Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Pinterest MeWe

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Sun & climate: moving in opposite directions

What the science says...

Select a level... Basic Intermediate Advanced

The sun's energy has decreased since the 1980s but the Earth keeps warming faster than before.

Climate Myth...

It's the sun

"Over the past few hundred years, there has been a steady increase in the numbers of sunspots, at the time when the Earth has been getting warmer. The data suggests solar activity is influencing the global climate causing the world to get warmer." (BBC)

Over the last 35 years the sun has shown a cooling trend. However global temperatures continue to increase. If the sun's energy is decreasing while the Earth is warming, then the sun can't be the main control of the temperature.

Figure 1 shows the trend in global temperature compared to changes in the amount of solar energy that hits the Earth. The sun's energy fluctuates on a cycle that's about 11 years long. The energy changes by about 0.1% on each cycle. If the Earth's temperature was controlled mainly by the sun, then it should have cooled between 2000 and 2008. 

TSI vs. T
Figure 1: Annual global temperature change (thin light red) with 11 year moving average of temperature (thick dark red). Temperature from NASA GISS. Annual Total Solar Irradiance (thin light blue) with 11 year moving average of TSI (thick dark blue). TSI from 1880 to 1978 from Krivova et al 2007. TSI from 1979 to 2015 from the World Radiation Center (see their PMOD index page for data updates). Plots of the most recent solar irradiance can be found at the Laboratory for Atmospheric and Space Physics LISIRD site.


The solar fluctuations since 1870 have contributed a maximum of 0.1 °C to temperature changes. In recent times the biggest solar fluctuation happened around 1960. But the fastest global warming started in 1980.

Figure 2 shows how much different factors have contributed recent warming. It compares the contributions from the sun, volcanoes, El Niño and greenhouse gases. The sun adds 0.02 to 0.1 °C. Volcanoes cool the Earth by 0.1-0.2 °C. Natural variability (like El Niño) heats or cools by about 0.1-0.2 °C. Greenhouse gases have heated the climate by over 0.8 °C.

Contribution to T, AR5 FigFAQ5.1

Figure 2 Global surface temperature anomalies from 1870 to 2010, and the natural (solar, volcanic, and internal) and anthropogenic factors that influence them. (a) Global surface temperature record (1870–2010) relative to the average global surface temperature for 1961–1990 (black line). A model of global surface temperature change (a: red line) produced using the sum of the impacts on temperature of natural (b, c, d) and anthropogenic factors (e). (b) Estimated temperature response to solar forcing. (c) Estimated temperature response to volcanic eruptions. (d) Estimated temperature variability due to internal variability, here related to the El Niño-Southern Oscillation. (e) Estimated temperature response to anthropogenic forcing, consisting of a warming component from greenhouse gases, and a cooling component from most aerosols. (IPCC AR5, Chap 5)

Some people try to blame the sun for the current rise in temperatures by cherry picking the data. They only show data from periods when sun and climate data track together. They draw a false conclusion by ignoring the last few decades when the data shows the opposite result.


Basic rebuttal written by Larry M, updated by Sarah

Update July 2015:

Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial


This rebuttal was updated by Kyle Pressler in 2021 to replace broken links. The updates are a result of our call for help published in May 2021.

Last updated on 2 April 2017 by Sarah. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Argument Feedback

Please use this form to let us know about suggested updates to this rebuttal.

Related Arguments

Further viewing

Related video from Peter Sinclair's "Climate Denial Crock of the Week" series:

Further viewing

This video created by Andy Redwood in May 2020 is an interesting and creative interpretation of this rebuttal:


Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  

Comments 851 to 898 out of 898:

