront every skeptic with the same attack of “you don’t understand science.” That just boils down to saying we are wrong because we disagree you who “understands all”. And you often like to imply that we don’t even understand ourselves. While those criticisms of yours consistently lack substance. And consistently no one ever discusses the off beat variable stars that defy standard life cycles.
http://www.phy.duke.edu/courses/055/faqs/faq15/
How is the Sun stable?
The thermal pressure from nuclear “burning” counteracts the gravitational pressure. An equilibrium exists: when a star like the Sun contracts, it heats up, as gravitational potential energy is converted to thermal energy. But fusion rate is very sensitive to temperature, and a small increase in temperature increases the fusion rate a lot. When the fusion rate increases, the star expands. When it expands, it cools. The fusion rate decreases, and the star goes back to its original size. These effects combine to give the star a very stable equilibrium point: any small departure from this equilibrium leads to a change which brings it back to the original state.
Ray Ladbury. Here is a question showing what I don’t know, and feel free to educate my “ignorant brain”. At the sun’s core it is estimated that 3.6 ×10 to the 38 hydrogen nuclei are calculated to be transformed into helium nuclei by fusion every second. My question to those who know better than I ,is this. How do the less dense Hydrogen nuclei displace that rapidly growing core of more dense Helium nuclei? In geology we see turbidite flows that readily stratify with the most dense material at the bottom. That would be helium. And given the tremendous density at the core that greatly delays the escape of photons suggesting very little fluidity and convecting in the core, I would think that Helium nuclei are more likely to just concentrate in the core. So how does that square with the standard idea that a slight expansion due to heating by nuclear fusion causes and expansion and then rapid feedback of cooling and contraction? As we progress away from the core fusion becomes less likely and eventually would stop theoretically at around 150,000km from the core’s center. And add to that, the fact that calculations of parameters needed to satisfy the core fusion process put’s the sun on tenuous footing and requires quantum tunneling to overcome electrostatic repulsion. And since we can’t see into the sun’s core to prove anything, well I just like to have competing hypotheses because there are truly lots of questions, even if only asked by ignorant people like myself.
Gusbob,
I hate to be a broken record, but I really, really want to know, so I’m going to ask again:
What exactly is your background? Do you have formal training in physics? Math?
You’ve hinted that you teach. What? And at what level?
As I said before, I can’t be the only person here who’s curious.
JC
JC,
With all due respect to your query, first given past hostile personal attacks and slander, I do not feel comfortable discussing my personal life on this forum. Second in this format there is much that can be fabricated, so the value of personal discussion is questionable. If I told you I was a research scientist, would you believe me?
Second, I expected rough treatment for my sceptical ideas. I find that edifying. So I want the ideas to be the focus, not the presenter of those ideas. Unfortunately discussions keep regressing to personal attacks more than I expected or hoped for on a scientific forum.
Therefore I will ignore all questions about my personal life.
You’re conflating “a very stable equilibrium point” with your claim of a “steady state balance” — not the same.
re: 264. Goodness, it is now 2008. The first link is to the chart at http://www.oar.noaa.gov/spotlite/archive/images/sunclimate_3b.gif has an x-axis that ends around 1985, for pete’s sake. We are now talking about anthropogenic effects (manmade CO2 and other GHGs) whose net forcings since around 1970 have exceeded the net forcings of natural effects (e.g. solar influences). In other words, natural forcings alone do not explain the warming trend over the past 35+ years. That is fundamental. We are talking about relatively recent warming trends, not 50-100 years ago. And bear in mind that the warming rate will increase.
Cherry-picking data trends from outdated charts seems to be the last resort of skeptics. Witness all the skeptics who jumped erroneously on the 1998 hot year (which they conveniently neglect to add was enhanced by a very strong El Nino) as “proof” of the starting of supposed global cooling in the past (insignificant) 10 years, enhanced by some cooling early this year due to La Nina.
# Hank Roberts Says:
You’re conflating “a very stable equilibrium point” with your claim of a “steady state balance” — not the same.”
OK it seems my words need to be more precise here. What is your point?
Dan says”In other words, natural forcings alone do not explain the warming trend over the past 35+ years. ”
So Dan are you suggesting that natural forcings must show a linear relationship. No lag times? Ignore the ocean’s heat capacity? The purported cherry picking can happen from all sides of this argument. La Nina and the PDO become excuses separate from climate when there is cooling but part of climate when it is warming? Please be a bit more objective here.
