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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

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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:


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Comments 501 to 550 out of 1270:

  1. not sure I agree with your math Gord. TE*1E4 = (C/(4*SB*(1-GHG))*(1-A) where TE = temp earth C is solar constant SB is stefan Bolz. constant GHG is the greenhouse effect A is albedo If we assume no GHG effect and assume solar constant is 1366w/m2 ( as measured) and albedo of 0.3 then resolving the equation gives: TE*1E4 = (1366/4*5.67*1E-8)*0.7 which results in TE = 254abs. And no, the sun is presently not the only energy source. It may be the largest ( even by a long way) but the earth has internal heat (vulcanism) frictional heat from gravity ( earth moon barycentre is inside the earth) heat from burning FF's, heat from radioactive decay - to name but a few.
  2. As stupid as ever, Gord. Way to be consistent! ""In the absence of the greenhouse effect and an atmosphere, the Earth's average surface temperature of 14 deg C (57 deg F) could be as low as -18 deg C (-0.4 deg F), the black body temperature of the Earth."" That's what wikipedia says, then. It's not what I say. It's not what scientists say so long as they proofread well. It should be, 'In the absence of the greenhouse effect, the Earth's average surface temperature would be about -18 deg C.' I've told you this before. Did it ever occur to you that some of your sources might have rounded the sun's effective temperature (effective as in the temperature that an isothermal blackbody would have that emits the same radiant flux - actual photosphere not being isothermal through it's visible depth, etc.)? Observations: The Earth reflects about 30 % of the solar radiation it intercepts. Observations: The Earth emits to space less than is emitted from the surface, and the total emission to space is that which a blackbody (of the same size and shape) would emit if at about 255 K. Specifically, the emission to space is particularly reduced in places with high cold cloud tops, and in various intervals of wavelengths where H2O, CO2, and various other gases contribute opacity to the air - a spectral pattern not at found in the optical properties of the surface. (I've told you this before.) The Sun is the only energy source in an intermediate sense. Ultimately, the sun is not a source - the energy came from matter that came from energy+matter at some previous time. More proximately, there is energy in the climate system and the climate system can gain and lose energy, and energy can be redistributed within it. (I'VE TOLD YOU THIS BEFORE.) Your equation has a minor error: TE = TS ( ( (1-a)^0.5 * Rs)/(2*D) ) )^0.5) should be TE = TS ( ( (1-a)^0.5 * Rs)/D) ) )^0.5) (Mizimi - other than that, his formula is the correct one (a broken clock is correct twice a day (unless it has AM/PM - with digital, 'all bets are off')) - it would look more intuitive if written this way: TE = TS * [ (1-a)^0.5 * (Rs/D) ]^0.5 or TE = TS * (1-a)^(1/4) * (Rs/D)^(1/2) derived from TE^4 = TS^4 * (1-a) * (Rs/D)^2 and while I figured out what you mean by TE*1E4, that would appear confusing to many people; 1E4 could be interpeted as 1 * 10^4, so that it appears that you just multiplied TE by a constant of 10,000.)
    Response: This topic is covered in We're heading into an ice age.
  4. Gord - For the first time ever, you have truly found a real and significant mistake. I did temporarily forget the factor of 4 for the Earth's surface area divided by it's cross section, which of course has a square root of 2. Your equation was correct and mine was erroneous. It is TE = TS ( ( (1-a)^0.5 * Rs)/(2*D)) ) )^0.5) But everything else you say is just stupid, at best. As usual. I should pity you.
  5. Might be worth pruning this thread and moving some of the stuff to a background file, else it's just going to keep growing with tangential stuff (most retroreflective signs use glass beads that work the same way moisture does: Not to mention the stuff that completely misses the mark but keeps whizzing by over and over.
  6. "most retroreflective signs use glass beads" Thanks, Hank.
  7. "What the science says... Solar activity has shown little to no long term trend since the 1950's." This is incorrect. Although the maximum amplitudes of sunspot numbers have gently declined since the 1960's, the short duration of the minima until the most recent has meant that the average sunspot number increased right up to 2001, shortly before the rapid warming ended. The measurement of TSI is a controversial area, with two teams disagreeing over the splicing and calibration of the data. The science is not settled here.

