Climate changes may be linked to changes in the number of on the surface of the sun.

Dark spots on the sun because the dark spots are the cooler part of the sun

Its in the national history museum and you can't se the original because its locked away in a vault 

Humid continental climate is found in the interior of continents between the 30 and 60 degrees latitude, but usually above the 40 degree line.   40 degrees north of the equator means less direct sunlight and therefore less warmth.   this climate is mainly found in the northern hemisphere since there are no major landmasses in the southern hemisphere.  if you live in northern indiana, you know all about humid continental because that is the climate type you have!