  1. Perhaps you better have a look at this paper - note the authors = for latest on solar forcing before leaping to conclusion that solar is underrated. It also appears that you do not understand IPCC figure that KR posted. Noone expects (it would be utterly improbable) that temperatures follow the multimodel mean. You might want to look at this posting at RC for further explanation. Finally, a close study of Hansen et al 2011 might be useful. Especially note the comments on model handling of aerosol forcings in light of Argo data.
  2. Well, I didn't understand the figure. Of course, because the IPCC didn't adopt it the right way from the original (Stott et al (2006b)). In the original work it is as I told that it has to be: while the global dimming the only natural caused temperature is higher than the total (anthro+nat). So what did the IPCC do, or at least the authors that wrote the chapter?! (Possibly this may be the reason why the link to the corresponding appendix is now broken in the IPCC documents. Who knows...) Ok, I'm again off topic. Back to it. The first paper you've linked is a good chance to get enhanced knowledge about another part of Sun's influence. But, if you are aware of it, this is in addition to the solar components that were used so far (TSI and SSN) and it is surely not the only parameter that may be of importance. Perhaps it will come up to the IPCC documents in the future (I hope so). As to Hansen, I will have a closer look at it. But obviously he didn't know about the global dimming because in Fig.1 (base of the whole work) the net forcing is steadily rising (except the volcanoes) what definitely would have disabled a cooling that was observed. I'll come back to it (in the right topic, of course).
  3. Joe, I cant make sense of your sentence. ": while the global dimming the only natural caused temperature is higher than the total (anthro+nat)." Its certainly not obvious to me why you think IPCC misrepresents Stott. What do you mean by "global dimming"? "it is surely not the only parameter that may be of importance" Well when you have some other parameter that makes physical sense, let us know. Meanwhile I will continue to look at the well-established, measurable physics of GHGs. If you ignore them, you cant get planetary temperature right so why do think changing their forcing is so insignificant compared to same change in solar forcing?
  4. The IPCC did run 14 'anthro+nat' models and only 5 'nat' models that possibly were independent from the other (the last is not to prove, because the description is not longer available). This cannot be the correct method because Stott had a dependence between the models. If the anthropogenic forcings sum in a negative net forcing (what is necessary for a global cooling caused by the overwhealming of GHGs by aerosols, what commonly is called 'global dimming', occured mid century), then it is obvious that the natural forcings must show higher temperatures as far as they had no change in intensity (as to the time until '63, natural forcings had always caused a warming). If you use independent models (at least 9 of the 'anthro+nat' were it definitely) there cannot be a correct result. Otherwise we would not speak about a 'primarily anthropogenic' driven cooling. That was what made it curious to me. Possible additional influences could be, as told before, for example number and intensities of flares. Each major flare destroyes an huge amount of high-stratospheric Ozone what reduces the absorption of high frequency radiation there. This, of course, has only a small short term influence, but the long term effect that results in the lagrer absorption by oceans is currently not researched, but this is currently the only explanation for the sharp rise of the OHC in 2003. In this year we've seen the most and most intense flares, culminated in the biggest flare ever measured (X28..X40, not quite sure, because the direct measurements are only possible until X17.2).
  5. JoeRG - "The IPCC did run 14 'anthro+nat' models and only 5 'nat' models... " That would be quite amazing, considering that the IPCC collected data and science from many contributors, but did not run any research itself. I suggest you check the various reports for links to the original works. You appear to feel that 'solar flares' have a much larger effect - but unless you can point to some data, perhaps a paper or two, that supports your hypothesis, preferably with some suggestion as to mechanism, it's just an unsupported opinion, not science.
  6. ... in (a) as obtained from 58 simulations produced by 14 models with both anthropogenic and natural forcings. ... The simulated global mean temperature anomalies in (b) are from 19 simulations produced by five models with natural forcings only. Well, this is taken from the caption of the figure (and I do not expect that all of the models were made by the autors). So what would you expect from one who's reading this, unable to find any description (because of dead links, just a hint that leads to Stott) and finally realizing that the graphs did match neither the original model nor the physical behaviours that are to expect? Should he say "hurray, it's from the IPCC, it's fine"? Of course, very amazing. I suggest you check the various reports for links to the original works. I would, if you can give me the list of the used models. I can't get it from the IPCC page. Regrettably there is no 'Appendix 9C' -for whatever reasons- where the underlying papers/reports would have been listed. Besides, you argued -using this figure- that the models are 'excellent'. I showed -using the same figure as well- that they are not, at least if modified by the IPCC, because of mismatches to reality and, as shown by pointing out the difference to Stott, wrong adaptations. (Of course, it's a completely different topic.) Back to topic. You are right, the flares are quite a hypothesis. But, perhaps you can give another possible explanation (eventually a paper) for the needed ~3W/m² of positive radiative imbalance. With the value of Trenberth 2006/2009 (0.8..0.9W/m²) it would need about 5 years to get the observed OHC-rise (by 6*10^22J) that obviously occured within a single year - given that the measurements are correct.