    While there is some debate over the long term trend of solar activity, the debate is essentially over whether the sun is showing a slight warming trend or a slight cooling trend. Either way, the sun cannot have played more than a minimal part in recent global warming. Nevertheless, various independent measurements of solar activity all confirm the sun has shown a slight cooling trend since 1978. This means rather than contribute to global warming, solar activity has actually had a slight cooling effect on climate.

  8. Although it is somewhat speculation, lead may have offset warming from 1940 to 1980 and therefore the links between global temperature and sun activity could be weaker then expected Sorry i cant find the actual paper this has been published in. I'm posting this for debate not because i sincerely believe there is a direct correlation here
    Response: The paper is Inadvertent climate modification due to anthropogenic lead (Cziczo 2009). Thanks for the link - an interesting paper. I wonder if it'll have any impact on our understanding of mid-century cooling.
  9. Correction/Clarification: What I refered to as an "emission distribution" in comment 501 and perhaps subsequent if not prior comments: --------- "This can be extended farther. Suppose we are interested in the absorption of I#f. For all the fractions of dw that are scattering or reflection cross sections per unit area, the fate of those fractions of I#f can be traced farther, through successive scatterings and reflections, until every last bit is absorbed. This will be a distribution of dw that may extend outside of the path and over other paths, perhaps over some volume. It is the distribution of the absorption of I#f(O). Assuming local thermodynamic equilibrium within each unit volume, It is also the distribution of the emission of I#b(O) - multiplying the distribution density by I#bb(T) and integrating over the distribution gives the I#b(O) value, where I#bb(T) is the blackbody intensity (normalized relative to refraction) as a function of T, however it varies over space." "I#f(O) also has an emission distribution that can be found, tracing back in the opposite direction from point O." ---------- It should be clear that by "emission distribution", I was refering to a distribution in visibility, which, when weighted by the blackbody radiant intensity for the temperature at each location and then integrated over volume, would give the radiant intensity coming from the direction considered at the location considered. However, this is more correctly called the "weighting function", which avoids confusion, since it would also make sense to think that the emission distribution IS the blackbody radiation intensity weighted by the weighting function.
  10. Solar activity didn't cause global warming, it caused several really hot years. Volcanic activity in the oceans have caused most of the ice melt on the ice caps. Or I should say where the warm waters from volcanic activity has effected the ice. Ice on land has increased, this you would expect with the heating up of the oceans. Moisture is being pumped into the air, and this warm moist air is turning into snow. Now that the solar activitty has settled down you can expect to see a hell of a lot more snow. This is going to do nothing to build up the Ice caps, because the waters in the oceans are still being heated up by volcanic activity. Nor do I expect to see a reduction in volcanic activity in the oceans. I find it strange that with ever increasing volcanic activity in the news, tsunamis, and earthquakes that this has been overlooked and ignored. The carbon sink suddenly becomes saturated and still it is attributed to man made hydrocarbons. Yet it was not a gradual build up that was expected but sudden saturation, again underwater volcanic activity was totally ignored but is the most logical reason for the sudden saturation of the carbon sink. But never fear, the "we are all going to die!" bunch can take solace in the fact that we are in for a lot of really cold weather and even greater storms generated by extreme temperature differentials. This is not something you would expect to happen with total global warming, if anything storms should be milder. Before anyone argues with me, you should probably check out the rise in tectonic activity around the world. How this tectonic activity has changed the ocean floor not to mention ocean currents. Don't argue, look first.
  11. Did anyone answer the question as to why correlation has to be between increase and sun activity and temperature. As I heard it stated, I can put a pot of cold water on my stove, heat up my stove from fold to a constant temperature quickly, and then have the water take much longer to heat and continue to heat up even after my stove is at a constant temp. Why is it any difference from the sun? Especially now as the sun activity seams to be declining and the temperatures of the last decade are stagnate.
    Response: This issue is examined in Climate time lag.
  12. These words spring to mind. “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” and "If we knew what it was we were doing, it would not be called research, would it?". -- Albert Einstein (1879-1955) [German physicist] Just because its warming does not PROVE its CO2. Cause and effect issues. The commentary on radiative "forcing' is also a bit hard for me to understand. Is it another word for Convection? After all, hot gases rise (when not trapped in a glass greenhouse) and when surrounded by cooler gases, they lose that latent heat, clods are created, humidity changes. Where are the records and observations of the changes in humidity and cloud cover?.
    Response: "Just because its warming does not PROVE its CO2. Cause and effect issues."

