scientifically speaking sample of 100 years says absolutely nothing...im not taking sides here but since you tagged it "science" i beg to differ...trying to come to any conclusion based on this feels like trying to prove a point without almsot any evidence:)
This graph simply depicts the measuring of the pulse, there is a mountain of good data behind this diagnosis stretching back millenia via ice cores, paleo-climate data, speleothems etc. etc.