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Do solar cycles cause global warming?

What the science says...

A full reading of Tung 2008 finds a distinct 11 year solar signal in the global temperature record. However, this 11 year cycle is superimposed over the long term global warming trend. In fact, the authors go on to estimate climate sensitivity from their findings, calculate a value between 2.3 to 4.1°C. This confirms the IPCC estimate of climate sensitivity.

Climate Myth...

Solar cycles cause global warming

A new peer-reviewed study on Surface Warming and the Solar Cycle found that times of high solar activity are on average 0.2°C warmer than times of low solar activity, and that there is a polar amplification of the warming. This result is the first to document a statistically significant globally coherent temperature response to the solar cycle, the authors note (source: Mark Morano).

The study is Surface warming by the solar cycle as revealed by the composite mean difference projection by Charles D. Camp and Ka Kit Tung. They find a global warming signal of 0.18°C attributable to the 11-year solar cycle. Eg - from solar minimum to solar maximum, global temperatures increase 0.18°C due to an increase in Total Solar Irradiance (TSI). To find the solar signal, they detrended the temperature data by removing the global warming trend. They found the detrended temperature correlated well with the solar cycle.

TSI including 11 year solar cycle vs detrended surface temperature
Figure 1: Detrended temperature (solid) compared to TSI (dotted) (Camp 2007)

However, a fair degree of climate variability contaminated the signal. Volcanic eruptions in 1982 and 1991 coincided with solar maximums. Similarly, the El Nino peak of 1998 occured during low solar activity. Tung and Camp filtered out the noise using various statistical techniques and found an even higher correlation with the solar cycle.

They concluded that from solar minimum to maximum (eg - from 1996 to 2001), the forcing from the sun increases global temperatures by 0.18°C. Conversely, from solar maximum to minimum (eg - from 2001 to 2007), the reduced forcing from the sun cools global temperatures by 0.18°C. This 11 year cycle is superimposed over the long term global warming trend.

Climate Sensitivity

Camp and Tung explore the ramifications further in a follow-up paper Solar-Cycle Warming at the Earth’s Surface and an Observational Determination of Climate Sensitivity. Independently of models, they calculate a climate sensitivity between 2.3 to 4.1°C. Eg - if CO2 levels are doubled, global temperatures will increase around 3.2°C. This confirms the IPCC estimate of climate sensitivity. In Tung's own words, "The finding adds to the evidence that mainstream climate models are right about the likely extent of future human-generated warming. It also effectively rules out some lower estimates in those models."

The other significant finding is that solar forcing will add another 0.18°C warming on top of greenhouse warming between 2007 (we're currently at solar minimum) to the solar maximum around 2012. In other words, solar forcing will double the amount of global warming over the next five to six years.

Last updated on 9 July 2010 by John Cook.

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Comments 1 to 50 out of 60:

  1. Very interesting, I'll study your link. There is much interesting work by UNC prof Jose Rial (and others)on D&O paleoclimate cycles. They need to consider "tipping points" and occasional chaos, extremes that might be of interest. Jose also is a seismic scientist, his abstract re arctic ice follows: Measurements of seismic activity in Greenland's ice sheet indicate the activity is related to the ice sheet's probable fragmentation due to global warming. Project SMOGIS (Seismic Monitoring of Greenland's Ice Sheet), a collaboration between UNC-Chapel Hill and the University of Colorado at Boulder, has detected intense microearthquake activity throughout the region close to the Jacobshavn glacier, one of the world's fastest moving glaciers. The seismic activity is clearly related to glacial sliding (at the base of the ice sheet) and crevassing, or large fractures expanding under the increased warming. "The area we are inspecting could be seen as belonging to the buttresses of a giant cathedral, which is the Greenland ice sheet," Rial said. "If the buttresses fail, the entire cathedral could collapse, perhaps in just a few years. This may be part of what has been called abrupt climate change." I don't know where this might fit in your list should it belong. Thanks and congratulations on a GREAT site.
  2. ourphyl: Have a look at 'It's volcanoes'. Quietman has posted some relevent and interesting information and useful links.
  3. Camp & Tung assume the IPCC's accepted sensitivity is accurate. If we take their numbers and lower the sensitivity to Spencer's numbers we get a very different result. Their study is on the solar forcing, the feedback is assumed.
  4. Re #3 That's incorrect. Tung and Camp derive a value for the earth's climate sensitivity to raised CO2 that is completely independent of the so-called "IPCC's accepted sensitivity". That's the whole point of their work! They analyze the solar cycle contribution to warming and (according to their analysis) derive an INDEPENDENT measure of the climate sensitivity. Their value is (see equation 2 on line 379 of their manuscript): 2.3 oK < DeltaT(2xCO2) < 4.1 oK In other words according to Tung and Camp, the Earth warms by around 3 oC (plus/minus a bit) for each doubling of atmospheric CO2 concentration. The fact that this value is pretty much in line with all of the other scientific analyses of climate sensitivity (as compiled by the IPCC) is interesting and may be taken as further evidence of a consistent arrival at the climate sensitivity using a number of different methods. But it is an ENTIRELY INDEPENDENT measure and doesn't assume anything whatsoever about "the IPCC"! That's pretty straightforward...
  5. Isn't there another, longer cycle superimposed over this one? I seem to remember 81 or 181 years, but I can't remember which. I am surprised that the sunspot cycle could even contribute as much as .18C, seeing that most of the radiation change is in either fairly low RF frequencies or in X-ray spectrum. Then again, X-rays are well absorbed by the atmosophere, so they really do turn into heat.
  6. Isn't there another, longer cycle superimposed over this one? I seem to remember 81 or 181 years, but I can't remember which. I am surprised that the sunspot cycle could even contribute as much as .18C, seeing that most of the radiation change is in either fairly low RF frequencies or in X-ray spectrum. Then again, X-rays are well absorbed by the atmosophere, so they really do turn into heat.
  7. There is a widespread belief that global warming is caused by sunspots. This is the result of a 2006 NASA prediction that near the end of 2010 there would be a higher than normal solar maxima. We have to be more careful with our predictions. This was picked up by a TV station which specializes in potential disasters. Dire predictions of super solar storms which could shut down our electrical power distribution network indefinitely. The reality is that the newest NASA predictions are for a solar maxima in 2013 and that this will be a mild maxima. As of November 1, the sunspot number was 30 whereas the 2006 prediction called for a sunspot number as high as 175 at this time. The problem was that they hadn't waited for the true minima which occurred late 2008 and early 2009. The problem is that few people are aware of the truth that we have been in an extended quiet period of the sun for close to 7 years.
  8. The statement "This confirms the IPCC estimate of climate sensitivity" is incorrect. The level trend (maybe even slightly declining trend) from 1 January 2003 until the present (July 2011) places serious questions upon the IPCC guesses because CO2 has continued to rise linearly and they cannot blame the 11 year cycle any longer. Where they went wrong was in not recognising the 934 year cycle and the 59.6 year cycle which wer both rising 1970 to 2000. See for much mre detail.

    [DB] Climastrological attempts to explain away the known radiative physics of CO2 warming due to semimythical cycles can be aptly described as "Mathturbation".

  9. "The other significant finding is that solar forcing will add another 0.18°C warming on top of greenhouse warming between 2007 (we're currently at solar minimum) to the solar maximum around 2012. In other words, solar forcing will double the amount of global warming over the next five to six years." 2011 is already the costliest year for natural disasters Well, I feel really cheerful now! ;)
  10. The link under the figure above is broken. The paper can be found (at least today) at This is the first paper I've seen that successfully shows the correlation between the solar cycle and surface temperature. Lean and Rind [Geophys. Res. Letts 35, L18701 (2008)] certainly suggest that it's been true from 1600 to 1995 or so, and get similar numbers for the size of the effect. I'm one of those people on the wrong side of the paywalls, and I'd be very interested to know how well this work has been found to hold up. Since it's in the same direction as any effects due to cosmic rays, I think it might well mask those effects entirely.

    [DB] Fixed link.