    That is true. The reason we know the warming is caused by CO2 is because satellites and surface measurements are observing more infrared radiation being trapped at the specific wavelengths that CO2 absorbs energy. That is what is meant by 'radiative forcing' which is just another term for an imposed energy imbalance. More CO2 is causing less radiation to escape back out to space which causes an energy imbalance. The result is the planet is accumulating heat.
  13. If it was only the troposphere & near-surface that was showing warming, then I might-just might-be prepared to accept that something other than GHG was the cause of the last half-century of global warming. What concerns me, though, is that the Stratosphere has been COOLING over that same period of time (minus a few spikes due to a few huge volcanic eruptions). If the sun were the cause of the warming, then the warming would be spread throughout the entire atmosphere, yet instead the warming simply *stops* at the tropospheric level. This suggests that long-wave radiation is being trapped in the troposphere by.....Greenhouse gases!
  14. Another point. Even with historic low sunspot numbers, global temperatures have still remained above +0.5 degrees over the 1951-1980 mean for the last decade. What happens if we see a sudden surge in sunspot numbers over the coming 22-33 years? Will we see an increase in the rate of warming-per decade-to as much as +0.3 to +0.4 degrees per decade? Its uncertainties like this (& the positive feedbacks of CO2 release from oceans & increased levels of water vapor) which makes me think we should engage in the precautionary principle-namely to immediately begin making sensible changes in our generation & use of electricity to reduce the CO2 emissions associated with our economies (not by reducing GDP, but by reducing both the KW/$ GDP & the tCO2e/$ of GDP.)
  15. This solar graph has some resemblance to the tree ring proxy graph where mike's nature trick was applied to - to hide the decline. So couldn't you just use the trick as well? Then it would fit the instrumental data better. (This is not meant as a mocking, a serious reply would be appreciated.)
    Response: It's funny you should mention that. I'd not thought of it that way before but "hide the decline" is exactly what the Great Global Warming Swindle did when comparing sun to climate. They deliberately cut off solar levels at 1975. And as if this graphs wasn't misleading enough, they also "hide the incline" of temperature rise in 1980 - global temperatures actually go off the chart if you extend them to current temperatures:

    Great Global Warming Swindle: global temperature vs solar activity

    As for "Mike's Nature trick", that situation is the case where the decline is not a decline in temperatures but a decline in tree ring growth's response to temperature. So it's entirely appropriate to not use tree rings as a proxy for temperature after 1960 when some other factor is clearly influencing tree ring growth. More on tree ring divergence...
  16. Wow, thanks for the fast reply. It has been a while since I've seen the propagandistic "great global warming swindle" but it look like you're quite right about them hiding the decline. even tough it seems to me they at least didn't substitute it with instrumental data (i guess the red curve is the one for solar activity?) - but it's bad enough anyway. if the factor which is influencing tree ring growth is profoundly understood then it should be possible to correct for that influence, wouldn't it? Will read your page on that subject now.
  17. This paper (, published in 2007 by Eigil Friis-Christensen and Henrik Svensmark at the Danish National Space Center, is a response to Lockwood and Fröhlich's paper disputing the correlation between solar activity and land surface temperature. This new paper discusses the correlation between cosmic rays (solar activity) and sea surface temperature/atmospheric temperature. In both cases there is a clear correlation. While Lockwood and Fröhlich are correct in saying there is a divergence between solar activity and land surface temperature, the correlation remains true for two other temperature data sets (sea surface temp. and tropospheric temp.) Thus, one must question the validity of the land surface measurements, and admit the possibility that the sun may be playing a major role in current global warming.
  18. michaelkourlas, that 2007 paper by Friis-Christensen and Svensmark is old news. See Svensmark and Friis-Christensen rebut Lockwood’s solar paper.
  19. @Tom Dayton Thanks, I hadn't seen that.
  20. The problem of correlating the earth's global temperatures with observed driving factors is complex at best. Our weather is dominated by the oceans. These comprise 70 percent of the globe surface and represent a tremendous heat sink which is circulating continuously. As such we would expect that observed temperatures would have an appreciable time lag behind the driving factors.I would expect the time lag to be more than two solar cycles. Any calculation of the earth’s thermal balance would have to include a deep understanding of the interaction of the solar radiation with the ocean areas. The past observations of long term global shifts (the medieval warming and the little ice age) would suggest that the sun’s variation has caused large temperature changes in the past. In examining sunspot average numbers with smoothing filters of 25 to 30 years shows a significant increase from 1920 to 1970. Could that be a cause of the global temperature increase? Sunspots not only affect the total radiant energy, but also the frequency distribution. Also since oceans comprise 70 percent of the globe surface, are land measurements a true indication of global temperatures? I believe that ascribing the global temperature increase to the effects of greenhouse gasses is a vastly simplified solution to a very complex problem.