  7. JoeRG I believe the correct Stott reference is to Stott et al 2006, Transient Climate Simulations with the HadGEM1 Climate Model: Causes of Past Warming and Future Climate Change. A very similar work, although more focused on predicting than back-casting, that isn't pay-walled is Stott et al 2006, Observational constraints on past attributable warming and predictions of future global warming. Figure 1 of the second link shows a similar pattern, with current warming not explainable without anthropogenic influence. " argued -using this figure- that the models are 'excellent'. I showed -using the same figure as well- that they are not, at least if modified by the IPCC, because of mismatches to reality and, as shown by pointing out the difference to Stott, wrong adaptations." The models, with anthropogenic forcings included, track observed temperatures quite well. They seem to include a fairly accurate internal representation of the physics and the effects - I don't think you have any basis for stating otherwise. As to ocean warming (a completely different topic, mind you, and you should look at the appropriate links using the Search box), keep in mind that (a) our measurements of OHC are far from complete, especially at depth, and (b) circulation variances in the oceans are expected to show variations on a 5-10 year timespan.
  8. In this post /news.php?n=868#58115 Tom Curtis partially attributes cooling since 2008 to an exceptionally low solar minimum. But he effects of a solar minimum are vastly more complex than "cooling". Just two examples, the drop in solar UV (much greater %-age than TSI) creates stratospheric cooling which becomes uneven and creates blocking patterns. Those blocking patterns may induce heat waves or other extreme weather, perhaps generally globally cooling, but not simple. Another factor is high GCR which may produce more low clouds which may also be cooling or perhaps not. The other consideration for Tom is that solar effects, even the simplistic drop in TSI, are subject to the same thermal inertia as AGW (if not more). For example the entirety of lowered TSI could easily be "masked" from appearing in the GAT by a rise in SST (e.g. from El Nino). In that case (I'm not saying that happened recently or not), the solar minimum essentially only causes an OHC drop.
  9. skywatcher, my previous post on this thread applies to you as well. The "solar minimum" is not an adequate explanation of why the 2000's were not hotter. Specifically, any change in TSI is applied directly to the oceans, unlike changes in GHGs which mostly melt ice. All other solar changes change the weather which may create temporary warming or cooling. The solar to ocean connection is direct: the sun heats the ocean. A drop in solar TSI due to the "solar minimum" can easily be offset (or "masked") by a relatively small amount of SST warming, the best example being El Nino. Thus, solar mimima do not automatically create atmospheric temperature drops.
  10. Eric (skeptic) - "Specifically, any change in TSI is applied directly to the oceans, unlike changes in GHGs which mostly melt ice. All other solar changes change the weather which may create temporary warming or cooling." Eric, this is so far off that it's close to being not even wrong. Changes in radiative forcing from TSI or from GHG's have slightly different distributions (particularly in the stratosphere), but all radiative forcings affect the oceans, the ice caps, and the weather. Unless you have a reference or two to support this, I would have to consider your last post or two simply unsupportable.
  11. KR, do we really need a reference for this? The planet is 72% ocean and weighted more towards low latitudes where the sun is more direct. The highest energy portion of the solar spectrum, about 1 micron and less, are able to penetrate deeper and heat deeper. A lowering of ocean heating due to slightly lower TSI can be easily outweighed by an increase in SST due to the phenomenon like ENSO (warming from less wind, fewer clouds, etc). Thus solar minima are easily outweighed by other factors.
  12. Eric S, why would that apply to me? If you're meaning my post on the thread you link to in #858, my comments were in relation to Tamino's filtering out of 'exogenous factors', in his post How Fast is the Earth Warming?. Since 1998, we have gone from very strong El Nino forcing to a very strong La Nina forcing, and from a solar max to a solar min. Tamino has quantified the adjustments to the timeseries driven by each of these exogenous factors, and for RSS, he estimates solar forcing to have dropped 0.1C of temperature equivalent over the decade for RSS, 0.05C for GISS. Larger forcings (range of up to +0.4/-0.2) are attributable to ENSO, which is right in line with my previous understanding of the forcings. The global-scale solar forcing is perfectly real, but small, and has indeed hindered temperatures over the past decade. It is interesting to note that the 2000s were even hotter than expected on a decadal scale, given the decadal increases from the 1970s, 1980s and 1990s. It's just that relatively speaking the earlier years of the 2000s were hotter and the later years were 'cooler'.