  11. A new paper by Kristoffer Rypdal demonstrates that the cycles in the temperature series found by Camp and Tung are caused by volcanic eruptions, not the solar cycle. Citing from the paper: "In particular, the cyclic GMST variations reported by Camp and Tung [2007] is naturally explained as a result of a succession of volcanic eruptions, ending with Mount Pinatubo in 1991." Reference: Rypdal, K. (2012), Global temperature response to radiative forcing: Solar cycle versus volcanic eruptions, J. Geophys. Res., 117, D06115, doi:10.1029/2011JD017283.
  12. Two links with some differing findings, namely increasing TSI activity since 1850. What is wrong here? (found matching with with USA daily max temp!) and (see figure "historical TSI reconstruction"-> TSI increase!)
  13. Falkenherz - The Washington Times article (not a peer-reviewed paper, mind you) authored by Soon and Briggs did not identify their source of TSI data, making it extremely difficult to evaluate. The second TSI estimate is based on Lean 2005 - Knopp and Lean 2011 downgrades recent forcings based on corrected satellite calibrations, noting that "Climate change studies that use published TSI time series to accredit solar responses must be cognizant of the possible errors in the record; otherwise climate variability is incorrectly attributed to solar variations that are in fact instrumental drifts." Finally, there are multiple papers indicating, as with Lockwood and Frohlich 2007, Recent oppisitely directed trends in solar climate forcings and the global mean surface air temperature, that:
    ...the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar variation is amplified.
  14. Note that I've contacted both Soon and Briggs asking about the source of their TSI data. Neither has responded. Note also that the Colorado/Lean 2005 reconstruction shows no TSI increase on average over the past ~50 years.
  15. From the William Briggs blog, a rather curious statement: Luis Dias on 7 September 2012 at 11:34 am said:
    "Leif Svalgaard [refers to posts on WUWT] seems to take great exception to your solar radiation curve." He’s extremely up in arms about it. What do you have to say about what he says, mr Briggs?
    Briggs on 7 September 2012 at 2:07 pm said:
    Luis, Asked Soon. He said “we can make this independent of any TSI curve. I really meant it when I said, we got evidence for Arctic, China and USA temperatures to very co-varying somewhat similarly.” I’ve seen several of these other plots and can verify. For instance, we sent four to the Washington Times; they printed just the one. Willie and I are hunting around for other outlets (with more exposure than this small blog) to show the others. Willie also asks, in the proper spirit, “Svalgaard knew his curve is correct?”
    (Emphasis added) I find it quite odd, in an article on the relationship between TSI and temperature, to state that "we can make this independent of any TSI curve". Regardless of the (as yet not provided) provenance of their TSI data, that statement seems to call into question the entire Soon and Briggs article...
  16. Willie and I are hunting around for other outlets (with more exposure than this small blog) to show the others.
    Why? Have we grown tired of publishing scientific papers in science journals?
  17. Now if Phil Jones had said something like that . . .
  18. KR @15 - the correlation between local temps and TSI is independent of TSI? I think the 'statistician to the stars' may be losing it. I'm also glad that reputable media outlets have not published this utter nonsense.
  19. #15 KR - very interesting statement. I have to wonder if Soon and Briggs' graph at Washington Times is hand-drawn. Two graphical things lead towards that conclusion, one noticed by somebody else, the second by me (full resolution source, from newspaper article): 1: First, it is apparent that lines on the graph do not always join up smoothly, always progressing forwards in time, as they would if they were generated by a plotting program from a single series of data. This is most apparent around 1935 and 1953 in the "solar radiation" curve. In both cases, the line appears to go "backwards", or is not joined, and so is not a normal single time series. It may suggest multiple data sources, or poor tracing of a single data source; either is very poor practice. 2: Second, several of the line segments are perfectly vertical, despite both series being ostensibly continuous time series, and the resolution of the plot being sufficient (580 pixels/180 years) that lines of a year's length should all be non-vertical. Again, data should always progress forwards in time. No automatic plotting pachage that I am aware of would produce a plot like the one above. Examples are in the temperature plot around 1850 and 1895, and in the solar radiation plot at about 1960. The line segments frequently cover many years, and are clearly smoothed data, so there is no reason to think that what is being presented is monthly data (which would be of a resolution to allow vertical segments). These very strongly suggest to me that the plot, uness it can be shown otherwise by the authors, is traced by hand, using a package such as Illustrator. The only other explanation is that there are multiple points for the same year, or even two points which go back in time, neither of which should exist in a timeseries plot like this. These features, along with the lack of a source for the solar data, make me very suspicious indeed of the graph's provenance. It may just reflect poor practice (though what user of climate data cannot plot data from a spreadsheet?). The Comments Policy forbids me from speculating on other possible motives.