[Response: No. People have included all of those things and it still comes out that natural forcings and internal variability are not enough. Meanwhile, including anthro effects does match. – gavin]
re: 270. Oh please Gusbob, I am being quite objective. Cherry-picking data does not happen from both sides; it is always the denialist/skeptics. No one has said La Nina is an “excuse”; it is a simple scientific fact. Nothing more needs to be said re: natural forcings per Gavin’s comment.
Frankly, it is you who is not remotely objective at all. Your mind is made up, despite the extensive, peer-reviewed science that has been conducted to date on this specific issue. It is nothing short of arrogance to assume you know something that has not been investigated and peer-reviewed by literally thousands of climate scientists across the world. If you make no effort to understand the scientific method or fail to read the science, you have no grounds to stand on. What so ever.
[Response: No. People have included all of those things and it still comes out that natural forcings and internal variability are not enough. Meanwhile, including anthro effects does match. – gavin]
Gavin I am curious just how much solar input is allocated into the models for which you make the above claims, and starting from when? Do these models input a figure determined by the doubling of solar input over the last 100 years as observed with sunspot activity and solar magnetic fields? Or does it allocate a figure based only on the 1% change determined by satellites over the past 25 years when sunspot activity plateaued? And could you reference a link to those models and and their solar parameters please? Thanks.
[Response: A doubling of solar input?!?! I think we would have noticed that. More realistically, modellers use whatever the solar physicists give us – that has included Hoyt and Schatten, or Lean et al (and various updates) up to Foukal et al. The most recent analyses reduce the solar changes even further, but none of them give an accelerated trend in the last thirty years. You can look up Stott et al, Hansen et al etc. – gavin]
Response: A doubling of solar input?!?
I did write to hastily. I meant to say an increase in input based on the doubling of sunspot activity and solar magnetism.
I will look at the papers mentioned. You neglected to mention the time frame. If we merely measured a pot of boiling water during the time it is boiling, we may conclude no change in heat input, but we would have neglected the increased heat that brought it to boil.
Gavin,
A quick look at the Hansen et al 2005 paper Earth’s Energy Balance: and which you are a co-author ( so I will refer to it as “your paper”) estimates solar irradiance from 1880 to 2003 as changing by .22 W/m2. Do you know how the number was derived?
Also if it was derived using 1366w/m2 TSI then it gives me a .01% increase in TSI. Or if I use 342 w/m2 it suggests a .06% increase. The paper doesn’t really state that very clearly.
Some authors have suggested that TSI has increased by .2% since the Maunder minimum using 1366 TSI.. Granted this estimate extends back for a longer period of time than your paper, but that could be a 20 fold underestimation of heat input if we consider that the energy could have been absorbed by the oceans and was in the pipeline, to borrow a phrase. Did you and Hansen et al account for the solar heat that was in the “pipeline”? From the paper it appears not.
Also I would suggest that just using an average TSI is really not a very good way to evaluate how TSI changes affect energy input into our climate system. For example at the equator where the impact of any % change in TSI would have the greatest impact there is above average area covered by oceans. Also there are differences in cloud coverage. None of these things seemed to be addressed in your models. I am curious how your assumptions were made?
One final question, in your paper the measurement’s of the ocean’s heat content was used as a confirmation of the earth’s energy imbalance. Gouretski and Koltermann (2007) have suggested that heat content was over-estimated due to warm biased XBT’s. Since that article was used to argue against the interpretation by Lyman et al (2006) that the oceans are now cooling (Correction to “Recent Cooling of the Upper Ocean” by Willis et a l (2007), draft copy. Has that paper been accepted so I can get the correct reference?), does that Gouretski article also suggest that the models overstated the energy imbalance?
And if I may suggest a helpful hint for all readers, that when referencing a paper the dates would help them find the correct paper so everyone is on the same page.
gusbobb writes:
Yes, it has. Rose quite a bit in the early part of the 20th century. But since about 1950 it has been roughly flat, so you can’t use it to explain the sharp upturn in global warming of the last 30 years.
In the last 100 years? How were we measuring the sun’s magnetic field in 1908?
You understand wrong. Get the temperature anomalies for 1998-2007 and run a linear regression on them. The trend is up, not flat.