  13. Eric, you're barking up a very wrong tree in your last three posts as well - as KR states, GHG's most certainly do not just 'mostly melt ice' - why would enhanced GHGs not impact temperatures at midlatitudes or tropics, therefore warming the oceans? If solar energy penetrates the oceans, the variations also penetrate the oceans, regardless of whether ENSO variations temporarily mask those variations. GHG-driven forcings also enter the oceans. Weather pattern changes may also be GHG-driven (creates stratospheric cooling...), and sea ice reduction-driven (altering surface evaporation, temperature and pressure patterns). Do you have any evidence for your assertions?
  14. skywatcher: the statement "The global-scale solar forcing is perfectly real, but small, and has indeed hindered temperatures over the past decade." is not supportable. Here is a supportable statement: "the small but real change in solar forcing has lowered the energy of the earth system by a small amount. That loss of energy may or may not manifest in lowered atmospheric temperatures since other ocean-related factors such as ENSO are much larger than the ocean-related solar heating/cooling."
  15. skywatcher, there are probably threads that explain why GHG energy (LW) doesn't preferentially enter the ocean, but I'll have to look around.
  16. My #865 seems to be contradicted by this: and follow-on threads. It's going to take me a while to read through these.
  17. Ugh, my comment in 859 "unlike changes in GHGs which mostly melt ice" is wrong. See figure 3, the model results in part 4 of science of doom (please follow link above since the part 4 link is squirrely). Specifically, the heating of the ocean from changes in GHG (downward LW changes) is no different from changes in solar radiation despite the latter's deeper penetration. Now that I've corrected that tangent, please realize that my original point remains intact which is that the small TSI drop from the recent solar minimum can be easily outweighed by ENSO. That means the solar minimum does not necessarily translate to the atmosphere.
  18. Eric @867, I am unsure why you are arguing this point. Yes, a solar minimum coincident with a strong El Nino will result in a warm year, but not as warm as a strong El Nino coincident with a solar maximum. More importantly, a solar minimum coincident with a La Nina, as occurred in 2008, will result in a cooler year than an equivalently strong La Nina by itself. If the solar minimum and La Nina also coincide with increasing sulphate concentrations, either due to a large tropical volcano or industrial emissions, it will be cooler still. 2008 happened to coincide with all three, yet was still the 12th warmest year on record, and warmer than any year prior to 1997 on the instrumental record going back to 1850 (hadcrut3 global). That also means there is a significant probability that it was warmer than any year in the MWP. According to Mark Twain's famous definition, climate is what you expect, and based on our expectations (and denier descriptions), 2008 was a cold year a. When the 12th coldest year in (probably) over a thousand years is cold according to our expectations, our expectations have changed significantly. That is climate change, and GHG emissions is the only explanation that makes any sense.
  19. Tom, AGW is real and shown by La Nina in 1989 producing -.21 on UAH and La Nina in 2008 producing -0.3 or so (from the graph of 13 month running average). But that is not the point. The solar minimum being advanced as a theory for cooling in the other thread(s) is already part of the La Nina SST measurement (the drop in solar energy has lowered that measurement) so there is no coincidence of various factors (excluding the aerosols discussed on the other thread) There is simply energy and we have no really precise way to measure how much the energy of the earth changed due to those factors (and others). Simply put, by measuring the atmosphere we can make no conclusions about the effects or lack thereof of the solar minimum, especially in such a short period of time.
  20. correction: should say "-2.1" for the 1989 number
  21. Eric (skeptic) @869, we do not need to determine the change in incoming energy from a solar minimum by plotting atmospheric temperatures. We can, and do, measure it directly. Consequently we can come to conclusions about its effects on atmospheric temperatures, although the uncertainties are large.
  22. Tom, I don't think we can measure all the effects of TSI completely even if we can measure it accurately outside the earth's atmosphere. For starters the spectral changes can make a big difference (e.g. solar UV dropped a lot more by %age than TSI and although solar UV is less energetic, it has a large effect on the stratosphere). Second, the effects of TSI or any other energy changes are subject to the same constraint as GHG energy equivalents, namely that there is a thermal lag caused by the ocean. That lag is very difficult to measure since OHC is a difficult measurement especially over the short run. To reiterate my basic point, the comment that the solar minimum since 2008 should have caused cooling but didn't (or words to that effect) is unsubstantiated. It shows up a lot on other threads.