  20. Andy S noted to me the possibility that the drafting was done by the Washington Times. That is a reasonable explanation for the poor plotting, but why on earth would they plot reverse slopes? Very poor plotting/tracing whoever did it! What remains are the substantive questions as to the source of the "solar radiation" curve. It is clearly plotted poorly, and does not appear to relate to other estimates (proxy or direct) of solar irradiance. Adding that to the cherry-pick of US land daytime temperatures (rather than global, or full daily, ie day and night), and this graph is very poor indeed. Soon and Briggs, show your working please!
  21. The closest match to the curve Soon & Briggs posted (that I've seen) is Hoyt & Schatten 1993, Fig. 10. The S&B graph differs in that it extends later (with the odd issues of verticals and doubled lines) than H&S, and is offset by ~10 W/m^2, but the overall shape is strikingly similar. The H&S graph was an 11-year running mean of multiple solar models including solar cycle length. A H/T to Leif Svalgaard on WUWT, who noted:
    ...looks like the discarded 20-yr old Hoyt & Schatten data, which today is not generally accepted...
    Again, as others have noted - Soon and Briggs simply have not sourced their TSI data, which doesn't match any current TSI record I am aware of.
  22. Thanks for taking up my question. IMO, this is the first real observation which I found and could finally lead to a sound sceptical argument about AGW. I think we can agree that, no matter how accurate that graph in the WP is drawn, it does match the generally observable trend from other TSI records: No matter how we might find issues with the WP-graph, the graph "historical TSI reconstruction" on does also show a correllation of TSI and global (not only USA) rising temperature trend. Now, if I understand correctly, that correllation is not really being challenged as concerning the first half of the 20th century, right? According to what KR did quote, we look merely at the time since 1985, where TSI goes downwards. Others say we need to look at the time since about 1960. So, it is only from that point of time that GHG could really take over as a driver, right? But, atmospheric temp seems again to align to the weaker TSI, by keeping moreless its level since 1998. However, we then argue that it is the global oceanic temp, which continues to rise. Correct? If I go by simplified logic, it should be like that: +TSI +GHG = strong raise of global temperature -TSI +GHG = weaker raise of global temperature (if at all, if you look at the lag at the climax shown by the ice core curves...) If we observe merly atmospheric global temperature, this simplified logic seems to apply and our AGW Theorie seems to fail. Atmospheric temperatur does indeed not rise for about 10 years! But if we put emphasis on the oceanic global temperature, we instead observe a continued strong raise of global temperature, right? Which is odd, too. If it should be mainly GHG as responsible factor, could that raise really be that strong? It should be weaker than a bundled raise of TSI and GHG together, right? Or do we commit an error by taking into account oceanic temperature somehow in a wrong way? Or do we still not understand TSI, or other influences and its effects on earth correctly? This seem at least to be possibilities. Along these lines, another observation: I always understood IPCC arguing that climate is a long term issue, and that we observe a rather strong raise of 0,8 degree since 1850. But suddenly, I see here that most of the raise can be aligned with historical TSI-data (as far as we know...) and it is only 1960 or 1985 where GHG really could kick-in. This does not seem consistent, do we have AGW by GHG emissions since 1850 or since 1960/1985??? I am confused.
  23. Falkenherz - Actually, the differing recent behavior of TSI and temperature are a very strong argument for anthropogenic global warming. In the past solar variations (and volcanic aerosols, with an overlay of ENSO) has been one of the biggest drivers of varying climate. That's no longer the case. Since mid-century the rising influence of anthropogenic greenhouse gases has been statistically separable from natural drivers. And hence solar cycles do not cause recent global warming. To quote a popular TV show, "...that myth is busted!" Source: "Comparison between global mean surface temperature anomalies (°C) from observations (black) and AOGCM simulations forced with (a) both anthropogenic and natural forcings and (b) natural forcings only..."
  24. And for yet another paper on the decoupling of solar and surface temp, see Pasini et al. (2012). That paper finds the departure date at around 1960.
  25. KR, DSL, thanks again. So, taking into account of what we think we know about TSI, we are basically not talking about a GHG-attributed warming of 0,8 Degree increase in 100 Years, but about a 0,2 Degree increase in 50 Years. I looked up the 4th IPCC report summary to confirm this, here: (the average from the table should be around said 0,2 Degree) 0,2 Degree is something very different to 0,8 Degree. Nevertheless IPCC includes the latter in its summary here (first bulletpoint): This is for me a serios and intentional miscommunication from IPCC. So, setting things straight, the current models take those 0,2 Degree and extrapolate from it a future GHG-induced rise of 3 Degrees for 100 Years. I must admit that makes me now much more sceptical than I was before. How can this possibly fit to the icecore-data, where CO2 lags behind (=still rises up) and temperature nevertheless is falling in accordance with the TSI, maybe even with a lag to declining TSI which would correspond to what we observe today? Where can I find more information on TSI data related to the icecore-data?
