How many people in this forum know about AND can explain the existence of meltwater pulses 1A (14700 years before present (yBP)- 13500 yBP), 1B (11600 yBP - 11300 yBP), 1C (8200 yBP-7600 yBP)? Just to give you a hint, there was no industrial human activity in those days and the population of humans was about 1 million.