In addition to the other observed factors such as a long sunspot cycle and minima and PDO flip, now we’ll add some aerosols to the mix. Volcanism has been quiet for the most part for a few years. This should have a cooling effect on the southern hemisphere.
I’ll point out that the effects on atmospheric albedo is yet unknown and depends on the strength of eruption, and quantity of ash and aerosols ejected into the stratosphere.
The volcano, 800 miles south of the capital Santiago, had not erupted for more than 450 years and was considered dormant.
But it is now belching enormous clouds of thick ash that have drifted across a large area in both Chile and the Argentine province of Chubut, where an airport was forced to close.
Just six miles away, the town of Chaiten has a population of 7,000. Long used to the menacing form of the 3,000-foot mountain, it is now overshadowed by a towering column of ash.