Sunspots, CO2, and their correlation with climate change

The argument over humanity’s contribution to climate change is heating up in America and around the world as legislation meanders its way through the Senate and governments prepare for the UNFCCC meeting later this year. 

Onone side, climate and environmental activists cite examples of highlevels of CO2 as the primary driver of the greenhouse effect.  Thecontrary argument states that warming and cooling trends on Earth aredriven predominantly by cycles of solar output originating with thesun. 

If the former activists are correct, then humanity can takelegitimate steps to reduce the factors contributing to climate change. If the latter argument is on point, then taking measures to reduceemissions is simply an economic experiment.

The current bill inCongress and the agenda being seriously discussed by the governments ofthe world ahead of the Copenhagen conference later this year attemptsto set a course to significantly lower CO2 emissions over the comingdecades.  This strategy takes into account data from respectedscientists that point to a correlation between CO2 levels andtemperature rises over the past 800,000 years.

Similarly,advocates for the contrary argument of solar variation causing climatechange rely on data that points to correlations between solar activityand changes in temperature.

In both cases, correlations exist; but as the cartoon above draws the distinction, in mathematical statistical scenarios, "Correlationdoesn’t imply causation, but it does waggle its eyebrows suggestivelyand gesture furtively while mouthing ‘look over there’".  (Columbia)

Boththe CO2 and solar variation correlations are suggesting that we lookmore into these phenomena.  One we can do something about; the other wecan not.  The question being asked now in the debate is whether or notdoing something about climate change will affect the outcome in waysthat we desire.  Should the governments of the world unite to reducegreenhouse gas emissions, or should the governments of the world allowfor the continuance of business as usual?  Seemingly, both arestrategies for dealing with climate change.

Advocates of thesunspot theory argue that not enough attention has been paid to solarforcing as the driver of climate change.  "It is found that currentclimate models underestimate the observed climate response to solarforcing over the twentieth century as a whole, indicating that theclimate system has a greater sensitivity to solar forcing than domodels.  The results from this research show that increases in solarirradiance are likely to have had a greater in?uence on global-meantemperatures in the ?rst half of the twentieth century than thecombined effects of changes in anthropogenic forcings"; but the paper goes on to also state, "Neverthelessthe results con?rm previous analyses showing that greenhouse gasincreases explain most of the global warming observed in the secondhalf of the twentieth century". (Peter Stott)

Not to be confused with P. Stott (above) from the Hadley Centre for Climate Prediction and Research in the UK, Phillip Stott,professor of biogeography at the University of London, does not addressthe idea of solar variation directly, but tackles the larger issue ofclimate change.  "The global warming myth harks back to a lostGolden Age of climate stability, or, to employ a more modern term,climate ‘sustainability’.  Sadly, the idea of a sustainable climate isan oxymoron.  The fact that we have rediscovered climate change at theturn of the Millennium tells us more about ourselves, and about ourdevices and desires, than about climate.  Opponents of global warmingare often snidely referred to as ‘climate change deniers’; preciselythe opposite is true.  Those who question the myth of global warmingare passionate believers in climate change; it is the global warmerswho deny that climate change is the norm."

Before humanintervention, the climate on Earth changed regularly.  The governmentsof the world have a responsibility to ensure economic prosperity totheir citizens; they were not entrusted with controling the climate. Even as evidence points to greenhouse gases as a contributor to climatechange, will it be possible to change the outcome by manipulating onlyone of the variables?  That question is often taken on by advocates ofthe sunspot correlation.

Peter Stott presented his data on solar variationto the UNFCCC bodies in 2007.  Philip Stott, a skilled debater and nota climate scientist, used his knowledge of climate change in anOxford-style debate aired on NPR

BothStotts were successful in their endeavors, one proving that sunspotshad an effect on climate change and the other proving that sunspots hadan effect on climate change.  The former argued that human actions wereadding to the effects of solar variation on the Earth.  The latterargued that climate varies on earth naturally, so to try to mitigatehuman impacts is a fruitless endeavor; the latter was subsequentlyaccused of using unscientific measures and misleading strategies (ClimateProgress) to influence public opinion.

Effects of solar variationson the Earth are still largely undefined.  Many of the hypothesessurrounding solar variation are significantly less developed than thescience surrounding anthropogenic effects.  "Changes in the Sun’sbrightness over the past millennium have had only a small effect onEarth’s climate, according to a review of existing results and newcalculations performed by researchers in the United States,Switzerland, and Germany."  There is a correlation between sun cycles and climate change, but  "Ourresults imply that, over the past century, climate change due to humaninfluences must far outweigh the effects of changes in the Sun’sbrightness." (UCAR)

Theclimate has been and still is a complex system with multiple inputvariables and output effects; the interplay responds to forces from thesun, the oceans, the environment, and yes, human interactions with it. The idea that the sun is the sole determining factor of climate changeon Earth is as preposterous as the claim that CO2 is the drivingfactor.  Both contribute to the dynamic process.

The problemwith advocates for the sunspot hypothesis is that the idea lends itselfto a passive approach to dealing with the effects of climate change. BBC stated in a piece called Sunspots reaching 1000-year high that "thislatest analysis shows that the Sun has had a considerable indirectinfluence on the global climate in the past, causing the Earth to warmor chill, and that mankind is amplifying the Sun’s latest attempt towarm the Earth".

This gets at theheart of the problem of inaction.  Modern human society is escalatingthe natural effects of the process of climate change.  To take measuresto reduce the level of greenhouse gases that are aggravating thesituation is the responsible thing to do; it is what governments aroundthe world were created to do, particularly Democracies entrusted withprotecting the people under its care.  To not act would be considereddereliction of duty.

We know CO2 and solarvariations affect the climate on Earth.  We can certainly change thestructure of our global energy markets to change the level of CO2humanity is emitting; we can’t change the solar output from the sun. Will lowering the level of greenhouse gas emissions from human societybe enough to slow down climate change to a more manageable pace?



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