    You make some good points. Yes, there is a climate lag. An important point to realise is that the lag doesn't mean there's a gap between a forcing (eg - warming sun) and the climate response. Climate responds immediately to a forcing. The lag refers to the time it takes for the climate to reach equilibrium after an imposed forcing.

    For example, say the sun warms. As the sun warms, there is more energy coming into our planet than escaping back to space, so the planet starts accumulating heat and warms. Eventually the sun stops warming. At this point, there is still more energy coming in than radiating back to space so the planet continues to warm. As the planet warms, it radiates more energy out to space. Eventually the energy out increases to match the energy coming back in and the planet is in equilibrium again. The time it takes for the planet to reach equilibrium is the climate lag.

    Currently what is happening is the planet's energy imbalance is increasing. We are not approaching equilibrium which is what you would expect if we were responding to an earlier period of warming sun. Instead, something else is causing less energy to escape out to space. Satellites measuring the radiation escaping out to space find that the less energy is occuring at the wavelengths that carbon dioxide absorb energy. So at a time when CO2 levels are reaching the highest levels in over 15 million years, we're also observing less energy escaping to space at the very wavelengths that CO2 absorb infrared radiation.

    These topics have been covered in previous posts. There is a post that goes into more detail re climate lag. We peruse the many papers that examine the possibility that the sun is causing global warming. You make a good point about the importance of oceans - not only do they comprise most of the Earth's surface, they also absorb most of the infrared radiation that is trapped by greenhouse gases. Consequently, a better metric for global warming is the planet's total heat content which includes all the heat accumulating in the oceans.