Re Gusbob @ 270 & 274:
Sorry, Gusbob, you don’t get to quote this NOAA graph
http://www.oar.noaa.gov/spotlite/archive/images/sunclimate_3b.gif
as proof of tight correlation between rising ocean temperatures and sunspot activity, and then invoke ocean lag time to explain continued warming 20+ years after solar activity peaked without someone crying foul.
That thin ice under your feet just broke.
Barton Paul Levenson Says: Yes, it has. Rose quite a bit in the early part of the 20th century. But since about 1950 it has been roughly flat, so you can’t use it to explain the sharp upturn in global warming of the last 30 years.”
BPL you are wrong. Just do the math! Compare sunspot numbers from the first half to the last half of the century and yo see that there has been greater sunspot activity the last half of the century. I averaged the annual sunspot numbers to get:
48.8 sunspost average 1901 to 1953
76.4 sunspost average 1956 -2006
75.7 sunspost average 1977-2006
So yes the latter half may be rather flat for the past 50 years but it is flat at an exceptionally high rate. Here is a link to annual sunspot numbers from a somewhat reliable source if you want to check my math.
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/YEARLY.PLT
Here is a link to paper published in Nature on estimating solar magnetic fileds.
http://www.wdc.rl.ac.uk/wdcc1/papers/nature.html
And your argument regarding upward trend vs downward trend becomes rife with political sentiment as either side can choose the start point that gives a trend to their liking. In recognition of that problem, and the fact that we could generate a trend either way over the past decade or so, it might be more fair to say there is no reliable trend. That is close enough to match the plateau of solar activity.
Jim Eager Says: Sorry, Gusbob, you don’t get to quote this NOAA graph
http://www.oar.noaa.gov/spotlite/archive/images/sunclimate_3b.gif
as proof of tight correlation between rising ocean temperatures and sunspot activity, and then invoke ocean lag time to explain continued warming 20+ years after solar activity peaked without someone crying foul.”
You can cry foul JE but you misplace the lag time effect. The lag time effect refers to the effect of heat stored in the ocean and subsequently released to warm land temperatures. I hope that clears the ice for you.
[Response: That one is almost worth a red card. The increased heat in the oceans doesn’t get ‘released’ to warm the land – it pretty much just stays there. The land warms because of the forcings (either solar or GHG etc.) and that is only delayed by the siphoning of heat to the oceans. – gavin]
gusbobb (265), I may be totally missing your real point, but taking your question at face value (and, BTW, I am not a cosmologist, just a curious chap): If a star’s core burning is radiative the fusion takes place more or less uniformly in the core and the He molecules rest where they are born. If the burning is convective the core churns and He tends to congregate at the very depth of the core (and, btw, does not generate photons in the dense He as it is not undergoing fusion — yet.) It’s a complex determination, but as a rule stars less than about 1.4 solar mass have radiative cores. Also relevant, the core pressure is a function of the number of “particle entities” (a nuclei is one particle), not mass. So when 8 ionized H particles (4 nucleons/nuclei and 4 electrons) fuse to 3 HE particles (1 nuclei (with 4 nucleons under the covers) and 2 electrons) the internal pressure decreases.
gusbobb, I may have missed it in the lengthy article, but how do they measure/estimate the solar magnetic fields back in the mid-1800s?
Re Gusbob @ 278:”I hope that clears the ice for you.”
Sorry, Gusbob, it does not clear anything up. That ice is all gone.
Either the graph shows ‘close correlation’, or there is a lag, you can’t have both.
[Response: That one is almost worth a red card. The increased heat in the oceans doesn’t get ‘released’ to warm the land – it pretty much just stays there. The land warms because of the forcings (either solar or GHG etc.) and that is only delayed by the siphoning of heat to the oceans. – gavin]
Hey Gavin, I was wondering if you were still here. I had some questions above regards the Hansen paper you cited.
I must say I am utterly amazed at your statement that “heat in the oceans doesn’t get ‘released’ to warm the land – it pretty much just stays there.”
