Fixing the Spotty Sunspot Record?

One of the variables in the climate change story is solar activity, especially sunspots. Oscillating sunspot activity is one natural factor sometimes singled out as an important variable, with some climate skeptics pointing to rising sunspot activity in the 20th century as a possible major cause of the modest warming we experienced. Most computer climate models place only modest weight on sunspot activity, but recently the lull in current sunspots has been listed as one of the probable causes of The Pause, so as usual the climatistas seem to be trying to have it both ways.

Sunspot data go back more than 400 years, to the development of the modern telescope and astronomers who kept daily records of the sunspots they could observe. Like any such data series, there are likely problems with consistency and data quality, especially with advancing telescope technology. Nature magazine reports that sunspot data have received “a makeover.” Lo and behold, the revised data casts doubt on the theory that rising sunspot activity correlates with warming, which means—hallelujah!—greenhouse gases are back in business, baby!

Notably, the revised sunspot tally shows that solar activity has not risen in recent decades, as once thought. Some had linked this idea of a sunspot ‘Grand Maximum’ to hotter temperatures on Earth.

“We find no such Grand Maximum,” says Frédéric Clette, an astronomer at the Royal Observatory of Belgium in Brussels. “There has been nothing exceptional about the level of solar activity.”

Revised data, eh? Where have we heard this before? Please tell me Michael Mann isn’t involved in “revising” the data.

Sure enough, these seems to be less of a “consensus” that the convenient revision is correct:

Given the intense public interest in solar forcing and climate, the work is likely to be carefully scrutinized. Douglas Hoyt, a solar physicist and co-inventor of the Group Sunspot Number, says that the new reconstruction is “not very convincing”. Among other things, he disagrees with Clette’s team discarding the results of a particular observer in the late nineteenth century, and he says that other studies support the idea of a slow rise in sunspot numbers in the past several centuries.


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