  26. Falkenherz, even if we assumed your discovered "serios and intentional miscommunication from IPCC" were true, your following statements are non sequiturs (logical fallacy): - past temperature increases are not extrapolated forward by the climate models; the models are based on atmospheric physics not statistics - because some relationships existed in the past (increasing CO2 being a feedback) does not mean that it has to be like that now (CO2 being a forcing agent) - correlation is not equal to causation As the responses to your comments above and the IPCC report you studied explain, the increase in TSI can possibly explain early 20th century warming, but not late 20th (and current) century warming. Current warming has not yet reflected the observed CO2 increase, aka we are in equilibrium yet. Your hint towards "it has not warmed since 1998" is a myth dealt with on another thread. If you find a way to get your hand on TSI data covering the glaciations, and a way to show that it was rather TSI not Milankovitch cycles driving them, make sure you publish that. (sorry for the satire, but your comments have drifted into trolling)
  27. gws, let's not start with polemics, I am seriously interested in AGW, what I just do is trying to link things together. These here are some factors I don't understand. I think I understand now the way GHG work, but TSI still is a topic I have to learn about. So sorry when I confuse TSI with Milankovitch cycles, I just assumed TSI is what arrives from the sun as measurable on earth, whether it comes from sunspots or from a shifted orbit or axis. I also understand that oceans still have warmed since 1998, and the total is still a warming. But at the same time it is also a fact that the atmosphere has not warmed any further since 1998, right? But that was not my point in my above post. I just wanted to say that it makes sense that a dropping TSI could lead to a non-warming up atmosphere because it is the fastest feedback, compared to the ocean. My point in my last comment was, that I always understood and read about 0,8 Degree/last100years attributed to AGW. But, based on what I read here and in the IPCC report, that is not really true. Can you confirm that at least that? The essay linked by DSL says in its conlusions: "At the same time greenhouse gases total radiative forcing has shown a strong Granger causal link with temperature since the 1940s up to the present day." So, they also do not start at 1890, but at 1940 (again a different date, instead of 1960). But, bottomline, that only that is my point, we should rather look at and communicate the historical amount of GW that can really be attributed to aGHG. This seems to be less than 0,8 Degrees so far, even though I know we are not in equilibrum yet. I still need to understand which factors make the models match the facts that ~0,2 Degree in the past 50 years leads to a possible new equilibrum at +3-6 Degrees for a CO2-doubling. Models might not extrapolate historical data, that would indeed be too simple, but all models advertise that they match up with historical data. So first let's clarify the observable historical data.
  28. Falkenherz, I cannot answer in detail all your questions as that would be equivalent to reciting much of the AR4 and associated literature. But I shall make an attempt at some of your inquiries. - TSI is the measured "output" from the sun; it changes on geological time scales based on the nuclear reaction cycle in our star, which is and has been very stable; as you can see from the y-axis in your own link, its relative change (sun spots cycle, impacting radiation arriving at Earth on "short" time scales) is small - no, the atmosphere has further warmed since 1998, check, e.g., here - the IPCC has not attributed all observed warming ("0.8 deg C") to increased GHG alone - you are making the mistake of wanting to assign a single measure to a single cause; observed warming is a combination (sum) though between different forcings, and while the GHG forcing is currently the largest one, it is counteracted by an also anthropogenically caused increase in atmospheric aerosols; some people use the term "masked" to characterize the apparent lack of more warming caused by aerosols vs GHG only - these facts enter the IPCC graphs you see above to create the "match" between model and observations, and the lack of such when ignoring GHG forcing - aerosol levels are not expected to continue increasing much further (that will be reevaluated in light of rapid FF development lacking particle filters in Asia), while GHG levels are
  29. Falkneherz, you seem to expect a linear response from changes in GHG forcing. I suggest doing a little more research on transient climate response and equilibrium climate response. What the article I linked to was pointing out, as gws notes, is that solar was the dominant forcing in the early 20th century, and GHG forcing was dominant in the last half of the century. GHG forcing became detectable during the 1940s, but it didn't overwhelm solar variation until the early 1960s. That also doesn't mean that the solar signal has no effect on the trend. That's why studies like Foster & Rahmstorf (2011) are so important. F&R removes the signals of solar, aerosols, and ENSO from the last 30 years of the major surface/lower trop temperature analysis ensemble. If no AGW exists, F&R should have found a slightly bumpy flat line or an insignificant trend. Instead, they found a trend of about .17C per decade over the period.
  30. 27, Falkenherz, Some points of reference for you to research: 1) Milankovitch cycles overall only fractionally change the amount of energy received by the Earth. What changes, rather, is the distribution of that energy over the globe in space and time (i.e. how much at what latitudes during what season). Look here. 2) The atmosphere has warmed since 1998. And both 1998 and the end of 2011 are cherry picks, because 1998 was the strongest El Niño in memory, while 2011 was a La Niña. It's like comparing your income on the day you work two jobs to the day you sleep in. It says nothing about how much you are likely to make in a year. Look here. And here. And here. 3) "I still need to understand which factors make the models..." Yes. Look here. And here. And here. 4) "...but all models advertise that they match up with historical data." Yes. Look here. [And I wouldn't put too much weight behind what Pielke Sr. (or Jr.) posts on the subject.]
