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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.

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Climate Hustle

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

 

Last updated on 2 April 2017 by Sarah. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

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Further viewing

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

Comments

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Comments 1251 to 1265 out of 1265:

  1. The Sun was classified as a G2V main sequence Yellow dwarf star, and oddly it still is. But the fact is it no longer is a yellow star, it's a white star. The once yellowish sun is now a brilliant metallic white, as result of an increase in the average temperature of the photo sphere of approximately 200 degrees kelvin.
    It is possible to actually prove this increase in temperature to yourself.
    The only equipment and materials you need are an astrophysical publication in book form that predates 1980 and gives the photosphere temperature and classification of the Sun , a camera, and a color/temperature star classification chart . All publications no matter where they originate that predate 1980 will say the Sun is a G2V main sequence yellow dwarf star. with a photosphere temperature of 5600-5750 Kelvin. It will also describe the visible overall appearance of the Sun as "pale yellow", which correlates with that temperature color -wise. There may be an image showing you how the Sun appears, usually just a circle of pale yellow. If you reference a star color /temperature chart you will find this to be true, that 5750 correlates with a pale yellow star.. The Sun as a G2 star was on the upper end of the "yellow" classification, but as it gained 200degrees K to 6000K , it's classification changed from G2 to F-9, which is on the lower end of the "white" star classification temperature and color.

    Response:

    [TD] See MA Rodger's response comment in the Other Planets are Warming thread. Everybody please post further responses here in this It's the Sun thread.

  2. This is a response to MA Rodger's answer in the Other Planets are Warming.

    I failed to finish the comment @1251, but the reason why I found the argument interesting is because everyone can in an easy way, and with rather simplistic material, prove for themselves that the Sun has in a 40 year period gone from being "yellowish" to a pale-white metallic color. This change in color represent a change in temperatur which we can call X. If the data doesn't show X change in temperatur during this period; is the data wrong or is the empiricall method used missleading?

  3. Source,

    An interesting question to post on a scientific blog.  Which is more accurate:

    1)  Carefully calibrated scientific instruments operated by highly trained specialists over a period of decades or

    2) Untrained novices eyeballing 40 year old photographs taken at unknown locations and atmospheric conditions and comparing them to what they see on a randomly selected day outside their home.

    I will note that at my home the color of the sun is different at noon than it is at sunset and differs depending on the clouds and air pollution in the sky at the time of observation.

    I think the readers here at SkS will be able to reach their own conclusions.

  4. michael sweet @1253,

    As you say, the Sun's colour is dependent on what you are looking through to see it. Out in space, where there is nothing in the way, the Sun appears white as the red and blue parts of the spectrum cancel each other out. This German graphic shows how more of the blue part of the visible spectrum is lost in the clear atmosphere, causing the yellowish colour.Sun's spectrum

  5. michael sweet @1253

    In my defence, the photograph(s) were used in the scientific litterature back in the 80's, and I'm pretty sure they were taken out in space. What I am looking for is the color index of the Sun from pre-80's till today, then I would give up the theory.

  6. Sourcer,

    As MA Rodger pointed out to you here, the energy emitted by the Sun has remained in the range 1360-1364 W/m2 since 1975 (longer records are available).  If the temperature of the Sun changed than the energy received on Earth would change.  Ergo the temperature of the Sun has remained constant since 1975 (and actually longer than that).

  7. S0urce @1255,

    You are, I feel, asking for a scientific reference which specifically says the colour of the Sun is changed or unchanged since 1975. If there has been no such colour change, there is hardily likely to be such a reference.

    The NASA Factsheet for the Sun describes its Specral Type as G2V. We can assume this is the current classification, the Factsheet having been last updated February 2018. The Specral Type of a star is defined by its temperature G2. The roman numeral V defines its luminocity (or size). Indeed, The Spectral Type G2V is a direct indicator of a star's colour as it can be determined from ratio of the star's radation flux of in the visible wavebands 500-600nm and 390-490nm, yielding a value (B-V).

    You are asserting up-thread that the Sun's temperature has risen and that it sould now be classified as F9V. The NASA Factsheet says otherwise.

    And the Sun's Spectral Type was G2V according to Gray (1992) 'The Inferred Color Index of the Sun' and if that is not early enough for you, Gray (1992) cites Morgan & Keenan (1973) 'Spectral Classification' who also give the Sun's Spectral Type as G2V.

    This scientific evidence, I would suggest, is quite conclusive.

  8. michael sweet @ 1256, MA Rodger @1257

    Thank you for the answer and linked sources. I've to agree that the scientific evidence is quite conclusive, and that my theory of a color/classification change from yellowish to pale-white metallic or G2 to F-9 doesn't seem to hold.