  21. A graph of sunspot count vs. time shows that some cycles are high for short periods and some are not as high but for longer periods. The relevant measure is energy which is the combination of both magnitude and time as in the time-integral of sunspot count. Subtracting the energy radiated from the planet results in the net energy retained by the planet. An appropriate scale factor relates net energy to average global temperature anomaly. Combine this with the Effective Sea Surface Temperature and the result is a model that accurately predicts average global temperature anomalies since 1895. That is 114 years…and counting. It is not necessary to include changes to the level of CO2 or any other ghg. Anyone that can use EXCEL can do this. Or, see it done already at which has links to the source data. (Replace all references to PDO with ESST which is short for Effective Sea Surface Temperature).
  22. Dan, I've seen that writeup elsewhere. Could you go through it step-by-step, being especially careful to help us understand the following things written by the author: --"The proportionality constant, 6.36E-9, was adjusted to get a fairly constant net energy from 1700 to about 1940"; Why? --"The up trend or down trend periods ascribed to the Pacific Decadal Oscillation (PDO) are taken as 32 years long for all periods." Why 32 years for all periods? --"The temperature range for the PDOs alone was taken to be 0.45 K for all of the PDOs." Why? For a PDO downtrend, the value added to the above sunspot calculation is 0.45 minus 0.45 multiplied by the fraction of the PDO time period that has taken place." Why?
  23. The reference site for sunspot count starts the data at 1700. If you do the conservation of energy assessment, the resulting graph fluctuates about a trend until about 1940 and then the trend rises continuously thereafter. The graph reveals that the trend of radiation energy balance changed in about 1940. The constant (it is actually 6.52E-9, the value 6.36E-9 was a misread) ‘normalizes’ the calculation for the 240 years prior to 1940. Oceans cover about 71% of the earth’s surface. A simple calculation reveals that the heat storage capacity (thermal capacitance) of the oceans to a depth of 700 meters is about 200 times that of everything else on the planet. Thus the average temperature of the oceans is by far the best indicator of whether the planet is actually changing temperature. The data at shows that the planet stopped warming in about 2005. The next two ‘why’s relate to a discovery of the research. There are many ocean currents. Temperatures vary along the path of each current. The agencies that report average global temperature (agt) only use the temperature of the part of each current path that happens to be at the surface. Thus the contribution to the agt reports varies even though there is no intrinsic net gain of loss of energy over the entire circuit of each current. There are many different currents of which PDO is only one. The discovery is the net effect of all of the currents and is better identified as Effective Sea Surface Temperature (ESST). So replace all references to PDO with ESST. The discovery in time and magnitude is the ESST which produces the observed match of measured values. The last ‘why’ relates to simply a detailed instruction of how to do the arithmetic.
  24. Thanks for the amplification, Dan. I don't find the author's argument persuasive. The way it falls apart before the period where his numerical forcing no longer functions with available data versus the target objective offers a hint of the underlying problem. Here's a key remark by Gavin Schmidt relevant to the paper you cite: The potential for self-delusion is significantly enhanced by the fact that climate data generally does have a lot of signal in the decadal band (say between 9 and 15 years). This variability relates to the incidence of volcanic eruptions, ENSO cycles, the Pacific Decadal Oscillation (PDO) etc. as well as potentially the solar cycle. So another neat trick to convince yourself that you found a solar-climate link is to use a very narrow band pass filter centered around 11 years, to match the rough periodicity of the sun spot cycle, and then show that your 11 year cycle in the data matches the sun spot cycle. Often these correlations mysteriously change phase with time, which is usually described as evidence of the non-linearity of the climate system, but in fact is the expected behaviour when there is no actual coherence. Even if the phase relationship is stable, the amount of variance explained in the original record is usually extremely small. Schmidt on solar forcing The arbitrary choice of a 32 year PDO cycle here is an example of what Schmidt describes. Another problem is that the amount of power from solar variation available is not enough to warm the ocean as much as we've seen happen, so looking to variation to explain the ocean's warming is a non-starter in any case. Meanwhile, an unqualified claim of cessation of warming since 2005 is not really defensible. To support a conclusion that warming has ceased since 2005 you'd first have to explain why five years of data have more statistical power than fifty.