  23. Eric (skeptic) The physics of transmission of radiation as a function of wavelength is pretty solid (e.g. MODTRAN); it really isn't a source of significant uncertainty. The comment regarding thermal inertia of the oceans is also misguided. The thermal inertia of the oceans is a large part of the reason that there is unrealised warming to come due to the CO2 emissions made so far. However that doesn't mean there is not also an "instantaneous" response to a change in forcings. To demonstrate that is the case, the aerosols from volcanic eruptions cause an immediate drop in temperatures for a couple of years. If thermal inertia of the oceans buffers use from changes in solar forcing, you need to explain why it doesn't also buffer us from the negative forcing from volcanos. If you think that the comment that the solar minimum should have an effect is unsubstantiated, then again you are incorrect. Tamino has shown that solar activity has a small, but non-zero effect on temperature, see this post for details, the plot of the effect of solar activity on temperatures is below The peak-to-trough difference is about 0.1-0.2 degrees C, depending on which dataset you look at.
  24. Eric (skeptic) @872: 1) While the change in UV radiation absorbed in the stratosphere may change weather patterns because of its effect on jet streams and the Hadley circulation. It will not result in a different level of energy absorbed than that predicted by Line By Line models for that change. It certainly does not result in no effective change in the energy balance at either the top of the troposphere or the surface as you are implying. 2) The change in TSI associated with the solar cycle has been shown to have small effect on the solar cycle. The best prediction of the lag involved is 2 months (see discussion for Dikran's link). For large changes in solar output, as for example between 1910 and 1950, the lag is ten years. The reason for the difference is that the rate of change in surface temperature depends on the difference between the current temperature and the equilibrium temperature. For small changes as with the solar cycle, a small change in surface temperature will bring the surface close to equilibrium and slow further changes beneath the level of statistical detectability. For large continuous changes the disequilibrium is long lasting and hence the change in temperature detectable for a long time. 3) There is a difference between a change that induces a change in equilibrium, and a change that counters a previous change that effects equilibrium. If there is a forcing of +1 W/m^2 at the top of the atmosphere, the surface needs to warm to bring OLR and solar radiation back into balance. The heat required to bring the temperature back to balance is large compared to the additional heat gained each year due to the imbalance, hence thermal lag. But if there is a temporary reduction in TOA forcing by 1 W/m^2, the surface is already at the right temperature for the new, but temporary TOA balance. As no change of temperature is required, not lag will be present. This is the circumstance when a solar minimum is superimposed on a background of rising temperatures due to a rising GHG concentration. The rising GHG concentration requires a higher surface temperature to re-establish equilibrium. But the solar minimum reduces the surface temperature required for the temporary equilibrium, thereby immediately reducing rates of warming.
  25. Tom (874), that is interesting, but seems like an odd dichotomy. Lag of decades for CO2, lag of a decade for a similarly large change in solar output, but only 2 months for the small solar cycle TSI change. I think the answer is in your #3, that there is no lag for solar TSI cooling as you explain, but a lag for every type of warming no matter what the source (essentially the ocean absorbing the extra warmth). That seems consistent with the statement: "we should see a slowing of warming with the solar minimum" although not necessarily cooling. Your logic for why we should see that "slowing of warming" right away seems very sound, so I believe I was wrong about implying a "lag for cooling" up thread.
  26. Eric (skeptic) @875, first, I think there may be a difference in definition. Specifically, when talking about thermal lag for CO2, we are talking about the period of time to reach 60% (or there about) of the equilibrium response. When we talk about thermal lag for seasonal temperature changes, we are talking instead about the time difference between the peak (minimum) insolation and the peak (minimum) temperature response. That is because the oscillating insolation does not leave enough time for 60% of the equilibrium response to be reached. Rather, the insolation falls below the equilibrium level of the current temperature long before it reaches that point. The same is certainly true for the solar cycle, and probably true for changes in TSI over the 20th century in general, which first fell, than rose to about 1950, then fell again, then rose almost as far, and then fell gradually. Consequently thermal lag for insolation probably measures the period to peak measurable response rather than the period to a certain percentage of