writes "According to Bill Livingston and Matt Penn of the National Solar Observatory in Tucson, Arizona, sunspot magnetic fields are waning. The two respected solar astronomers have been measuring solar magnetism since 1992. Their technique is based on Zeeman splitting of infrared spectral lines in radiation emitted by iron atoms in the vicinity of sunspots. Extrapolating their data (PDF) into the future suggests that sunspots could completely disappear within decades."
To motivate their interest the researchers mention the Maunder Minimum
, which occurred beginning in 1645 and coincided with the coldest part of the so-called "Little Ice Age." Sunspot counts during this period were as low as 1/1,000 of the numbers seen in modern times.