Answering a fair question :: does the Sun drive global warming?

So a friend asked me yesterday about the idea that global warming is occurring because the sun is getting hotter and Mars and Pluto are also warming. As I’m still learning a lot on this topic, I dug down a bit to figure out, why is this not the case?

First, the sun’s peak output has not increased since 1979 and also moves in 10-13 year cycles that don’t correlate with atmospheric temperature rises (see chart here and below). Second, many factors besides the sun drive warming, and the very long orbital cycles of Mars and Pluto (2 and 248 Earth years, respectively) mean that solar activity would be unlikely to cause warming on all 3 planets at the same time. Scientists even found that Pluto is warming despite being in an orbital movement away from the sun. (Greenhouse effect probably to blame).

Third, the other planets in the solar system aren’t warming. (helpful backup articles from New Scientists on the Sun and Mars/Pluto). And #4, data claiming to show a correlation between sun activity and Earth atmospheric temperature, have in several prominent cases either overstated small correlations, or misinterpreted the underlying data.

On the fourth point, for a summary of how some of the most influentially misleading science on this topic was based on faulty data analysis, use of incomplete data sets, or even inappropriate data sets, dig this article from EOS / The American Geophysical Union. The initial findings by the scientists were later corrected both by themselves and others, yet their original work continued to draw attention to the solar-system-did-it theory. It even lead to an award-winning documentary and the reworking of some Danish high schoolers’ science curricula!!! I’m all for balanced debates, but in light of what we know now, this is nuts. If you’re interested in more details, here’s the lead off from the Eos article (pdf):

The last decade has seen a revival of various
hypotheses claiming a strong correlation
between solar activity and a number of terrestrial
climate parameters.Links have been made
between cosmic rays and cloud cover, first
total cloud cover and then only low clouds,
and between solar cycle lengths and northern
hemisphere land temperatures.These hypotheses
play an important role in the scientific debate
as well as in the public debate about the possibility
or reality of a man-made global climate
change.

Analysis of a number of published graphs
that have played a major role in these debates
and that have been claimed to support solar
hypotheses [Laut, 2003; Damon and Peristykh,
1999, 2004] shows that the apparent strong
correlations displayed on these graphs have
been obtained by incorrect handling of the
physical data.The graphs are still widely referred
to in the literature,and their misleading character
has not yet been generally recognized.Readers
are cautioned against drawing any conclusions,
based upon these graphs, concerning the possible
wisdom or futility of reducing the emissions
of man-made greenhouse gases.

These findings do not by any means rule
out the existence of important links between
solar activity and terrestrial climate. Such links
have been demonstrated by many authors over
the years.The sole objective of the present analysis
is to draw attention to the fact that some of the
widely publicized,apparent correlations do
not properly reflect the underlying physical data.

Solar trends

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4 comments

  1. Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature

    “There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.”

    http://www.pubs.royalsoc.ac.uk/media/proceedings_a/rspa20071880.pdf

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  2. Thanks for this man! Looks like a tour-de-force of empiric and modeling-driven evidence against the correlation of solar activity and increasing surface temperatures over the last century. I look forward to diving deeper into this! Back to work for now, but I feel some follow-up posts in the making…

    Like

  3. Heather · · Reply

    You might also be interested in this website – it lists many common arguments to global warming and the evidence that the author has found to counter these arguments. Just a place to start!

    http://gristmill.grist.org/skeptics

    Like

  4. right on!

    Like

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