    Response:

    [PS] And thank you too for your contribution. Constructive debate happens best when both sides acknowledge errors and misunderstandings, and clearly indicate what they agree with in an opposing argument and what they continue to disagree with.

  9. SOurce's acknowledgment at 1258 is highly commendable. I am tempted to ask: where did this hypothesis of an abrupt and large change in the Sun's photosphere temperature initially come from?

  10. Philippe Chantreau @1259,

    The 'hypothesis' is a little off-stage so not directly linked to climate change, instead appearing within the general conspiracy-theory community. See here or here.

  11. Hi Again,

    I shared the "Sun & climate: moving in opposite directions" link on a public forum with the snipet: In the last 35 years of global warming, the sun has shown a slight cooling trend. Sun and climate have been going in opposite directions. In the past century, the Sun can explain some of the increase in global temperatures, but a relatively small amount.

    A climate denier swooped in all angry and made these comments: As for that 35 year cooling trend, a child can see the fallacy in that arguement.

    Cooling trend from what? The highest cycle in the 400 years observed. Yet this is followed, in your 35 years of "cooling" by the 2nd and 3rd highest cycles is it not? So against the 400 year average output is still greatly higher- why would we expect cooling of any kind, which could only happen if output was LOWER than the 400 year average? (Solar output is still far higher during the entire 35 years than it was for 400 prior so the sun is still forcing warming, not cooling as you claim).

    I am not quite sure how to respond.


  12. "The highest cycle in the 400 years observed"


    Only if you're talking about the 1960s

    Historical TSI

    TSI has dropped off since then while temperatures continue to rise.

    TvsTSI

    Actual scientists have unpacked the contributions of natural forcings to climate change; only by including the human-caused warming forcing can the upward rise in observed temperatures be explained.

    Natural forcings

    And actual scientists have quantified the warming forcing from the GHG emissions from the human burning of fossil fuels and have found them to be over 50 times greater than the slight extra warming coming from the Sun itself since 1750

    It's not the sun

    Your "friend" is no scientist.

  13. @1262 Daniel Bailey

    Thank you!  I learn so much from you guys when I post the denier claims that I'm not confident in answering. 

    Thank you so much! :)

  14. Hi Daniel @ 1262
    Would you mind explaining how scientists differentiate between human generated and nature generated CO2?

    I've found that there are two different isotopes for the human imprint vs. natural CO2.

    Are there other methods besides the identifying the different isotopes and what methodologies are used to test these different contributors?

    Thank you!

    Response:

    [PS] that would be offtopic here. Please see this rebuttal for two other methods used to constrain CO2 origins.

  15. Thanks [PS]!

  16. Hello,

    could you explain to me, why "The solar radiative forcing is TSI in Watts per square meter (W-m-2) divided by 4 to account for spherical geometry", when only half of the Earth is being shined on by the Sun? Also why are other Sun cycles being ignored, not to mention galactic rays possibly influencing cloud formation. Thank you

    Response:

    [PS] Why do you believe that these are "ignored"? Solar influences are discussed in every IPCC report and AR4 Chp 7 examined the science around cosmic rays in some detail.

  17. ThirdStone @1266 ,

    the ratio of area of a disc (receiving sunshine) to the area of a sphere is 1:4 and hence the division by 4  

    The scientists look very carefully at sun activity, and find that the 11-year cycle of solar activity is too slight to produce noticeable cyclic fluctuation in climate.   Or did you have some other factor in mind?

    "Cosmic Rays" are a failed hypothesis for climate change, and can be dismissed.   A triple fail, because (A) CR effects appear non-existent for the period (since mid-20th Century) that CR levels have been measured directly, and (B) likewise the paleological (proxy) measurements of CR variation show no appreciable link to climate changes, and (C) the 2016 experiments at CERN show negligible CR effect on cloud nucleation (negligible in comparison with the nucleation from marine-origin particles).   As they say: Cosmic Rays were a "Nice Try" as an idea for climate influence, but when tested against reality, they were a major fail not just on one way but on three separate ways of testing.

    Response:

    [PS] Surprising to see cosmic rays still coming up but for more detail (and the papers which tested the hypothesis) see "its cosmic rays" myth.

  18. ThirdStone,

    You should ask yourself how you came to bring the question "why is this being ignored" instead of "is it true that this is being ignored."

    You show very little familiarity with the subject in your disk to sphere comment. It is very likely that you were subject to faulty sources of information, which you nevertheless found credible enough to then come here asking a question indicating you accepted as an established fact that these influences were being ignored, when in fact they have been carefully considered and evaluated. Why did you find the faulty information credible? How much scrutiny did you apply to it?

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