Fuck I love this story.
Ill be watching close if this dip keeps on dippin. (Notice the decline started about the time POTUS got in kek).
https://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_October_2018_v6.jpg
Its based off satellites so not to sure. 1997-98 was the largest el nino event on record, so id say it was that.
https://en.wikipedia.org/wiki/1997–98_El_Niño_event
Yeah definitely, just like surface temp are hotter because a fair amount of measurements are taken from airports and other places around cities, which will be hotter because the black asphalt absorbs heaps more heat.