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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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Sun & climate: moving in opposite directions

What the science says...

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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

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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:

Myth Deconstruction

Related resource: Myth Deconstruction as animated GIF

MD Sun

Please check the related blog post for background information about this graphics resource.


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Comments 126 to 150 out of 1304:

  1. On Venus: When the Galileo satellite passed by, it collected a lot of interesting data. Including the fact that at IR levels, the atmosphere appears strongly absorbing IR. This is attributed to the SO2 clouds. There is further thought that the 'greenhouse' effect on Venus is caused by high level SO2 clouds rather than lower level CO2, and that most of the solar energy absorbed is via SO2. Any water vapour present would have been dissociated by UV and 'blown away' by the solar wind due to the lack of a magnetic field, thus stripping the planat of water. Currently there is a project to carry out a detailed 2 year investigation of Venus' climate and compare its' evolution with our own.
  2. Pep Thanks, that works. Mizimi They have determined that some volcanos also eject high amounts of SO2 on earth. It was mentioned in one of the articles that I linked on the volcanos thread here.
  3. July by Beck on 180 yrs of chemical CO2 analysis...showing previous values of CO2 from 1800'2 have been "beck's 180 year analysis of CO2"....lots of info.
  4. Millions tons of SO2 in the stratosphere, Mt. Pinatubo was a great example. Now it’s overestimated or was. The scare tactic is dying.
  5. Here is the "180_years" PDF.
  6. Pep That was an interesting read, even if it was a draft copy. I found the sections on ENSO and other ocean oscillations particularly of interest. Thank you.
  7. I would take 180 years with a grain of salt. :) welcome
  8. Pep Actually I have not read it yet and I don't know if its the same as what Mizimi read but I will take a look at both links later.
  9. The site contains the full extract; the other is an abstract of the pertinent findings. One possible way to check 'accuracy' is to check out the annual coal tonnages around the 1850-1960 periods as oil did not supplant coal until after this period. I rather suspect (!!)a surprise, especially since coal-burning appliances were notoriously inefficient in those times. Equally much wood was burnt during this period? rather a lot I think, and in very inefficient ways.
  10. Mizimi In rural America, coal and wood still warm many homes, albeit the systems have become somewhat more sophisticated than they were when I was growing up. I would like to use a windmill here but they are quite expensive. I'm waiting for the prices to come down.
  11. R. Keeling has posted a rebuttal and Beck has posted a reply so the debate has begun.
  12. A theory must do two things it must explain what has been observed and it must be useful to predict the result of future experiments. A theory that fails in either way is discarded. In both cases the AGW by CO2 hypothesis has some big trouble. Please don't try to make it a theory. We need it to be much better, but I don't know if it needs to be discarded.
  13. WA I agree. BTW Have you had a chance to view any of the articles that I linked to on the volcanos thread? Every time I look for newer articles I run across another one on climate sensitivity to something or another. Spencer says it lower to CO2, Kay says it higher for TSI and the last article I posted a link to in volcanos says it's plate tectonics.
  14. sorry, my s key must be sticking in the up position.
  15. Pep I just finished reading the short version Beck draft. What did you find objectionable? Mizimi What web site are they posting this argument on?
  16. Yeah I've been looking. I think we may be running headlong in the wrong direction. The satellite data that was supposed to prove a positive feedback from CO2 causing increased water vapor in fact show the opposite. I don't say we are certain but it is starting to look like there is no way CO2 can be a large climate driver. Coupled with the paleo record clearly saying it isn't...
  17. The evolution of C4 plants happened around the Miocene/Pliocene interface when CO2 levels were lower than today and C4 plants began to develop.. C3 plants cannot cope with low CO2, they require 180 -220ppm for successful growth. Experiments indicate a 58% reduction in photosynthesis if the level is dropped from 380ppm to 150ppm and up to 90% reduction below 150ppm. C4 plants require a lower ppm value as they are 'more efficient': the first C4's were grasses. Before the appearance of grasses, most plants used phosphoglyceric acid (3 carbon atoms)to photosynthesise. Hence the name C3. Grasses, on the other hand, use oxaloacetic acid ( 4 carbon atoms) for photosynthesis, and are called C4 plants. As C4 plants were more efficient they began to dominate the planet creating vast eares of savannah and effectively locking up CO2. Thure Cerling has demonstrated that C4 plants "fixed" large volumes of CO2 from the atmosphere during photosynthesis and subsequently into the soil upon death. It is considered that this lowered the level of CO2 and thus GMT, resulting in the extinction of many of the large mammals. Keelings response to Becks paper: Beck reply:
  18. Mizimi Thanks
  19. Mizimi and Pep After reading both comments and the rebuttal I tend to agree somewhat with Beck, but also fail to see the relavence to sensitivity.
  20. Mizimi I am not familiar with C3 and C4 (except for the plastique kind) but from what you said I take it that pines are C3 and maples, elms and oarks are C4. What about the leafy evergreens like cedars, C3 or C4?
  21. QM: Plants are classed biochemically as C3, C4 and CAM. C3 plants are the earliest evolved class and include all trees, bushes, shrubs with high wood/lignin & tannin content. They are the source of coal. C4 plants evolved relatively recently (8mya) and essentially are the grasses..oats, wheat, barley,bamboo alfalfa and so on. They can be woody (bamboo) but use a 4-carbon molecule in photosynthesis, hence the name. CAM's are specialists...they have means to cope with stress...high Temp, low water or CO2 etc...and include cacti, succulents and so on. Because C4 plants are more efficient chemically than the others, they return LESS CO2 to the atmosphere during respiration (about 25% less than an equivalent C3)so eventually lock up CO2.
  22. Mizimi Ok, I thought you meant trees as I had read somewhere that some are better than others as carbon sinks. I also had read that grasses were better carbon sinks than trees but not why. Interesting, thank you.
  23. QM: I did mean trees as well as other plant types. Plants ( and trees) using C3 process are the oldest species; C4 plants are newcomers. So trees ( of all types ) are C3's. C3's can tolerate much higher levels of CO2 than C4's as in early epochs, but they cannot work with low levels of CO2 (under 220ppm for example). C4's can work with very low levels of CO2 because they concentrate the gas in tissue before using it. BUT they don't like very high CO2 levels according to recent research...though this is contended by others.
  24. Mizimi Thank you, I was not aware of that.
  25. Pep John's thread on Solar Cycles is also relavent to this thread. Naturally when I used this in the Arctic Sea Ice Melt thread I was attacked by alarmists who apparently did not read it.

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