  31. Falkenherz, your central argument seems to be that because there are other factors in play it is incorrect to attribute all of the 0.8 C observed warming to GHGs. The problem with this is that research indicates that the net effect of all those other factors has been cooling... such that without them the impact of GHGs alone would have been greater than 0.8 C. Milankovitch cycles involve a lot of factors, but the primary glacial/interglacial trigger corresponds to an orbital tilt. Basically, when the tilt of the planet causes the northern hemisphere to be angled closer to the sun the net absorption of sunlight increases (because there is more land in the northern hemisphere than in the southern) even though the total amount of sunlight reaching the surface hasn't changed (the SH gets just as much less as the NH does more). The 'no warming since 1998' bit is an outdated statistical fallacy even when properly constrained to the surface atmospheric temperature. It was derived by taking the anomalously high temperature in 1998 as a starting point and then pretending that because the trend of increasing temperatures after that point had not gone on long enough to reach 95% statistical significance yet (i.e. passed a mathematical test to indicate that the observed trend was likely 'real' rather than caused by random 'noise' in the data) that there 'was no warming'. That was nonsense to begin with... but it is now outdated nonsense. The increasing temperature trend since 1998 now does pass a 95% statistical significance test. Try 'no statistically significant warming of the surface atmosphere since 2005'... the next really hot year in the record which is still too recent to pass 95% statistical significance. It'll still be deceptive nonsense, but not outright false like the 1998 claim you were repeating.
  32. Falkenherz - ...we are basically not talking about a GHG-attributed warming of 0,8 Degree increase in 100 Years, but about a 0,2 Degree increase in 50 Years. Where are you getting that? The 1901-2005 land global temperature trends in that table are 0.84, 0.68, 0.69, and 0.69 C, with ocean global temperatures increasing over that period at 0.67 C. Over the more recent 25 year period of 1979-2005 the numbers are much higher: ~0.31 C per decade land, ~0.134 C per decade ocean - certainly not 0.2 C. I believe you have misread something; and claiming miscommunication from the IPCC based upon misreading a table is quite inappropriate. Actually, without human activity, based on the natural forcings, we should have seen roughly a 0.2 C decrease in temperature over the last 100 years, or a difference from current temperatures of ~0.8 C. --- I really hate to say this, but you seem to be hunting for any 'sticky' skeptic point possible - and in the process not fully reading the references, or looking at the data. If you consider the full set of data, you will not (IMO) find any significant support for the 'skeptic' arguments; the data, the evidence points all but a tiny minority of climate researchers towards AGW.
  33. Hey, thanks for the explanations and links. IPCC should really ready the next report and be a bit more clear about this part. They filed 0,76 Degree under "Direct Observations of Recent Climate Change", so yeah, they did not directly attribute it to AGW, but neither they did to other factors, and the whole report is about AGW, isn't it. Also, in the passage I quoted, the IPCC speaks of a linear warming trend of 0,13 Degree per Decade over the last 50 years, which in sum would be 0,65 Degree for 50 years. So, putting numbers together as IPCC placed them, not more than 0,09 Degree (0,65+0,09+0,74) was caused by TSI before GHG became a dominant factor from 50 years ago. That again seems to be too much the other way around, and this result is also in conflict with the temperatures shown in the graphs by KR here, at 06:15 AM on 15 September, 2012. And if I put that together in an incorrect way (because you probably cannot add up trend figures to an absolute total?), this shows for me that the data was presented in an incorrect context. I think, all the explanations are fine and sound kind of logic, but the data needs to be presented in a clear and coherent way, first. Again, thanks a lot for the explanations.
  34. KR, yes I hunt for any stick, because I want to be able to reply to any sceptic argument. So I am assuming the role of one, here. You can be sure I do the opposite on a sceptic website. So let me summarize so I can use this in discussions: - global temp increase from 1850 to 2005 is about 0,76 Degree - TSI factors into this figure, but latest since 1965 cannot explain the increase by the observed amounts ... aaaand I am back to what puzzled me and why I started commenting here: How much of those 0,76 Degree is TSI and what is GHG (before/after 1960)??? It is just, as KR pointed out, I don't really seem to understand how to put this decadal trend figures into context. At least roughly speaking, there should ne some connection between absolute rise between absolute increas and the the calculated decadal trend figures? How? Why do IPCC and others throw them together without making at least a distincion?
  35. "the whole report is about AGW, isn't it." well actually, no, it discusses both natural and anthropogenic climate change. The Technical Summary makes it very clear that both natural and anthropogenic forcings are necessary to adequately explain the observed patterns of climate change.