  25. The paper at the link at post 523 is an engineering analysis using the first law of thermodynamics applied to credible published data. It is very common to look at sunspots in terms of either just the number of them at any time or some time factor relating to a solar cycle. It should be obvious that a short wide solar cycle would have the same influence on planet energy as a tall narrow solar cycle. The way to take both number and time in to account is with the time-integral of sunspot number. I have found lots of papers that considered just sunspot number or just a time factor where they found poor correlation. However, I know of no other papers that considered the time-integral of sunspot number which has excellent correlation with measured temperature anomalies. The ESST for the last 114 years…and counting is defined as 32 year up trends followed by 32 year downtrends in a repeated 64 year cycle of magnitude 0.45 C and peaks in 1941 and 2005. When anomalies from the ESST cycle are combined with the equivalent anomalies from the sunspot time-integral calculation, the result is an excellent prediction of average global temperature anomalies since 1895. There are many ocean currents. PDO, ENSO, AMO, etc. and they are all occurring at the same time. Each of the currents has its own cycle time and phase relation with respect to the other currents. The NET effect of all of these currents since 1895 apparently matches the numerical cycle defined above. Prior to 1895 the phase relation may not have resulted in producing the noted temperatures or possibly the temperature measurements were inaccurate. As stated in the paper, future temperature anomalies depend on future sunspot numbers and future [ESST] behavior neither of which has been confidently predicted. When these can be predicted, then the model will predict future agt. Until then the model, which shows no signs of being wrong since 1895, provides the best estimate. It is certainly better than the IPCC prediction which has failed miserably for years. The perception that the only influence that the sun has on earth’s climate is by total solar radiation (TSI) is apparently wrong. In a separate analysis, I discovered that average global temperature is sensitive to average cloud altitude which determines average cloud temperature and thus the rate at which the clouds and thus the planet radiates energy to space. Others have shown that fewer sunspots correlate with more low level clouds. The overall mechanism sequence is: Fewer sunspots; reduced solar magnetic shielding of earth; increased galactic cosmic rays penetrating the atmosphere; increased low-level clouds; lower average cloud altitude; higher average cloud temperature; increased cloud-to-space radiation; lower agt. A rising temperature trend is going to be the conclusion if our knowledge is limited to statistical analysis and a 50 year period. However, if the record had started with best estimates of temperatures during the Medieval Warm Period the statistical trend would be down. The agt downtrend since 2005 was predicted by the model. The important point in all this is not so much what the agt is going to do but that, since agt can be accurately predicted with no need to consider change to the level of any ghg, then change to the level of CO2 or any other ghg has no significant influence on agt.
  26. Dan, I take it then that you are the author?
  27. Since sunspot activity is observed for numbers, energy and radiation charistics a complete thermal balance with the earth is a very difficult if not impossible task. I believe that the oceans with their tremendous heat capacity are the key to the earths global temperature. The sunspot numbers count could be used as an indication of the sun's variation from a nominal output. I plotted an a weiighted sunspot number vs time from 1770 to the present. The average sunspot was developed using weighting factors of .4, .3, .2 and .1 for the periods of 0-10, 10-20, 20-30 and 30-40 years before the date of the data point. The resulting plot is consistant with observed long term temperature trends. It would predict the rapid temperature increase of the past century.
  28. Cliff Oates, can you attribute any physical meaning to your linear weighting function? It looks a bit arbitrary.
  29. It is arbitrary. I looked a little at other averaging methods. The general shape of the sunspot averaging results are similar. All show that an increase in global temperatures would be expected after 1920. I believe that the overall time period is of the order of 40 or more years. Other weighting factors may be more appropriate, but I don't know how to determine them. This approach is only for long term temperature studies. Short term temperature responses will neccessarily scatter around the longer trends. Since the Little Ice Age was likly the result of the lack of sunspot activity this shows that solar activity should not be ignored even though direct quantification cannot be derived. Is there any real reason to believe that greenhouse gasses are any more responsible for global temperatures than solar activity?
    Response: Is there any real reason to believe that greenhouse gasses are any more responsible for global temperatures than solar activity?