The heat in poleward moving ocean currents does not just “stay there”, locked in the ocean. So you must have mispsoke when you said the heat stays there. I am sure you wouldn’t take my word for it but for example from Stammer et al 2004 “The Northern Hemisphere north of 10_N loses heat to the atmosphere as does the Southern Hemisphere between 10_ and 40_S and south of 60_S. Note also that heat loss by the ocean to the atmosphere in the Southern Hemisphere occurs to some extent in the South Pacific, but is most intense in the Indian Ocean. Much of the latter energy must be imported from the Pacific through the Indonesian Throughflow or the Southern Ocean”
If your models don’t account for heat released to the atmosphere they may lead to erroneous interpretations.
If seasonal heat can move in and out of the ocean I am not sure how you could argue that increases in decadal and centennial heat would just “stay there”. How much heat stays in the ocean will be a function of temperature differences at the boundaries, vertical mixing, and winds and wind generated turbulence.
But speaking of red cards, some of the ocean circulation models you may work with add these fudge factors to constrain overheating that happens between grids when the models are run, raises a few red flags. Do they still use those fudge factors? If not what changed theoretically to make the models more realistic.
[Response: Possibly you are being deliberately obtuse, but just in case you aren’t, I was referring to the total increase of heat content in the oceans which appeared to be what you were referring to. Of course the ocean has variable heat fluxes at the surface, and of course it transports a tremendous amount of heat but on long time scales all that sums to zero (almost by definition). The long term increases in OHC reported by Levitus et al (2001), Willis et al (2004), Ishii (2008) etc. however are not going to ‘come back out’ to warm the surface unless climate forcings start going down and the net TOA imbalance reverses. As to ‘fudge factors’ – you are presumably referring to ‘flux corrections’ which were used early on in climate modelling to account for mismatches between atmospheric model and ocean model fluxes. Almost all the main modelling groups (Hadley, MPI, GISS, GFDL, NCAR etc.) have dispensed with them (GISS never used them), relying instead on fixing the models so that they weren’t necessary. And as to your forcing calculation, I was waiting for someone else to point out your error, but since no-one has, I will point out that for the solar forcing to be compared with other forcings, the TSI change needs to be divided by 4 (to account the fact the Earth is round and spinning) and multiplied by 0.7 (to account for the albedo). – gavin]
gusbobb writes:
The key word there is “flat.” If something is flat for 50 years, it can’t explain something else that is rising slowly for 20 years and then rising steeply for the next 30. “__” can’t explain “_/”.
# Barton Paul Levenson Says:
“The key word there is “flat.” If something is flat for 50 years, it can’t explain something else that is rising slowly for 20 years and then rising steeply for the next 30. “__” can’t explain “_/”.”
BPL you are flat wrong. Do a little experiment at home to prove it. Turn your stove burner to 300 degrees. Get a big pot of cold water and put it on the burner. Measure the water temperature and burner temperature over time. The burner will give you a flat temperature while the pot of water gradually increases to boiling.
Rod B Says: I may be totally missing your real point, but taking your question at face value (and, BTW, I am not a cosmologist, just a curious chap): If a star’s core burning is radiative the fusion takes place more or less uniformly in the core and the He molecules rest where they are born”
RB I agree that in that context the He molecules would rest where they were born. That implies that subsequent hydrogen fusion is relegated further out from the core’s center. As we progress outwards the pressure drops and likewise the probability of enough energy for H fusion to take place. Assuming the sun has passed through half of its solar life cycle, we should have a large core of helium and much lower probabilities of fusion because the H is now only found on the outer edges of the core. That scenario raises questions to how correct the model really is.
Yeah, Gus, but you’re confusihng weather and climate again.
Watching the water, what you see is a change in the rate of change. It’s warming up slowly, then faster, then slowly again.
Gavin said”And as to your forcing calculation, I was waiting for someone else to point out your error, but since no-one has, I will point out that for the solar forcing to be compared with other forcings, the TSI change needs to be divided by 4 (to account the fact the Earth is round and spinning) and multiplied by 0.7 (to account for the albedo)”
It wasn’t an error but asking for clarification. I said “Also if it was derived using 1366w/m2 TSI then it gives me a .01% increase in TSI. Or if I use 342 w/m2 it suggests a .06% increase. The paper doesn’t really state that very clearly.” TSI gets reported differently by various authors. That makes it hard to tell if we are comparing apples to oranges.
Gavin said,”Possibly you are being deliberately obtuse, but just in case you aren’t, I was referring to the total increase of heat content in the oceans which appeared to be what you were referring to. Of course the ocean has variable heat fluxes at the surface, and of course it transports a tremendous amount of heat but on long time scales all that sums to zero (almost by definition).”
