time scales
if we look at a time scale of billions of years the globe is definitely going to get warmer. over this time period the sun is going to expand into a red giant bigger than the orbit of the earth. if the earth still exists it will be mighty mighty hot inside the sun. on a scale of dinosaur years the earth has been pretty much the same temperature. the dimmer sun was more/less balanced by more geothermal heat escaping. over millions of years you can see periodic patterns of warm periods and cool periods. millions of years ago it was a 41k year cycle. which matches one of many celestial processes. why that one? i have no idea. in the last million years it's a 100k year cycle. which matches a couple of celestial processes. why these? i have no idea. why did it switch? i have no idea. perhaps because they are in phase and whatever effect they produce combined is bigger than the 41k one alone. which is bigger than either individually.