A couple of months ago, in “Ice Age predictions are premature”, I discussed an alternative climate theory that has been exciting anthropogenic climate change skeptics this year. Climate change, it was argued, was overwhelmingly influenced by sunspot incidence, and the current dying solar cycle 23 had led to a period of quiescence that, if continued, would lead to a minor ice age.
Since then the sun has continued to be alarmingly quiescent–this isn’t unprecedented, but you have to go back about a century to find similar periods. However, David Hathaway of the NASA Marshall Space Flight Center reports that there has been recent activity, and in October, for the first time, sunspots from the new solar cycle, 24, have outnumbered those from the dying cycle. Hathaway takes this as a sign that solar cycle 24 is kicking off, but sounds a note of caution: “We’re still years away from solar maximum and, in the meantime, the sun is going to have some more quiet stretches.”
As I noted in my previous piece, the anthropogenic climate change skeptics had been getting quite excited by the quiet sun because they believe this would cause significant drops in global temperature lasting for several decades, similar to the “little ice ages” that accompanied previous long-lasting mimima. If their hypothesis is right, a small ice age like that would show rather conclusively that existing climate models were grossly inaccurate. The recent solar activity, which has also produced solar flares. means that the sun probably isn’t as quiescent as some of the solar activity climate change proponents had hoped. Irrespective of whether their alternative climate theory is correct, we probably won’t get any new data to test it with.