    This question is answered in The empirical evidence for an enhanced greenhouse effect. Just to clarify, greenhouse gases aren't the sole driver of climate but over the last few decades, the forcing from CO2 have been greater than any other climate forcing (as well as the fastest rising).
  30. In answer to response. There is nothing to show that greenhouse gasses caused global warming except that co2 has increased concurrently with the warming. The increase in sunspot numbers during the same period could have been totally responsible. Greenhouse gasses are an over simplified solution to a complex climate phenomenon and again seems to ignore the effects of the oceans interaction.
    Response: There is nothing to show that greenhouse gasses caused global warming

    I suggest you read through the empirical evidence for an enhanced greenhouse effect. Satellites find less infrared radiation escaping at CO2 wavelengths. Surface measurements find more infrared radiation returning back to Earth at CO2 wavelengths. This is experimental evidence for a direct causal link between increased CO2 and a build-up of heat in our climate.

    I also suggest you read the article above. Sunspot numbers have shown a long term declining trend during the last few decades of global warming.
  31. Sunspot numbers averaged 45.8 from 1749 to 1920. they averaged 72.7 from 1920 to October 2009. This is an increase of 59 percent. If the Maunder Minimum from 1640 to 1710 was somewhat responsible for the Little Ice Age, this increase cannot be ignored.
  32. Cliff Oates, indeed no one ignores it and we are grateful to the sun for pulling us out of the LIA. And we are also grateful for not increasing activity from the '50s at least up to now, it could have been worse.
  33. This is the first time in my life that i see the IPCC accused of over-emphasizing the role of the sun. Never say never, indeed.
  34. Total Solar radiation has had a large effect on climate chane based on the scientifc article below: Combine the information below with the closing of the ozone hole in the past 20 years and that in itself could explain all of the global warming from the past 25 years. Phenomenological solar contribution to the 1900–2000 global surface warming We study the role of solar forcing on global surface temperature during four periods of the industrial era (1900–2000, 1900–1950, 1950–2000 and 1980–2000) by using a sun-climate coupling model based on four scale-dependent empirical climate sensitive parameters to solar variations. We use two alternative total solar irradiance satellite composites, ACRIM and PMOD, and a total solar irradiance proxy reconstruction. We estimate that the sun contributed as much as 45–50% of the 1900–2000 global warming, and 25–35% of the 1980–2000 global warming. These results, while confirming that anthropogenic-added climate forcing might have progressively played a dominant role in climate change during the last century, also suggest that the solar impact on climate change during the same period is significantly stronger than what some theoretical models have predicted.
  35. More data on total slar irradiation. The graph in the link shows the irradiation has been quite a bit higher in the last decade. Total solar irradiance describes the radiant energy emitted by the sun over all wavelengths that falls each second on 1 square meter outside the earth's atmosphere--a quantity proportional to the "solar constant" observed earlier in this century. It measures the solar energy flux in Watts/square meter. The data contains six sets of satellite observations: values from NIMBUS-7, from the Solar Maximum Mission (SMM) spacecraft, from the Earth Radiation Budget Satellite (ERBS), from the NOAA-9 and 10 platforms, and from the Upper Atmospheric Research Satellite (UARS). Measurements span the periods: NIMBUS-7 16 Nov 78-13 Dec 93; SMM 16 Feb 80-01 Jun 89; ERBS 25 Oct 84-21 Dec 94; NOAA-9 23 Jan 85-20 Dec 89; NOAA-10 22 Oct 86-01 Apr 87; UARS 5 Oct 91-30 Sep 94. -------------------------------------------------------------------------------- To get to our FTP archive of solar irradiance data, click here. For more information on the various satellies, click on the appropriate hypertext link: NIMBUS-7 UARS/ACRIM II ERBS go to Solar Data Services Home
  36. neerndt, "the irradiation has been quite a bit higher in the last decade." do you mean the solar maximum of the well known 11 years cycle? We're now at a solar minimum, a quite prolonged one indeed. But it does not look like it's going to impact the actual trend that much.
  37. Another link between the sun and earth climate broken. It's the old Scafetta et al. 2003 hypothesis of a link between solar flares or other sun related fluctuations (e.g. Scafetta et al. 2004 and West et al. 2008) and temperature variability. In a new paper Rypdal et al. found that the claimed "complexity linking" is due to a faulty analysis and that proper tests show that the opposite is true: "These results suggest that the stochastic properties of the global temperature record is governed by the long-memory internal dynamics of the climate system and are not linked to the short-memory intermittent fluctuations which characterize the solar output." In a interview reported by Rypdal adds: "A corresponding theory of global warming of solar origin does not exist. What does exist is a set of disconnected, mutually inconsistent, ad hoc hypotheses. If one of these is proven to be false, the typical proponent of solar warming will pull another ad hoc hypothesis out of the hat. This has been the strategy of Scafetta and West over the years, and we have no illusion that our paper will put them to silence" Quite a strong statement, I'd say.
  38. Isn't it possible that the Sun is causing an increase in temperature of the core of the earth by way of radiation that passes harmlessly through the atmosphere and crust much like a microwave oven? Or is this just impossible? thanks
  39. Friend, the microwave power emitted by the sun is many orders of magnitude lower the the IR or visible emission. I'd not expect any significant effect.
  40. Basic question- This topic addresses a skeptic's argument that sunspots have been increasing. The scientific rebuttal says the sun is cooling. Does sunspot activity = sun's temperature as the rebuttal implies?
    Response: "Does sunspot activity = sun's temperature as the rebuttal implies?"

    There's more to it than that. Solar activity is measured by more than just sunspots - we directly measure solar output using satellites. When the various satellite records are stitched together, they find a slight cooling trend over the satellite record. However, direct measurements only go back to 1978.