equilibrium response as with CO2. The difference is not because of the different source of forcing, but because the CO2 forcing is increasing monotonically (note: CO2 forcing, not total or total anthropogenic forcing). Second, the level of the forcing for changes in TSI and especially for the solar cycle are not large, and certainly not nearly the same size as the CO2 forcing. Remember that the greatest change in TSI in the twentieth century (from 1910 to 1950) accounted for approximately a third of a slower warming than that at the end of the twentieth century which can be attributed exclusively to CO2 (but only in that the other factors canceled out). Consequently the peak solar forcing is at most a third of the peak CO2 forcing in the twentieth century, which means the resulting decadal temperature change from solar alone is not greatly different from the annual variation in mean global temperature. If the temperature is rising then falling due to an oscillating forcing, it will approximate to a sine wave. It will first rise slowly, then quite rapidly, and then slow down again. For a weak forcing, it is probable that only the change in temperature during the rapid rise will be statistically detectable, particularly if the forcing is very weak (solar cycle) or there are only one or two examples to test against (major TSI changes). Consequently the end of the peak measurable change of temperature will coincide with the end of that rapid rise rather than the actual peak which will be obscured by year to year temperature variations. Third, and particularly for the the solar cycle, because annual temperature fluctuations are large compared to those induced by the solar cycle, it is probable that after a short period of time a random fluctuation will bring the temperature up to the peak response point. From that point the higher (or lower) insolation will be acting to dampen departures from that temperature rather than lifting (or lowering) the temperature to that point. And as we have established, there is no thermal lag for that. Consequently the two month lag (which I and, more importantly as he has reasonable claim to expertise in this area, Tamino find surprising) may just be the average period until a random fluctuation shifts the temperature towards the effective equilibrium temperature. My point is not that any of these factors is shortening the "thermal lag" period for TSI variations including the solar cycle. It is that there are good reasons to expect weak, and fluctuating forcings to exhibit a reduced lag response both because their full response is never exhibited due to lack of time, and because noise can swamp out the more subtle parts of the signal. I do not suppose these are the only ways that can happen, and nor can I claim to know how much each factor is relevant in particular cases. But I do know that the difference between the thermal lag duration for CO2 and solar forcings is a function of characteristics of those forcings, not special pleading.
  27. Eric (skeptic) In comparing the lag of decades for CO2 and months for the 11 year solar cycle you appear to be confusing "equilibrium" and "instantaneous" responses of the climate. Think of the thermal inertia of the oceans as acting like a damper in a car suspension system; if you increase the weight of the car, it will slowly sink on its suspension at a rate depending on the damping. If you put a 100kg weight in the car, it doesn't immediately sink an inch, it takes a fraction of a second. If you fit stiffer dampers, it will take longer. So there is an "equilibrium" response of the suspension that is larger than the "immediate response" (it starts settling immediately, but it takes time to get to its equilibrium position). Now consider what happens if you drive down a cobbled street (i.e. a cyclic forcing), the damper then will attenuate the oscillation in ride height, and you will find there will be lag introduced in the ride height relative to the road surface, but there is no "equilibrium response" as the cobbles don't change the equilibrium ride height.
  28. Tom, I must take issue with your statement "Second, the level of the forcing for changes in TSI and especially for the solar cycle are not large, and certainly not nearly the same size as the CO2 forcing." Please double check these numbers, but 11 year TSI amplitude is 0.1% or 1366/1000/4 or 0.34 W/m2. For CO2 over 11 years it is 22 ppm or (22/280)*3.7 or 0.29 W/m2. That means they are roughly the same amplitude over that phase of the solar cycle. Dikran, perhaps you can check those numbers too, I don't see how the damping on the CO2 rise can be any different than the damping on the TSI oscillation. Aren't they exactly the same?
  29. Eric, the point is that you are confusing the instantaneous response with the equilibrium response. The climate starts responding to CO2 rapidly just as it does the 11 year solar cycle, but in the case of CO2 it eventually overcomes the inertia (as it is monotonically rising) but the 11 year solar cycle doesn't as it alternates phase far earlier than thermal inertia is overcome. If TSI gradually increased (rather than oscillated) it too would have an equilibrium response that would only be fully realised after several decades, but temperatures would start to rise immediately. I don't know if you have an engineering background, but it is the difference between the equilibrium response and transient response of a system described by differential equations. They are not the same thing.
