The rather passionate rebuttal of the Scafetta and West solar variability hypothesis by Philip Duffy, Benjamin Santer, and Tom Wigley seems to clearly show some weaknesses in the Scafetta and West model. Nevertheless, Duffy and coauthors ignore a data trend that weakens the argument for climate change based almost solely on greenhouse gas emissions. Their own figure 2 clearly illustrates that although GHG emissions have continued to increase at an enormous rate, global temperatures have not increased over the past decade and have actually slightly decreased overall since the record-setting warmth of the 1998 El Niño maximum. Also, last year’s apparently anomalous low temperatures occurred during a year of extremely low solar activity (and a possibly weak La Niña), despite the aforementioned increase in GHG emissions and without a significant volcanic eruption.
Although the various current climate models are getting better at re-creating the past, they still fail in accurately predicting the future, especially with their emphasis on GHG emissions. So it certainly doesn’t hurt to examine other models such as Scafetta and West’s. If there exists a single climate model from a decade ago that based climate change predominantly on GHGs and that predicted the past 10 years of cooling, I would love to see a reference to it.