  36. Uhm... I think I lead myself astray from the original question. I came here because of the WP graph, which shows a continuous upwards trend of TSI, as does also the graph "historical TSI reconstruction" on So... the answer to the original is, the TSI should not got upward during the last few years, but even it it may still be upward on a longer time axis, it still cannot explain the increasing decadal trend of rising global temperature???
  37. .... aaand my english becomes more and more horrible, sorry for that, this kind of shows my confusion. Let me restate with some corrections: "So... the answer to my original question is; ACCORDING TO CURRENT DATA, the TSI should not GO upward during the last few years, but even IF THERE WOULD still be AN upward TREND on a longer time axis, THIS ALSO cannot explain the increasing decadal trend of rising global temperature???" [I hope that is a slightly less horrible english] I stop posting now, but am grateful for all answers.
  38. Falkenherz, Just for reference... the IPCC does nothing more than accumulate and report on the state of the science. When you say "the IPCC says..." what you really mean is "back in 2007, based on the state of the science at that time, the IPCC reported that..." The main takeways are: 1) The IPCC is merely reporting the primary belief of scientists in the field at the time, based on published and un-refuted papers. 2) The science and the world keep advancing. There have been a large number of studies since 2007 that affect both the value (0.76) and how that value is interpreted (e.g. Huber and Knutti 2011, Foster and Rahmstorf 2011). Any time anyone takes the approach "The IPCC says..." that should immediately give you pause. Quoting an IPCC statement on the state of the science 5 years ago, as if time is frozen and the IPCC are themselves experts declaring truth, is just wrong.
  39. Has anybody found more details on the source of the TSI data in the graph of the Washington Times, which is named "University of California-Berkeley Earth-Surface Temperature Project"?
  40. Dear co-commenters, my main question has not been answered, instead I received a lot of corrections on some of my (admittedly wrong) conclusions, and some nitpicking on words. But, on the basic questions, I am still unclear what to think. 1. The graph in the Washington Times (Source: "University of California-Berkeley Earth-Surface Temperature Project" -> so it IS based on scientific work?) shows a continuous upwards trend of TSI, as does also the graph "historical TSI reconstruction" on I am asking about the long-term observations on TSI, not only since 1960. There are people like Leif Svalgaard on WUWT who deny any TSI increase since 1800 (if I understood his ppt presentation which he linked there correctly). 2. If people say that TSI since 1960 is not raising anymore and that is why GHG have to be the dominant driver: Did people think about possible lags to TSI forcings in our climate system? Couldn't it be that global temperature is still rising because of the TSI forcings from before 1960? 3. If we nevertheless assume (or have evidence?) that the TSI is not high enough to further raise global temperature, how come that I always encounter the claim that there is a rise of +0.76°C since 1850, and "most" of it was caused by AGW? I hold my claim that this is a miscommunication, and I am asking of how much is exactly attributed to GHG after removing the TSI forcing. When I look for answers, I am suddenly confronted with decadal trends, which in fact does not answer my question. I read the one essay from Pasini et al. (2012) which is trying to answer this (link provided by DSL further up). But if I understand that essay correctly, their only evidence is a so called Granger causality. Looking this mathematical contruct up on wikipedia, I think this can hardly be treated as sound evidence, rather as an indication that there could be evidence.
  41. Falkenherz@40 "Couldn't it be that global temperature is still rising because of the TSI forcings from before 1960?" I have a hard time understanding this point. The problem AFAIK is that up until this timepoint the TSI/temperature has been coupled directly without any delay. Now you propose that there is a delayed mechanism hidden somewhere that continues to heat up the atmosphere (and apparently upper 2000m of the sea). Furthermore the mechanism is at least as strong as the apparent TSI-effect was. So the question is: Why hasn't this mechanism revealed itself earlier and where was the heat hidden?
  42. To my question 3, I think I got it; from "it's the sun", nicely explained there, thanks. According to figure 8 over there, for the last 100-150 years, there is very roughly about 22% of solar contribution to global warming. Translating this into the kind of answer I was looking for in question 3, roughly about 0,6 Degrees of the 0,76 Degrees raisal of global temperature in the last centuries cannot be attributed to TSI and must be due to GHG. I hope this is roughly correct. Now I just need to understand what TSI data is correctly used and how they translate TSI into temperature... on to more articles to read! I anybody could still bring some light (or links) into questions 1 and 2, please.
  43. Lanfear, if this is true, then my question is answered. But how do we know that global temperature and TSI were coupled directly? If I see curves (like in figure 15 here, especially the one from "Lean 2000", then there might as well be a lag, since TSI seemed to go upward already a long time, roughly since 1700, by a total of roughly 2,5 W/m2 since then.