  30. Eric, I think your comparison is apples and oranges. First, as to the cycle, while the change in amplitude could be 0.34 W/m2, it's not really fair to treat the minima as the baseline, so you're really talking about +/- 0.17 W/m2. It's also not a square cycle, jumping from minimum to maximum in one leap, so the duration of time spent at that full increase or decrease is low, with the majority of the cycle spent within 0.09 W/m2 or even less. Also, every positive swing has the negative swing, so any lag at all is going to be very muddled (with the counter/braking action starting before the original action is able to take effect). Second, for changes between cycles, the difference is even less than 0.34 W/m2, much less. In the past three cycles, the variation from the first to the third maximum (eyeballing it) looks to be less than one one hundredth of one percent, while the minima have no apparent change.
  31. Eric, Just to make it a little clearer, no net change in minima, and a net change in maxima of about 0.03 W/m2 i the past 33 years, would net out (since most of the time is spent in the basically unchanged ups and downs of the cycle) to probably an addtional 0.03 W/m2 for maybe 6 or 9 of those 33 years, or at best 1/4 of the time, meaning a net of 0.0075 W/m2... a completely inconsequential number.
  32. Eric, Whoa! Lastly, I just noticed that you bumped the CO2 forcing down to only consider the change in forcing, i.e. in the increase during an 11 year period. But the CO2 forcings are cumulative, where the TSI changes are not. It's hardly a fair argument to compare 11 years of TSI changes (which net to zero!) to 11 years of CO2 changes which pile on top of decades of previous change in the value. Those are not the two values under discussion (11 year change in CO2 versus 11 year change in TSI, which itself is probably less than 0.0025 W/m2 anyway -- you have to measure the areas under the two curves to get a true number).
  33. Sphaerica, your first post didn't really address my concern because you turned the 11 years of increase into a shorter interval of high solar. Then your second post changed the topic to secular solar changes and I have no argument with it (they are small). In your third post you resumed the original topic but missed my point which is quite simple: there is an interval of 11 years in which the TSI forcing increases roughly the same amount as CO2 does during that same interval. It is then balanced by the next 11 years of decreasing TSI forcing. Dikran, you are suggsting that the earth has a different thermal intertia to TSI changes than to CO2 changes. I don't see how that can be true. Tom, regarding your statement "Second, the level of the forcing for changes in TSI and especially for the solar cycle are not large certainly not nearly the same size as the CO2 forcing" would make sense if it was simply appended with "in total" or "since preindustrial" or "ongoing long term". Then we would all be able to violently agree.
  34. Eric (skeptic) @883, first, Sphaerica's 880 and 881 are I believe restatements of my first point in 886. So are Dikran's 877 and 879, though he states it with greater clarity and economy than I do. Second, I think the best way to state it is that the unrealized instantaneous forcing is very much larger for CO2 than for TSI changes associated with the solar cycle, and significantly larger than for TSI changes at any time in the twentieth century. By "unrealized instantaneous changes" I mean the change in total forcing due to a given factor at anytime minus the change in OLR due to changes in surface temperature at the same time. I take it that is what you mean by "ongoing long term forcing", and also what Sphaerica was describing in his 882. That being the case, we can all now agree furiously together on this point.
  35. Eric (skeptic) wrote: "Dikran, you are suggsting that the earth has a different thermal intertia to TSI changes than to CO2 changes. I don't see how that can be true." No, I am not suggesting any such thing. The thermal inertia of the earth has the same effect on warming due to TSI changes as it does on CO2 changes. The point is that you are comparing the equilibrium response to CO2 forcing with the transient response for TSI, so you are not comparing like with like. If TSI forcing was steadily rising just as CO2 radiative forcing is, then there would be a transient response (the Earth would start warming essentially immediately), but the full warming would not be realised for some decades (the equilibrium response). However, TSI is not steadily rising, it is oscillating, which is why the delay being discussed in relation to the 11-year solar cycle is not the delay before equilibrium is reached, it is a phase shift caused by the thermal inertia of the oceans. Until you understand the difference between a transient and an equilibrium response in a dynamical system, you are unlikely to resolve your confusion.
  36. Dikran, I think Tom explained it pretty well in 884. Past CO2 forcing plus thermal intertia (to warming) have produced an unrealized forcing which exceeds any natural forcing since secular natural forcings are all very small. Thus the GAT effect of such a forcing is much larger than the GAT effect of any cyclical natural forcing like TSI.
  37. Great Post! It's 2011, and we in the US are in the middle of another Summer heat wave and severe drought. I used a few arguments from this post to totally debunk someone in my office who was trying to use the "11-year solar cycle" argument to explain this drought.
