Since 1940 and until about 10 years ago we have had the highest activity of the sun in a 1,000 years. (skepticalscience.com)
From Solanki, Usokin, Kromer, Shussler, Beer's, 2004 paper «Unusual activity of the Sun during recent decades compared to the previous 11,000 years» (realclimate.org)
She adds, «We think that a change in the magnetic activity of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data.» (sciencedaily.com)