    So we use proxies to go further back. Sunspots go back to the early 1600s and are a good proxy for solar output. We can confirm this by comparing them to the direct satellite measurements when the two records overlap.

    Here's more info on how we measure solar activity...
  41. Thanks.. I clicked on the link. It was a little more difficult for me to undestand- lots of acronyms. But I will try. It talks about TSI (Total Solar Irradiance) and a debate over how to measure it. I tried to gleen sunspot info from it. It appears to use sunspot activity to reconstruct TSI. TSI corrolates to sunspots. The argument is complicated for me- trying to focus on sunspot activity, the skeptic claim is that it is increasing. The science response says it is decreasing. (confirmed by corrolating TSI in the other link) Is that correct- sunspot activity is decreasing?
  42. JSFarmer, look yourself. The picture is from a NASA site.
  43. Thanks for the link... It appears to confirm both the skeptics' argument and the science rebuttal. Is that correct?
  44. JSFarmer, yes if you you exclude the last half century. Problem is that no one says that the sun is irrelevant in general, scientists say it's not the only one. This is expecially true in the last fifty years, being the TSI flat or even slightly declining.
  45. Thanks, I appreciate that there are many factors. I am trying to focus though, since its a complicated subject for me. I am trying to examine Skeptics' #1 argument, sunspots- that the sunspots are increasing, and the Science rebuttal that they are decreasing. Can you elaborate on your statement that the Skeptics' sunpot claim is true only if you exclude the last half century? The chart you provided is more of a visual representation so I'm not sure how to interpret it. The lows in the chart seem pretty consistant- seems to hit 0 every decade like clockwork. The vaiations seem to come in the highs. If I break it down into roughly half century segments (segments of 5 highs each), I get this for the highs: years abt 200 abt 150 abt 100 abt 50 1960 - now 3 2 1905 - 1950 1 2 2 1850 - 1895 2 3 1790 - 1840 2 2 1 The last half century is the highest when eyeballing the highs. Can you be more specific on the decline for me? Is the decline hidden somewhere in middle of these cycles?
  46. JSFarmer, the last 50 years are indeed the highest of the last centuries. What I meant is that during the last half century sun's activity has been flat or declining.
  47. OK, got it... Thanks!
  48. Lockwood exhibits his bias in the context paragraph that precedes his scientific paper: "But there is a crucial difference about the climate change debate compared with many of its predecessors: humankind could often afford to wait for previous controversies to abate ... There is evidence ... that time for effective action is extremely short (Kriegler et al. 2009; Vaughan et al. 2009)." This type of unnecessary polemic is unscientific, and leads the reader to conclude that Lockwood is grinding a political axe -- not furthering any scientific understanding. Indeed, all evidence indicates warmer temperatures and higher levels of CO2 are beneficial, not harmful. So what is the purpose of Lockwood's context, if not to scare people into failing to use their objectivity when forming conclusions about anthropogenic global warming?
  49. Johno, I believe you're referring to Lockwood 2010, rather than any of the papers actually cited in this thread, right? But in any case, which part of the quotation do you disagree with? The first part of the quote just says that in past scientific controversies (e.g., geocentrism vs. heliocentrism) there was no particular urgency that necessitated action. There's no citation, but it seems fairly straightforward. If the "skeptics" of the time had the effect of slowing acceptance of the Copernican Revolution, there was no palpable consequence other than a slight retardation of scientific progress. The second part of your quote merely points out that in the case of global climate change, there is evidence that there will be more severe consequences for delay. Lockwood provides two citations to peer-reviewed papers that justify this claim. I don't read that as a "polemic" at all. Your final paragraph seems a bit problematic, though. You write all evidence indicates warmer temperatures and higher levels of CO2 are beneficial, not harmful. You must not be very familiar with the evidence -- perhaps you should spend more time exploring this site? Here is a good page to start with: Peer reviewed impacts of global warming. "Beneficial" and "harmful" are value judgments, and are only relevant within particular frames of reference. However, some impacts (e.g., amplification of the hydrologic cycle leading to increases in both drought and flooding) are likely to be economically and socially harmful more or less across the board.
  50. That said, thank you for pointing out Lockwood 2010, which is newer than the papers cited in this thread and which might be of interest to many readers.

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