  38. gcdem, The solar cycle has nothing to do with the Southern (especially Texan) drought. The main culpret has been the strong La Nina. Areas to the north experienced above normal precipitation (rain and snow), whereas southern areas were rain-starved. Similar occurrances accompanied past strong La Ninas, many of which were more severe than the current situation, particularly the mid 1950s.
  39. Hi all, Do you have a page dedicated to the Denialist claim that the IPCC itself admits it doesn't know what's happening with solar forcings at the following 2007 report page. IPCC 2.9.1 Uncertainties in Radiative Forcing
  40. Um, it's rather a long stretch from quantifying the uncertainties as of 2007 to "it doesnt know whats happening". As that reference points out, solar forcing is extremely well measured for last 25 years (direct measurement by satellite) but is "B" because of reliance on proxies prior to that. For more up to date look at the solar proxy uncertainties see this . Note that all forcings (indeed all scientific measurements) have uncertainties. What's important is the extent to which these can be quantified.
  41. I am not sure if any of you notice this or not, but the PMOD link goes to a data set that is a little too small of deviation for solar data collected in Earth orbit with daily entries. That is to say, the Earth's orbit is elliptical. For part of the year we are closer and the other half farther away. This results in a difference of about 90 W/m^2 between minimum and maximum. The data on PMOD at most varies by a few W/m^2 in a year. If you are measuring values on 22DEC2009 that are within 1 W/m^2 of values on 22JUN2010, then you have some issues with your data. That difference should be pushing 90 W/m^2. The difference in r value for the intensity calculations is about 5 million km. So, maybe the sources for this article should be revised.
  42. Thanks Scaddenp. One query regarding the forum software: every thought of switching to Wordpress? Wordpress is great software and has BBpress forums as a plug-in now. Commenting could have all the power of BBpress (or SMF or Phpbb3 or whatever other open source forum software you want).
  43. Disregard the last comment about Wordpress... I just realised how much work you've already put into the ipad and iphone apps and would hate to put you through all that again. (Not sure if Wordpress has simple translation into these formats but there you go). I just love powerful forum software, because... well... I didn't even get an email last time someone replied?
  44. This next argument seems to be another version of "It's the sun" that good old Willie Soon (and his $million from Exxon) have written. New Willie Soon paper Does anyone know any peer-review work on this yet? Is the journal it is in actually an authentic climate journal? Is it legitimate science about a LOCAL Chinese phenomenon or a hyped up local phenomenon that fraudster Denialists are using to try and confuse people about GLOBAL climate change?
  45. I've read the abstract of the Soon paper you linked to Eclipse. The temperature trends observed in China seem consistent with what is known about the 20th Century temperature trends in general IIRC - as a result of global brightening and dimming. So he may have that part right at least.
  46. And besides,the paper was about *China* and about the 20's and 40's for some reason. It's not as if he's discovered something controversial about the *globe now* is it? Cheers.
  47. Soons paper sounds to me like the results of a search for statistically significant trends and association with solar forcing region by region - which of course invalidates the test of statistical significance (unless multiple hypothesis testing issues are properly dealt with).
  48. Continuing from here. EtR's sunspot graph clearly shows the 1950s solar maximum; since then solar activity has in fact declined (hence the descriptive term maximum). A simple straight lines fit doesn't capture that important detail and is therefore irrelevant.
  49. To illustrate Muoncounter's point @898:
  50. Muon, Yes, solar cycle 19 was definitely the highest of the 20th century. However, cycles 21 and 22, in the 1980s and 1990s, were the next two highest, significantly surpassing anything during the early 20th century. The point is that sunspot activity was still high during the last portion of the 20th century. To expect temperatures to decrease based on the drop from a very high to just a high value would be comparable to expecting temperatures to drop because we added less CO2 to the atmosphere this year than last. A straight line fit does not capture the temperature profile of the 20th century, but does that negate the fact that an increase has occurred?
    Response: [Dikran Marsupial] Re your second paragraph, it is well know that there are multiple forcings that affect climate, hence nobody would expect a straight line fit. Please be less opaque in your posts as such obfuscation gives the impression of trolling.

Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  

Post a Comment

Political, off-topic or ad hominem comments will be deleted. Comments Policy...

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

Link to this page

The Consensus Project Website


(free to republish)

© Copyright 2022 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us