As someone who believes the sun is responsible for the climate of the earth, I find this fascinating.
I also need to follow-up on how they measured the solar activity over the last 9,300 years.
This via Nature:
“The recent prolonged solar minimum and subsequent weak solar cycle 24 have led to suggestions that the grand solar maximum may be at an end,” says this study on nature.com.
The study, published in 2015, looked at past variations of solar activity. In 2010, the study found, scientists estimated a mere 8% chance of a return to Maunder Minimum-like conditions within the next 40 years.
However, “the decline in solar activity has continued, to the time of writing, and is faster than any other such decline in 9,300 years.”
“If this recent rate of decline is added to the analysis, the 8% probability estimate is now raised to between 15 and 20%,” the paper continues.
“Numerous studies have identified links between past climate and solar variability42,43,” the paper points out. “During the Maunder Minimum (1645-1715), very few sunspots were seen despite regular observations44.”
Galileo started observing sunspots in 1611. And they were observed regularly thereafter. We have excellent sunspot numbers for the last 500+ years.
“The Maunder Minimum coincided with more severe winters in the UK and continental Europe,” the researchers agree. “On longer timescales, a grand minimum of solar activity, the Homeric Minimum (∼2,750–2,550 years before present), affected climate conditions through western Europe.”
The authors foresee a gradual descent to Maunder Minimum-like conditions, which will be last from a few decades to more than 100 years.