Gavin I think then what you were saying is that the increase in OHC is dependent on the radiative balance. Without a change in the radiative balance the heat stays there. I am interpreting you correctly?
I am simply stating that if there is radiative input to the ocean due to increased CO2 or the sun is increasing its output, then the ocean would warm on average. If that sun’s output decreased then the heat stored in the ocean would be released until a new equilibrium was created. If the sun has plateaued and is now lowering the radiative inout,as the new large scale equilibrium is approached, on smaller scales this heat is transported and released in different places. And depending on the amount of vertical mixing and depth of storage,heat is released at different times.
[Response: In the global mean zero-dimensional sense, a positive forcing (solar/CO2) that plateaus leads to a monotonic rise in ocean heat content that continues even past when the forcing stabilises, it just increases ever more slowly as it tends towards equilibrium. This net heating does not come back out. If you posit a different situation where the forcing comes back down again, then the oceans will cool, but so will the land. – gavin]
# Hank Roberts Says:
Yeah, Gus, but you’re confusihng weather and climate again.”
Huh? Again? I don’t see your point.
gusbobb (258, et al), one difference as I see it: while it is true that as He starts to build up in the center of the core, the inner core loses pressure. But that is mitigated by marginal gravitational collapse of the core which heats it and maintains the H burning/fusion at a similar rate even though it approaches “shell” burning rather than core burning (though the difference initially is academic). This tends to contract the star slightly though its surface temperature and luminosity increase slightly as it saunters through the main sequence. Plus the increasing core temp tends to increase the faster “CNO” fusion process which also mitigates the otherwise thought-to-be reduction in H burning. All this until the bulk of the core is non-burning He and only the inner shell is burning H (still at a good rate). This starts the Red Giant stage (way past a star’s half-life)… and maybe ties in with this thread — even us skeptics agree we’ll sure as hell get global warming then!
Your point on the solar model is well-taken, however. While there is pretty solid agreement at the highest general level on the model, there is considerable differences in much of the detail, even large scale detail. Maybe this too makes these posts relevant to RC and AGW. [;>) I ‘m still not sure of the relevance. Or are you referring to the GW model and the solar effect on it?? I can envision Gavin scratching his head, too!
Gus, You get a big swing every day/night, another with every big weather front, another from summer to winter, in the atmosphere. You see almost none of that below the top of the ocean on the short term; the ocean’s not warming up to follow the brief ups and downs, it’s warming by slow mixing as the top of it is exposed to conditions warmer on average than the previous average.
gusbobb writes:
Right. Gradually increases. It doesn’t stay flat for 2/5 of the time and then ramp steadily upward for the remaining 3/5 of the time. Your example is completely irrelevant.
Rod says”Your point on the solar model is well-taken, however. While there is pretty solid agreement at the highest general level on the model, there is considerable differences in much of the detail, even large scale detail. Maybe this too makes these posts relevant to RC and AGW. [;>) I ‘m still not sure of the relevance. Or are you referring to the GW model and the solar effect on it?? I can envision Gavin scratching his head, too!”
Rod I got involved in this thread first by stating my mistrust for how people use dark matter to explain things as was done by the authors of this thread’s initial article. From there it lead to my mentioning an attraction to some of the electrical explanations for current astronomical anomalies and that led to a flurry exchanges and personal attacks. So yes some posts may seem less relevant to the initial intent of this thread. But in a sense it all says there are lots of “galactic glitches” to be explained. I think solar influences on climate are not well understood and discounted to an extreme that detrimental to our understanding and this had created many tangential questions and statements.
In regards to the measure of historic solar magnetism, it is not a direct measurement. It is derived by comparing changes in the geomagnetic field which has been historically measured and interactions with sunspot activity.
If you posit a different situation where the forcing comes back down again, then the oceans will cool, but so will the land. – gavin]
Yes the land will cool but not necessarily in lockstep. Depending on the degree of vertical mixing It may take a year or 2. And as the oceans release heat into the atmosphere that heat is recorded in land surface temperatures.