  44. Falkenherz With regard to lags, if you look at the chart from the Washington Times article, clearly TSI appears to be lagging behind USA temperatures, not the other way round (until 1960 ish). Temps start rising in about 1860, but TSI falls until about 1890, temps fall from 1940, but TSI falls from about 1950. This would suggest changes in USA temperatures cause changes in TSI prior to 1960. However, the real point regarding lags is that there needs to be a reasonable physical explanation to explain why there should be a lag, rather than a mere statistical phenomenon. It is hard to see a physical mechanism that would explain why TSI changes have a lagged, rather than an instantaneous effect.
  45. Marsupial, my question Nr. 2 was not linked to the graph in the Washington Times. My question Nr. 2 was rather assuming that that graph was wrong and TSI acutally did not increase since 1960, as this seems to be in line with the theory which this website believes to be correct. So, what I meant with a lag is that the increase of TSI until 1960 probably did not directly relate to temperature, but only shows its effect after 1960. The rise of temperature between 1900 and 1960 would then have a cause in rising TSI from before 1900. Long term graphs always seem to show a long term raise of TSI. So basically, the question is, why can we exclude a TSI induced raise of global temperature which lags behind, say, roughly 50 or even 100 years?
  46. @Falkenherz As I said in the second paragraph of my previous post, there needs to be a plausible physical mechanism to explain why there should be a lag. Essentially the laws of physics are the reason why temperature doesn't lag 100 years behind TSI. Correlation is not cuasation, and a good way of avoiding falling into the trap of making an incorrect association is to require a plausible physical mechanism. Given the nature of noisy time series, there will often be an apparent corellation in time series if you adjust enough parameters of the anlysis (e.g. start/end points, lags etc.) purely by random chance. As the old statistical maxim goes "if you torture the data enough, eventually they will always confess".
  47. Falkenherz@43 "TSI seemed to go upward already a long time, roughly since 1700, by a total of roughly 2,5 W/m2 since then." Hmmm... where did you get that figure? The study you refer to states: "The cycle-averaged increase in TSI since the Maunder minimum is estimated to be ~1 W/m2." This is also supported by fig 14 (using the eye-chronometer). Regarding your point 2: There still remains the question of where that heat from the slightly positive TSI-trend is hidden? I think the only possible answer here would be the deep sea (>2000m). But then again, it seems to be working on a too slow pace for this case, if one is to believe the validity this claim: "Scientists estimate that it takes one section of the belt 1,000 years to complete one full circuit of the globe." In that case it would mean that we would be seeing the heat energy coming up from the MWA and not the latest TSI positive trend. As Dikran said in 44 (and repeated later, your're writing too fast :-), you need to come up with a more physical explanation, otherwise this is only (IMHO) a exercise in hiding the god.
  48. Falkenherz, when TSI started increasing way back when, the Earth heated and therefore started radiating more on its way to thermal equilibrium between the new, higher level of energy coming in, and the energy going out. It could not reach equilibrium, because the incoming radiation (from TSI) kept increasing. When TSI plateaued around 1960, the Earth still was working toward equilibrium by continuing to increase its outgoing radiation. But because the incoming radiation now was constant, the Earth should have crept closer to equilibrium. That closing of the energy imbalance between energy coming in and energy going out should have been reflected in the in-out gap decreasing. Instead, the in-out gap has continued to increase despite the constancy (or slight decline) of the incoming radiation. So there must be some factor reducing the energy going out. What could that be, do you suppose? See John's post on climate lag.
  49. Falkenherz wrote: "1. The graph in the Washington Times (Source: "University of California-Berkeley Earth-Surface Temperature Project" -> so it IS based on scientific work?)" Yes, that label would mean that the graph was part of a scientific study... if the label itself weren't fiction. The Berkeley Earth Surface Temperature (BEST) project concluded that past temperature studies were accurate (in contradiction of their initial assumptions) and that the observed warming was almost entirely due to humans. Their findings on solar influence can be summed up with the statement, "Solar variation does not seem to impact the temperature trend." So the question becomes, how did Soon and Briggs get a graph (which appears nowhere in the BEST studies) showing a 'strong correlation' between temperatures and solar variation from a study that concluded there was no correlation between temperatures and solar variation? The likely answer is that they took temperature data from BEST, TSI data from some other source, put them together on a graph, and falsely labelled the result as coming from the BEST study. The 'US daytime high temperature' values shown on the WT graph appear to match up with the 10 year moving average of such on this page from BEST. So far as I know the source of their TSI 'data' remains a mystery.
  50. Heh, now that I look more closely I note that while the 'shape' of the temperature line on the WT graph matches that on the BEST graph... the scales are different. WT shows all values ~2.5 C higher than the BEST graph. The X axis also appears to be off with various peaks being shown in slightly different years between the two graphs. This would seem to confirm skywatcher's earlier suggestion that the WT chart was produced by some method other than direct graphing of the data.

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