From Spaceweather:
RETURN OF THE SUNSPOT:
It's not much, but it is a sunspot. Breaking a string of 4 consecutive spotless days, tiny AR2552 emerged in the sun's northern hemisphere on June 7th.
Sunspots are of great interest as they are a good and observable proxy for solar output. During times of cooler than normal temperatures, observed sunspot activity was always very low. During the 1960's, when people were first starting to think about global warming, this was a period of very high sunspot activity.
Looking at the Solar Flux graph from yesterday's post: Our Quiet Sun we can see the the current solar cycle is quite a bit lower then previous ones - again, entering a period of low solar activity and cooler temperatures on Earth.