Lyman 2006 showed a slight cooling in line with decreased solar output and this year land temperatures have been falling. Based on solar activity I predicted the beginning of a cooling trend last year. Recent observations support the way I see things but it is way to early to say there is a significant climate trend or just weather. It is just a competing hypothesis. I would suspect the continued lack of sunspots will coincide with a persistent ebb in solar forcing and thus cooler land temperatures.
BPL, “Right. Gradually increases. It doesn’t stay flat for 2/5 of the time and then ramp steadily upward for the remaining 3/5 of the time. Your example is completely irrelevant.”
I missed your logic and evidence.
We have only directly measured the the sun’s output the past 25-30 years. A time when the sun had already reached its upper level and then plateaued, so very little change has been directly observed. The possibility I am illustrating is that the oceans have been warming to come into equilibrium with the sun’s recent high level of output. You can dismiss it. But it is not irrelevant.
Re #279 Rod B
Largely correct, but in a convective core the mixing will be even more pronounced. Even in radiative cores, any separating out of helium doesn’t happen because the temperatures are simply too high (i.e., scale height large compared to solar radius). Further out it may be different.
I found an article that’s a bit old but discusses the related elemental diffusion process:
http://arxiv.org/abs/astro-ph/9304005
…and remember that diffusion is not the same thing as gravitational separating out :-)
gusbobb writes:
We have good proxies which allow us to estimate it going back 400 years or so. Google “Judith Lean” or “Wang” + “Lean” for examples.
I dismiss it because it’s bloody stupid. If the oceans were warming because they were coming into equilibrium with a warmer sun, they would warm up fast at the beginning and slowly towards the end. They wouldn’t stay stable for 20 years and then suddenly warm up faster and faster for 30. Real thermal equilibrium doesn’t work that way.
BPL says,”If the oceans were warming because they were coming into equilibrium with a warmer sun, they would warm up fast at the beginning and slowly towards the end. They wouldn’t stay stable for 20 years and then suddenly warm up faster and faster for 30.”
You are making a lot of assumptions about vertical mixing. You stated trends of stable temperatures for 20 years lacks sufficient evidence. [edit]
[Response: Not really. The default assumption must be that vertical mixing is relatively steady over this period in the absence of any evidence to the contrary. It is you who is making unsupported assumptions that vertical mixing was really efficient for 20 years and then suddenly stopped being so. In fact, you can rule that out from CFC or CO2 concentration data in the oceans. – gavin]
Gavin,
Why would the default assumption be that oceans would warm “fast in the beginning and slowly at the end”? I would assume just the opposite. If we assumed a certain degree of intermediate vertical mixing, then I would expect near surface temperatures to remain within a narrow range until mixing has reached an equilibrium point.
It also has been shown that the XBT’s had a warm bias that significantly raised estimates of OHC in the last 30 years.
[edits are in order to maintain a discourse]
Gavin and BPL,
I suggest you both read Gouretski1 and Koltermann (2007) ( http://www.aoml.noaa.gov/phod/goos/meetings/2008/XBT/2006GL027834.pdf ).
First they conclude quite persuasively that the XBT data is warm biased and compared to CTD data it is warm biased by 0.2–0.4_C on average. This appears to be due to a faulty fall rate equation. There was a workshop discussing this problem recently. ( http://www.aoml.noaa.gov/phod/goos/meetings/2008/XBT/index.php )
That significant warm biases from XBT’s since the 1960’s raises major questions when compared with Folland et al’s (2001) estimates of global surface temperature of about 0.61 ± 0.16_C between 1861 and 2000. So your assumptions are based on questionable estimates. If you compare biases of the different measurements we see that “your sharp” increase in recent ocean temperatures is largely due to the sharp increase in the percentage of warm biased XBT’s used to determine temperatures.
Second in regards to assumptions of vertical mixing and heat storage, our estimates are based on very sparse sampling of the deeper layers.
Third if you look again at Figure 1 in Gouretski1 and Koltermann (2007.) and (assuming that the XBT warm bias will only change the relative heights on the vertical axis) we see below 100m we see that the temperature change is not “flat” as claimed but has 2 “bloody stupid” peaks. How do you square all this data. It appears the smoking gun is not as hot as once claimed.
>How do you square all this data[?]
One approach: read more recent work; follow a link for new papers citing a paper.
Performing your original search, Gouretski and Koltermann, in PNAS will retrieve 93830 results.
One example:
http://www.pnas.org/cgi/content/full/104/26/10768